// SPDX-License-Identifier: GPL-2.0
#include <linux/perf_event.h>
#include <linux/types.h>

#include <asm/perf_event.h>
#include <asm/msr.h>
#include <asm/insn.h>

#include "../perf_event.h"

static const enum {
        LBR_EIP_FLAGS           = 1,
        LBR_TSX                 = 2,
} lbr_desc[LBR_FORMAT_MAX_KNOWN + 1] = {
        [LBR_FORMAT_EIP_FLAGS]  = LBR_EIP_FLAGS,
        [LBR_FORMAT_EIP_FLAGS2] = LBR_EIP_FLAGS | LBR_TSX,
};

/*
 * Intel LBR_SELECT bits
 * Intel Vol3a, April 2011, Section 16.7 Table 16-10
 *
 * Hardware branch filter (not available on all CPUs)
 */
#define LBR_KERNEL_BIT          0 /* do not capture at ring0 */
#define LBR_USER_BIT            1 /* do not capture at ring > 0 */
#define LBR_JCC_BIT             2 /* do not capture conditional branches */
#define LBR_REL_CALL_BIT        3 /* do not capture relative calls */
#define LBR_IND_CALL_BIT        4 /* do not capture indirect calls */
#define LBR_RETURN_BIT          5 /* do not capture near returns */
#define LBR_IND_JMP_BIT         6 /* do not capture indirect jumps */
#define LBR_REL_JMP_BIT         7 /* do not capture relative jumps */
#define LBR_FAR_BIT             8 /* do not capture far branches */
#define LBR_CALL_STACK_BIT      9 /* enable call stack */

/*
 * Following bit only exists in Linux; we mask it out before writing it to
 * the actual MSR. But it helps the constraint perf code to understand
 * that this is a separate configuration.
 */
#define LBR_NO_INFO_BIT        63 /* don't read LBR_INFO. */

#define LBR_KERNEL      (1 << LBR_KERNEL_BIT)
#define LBR_USER        (1 << LBR_USER_BIT)
#define LBR_JCC         (1 << LBR_JCC_BIT)
#define LBR_REL_CALL    (1 << LBR_REL_CALL_BIT)
#define LBR_IND_CALL    (1 << LBR_IND_CALL_BIT)
#define LBR_RETURN      (1 << LBR_RETURN_BIT)
#define LBR_REL_JMP     (1 << LBR_REL_JMP_BIT)
#define LBR_IND_JMP     (1 << LBR_IND_JMP_BIT)
#define LBR_FAR         (1 << LBR_FAR_BIT)
#define LBR_CALL_STACK  (1 << LBR_CALL_STACK_BIT)
#define LBR_NO_INFO     (1ULL << LBR_NO_INFO_BIT)

#define LBR_PLM (LBR_KERNEL | LBR_USER)

#define LBR_SEL_MASK    0x3ff   /* valid bits in LBR_SELECT */
#define LBR_NOT_SUPP    -1      /* LBR filter not supported */
#define LBR_IGN         0       /* ignored */

#define LBR_ANY          \
        (LBR_JCC        |\
         LBR_REL_CALL   |\
         LBR_IND_CALL   |\
         LBR_RETURN     |\
         LBR_REL_JMP    |\
         LBR_IND_JMP    |\
         LBR_FAR)

#define LBR_FROM_FLAG_MISPRED   BIT_ULL(63)
#define LBR_FROM_FLAG_IN_TX     BIT_ULL(62)
#define LBR_FROM_FLAG_ABORT     BIT_ULL(61)

#define LBR_FROM_SIGNEXT_2MSB   (BIT_ULL(60) | BIT_ULL(59))

/*
 * x86control flow change classification
 * x86control flow changes include branches, interrupts, traps, faults
 */
enum {
        X86_BR_NONE             = 0,      /* unknown */

        X86_BR_USER             = 1 << 0, /* branch target is user */
        X86_BR_KERNEL           = 1 << 1, /* branch target is kernel */

        X86_BR_CALL             = 1 << 2, /* call */
        X86_BR_RET              = 1 << 3, /* return */
        X86_BR_SYSCALL          = 1 << 4, /* syscall */
        X86_BR_SYSRET           = 1 << 5, /* syscall return */
        X86_BR_INT              = 1 << 6, /* sw interrupt */
        X86_BR_IRET             = 1 << 7, /* return from interrupt */
        X86_BR_JCC              = 1 << 8, /* conditional */
        X86_BR_JMP              = 1 << 9, /* jump */
        X86_BR_IRQ              = 1 << 10,/* hw interrupt or trap or fault */
        X86_BR_IND_CALL         = 1 << 11,/* indirect calls */
        X86_BR_ABORT            = 1 << 12,/* transaction abort */
        X86_BR_IN_TX            = 1 << 13,/* in transaction */
        X86_BR_NO_TX            = 1 << 14,/* not in transaction */
        X86_BR_ZERO_CALL        = 1 << 15,/* zero length call */
        X86_BR_CALL_STACK       = 1 << 16,/* call stack */
        X86_BR_IND_JMP          = 1 << 17,/* indirect jump */

        X86_BR_TYPE_SAVE        = 1 << 18,/* indicate to save branch type */

};

#define X86_BR_PLM (X86_BR_USER | X86_BR_KERNEL)
#define X86_BR_ANYTX (X86_BR_NO_TX | X86_BR_IN_TX)

#define X86_BR_ANY       \
        (X86_BR_CALL    |\
         X86_BR_RET     |\
         X86_BR_SYSCALL |\
         X86_BR_SYSRET  |\
         X86_BR_INT     |\
         X86_BR_IRET    |\
         X86_BR_JCC     |\
         X86_BR_JMP      |\
         X86_BR_IRQ      |\
         X86_BR_ABORT    |\
         X86_BR_IND_CALL |\
         X86_BR_IND_JMP  |\
         X86_BR_ZERO_CALL)

#define X86_BR_ALL (X86_BR_PLM | X86_BR_ANY)

#define X86_BR_ANY_CALL          \
        (X86_BR_CALL            |\
         X86_BR_IND_CALL        |\
         X86_BR_ZERO_CALL       |\
         X86_BR_SYSCALL         |\
         X86_BR_IRQ             |\
         X86_BR_INT)

/*
 * Intel LBR_CTL bits
 *
 * Hardware branch filter for Arch LBR
 */
#define ARCH_LBR_KERNEL_BIT             1  /* capture at ring0 */
#define ARCH_LBR_USER_BIT               2  /* capture at ring > 0 */
#define ARCH_LBR_CALL_STACK_BIT         3  /* enable call stack */
#define ARCH_LBR_JCC_BIT                16 /* capture conditional branches */
#define ARCH_LBR_REL_JMP_BIT            17 /* capture relative jumps */
#define ARCH_LBR_IND_JMP_BIT            18 /* capture indirect jumps */
#define ARCH_LBR_REL_CALL_BIT           19 /* capture relative calls */
#define ARCH_LBR_IND_CALL_BIT           20 /* capture indirect calls */
#define ARCH_LBR_RETURN_BIT             21 /* capture near returns */
#define ARCH_LBR_OTHER_BRANCH_BIT       22 /* capture other branches */

#define ARCH_LBR_KERNEL                 (1ULL << ARCH_LBR_KERNEL_BIT)
#define ARCH_LBR_USER                   (1ULL << ARCH_LBR_USER_BIT)
#define ARCH_LBR_CALL_STACK             (1ULL << ARCH_LBR_CALL_STACK_BIT)
#define ARCH_LBR_JCC                    (1ULL << ARCH_LBR_JCC_BIT)
#define ARCH_LBR_REL_JMP                (1ULL << ARCH_LBR_REL_JMP_BIT)
#define ARCH_LBR_IND_JMP                (1ULL << ARCH_LBR_IND_JMP_BIT)
#define ARCH_LBR_REL_CALL               (1ULL << ARCH_LBR_REL_CALL_BIT)
#define ARCH_LBR_IND_CALL               (1ULL << ARCH_LBR_IND_CALL_BIT)
#define ARCH_LBR_RETURN                 (1ULL << ARCH_LBR_RETURN_BIT)
#define ARCH_LBR_OTHER_BRANCH           (1ULL << ARCH_LBR_OTHER_BRANCH_BIT)

#define ARCH_LBR_ANY                     \
        (ARCH_LBR_JCC                   |\
         ARCH_LBR_REL_JMP               |\
         ARCH_LBR_IND_JMP               |\
         ARCH_LBR_REL_CALL              |\
         ARCH_LBR_IND_CALL              |\
         ARCH_LBR_RETURN                |\
         ARCH_LBR_OTHER_BRANCH)

#define ARCH_LBR_CTL_MASK                       0x7f000e

static void intel_pmu_lbr_filter(struct cpu_hw_events *cpuc);

static __always_inline bool is_lbr_call_stack_bit_set(u64 config)
{
        if (static_cpu_has(X86_FEATURE_ARCH_LBR))
                return !!(config & ARCH_LBR_CALL_STACK);

        return !!(config & LBR_CALL_STACK);
}

/*
 * We only support LBR implementations that have FREEZE_LBRS_ON_PMI
 * otherwise it becomes near impossible to get a reliable stack.
 */

static void __intel_pmu_lbr_enable(bool pmi)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        u64 debugctl, lbr_select = 0, orig_debugctl;

        /*
         * No need to unfreeze manually, as v4 can do that as part
         * of the GLOBAL_STATUS ack.
         */
        if (pmi && x86_pmu.version >= 4)
                return;

        /*
         * No need to reprogram LBR_SELECT in a PMI, as it
         * did not change.
         */
        if (cpuc->lbr_sel)
                lbr_select = cpuc->lbr_sel->config & x86_pmu.lbr_sel_mask;
        if (!static_cpu_has(X86_FEATURE_ARCH_LBR) && !pmi && cpuc->lbr_sel)
                wrmsrl(MSR_LBR_SELECT, lbr_select);

        rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
        orig_debugctl = debugctl;

        if (!static_cpu_has(X86_FEATURE_ARCH_LBR))
                debugctl |= DEBUGCTLMSR_LBR;
        /*
         * LBR callstack does not work well with FREEZE_LBRS_ON_PMI.
         * If FREEZE_LBRS_ON_PMI is set, PMI near call/return instructions
         * may cause superfluous increase/decrease of LBR_TOS.
         */
        if (is_lbr_call_stack_bit_set(lbr_select))
                debugctl &= ~DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;
        else
                debugctl |= DEBUGCTLMSR_FREEZE_LBRS_ON_PMI;

        if (orig_debugctl != debugctl)
                wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);

        if (static_cpu_has(X86_FEATURE_ARCH_LBR))
                wrmsrl(MSR_ARCH_LBR_CTL, lbr_select | ARCH_LBR_CTL_LBREN);
}

static void __intel_pmu_lbr_disable(void)
{
        u64 debugctl;

        if (static_cpu_has(X86_FEATURE_ARCH_LBR)) {
                wrmsrl(MSR_ARCH_LBR_CTL, 0);
                return;
        }

        rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
        debugctl &= ~(DEBUGCTLMSR_LBR | DEBUGCTLMSR_FREEZE_LBRS_ON_PMI);
        wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
}

void intel_pmu_lbr_reset_32(void)
{
        int i;

        for (i = 0; i < x86_pmu.lbr_nr; i++)
                wrmsrl(x86_pmu.lbr_from + i, 0);
}

void intel_pmu_lbr_reset_64(void)
{
        int i;

        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                wrmsrl(x86_pmu.lbr_from + i, 0);
                wrmsrl(x86_pmu.lbr_to   + i, 0);
                if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
                        wrmsrl(x86_pmu.lbr_info + i, 0);
        }
}

static void intel_pmu_arch_lbr_reset(void)
{
        /* Write to ARCH_LBR_DEPTH MSR, all LBR entries are reset to 0 */
        wrmsrl(MSR_ARCH_LBR_DEPTH, x86_pmu.lbr_nr);
}

void intel_pmu_lbr_reset(void)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (!x86_pmu.lbr_nr)
                return;

        x86_pmu.lbr_reset();

        cpuc->last_task_ctx = NULL;
        cpuc->last_log_id = 0;
}

/*
 * TOS = most recently recorded branch
 */
static inline u64 intel_pmu_lbr_tos(void)
{
        u64 tos;

        rdmsrl(x86_pmu.lbr_tos, tos);
        return tos;
}

enum {
        LBR_NONE,
        LBR_VALID,
};

/*
 * For formats with LBR_TSX flags (e.g. LBR_FORMAT_EIP_FLAGS2), bits 61:62 in
 * MSR_LAST_BRANCH_FROM_x are the TSX flags when TSX is supported, but when
 * TSX is not supported they have no consistent behavior:
 *
 *   - For wrmsr(), bits 61:62 are considered part of the sign extension.
 *   - For HW updates (branch captures) bits 61:62 are always OFF and are not
 *     part of the sign extension.
 *
 * Therefore, if:
 *
 *   1) LBR has TSX format
 *   2) CPU has no TSX support enabled
 *
 * ... then any value passed to wrmsr() must be sign extended to 63 bits and any
 * value from rdmsr() must be converted to have a 61 bits sign extension,
 * ignoring the TSX flags.
 */
static inline bool lbr_from_signext_quirk_needed(void)
{
        int lbr_format = x86_pmu.intel_cap.lbr_format;
        bool tsx_support = boot_cpu_has(X86_FEATURE_HLE) ||
                           boot_cpu_has(X86_FEATURE_RTM);

        return !tsx_support && (lbr_desc[lbr_format] & LBR_TSX);
}

static DEFINE_STATIC_KEY_FALSE(lbr_from_quirk_key);

/* If quirk is enabled, ensure sign extension is 63 bits: */
inline u64 lbr_from_signext_quirk_wr(u64 val)
{
        if (static_branch_unlikely(&lbr_from_quirk_key)) {
                /*
                 * Sign extend into bits 61:62 while preserving bit 63.
                 *
                 * Quirk is enabled when TSX is disabled. Therefore TSX bits
                 * in val are always OFF and must be changed to be sign
                 * extension bits. Since bits 59:60 are guaranteed to be
                 * part of the sign extension bits, we can just copy them
                 * to 61:62.
                 */
                val |= (LBR_FROM_SIGNEXT_2MSB & val) << 2;
        }
        return val;
}

/*
 * If quirk is needed, ensure sign extension is 61 bits:
 */
static u64 lbr_from_signext_quirk_rd(u64 val)
{
        if (static_branch_unlikely(&lbr_from_quirk_key)) {
                /*
                 * Quirk is on when TSX is not enabled. Therefore TSX
                 * flags must be read as OFF.
                 */
                val &= ~(LBR_FROM_FLAG_IN_TX | LBR_FROM_FLAG_ABORT);
        }
        return val;
}

static __always_inline void wrlbr_from(unsigned int idx, u64 val)
{
        val = lbr_from_signext_quirk_wr(val);
        wrmsrl(x86_pmu.lbr_from + idx, val);
}

static __always_inline void wrlbr_to(unsigned int idx, u64 val)
{
        wrmsrl(x86_pmu.lbr_to + idx, val);
}

static __always_inline void wrlbr_info(unsigned int idx, u64 val)
{
        wrmsrl(x86_pmu.lbr_info + idx, val);
}

static __always_inline u64 rdlbr_from(unsigned int idx, struct lbr_entry *lbr)
{
        u64 val;

        if (lbr)
                return lbr->from;

        rdmsrl(x86_pmu.lbr_from + idx, val);

        return lbr_from_signext_quirk_rd(val);
}

static __always_inline u64 rdlbr_to(unsigned int idx, struct lbr_entry *lbr)
{
        u64 val;

        if (lbr)
                return lbr->to;

        rdmsrl(x86_pmu.lbr_to + idx, val);

        return val;
}

static __always_inline u64 rdlbr_info(unsigned int idx, struct lbr_entry *lbr)
{
        u64 val;

        if (lbr)
                return lbr->info;

        rdmsrl(x86_pmu.lbr_info + idx, val);

        return val;
}

static inline void
wrlbr_all(struct lbr_entry *lbr, unsigned int idx, bool need_info)
{
        wrlbr_from(idx, lbr->from);
        wrlbr_to(idx, lbr->to);
        if (need_info)
                wrlbr_info(idx, lbr->info);
}

static inline bool
rdlbr_all(struct lbr_entry *lbr, unsigned int idx, bool need_info)
{
        u64 from = rdlbr_from(idx, NULL);

        /* Don't read invalid entry */
        if (!from)
                return false;

        lbr->from = from;
        lbr->to = rdlbr_to(idx, NULL);
        if (need_info)
                lbr->info = rdlbr_info(idx, NULL);

        return true;
}

void intel_pmu_lbr_restore(void *ctx)
{
        bool need_info = x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO;
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct x86_perf_task_context *task_ctx = ctx;
        int i;
        unsigned lbr_idx, mask;
        u64 tos = task_ctx->tos;

        mask = x86_pmu.lbr_nr - 1;
        for (i = 0; i < task_ctx->valid_lbrs; i++) {
                lbr_idx = (tos - i) & mask;
                wrlbr_all(&task_ctx->lbr[i], lbr_idx, need_info);
        }

        for (; i < x86_pmu.lbr_nr; i++) {
                lbr_idx = (tos - i) & mask;
                wrlbr_from(lbr_idx, 0);
                wrlbr_to(lbr_idx, 0);
                if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
                        wrlbr_info(lbr_idx, 0);
        }

        wrmsrl(x86_pmu.lbr_tos, tos);

        if (cpuc->lbr_select)
                wrmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
}

static void intel_pmu_arch_lbr_restore(void *ctx)
{
        struct x86_perf_task_context_arch_lbr *task_ctx = ctx;
        struct lbr_entry *entries = task_ctx->entries;
        int i;

        /* Fast reset the LBRs before restore if the call stack is not full. */
        if (!entries[x86_pmu.lbr_nr - 1].from)
                intel_pmu_arch_lbr_reset();

        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                if (!entries[i].from)
                        break;
                wrlbr_all(&entries[i], i, true);
        }
}

/*
 * Restore the Architecture LBR state from the xsave area in the perf
 * context data for the task via the XRSTORS instruction.
 */
static void intel_pmu_arch_lbr_xrstors(void *ctx)
{
        struct x86_perf_task_context_arch_lbr_xsave *task_ctx = ctx;

        xrstors(&task_ctx->xsave, XFEATURE_MASK_LBR);
}

static __always_inline bool lbr_is_reset_in_cstate(void *ctx)
{
        if (static_cpu_has(X86_FEATURE_ARCH_LBR))
                return x86_pmu.lbr_deep_c_reset && !rdlbr_from(0, NULL);

        return !rdlbr_from(((struct x86_perf_task_context *)ctx)->tos, NULL);
}

static void __intel_pmu_lbr_restore(void *ctx)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (task_context_opt(ctx)->lbr_callstack_users == 0 ||
            task_context_opt(ctx)->lbr_stack_state == LBR_NONE) {
                intel_pmu_lbr_reset();
                return;
        }

        /*
         * Does not restore the LBR registers, if
         * - No one else touched them, and
         * - Was not cleared in Cstate
         */
        if ((ctx == cpuc->last_task_ctx) &&
            (task_context_opt(ctx)->log_id == cpuc->last_log_id) &&
            !lbr_is_reset_in_cstate(ctx)) {
                task_context_opt(ctx)->lbr_stack_state = LBR_NONE;
                return;
        }

        x86_pmu.lbr_restore(ctx);

        task_context_opt(ctx)->lbr_stack_state = LBR_NONE;
}

void intel_pmu_lbr_save(void *ctx)
{
        bool need_info = x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO;
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        struct x86_perf_task_context *task_ctx = ctx;
        unsigned lbr_idx, mask;
        u64 tos;
        int i;

        mask = x86_pmu.lbr_nr - 1;
        tos = intel_pmu_lbr_tos();
        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                lbr_idx = (tos - i) & mask;
                if (!rdlbr_all(&task_ctx->lbr[i], lbr_idx, need_info))
                        break;
        }
        task_ctx->valid_lbrs = i;
        task_ctx->tos = tos;

        if (cpuc->lbr_select)
                rdmsrl(MSR_LBR_SELECT, task_ctx->lbr_sel);
}

static void intel_pmu_arch_lbr_save(void *ctx)
{
        struct x86_perf_task_context_arch_lbr *task_ctx = ctx;
        struct lbr_entry *entries = task_ctx->entries;
        int i;

        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                if (!rdlbr_all(&entries[i], i, true))
                        break;
        }

        /* LBR call stack is not full. Reset is required in restore. */
        if (i < x86_pmu.lbr_nr)
                entries[x86_pmu.lbr_nr - 1].from = 0;
}

/*
 * Save the Architecture LBR state to the xsave area in the perf
 * context data for the task via the XSAVES instruction.
 */
static void intel_pmu_arch_lbr_xsaves(void *ctx)
{
        struct x86_perf_task_context_arch_lbr_xsave *task_ctx = ctx;

        xsaves(&task_ctx->xsave, XFEATURE_MASK_LBR);
}

static void __intel_pmu_lbr_save(void *ctx)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (task_context_opt(ctx)->lbr_callstack_users == 0) {
                task_context_opt(ctx)->lbr_stack_state = LBR_NONE;
                return;
        }

        x86_pmu.lbr_save(ctx);

        task_context_opt(ctx)->lbr_stack_state = LBR_VALID;

        cpuc->last_task_ctx = ctx;
        cpuc->last_log_id = ++task_context_opt(ctx)->log_id;
}

void intel_pmu_lbr_swap_task_ctx(struct perf_event_context *prev,
                                 struct perf_event_context *next)
{
        void *prev_ctx_data, *next_ctx_data;

        swap(prev->task_ctx_data, next->task_ctx_data);

        /*
         * Architecture specific synchronization makes sense in
         * case both prev->task_ctx_data and next->task_ctx_data
         * pointers are allocated.
         */

        prev_ctx_data = next->task_ctx_data;
        next_ctx_data = prev->task_ctx_data;

        if (!prev_ctx_data || !next_ctx_data)
                return;

        swap(task_context_opt(prev_ctx_data)->lbr_callstack_users,
             task_context_opt(next_ctx_data)->lbr_callstack_users);
}

void intel_pmu_lbr_sched_task(struct perf_event_context *ctx, bool sched_in)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);
        void *task_ctx;

        if (!cpuc->lbr_users)
                return;

        /*
         * If LBR callstack feature is enabled and the stack was saved when
         * the task was scheduled out, restore the stack. Otherwise flush
         * the LBR stack.
         */
        task_ctx = ctx ? ctx->task_ctx_data : NULL;
        if (task_ctx) {
                if (sched_in)
                        __intel_pmu_lbr_restore(task_ctx);
                else
                        __intel_pmu_lbr_save(task_ctx);
                return;
        }

        /*
         * Since a context switch can flip the address space and LBR entries
         * are not tagged with an identifier, we need to wipe the LBR, even for
         * per-cpu events. You simply cannot resolve the branches from the old
         * address space.
         */
        if (sched_in)
                intel_pmu_lbr_reset();
}

static inline bool branch_user_callstack(unsigned br_sel)
{
        return (br_sel & X86_BR_USER) && (br_sel & X86_BR_CALL_STACK);
}

void intel_pmu_lbr_add(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (!x86_pmu.lbr_nr)
                return;

        if (event->hw.flags & PERF_X86_EVENT_LBR_SELECT)
                cpuc->lbr_select = 1;

        cpuc->br_sel = event->hw.branch_reg.reg;

        if (branch_user_callstack(cpuc->br_sel) && event->ctx->task_ctx_data)
                task_context_opt(event->ctx->task_ctx_data)->lbr_callstack_users++;

        /*
         * Request pmu::sched_task() callback, which will fire inside the
         * regular perf event scheduling, so that call will:
         *
         *  - restore or wipe; when LBR-callstack,
         *  - wipe; otherwise,
         *
         * when this is from __perf_event_task_sched_in().
         *
         * However, if this is from perf_install_in_context(), no such callback
         * will follow and we'll need to reset the LBR here if this is the
         * first LBR event.
         *
         * The problem is, we cannot tell these cases apart... but we can
         * exclude the biggest chunk of cases by looking at
         * event->total_time_running. An event that has accrued runtime cannot
         * be 'new'. Conversely, a new event can get installed through the
         * context switch path for the first time.
         */
        if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip > 0)
                cpuc->lbr_pebs_users++;
        perf_sched_cb_inc(event->ctx->pmu);
        if (!cpuc->lbr_users++ && !event->total_time_running)
                intel_pmu_lbr_reset();
}

void release_lbr_buffers(void)
{
        struct kmem_cache *kmem_cache;
        struct cpu_hw_events *cpuc;
        int cpu;

        if (!static_cpu_has(X86_FEATURE_ARCH_LBR))
                return;

        for_each_possible_cpu(cpu) {
                cpuc = per_cpu_ptr(&cpu_hw_events, cpu);
                kmem_cache = x86_get_pmu(cpu)->task_ctx_cache;
                if (kmem_cache && cpuc->lbr_xsave) {
                        kmem_cache_free(kmem_cache, cpuc->lbr_xsave);
                        cpuc->lbr_xsave = NULL;
                }
        }
}

void reserve_lbr_buffers(void)
{
        struct kmem_cache *kmem_cache;
        struct cpu_hw_events *cpuc;
        int cpu;

        if (!static_cpu_has(X86_FEATURE_ARCH_LBR))
                return;

        for_each_possible_cpu(cpu) {
                cpuc = per_cpu_ptr(&cpu_hw_events, cpu);
                kmem_cache = x86_get_pmu(cpu)->task_ctx_cache;
                if (!kmem_cache || cpuc->lbr_xsave)
                        continue;

                cpuc->lbr_xsave = kmem_cache_alloc_node(kmem_cache,
                                                        GFP_KERNEL | __GFP_ZERO,
                                                        cpu_to_node(cpu));
        }
}

void intel_pmu_lbr_del(struct perf_event *event)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (!x86_pmu.lbr_nr)
                return;

        if (branch_user_callstack(cpuc->br_sel) &&
            event->ctx->task_ctx_data)
                task_context_opt(event->ctx->task_ctx_data)->lbr_callstack_users--;

        if (event->hw.flags & PERF_X86_EVENT_LBR_SELECT)
                cpuc->lbr_select = 0;

        if (x86_pmu.intel_cap.pebs_baseline && event->attr.precise_ip > 0)
                cpuc->lbr_pebs_users--;
        cpuc->lbr_users--;
        WARN_ON_ONCE(cpuc->lbr_users < 0);
        WARN_ON_ONCE(cpuc->lbr_pebs_users < 0);
        perf_sched_cb_dec(event->ctx->pmu);
}

static inline bool vlbr_exclude_host(void)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        return test_bit(INTEL_PMC_IDX_FIXED_VLBR,
                (unsigned long *)&cpuc->intel_ctrl_guest_mask);
}

void intel_pmu_lbr_enable_all(bool pmi)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (cpuc->lbr_users && !vlbr_exclude_host())
                __intel_pmu_lbr_enable(pmi);
}

void intel_pmu_lbr_disable_all(void)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        if (cpuc->lbr_users && !vlbr_exclude_host())
                __intel_pmu_lbr_disable();
}

void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
{
        unsigned long mask = x86_pmu.lbr_nr - 1;
        u64 tos = intel_pmu_lbr_tos();
        int i;

        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                unsigned long lbr_idx = (tos - i) & mask;
                union {
                        struct {
                                u32 from;
                                u32 to;
                        };
                        u64     lbr;
                } msr_lastbranch;

                rdmsrl(x86_pmu.lbr_from + lbr_idx, msr_lastbranch.lbr);

                cpuc->lbr_entries[i].from       = msr_lastbranch.from;
                cpuc->lbr_entries[i].to         = msr_lastbranch.to;
                cpuc->lbr_entries[i].mispred    = 0;
                cpuc->lbr_entries[i].predicted  = 0;
                cpuc->lbr_entries[i].in_tx      = 0;
                cpuc->lbr_entries[i].abort      = 0;
                cpuc->lbr_entries[i].cycles     = 0;
                cpuc->lbr_entries[i].type       = 0;
                cpuc->lbr_entries[i].reserved   = 0;
        }
        cpuc->lbr_stack.nr = i;
        cpuc->lbr_stack.hw_idx = tos;
}

/*
 * Due to lack of segmentation in Linux the effective address (offset)
 * is the same as the linear address, allowing us to merge the LIP and EIP
 * LBR formats.
 */
void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
{
        bool need_info = false, call_stack = false;
        unsigned long mask = x86_pmu.lbr_nr - 1;
        int lbr_format = x86_pmu.intel_cap.lbr_format;
        u64 tos = intel_pmu_lbr_tos();
        int i;
        int out = 0;
        int num = x86_pmu.lbr_nr;

        if (cpuc->lbr_sel) {
                need_info = !(cpuc->lbr_sel->config & LBR_NO_INFO);
                if (cpuc->lbr_sel->config & LBR_CALL_STACK)
                        call_stack = true;
        }

        for (i = 0; i < num; i++) {
                unsigned long lbr_idx = (tos - i) & mask;
                u64 from, to, mis = 0, pred = 0, in_tx = 0, abort = 0;
                int skip = 0;
                u16 cycles = 0;
                int lbr_flags = lbr_desc[lbr_format];

                from = rdlbr_from(lbr_idx, NULL);
                to   = rdlbr_to(lbr_idx, NULL);

                /*
                 * Read LBR call stack entries
                 * until invalid entry (0s) is detected.
                 */
                if (call_stack && !from)
                        break;

                if (lbr_format == LBR_FORMAT_INFO && need_info) {
                        u64 info;

                        info = rdlbr_info(lbr_idx, NULL);
                        mis = !!(info & LBR_INFO_MISPRED);
                        pred = !mis;
                        in_tx = !!(info & LBR_INFO_IN_TX);
                        abort = !!(info & LBR_INFO_ABORT);
                        cycles = (info & LBR_INFO_CYCLES);
                }

                if (lbr_format == LBR_FORMAT_TIME) {
                        mis = !!(from & LBR_FROM_FLAG_MISPRED);
                        pred = !mis;
                        skip = 1;
                        cycles = ((to >> 48) & LBR_INFO_CYCLES);

                        to = (u64)((((s64)to) << 16) >> 16);
                }

                if (lbr_flags & LBR_EIP_FLAGS) {
                        mis = !!(from & LBR_FROM_FLAG_MISPRED);
                        pred = !mis;
                        skip = 1;
                }
                if (lbr_flags & LBR_TSX) {
                        in_tx = !!(from & LBR_FROM_FLAG_IN_TX);
                        abort = !!(from & LBR_FROM_FLAG_ABORT);
                        skip = 3;
                }
                from = (u64)((((s64)from) << skip) >> skip);

                /*
                 * Some CPUs report duplicated abort records,
                 * with the second entry not having an abort bit set.
                 * Skip them here. This loop runs backwards,
                 * so we need to undo the previous record.
                 * If the abort just happened outside the window
                 * the extra entry cannot be removed.
                 */
                if (abort && x86_pmu.lbr_double_abort && out > 0)
                        out--;

                cpuc->lbr_entries[out].from      = from;
                cpuc->lbr_entries[out].to        = to;
                cpuc->lbr_entries[out].mispred   = mis;
                cpuc->lbr_entries[out].predicted = pred;
                cpuc->lbr_entries[out].in_tx     = in_tx;
                cpuc->lbr_entries[out].abort     = abort;
                cpuc->lbr_entries[out].cycles    = cycles;
                cpuc->lbr_entries[out].type      = 0;
                cpuc->lbr_entries[out].reserved  = 0;
                out++;
        }
        cpuc->lbr_stack.nr = out;
        cpuc->lbr_stack.hw_idx = tos;
}

static __always_inline int get_lbr_br_type(u64 info)
{
        if (!static_cpu_has(X86_FEATURE_ARCH_LBR) || !x86_pmu.lbr_br_type)
                return 0;

        return (info & LBR_INFO_BR_TYPE) >> LBR_INFO_BR_TYPE_OFFSET;
}

static __always_inline bool get_lbr_mispred(u64 info)
{
        if (static_cpu_has(X86_FEATURE_ARCH_LBR) && !x86_pmu.lbr_mispred)
                return 0;

        return !!(info & LBR_INFO_MISPRED);
}

static __always_inline bool get_lbr_predicted(u64 info)
{
        if (static_cpu_has(X86_FEATURE_ARCH_LBR) && !x86_pmu.lbr_mispred)
                return 0;

        return !(info & LBR_INFO_MISPRED);
}

static __always_inline u16 get_lbr_cycles(u64 info)
{
        if (static_cpu_has(X86_FEATURE_ARCH_LBR) &&
            !(x86_pmu.lbr_timed_lbr && info & LBR_INFO_CYC_CNT_VALID))
                return 0;

        return info & LBR_INFO_CYCLES;
}

static void intel_pmu_store_lbr(struct cpu_hw_events *cpuc,
                                struct lbr_entry *entries)
{
        struct perf_branch_entry *e;
        struct lbr_entry *lbr;
        u64 from, to, info;
        int i;

        for (i = 0; i < x86_pmu.lbr_nr; i++) {
                lbr = entries ? &entries[i] : NULL;
                e = &cpuc->lbr_entries[i];

                from = rdlbr_from(i, lbr);
                /*
                 * Read LBR entries until invalid entry (0s) is detected.
                 */
                if (!from)
                        break;

                to = rdlbr_to(i, lbr);
                info = rdlbr_info(i, lbr);

                e->from         = from;
                e->to           = to;
                e->mispred      = get_lbr_mispred(info);
                e->predicted    = get_lbr_predicted(info);
                e->in_tx        = !!(info & LBR_INFO_IN_TX);
                e->abort        = !!(info & LBR_INFO_ABORT);
                e->cycles       = get_lbr_cycles(info);
                e->type         = get_lbr_br_type(info);
                e->reserved     = 0;
        }

        cpuc->lbr_stack.nr = i;
}

static void intel_pmu_arch_lbr_read(struct cpu_hw_events *cpuc)
{
        intel_pmu_store_lbr(cpuc, NULL);
}

static void intel_pmu_arch_lbr_read_xsave(struct cpu_hw_events *cpuc)
{
        struct x86_perf_task_context_arch_lbr_xsave *xsave = cpuc->lbr_xsave;

        if (!xsave) {
                intel_pmu_store_lbr(cpuc, NULL);
                return;
        }
        xsaves(&xsave->xsave, XFEATURE_MASK_LBR);

        intel_pmu_store_lbr(cpuc, xsave->lbr.entries);
}

void intel_pmu_lbr_read(void)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        /*
         * Don't read when all LBRs users are using adaptive PEBS.
         *
         * This could be smarter and actually check the event,
         * but this simple approach seems to work for now.
         */
        if (!cpuc->lbr_users || vlbr_exclude_host() ||
            cpuc->lbr_users == cpuc->lbr_pebs_users)
                return;

        x86_pmu.lbr_read(cpuc);

        intel_pmu_lbr_filter(cpuc);
}

/*
 * SW filter is used:
 * - in case there is no HW filter
 * - in case the HW filter has errata or limitations
 */
static int intel_pmu_setup_sw_lbr_filter(struct perf_event *event)
{
        u64 br_type = event->attr.branch_sample_type;
        int mask = 0;

        if (br_type & PERF_SAMPLE_BRANCH_USER)
                mask |= X86_BR_USER;

        if (br_type & PERF_SAMPLE_BRANCH_KERNEL)
                mask |= X86_BR_KERNEL;

        /* we ignore BRANCH_HV here */

        if (br_type & PERF_SAMPLE_BRANCH_ANY)
                mask |= X86_BR_ANY;

        if (br_type & PERF_SAMPLE_BRANCH_ANY_CALL)
                mask |= X86_BR_ANY_CALL;

        if (br_type & PERF_SAMPLE_BRANCH_ANY_RETURN)
                mask |= X86_BR_RET | X86_BR_IRET | X86_BR_SYSRET;

        if (br_type & PERF_SAMPLE_BRANCH_IND_CALL)
                mask |= X86_BR_IND_CALL;

        if (br_type & PERF_SAMPLE_BRANCH_ABORT_TX)
                mask |= X86_BR_ABORT;

        if (br_type & PERF_SAMPLE_BRANCH_IN_TX)
                mask |= X86_BR_IN_TX;

        if (br_type & PERF_SAMPLE_BRANCH_NO_TX)
                mask |= X86_BR_NO_TX;

        if (br_type & PERF_SAMPLE_BRANCH_COND)
                mask |= X86_BR_JCC;

        if (br_type & PERF_SAMPLE_BRANCH_CALL_STACK) {
                if (!x86_pmu_has_lbr_callstack())
                        return -EOPNOTSUPP;
                if (mask & ~(X86_BR_USER | X86_BR_KERNEL))
                        return -EINVAL;
                mask |= X86_BR_CALL | X86_BR_IND_CALL | X86_BR_RET |
                        X86_BR_CALL_STACK;
        }

        if (br_type & PERF_SAMPLE_BRANCH_IND_JUMP)
                mask |= X86_BR_IND_JMP;

        if (br_type & PERF_SAMPLE_BRANCH_CALL)
                mask |= X86_BR_CALL | X86_BR_ZERO_CALL;

        if (br_type & PERF_SAMPLE_BRANCH_TYPE_SAVE)
                mask |= X86_BR_TYPE_SAVE;

        /*
         * stash actual user request into reg, it may
         * be used by fixup code for some CPU
         */
        event->hw.branch_reg.reg = mask;
        return 0;
}

/*
 * setup the HW LBR filter
 * Used only when available, may not be enough to disambiguate
 * all branches, may need the help of the SW filter
 */
static int intel_pmu_setup_hw_lbr_filter(struct perf_event *event)
{
        struct hw_perf_event_extra *reg;
        u64 br_type = event->attr.branch_sample_type;
        u64 mask = 0, v;
        int i;

        for (i = 0; i < PERF_SAMPLE_BRANCH_MAX_SHIFT; i++) {
                if (!(br_type & (1ULL << i)))
                        continue;

                v = x86_pmu.lbr_sel_map[i];
                if (v == LBR_NOT_SUPP)
                        return -EOPNOTSUPP;

                if (v != LBR_IGN)
                        mask |= v;
        }

        reg = &event->hw.branch_reg;
        reg->idx = EXTRA_REG_LBR;

        if (static_cpu_has(X86_FEATURE_ARCH_LBR)) {
                reg->config = mask;
                return 0;
        }

        /*
         * The first 9 bits (LBR_SEL_MASK) in LBR_SELECT operate
         * in suppress mode. So LBR_SELECT should be set to
         * (~mask & LBR_SEL_MASK) | (mask & ~LBR_SEL_MASK)
         * But the 10th bit LBR_CALL_STACK does not operate
         * in suppress mode.
         */
        reg->config = mask ^ (x86_pmu.lbr_sel_mask & ~LBR_CALL_STACK);

        if ((br_type & PERF_SAMPLE_BRANCH_NO_CYCLES) &&
            (br_type & PERF_SAMPLE_BRANCH_NO_FLAGS) &&
            (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO))
                reg->config |= LBR_NO_INFO;

        return 0;
}

int intel_pmu_setup_lbr_filter(struct perf_event *event)
{
        int ret = 0;

        /*
         * no LBR on this PMU
         */
        if (!x86_pmu.lbr_nr)
                return -EOPNOTSUPP;

        /*
         * setup SW LBR filter
         */
        ret = intel_pmu_setup_sw_lbr_filter(event);
        if (ret)
                return ret;

        /*
         * setup HW LBR filter, if any
         */
        if (x86_pmu.lbr_sel_map)
                ret = intel_pmu_setup_hw_lbr_filter(event);

        return ret;
}

/*
 * return the type of control flow change at address "from"
 * instruction is not necessarily a branch (in case of interrupt).
 *
 * The branch type returned also includes the priv level of the
 * target of the control flow change (X86_BR_USER, X86_BR_KERNEL).
 *
 * If a branch type is unknown OR the instruction cannot be
 * decoded (e.g., text page not present), then X86_BR_NONE is
 * returned.
 */
static int branch_type(unsigned long from, unsigned long to, int abort)
{
        struct insn insn;
        void *addr;
        int bytes_read, bytes_left;
        int ret = X86_BR_NONE;
        int ext, to_plm, from_plm;
        u8 buf[MAX_INSN_SIZE];
        int is64 = 0;

        to_plm = kernel_ip(to) ? X86_BR_KERNEL : X86_BR_USER;
        from_plm = kernel_ip(from) ? X86_BR_KERNEL : X86_BR_USER;

        /*
         * maybe zero if lbr did not fill up after a reset by the time
         * we get a PMU interrupt
         */
        if (from == 0 || to == 0)
                return X86_BR_NONE;

        if (abort)
                return X86_BR_ABORT | to_plm;

        if (from_plm == X86_BR_USER) {
                /*
                 * can happen if measuring at the user level only
                 * and we interrupt in a kernel thread, e.g., idle.
                 */
                if (!current->mm)
                        return X86_BR_NONE;

                /* may fail if text not present */
                bytes_left = copy_from_user_nmi(buf, (void __user *)from,
                                                MAX_INSN_SIZE);
                bytes_read = MAX_INSN_SIZE - bytes_left;
                if (!bytes_read)
                        return X86_BR_NONE;

                addr = buf;
        } else {
                /*
                 * The LBR logs any address in the IP, even if the IP just
                 * faulted. This means userspace can control the from address.
                 * Ensure we don't blindly read any address by validating it is
                 * a known text address.
                 */
                if (kernel_text_address(from)) {
                        addr = (void *)from;
                        /*
                         * Assume we can get the maximum possible size
                         * when grabbing kernel data.  This is not
                         * _strictly_ true since we could possibly be
                         * executing up next to a memory hole, but
                         * it is very unlikely to be a problem.
                         */
                        bytes_read = MAX_INSN_SIZE;
                } else {
                        return X86_BR_NONE;
                }
        }

        /*
         * decoder needs to know the ABI especially
         * on 64-bit systems running 32-bit apps
         */
#ifdef CONFIG_X86_64
        is64 = kernel_ip((unsigned long)addr) || any_64bit_mode(current_pt_regs());
#endif
        insn_init(&insn, addr, bytes_read, is64);
        if (insn_get_opcode(&insn))
                return X86_BR_ABORT;

        switch (insn.opcode.bytes[0]) {
        case 0xf:
                switch (insn.opcode.bytes[1]) {
                case 0x05: /* syscall */
                case 0x34: /* sysenter */
                        ret = X86_BR_SYSCALL;
                        break;
                case 0x07: /* sysret */
                case 0x35: /* sysexit */
                        ret = X86_BR_SYSRET;
                        break;
                case 0x80 ... 0x8f: /* conditional */
                        ret = X86_BR_JCC;
                        break;
                default:
                        ret = X86_BR_NONE;
                }
                break;
        case 0x70 ... 0x7f: /* conditional */
                ret = X86_BR_JCC;
                break;
        case 0xc2: /* near ret */
        case 0xc3: /* near ret */
        case 0xca: /* far ret */
        case 0xcb: /* far ret */
                ret = X86_BR_RET;
                break;
        case 0xcf: /* iret */
                ret = X86_BR_IRET;
                break;
        case 0xcc ... 0xce: /* int */
                ret = X86_BR_INT;
                break;
        case 0xe8: /* call near rel */
                if (insn_get_immediate(&insn) || insn.immediate1.value == 0) {
                        /* zero length call */
                        ret = X86_BR_ZERO_CALL;
                        break;
                }
                fallthrough;
        case 0x9a: /* call far absolute */
                ret = X86_BR_CALL;
                break;
        case 0xe0 ... 0xe3: /* loop jmp */
                ret = X86_BR_JCC;
                break;
        case 0xe9 ... 0xeb: /* jmp */
                ret = X86_BR_JMP;
                break;
        case 0xff: /* call near absolute, call far absolute ind */
                if (insn_get_modrm(&insn))
                        return X86_BR_ABORT;

                ext = (insn.modrm.bytes[0] >> 3) & 0x7;
                switch (ext) {
                case 2: /* near ind call */
                case 3: /* far ind call */
                        ret = X86_BR_IND_CALL;
                        break;
                case 4:
                case 5:
                        ret = X86_BR_IND_JMP;
                        break;
                }
                break;
        default:
                ret = X86_BR_NONE;
        }
        /*
         * interrupts, traps, faults (and thus ring transition) may
         * occur on any instructions. Thus, to classify them correctly,
         * we need to first look at the from and to priv levels. If they
         * are different and to is in the kernel, then it indicates
         * a ring transition. If the from instruction is not a ring
         * transition instr (syscall, systenter, int), then it means
         * it was a irq, trap or fault.
         *
         * we have no way of detecting kernel to kernel faults.
         */
        if (from_plm == X86_BR_USER && to_plm == X86_BR_KERNEL
            && ret != X86_BR_SYSCALL && ret != X86_BR_INT)
                ret = X86_BR_IRQ;

        /*
         * branch priv level determined by target as
         * is done by HW when LBR_SELECT is implemented
         */
        if (ret != X86_BR_NONE)
                ret |= to_plm;

        return ret;
}

#define X86_BR_TYPE_MAP_MAX     16

static int branch_map[X86_BR_TYPE_MAP_MAX] = {
        PERF_BR_CALL,           /* X86_BR_CALL */
        PERF_BR_RET,            /* X86_BR_RET */
        PERF_BR_SYSCALL,        /* X86_BR_SYSCALL */
        PERF_BR_SYSRET,         /* X86_BR_SYSRET */
        PERF_BR_UNKNOWN,        /* X86_BR_INT */
        PERF_BR_UNKNOWN,        /* X86_BR_IRET */
        PERF_BR_COND,           /* X86_BR_JCC */
        PERF_BR_UNCOND,         /* X86_BR_JMP */
        PERF_BR_UNKNOWN,        /* X86_BR_IRQ */
        PERF_BR_IND_CALL,       /* X86_BR_IND_CALL */
        PERF_BR_UNKNOWN,        /* X86_BR_ABORT */
        PERF_BR_UNKNOWN,        /* X86_BR_IN_TX */
        PERF_BR_UNKNOWN,        /* X86_BR_NO_TX */
        PERF_BR_CALL,           /* X86_BR_ZERO_CALL */
        PERF_BR_UNKNOWN,        /* X86_BR_CALL_STACK */
        PERF_BR_IND,            /* X86_BR_IND_JMP */
};

static int
common_branch_type(int type)
{
        int i;

        type >>= 2; /* skip X86_BR_USER and X86_BR_KERNEL */

        if (type) {
                i = __ffs(type);
                if (i < X86_BR_TYPE_MAP_MAX)
                        return branch_map[i];
        }

        return PERF_BR_UNKNOWN;
}

enum {
        ARCH_LBR_BR_TYPE_JCC                    = 0,
        ARCH_LBR_BR_TYPE_NEAR_IND_JMP           = 1,
        ARCH_LBR_BR_TYPE_NEAR_REL_JMP           = 2,
        ARCH_LBR_BR_TYPE_NEAR_IND_CALL          = 3,
        ARCH_LBR_BR_TYPE_NEAR_REL_CALL          = 4,
        ARCH_LBR_BR_TYPE_NEAR_RET               = 5,
        ARCH_LBR_BR_TYPE_KNOWN_MAX              = ARCH_LBR_BR_TYPE_NEAR_RET,

        ARCH_LBR_BR_TYPE_MAP_MAX                = 16,
};

static const int arch_lbr_br_type_map[ARCH_LBR_BR_TYPE_MAP_MAX] = {
        [ARCH_LBR_BR_TYPE_JCC]                  = X86_BR_JCC,
        [ARCH_LBR_BR_TYPE_NEAR_IND_JMP]         = X86_BR_IND_JMP,
        [ARCH_LBR_BR_TYPE_NEAR_REL_JMP]         = X86_BR_JMP,
        [ARCH_LBR_BR_TYPE_NEAR_IND_CALL]        = X86_BR_IND_CALL,
        [ARCH_LBR_BR_TYPE_NEAR_REL_CALL]        = X86_BR_CALL,
        [ARCH_LBR_BR_TYPE_NEAR_RET]             = X86_BR_RET,
};

/*
 * implement actual branch filter based on user demand.
 * Hardware may not exactly satisfy that request, thus
 * we need to inspect opcodes. Mismatched branches are
 * discarded. Therefore, the number of branches returned
 * in PERF_SAMPLE_BRANCH_STACK sample may vary.
 */
static void
intel_pmu_lbr_filter(struct cpu_hw_events *cpuc)
{
        u64 from, to;
        int br_sel = cpuc->br_sel;
        int i, j, type, to_plm;
        bool compress = false;

        /* if sampling all branches, then nothing to filter */
        if (((br_sel & X86_BR_ALL) == X86_BR_ALL) &&
            ((br_sel & X86_BR_TYPE_SAVE) != X86_BR_TYPE_SAVE))
                return;

        for (i = 0; i < cpuc->lbr_stack.nr; i++) {

                from = cpuc->lbr_entries[i].from;
                to = cpuc->lbr_entries[i].to;
                type = cpuc->lbr_entries[i].type;

                /*
                 * Parse the branch type recorded in LBR_x_INFO MSR.
                 * Doesn't support OTHER_BRANCH decoding for now.
                 * OTHER_BRANCH branch type still rely on software decoding.
                 */
                if (static_cpu_has(X86_FEATURE_ARCH_LBR) &&
                    type <= ARCH_LBR_BR_TYPE_KNOWN_MAX) {
                        to_plm = kernel_ip(to) ? X86_BR_KERNEL : X86_BR_USER;
                        type = arch_lbr_br_type_map[type] | to_plm;
                } else
                        type = branch_type(from, to, cpuc->lbr_entries[i].abort);
                if (type != X86_BR_NONE && (br_sel & X86_BR_ANYTX)) {
                        if (cpuc->lbr_entries[i].in_tx)
                                type |= X86_BR_IN_TX;
                        else
                                type |= X86_BR_NO_TX;
                }

                /* if type does not correspond, then discard */
                if (type == X86_BR_NONE || (br_sel & type) != type) {
                        cpuc->lbr_entries[i].from = 0;
                        compress = true;
                }

                if ((br_sel & X86_BR_TYPE_SAVE) == X86_BR_TYPE_SAVE)
                        cpuc->lbr_entries[i].type = common_branch_type(type);
        }

        if (!compress)
                return;

        /* remove all entries with from=0 */
        for (i = 0; i < cpuc->lbr_stack.nr; ) {
                if (!cpuc->lbr_entries[i].from) {
                        j = i;
                        while (++j < cpuc->lbr_stack.nr)
                                cpuc->lbr_entries[j-1] = cpuc->lbr_entries[j];
                        cpuc->lbr_stack.nr--;
                        if (!cpuc->lbr_entries[i].from)
                                continue;
                }
                i++;
        }
}

void intel_pmu_store_pebs_lbrs(struct lbr_entry *lbr)
{
        struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

        /* Cannot get TOS for large PEBS and Arch LBR */
        if (static_cpu_has(X86_FEATURE_ARCH_LBR) ||
            (cpuc->n_pebs == cpuc->n_large_pebs))
                cpuc->lbr_stack.hw_idx = -1ULL;
        else
                cpuc->lbr_stack.hw_idx = intel_pmu_lbr_tos();

        intel_pmu_store_lbr(cpuc, lbr);
        intel_pmu_lbr_filter(cpuc);
}

/*
 * Map interface branch filters onto LBR filters
 */
static const int nhm_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
        [PERF_SAMPLE_BRANCH_ANY_SHIFT]          = LBR_ANY,
        [PERF_SAMPLE_BRANCH_USER_SHIFT]         = LBR_USER,
        [PERF_SAMPLE_BRANCH_KERNEL_SHIFT]       = LBR_KERNEL,
        [PERF_SAMPLE_BRANCH_HV_SHIFT]           = LBR_IGN,
        [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT]   = LBR_RETURN | LBR_REL_JMP
                                                | LBR_IND_JMP | LBR_FAR,
        /*
         * NHM/WSM erratum: must include REL_JMP+IND_JMP to get CALL branches
         */
        [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT] =
         LBR_REL_CALL | LBR_IND_CALL | LBR_REL_JMP | LBR_IND_JMP | LBR_FAR,
        /*
         * NHM/WSM erratum: must include IND_JMP to capture IND_CALL
         */
        [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_IND_CALL | LBR_IND_JMP,
        [PERF_SAMPLE_BRANCH_COND_SHIFT]     = LBR_JCC,
        [PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT] = LBR_IND_JMP,
};

static const int snb_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
        [PERF_SAMPLE_BRANCH_ANY_SHIFT]          = LBR_ANY,
        [PERF_SAMPLE_BRANCH_USER_SHIFT]         = LBR_USER,
        [PERF_SAMPLE_BRANCH_KERNEL_SHIFT]       = LBR_KERNEL,
        [PERF_SAMPLE_BRANCH_HV_SHIFT]           = LBR_IGN,
        [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT]   = LBR_RETURN | LBR_FAR,
        [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT]     = LBR_REL_CALL | LBR_IND_CALL
                                                | LBR_FAR,
        [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT]     = LBR_IND_CALL,
        [PERF_SAMPLE_BRANCH_COND_SHIFT]         = LBR_JCC,
        [PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT]     = LBR_IND_JMP,
        [PERF_SAMPLE_BRANCH_CALL_SHIFT]         = LBR_REL_CALL,
};

static const int hsw_lbr_sel_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
        [PERF_SAMPLE_BRANCH_ANY_SHIFT]          = LBR_ANY,
        [PERF_SAMPLE_BRANCH_USER_SHIFT]         = LBR_USER,
        [PERF_SAMPLE_BRANCH_KERNEL_SHIFT]       = LBR_KERNEL,
        [PERF_SAMPLE_BRANCH_HV_SHIFT]           = LBR_IGN,
        [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT]   = LBR_RETURN | LBR_FAR,
        [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT]     = LBR_REL_CALL | LBR_IND_CALL
                                                | LBR_FAR,
        [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT]     = LBR_IND_CALL,
        [PERF_SAMPLE_BRANCH_COND_SHIFT]         = LBR_JCC,
        [PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT]   = LBR_REL_CALL | LBR_IND_CALL
                                                | LBR_RETURN | LBR_CALL_STACK,
        [PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT]     = LBR_IND_JMP,
        [PERF_SAMPLE_BRANCH_CALL_SHIFT]         = LBR_REL_CALL,
};

static int arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_MAX_SHIFT] = {
        [PERF_SAMPLE_BRANCH_ANY_SHIFT]          = ARCH_LBR_ANY,
        [PERF_SAMPLE_BRANCH_USER_SHIFT]         = ARCH_LBR_USER,
        [PERF_SAMPLE_BRANCH_KERNEL_SHIFT]       = ARCH_LBR_KERNEL,
        [PERF_SAMPLE_BRANCH_HV_SHIFT]           = LBR_IGN,
        [PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT]   = ARCH_LBR_RETURN |
                                                  ARCH_LBR_OTHER_BRANCH,
        [PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT]     = ARCH_LBR_REL_CALL |
                                                  ARCH_LBR_IND_CALL |
                                                  ARCH_LBR_OTHER_BRANCH,
        [PERF_SAMPLE_BRANCH_IND_CALL_SHIFT]     = ARCH_LBR_IND_CALL,
        [PERF_SAMPLE_BRANCH_COND_SHIFT]         = ARCH_LBR_JCC,
        [PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT]   = ARCH_LBR_REL_CALL |
                                                  ARCH_LBR_IND_CALL |
                                                  ARCH_LBR_RETURN |
                                                  ARCH_LBR_CALL_STACK,
        [PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT]     = ARCH_LBR_IND_JMP,
        [PERF_SAMPLE_BRANCH_CALL_SHIFT]         = ARCH_LBR_REL_CALL,
};

/* core */
void __init intel_pmu_lbr_init_core(void)
{
        x86_pmu.lbr_nr     = 4;
        x86_pmu.lbr_tos    = MSR_LBR_TOS;
        x86_pmu.lbr_from   = MSR_LBR_CORE_FROM;
        x86_pmu.lbr_to     = MSR_LBR_CORE_TO;

        /*
         * SW branch filter usage:
         * - compensate for lack of HW filter
         */
}

/* nehalem/westmere */
void __init intel_pmu_lbr_init_nhm(void)
{
        x86_pmu.lbr_nr     = 16;
        x86_pmu.lbr_tos    = MSR_LBR_TOS;
        x86_pmu.lbr_from   = MSR_LBR_NHM_FROM;
        x86_pmu.lbr_to     = MSR_LBR_NHM_TO;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = nhm_lbr_sel_map;

        /*
         * SW branch filter usage:
         * - workaround LBR_SEL errata (see above)
         * - support syscall, sysret capture.
         *   That requires LBR_FAR but that means far
         *   jmp need to be filtered out
         */
}

/* sandy bridge */
void __init intel_pmu_lbr_init_snb(void)
{
        x86_pmu.lbr_nr   = 16;
        x86_pmu.lbr_tos  = MSR_LBR_TOS;
        x86_pmu.lbr_from = MSR_LBR_NHM_FROM;
        x86_pmu.lbr_to   = MSR_LBR_NHM_TO;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = snb_lbr_sel_map;

        /*
         * SW branch filter usage:
         * - support syscall, sysret capture.
         *   That requires LBR_FAR but that means far
         *   jmp need to be filtered out
         */
}

static inline struct kmem_cache *
create_lbr_kmem_cache(size_t size, size_t align)
{
        return kmem_cache_create("x86_lbr", size, align, 0, NULL);
}

/* haswell */
void intel_pmu_lbr_init_hsw(void)
{
        size_t size = sizeof(struct x86_perf_task_context);

        x86_pmu.lbr_nr   = 16;
        x86_pmu.lbr_tos  = MSR_LBR_TOS;
        x86_pmu.lbr_from = MSR_LBR_NHM_FROM;
        x86_pmu.lbr_to   = MSR_LBR_NHM_TO;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = hsw_lbr_sel_map;

        x86_get_pmu(smp_processor_id())->task_ctx_cache = create_lbr_kmem_cache(size, 0);

        if (lbr_from_signext_quirk_needed())
                static_branch_enable(&lbr_from_quirk_key);
}

/* skylake */
__init void intel_pmu_lbr_init_skl(void)
{
        size_t size = sizeof(struct x86_perf_task_context);

        x86_pmu.lbr_nr   = 32;
        x86_pmu.lbr_tos  = MSR_LBR_TOS;
        x86_pmu.lbr_from = MSR_LBR_NHM_FROM;
        x86_pmu.lbr_to   = MSR_LBR_NHM_TO;
        x86_pmu.lbr_info = MSR_LBR_INFO_0;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = hsw_lbr_sel_map;

        x86_get_pmu(smp_processor_id())->task_ctx_cache = create_lbr_kmem_cache(size, 0);

        /*
         * SW branch filter usage:
         * - support syscall, sysret capture.
         *   That requires LBR_FAR but that means far
         *   jmp need to be filtered out
         */
}

/* atom */
void __init intel_pmu_lbr_init_atom(void)
{
        /*
         * only models starting at stepping 10 seems
         * to have an operational LBR which can freeze
         * on PMU interrupt
         */
        if (boot_cpu_data.x86_model == 28
            && boot_cpu_data.x86_stepping < 10) {
                pr_cont("LBR disabled due to erratum");
                return;
        }

        x86_pmu.lbr_nr     = 8;
        x86_pmu.lbr_tos    = MSR_LBR_TOS;
        x86_pmu.lbr_from   = MSR_LBR_CORE_FROM;
        x86_pmu.lbr_to     = MSR_LBR_CORE_TO;

        /*
         * SW branch filter usage:
         * - compensate for lack of HW filter
         */
}

/* slm */
void __init intel_pmu_lbr_init_slm(void)
{
        x86_pmu.lbr_nr     = 8;
        x86_pmu.lbr_tos    = MSR_LBR_TOS;
        x86_pmu.lbr_from   = MSR_LBR_CORE_FROM;
        x86_pmu.lbr_to     = MSR_LBR_CORE_TO;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = nhm_lbr_sel_map;

        /*
         * SW branch filter usage:
         * - compensate for lack of HW filter
         */
        pr_cont("8-deep LBR, ");
}

/* Knights Landing */
void intel_pmu_lbr_init_knl(void)
{
        x86_pmu.lbr_nr     = 8;
        x86_pmu.lbr_tos    = MSR_LBR_TOS;
        x86_pmu.lbr_from   = MSR_LBR_NHM_FROM;
        x86_pmu.lbr_to     = MSR_LBR_NHM_TO;

        x86_pmu.lbr_sel_mask = LBR_SEL_MASK;
        x86_pmu.lbr_sel_map  = snb_lbr_sel_map;

        /* Knights Landing does have MISPREDICT bit */
        if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_LIP)
                x86_pmu.intel_cap.lbr_format = LBR_FORMAT_EIP_FLAGS;
}

/*
 * LBR state size is variable based on the max number of registers.
 * This calculates the expected state size, which should match
 * what the hardware enumerates for the size of XFEATURE_LBR.
 */
static inline unsigned int get_lbr_state_size(void)
{
        return sizeof(struct arch_lbr_state) +
               x86_pmu.lbr_nr * sizeof(struct lbr_entry);
}

static bool is_arch_lbr_xsave_available(void)
{
        if (!boot_cpu_has(X86_FEATURE_XSAVES))
                return false;

        /*
         * Check the LBR state with the corresponding software structure.
         * Disable LBR XSAVES support if the size doesn't match.
         */
        if (WARN_ON(xfeature_size(XFEATURE_LBR) != get_lbr_state_size()))
                return false;

        return true;
}

void __init intel_pmu_arch_lbr_init(void)
{
        struct pmu *pmu = x86_get_pmu(smp_processor_id());
        union cpuid28_eax eax;
        union cpuid28_ebx ebx;
        union cpuid28_ecx ecx;
        unsigned int unused_edx;
        bool arch_lbr_xsave;
        size_t size;
        u64 lbr_nr;

        /* Arch LBR Capabilities */
        cpuid(28, &eax.full, &ebx.full, &ecx.full, &unused_edx);

        lbr_nr = fls(eax.split.lbr_depth_mask) * 8;
        if (!lbr_nr)
                goto clear_arch_lbr;

        /* Apply the max depth of Arch LBR */
        if (wrmsrl_safe(MSR_ARCH_LBR_DEPTH, lbr_nr))
                goto clear_arch_lbr;

        x86_pmu.lbr_depth_mask = eax.split.lbr_depth_mask;
        x86_pmu.lbr_deep_c_reset = eax.split.lbr_deep_c_reset;
        x86_pmu.lbr_lip = eax.split.lbr_lip;
        x86_pmu.lbr_cpl = ebx.split.lbr_cpl;
        x86_pmu.lbr_filter = ebx.split.lbr_filter;
        x86_pmu.lbr_call_stack = ebx.split.lbr_call_stack;
        x86_pmu.lbr_mispred = ecx.split.lbr_mispred;
        x86_pmu.lbr_timed_lbr = ecx.split.lbr_timed_lbr;
        x86_pmu.lbr_br_type = ecx.split.lbr_br_type;
        x86_pmu.lbr_nr = lbr_nr;


        arch_lbr_xsave = is_arch_lbr_xsave_available();
        if (arch_lbr_xsave) {
                size = sizeof(struct x86_perf_task_context_arch_lbr_xsave) +
                       get_lbr_state_size();
                pmu->task_ctx_cache = create_lbr_kmem_cache(size,
                                                            XSAVE_ALIGNMENT);
        }

        if (!pmu->task_ctx_cache) {
                arch_lbr_xsave = false;

                size = sizeof(struct x86_perf_task_context_arch_lbr) +
                       lbr_nr * sizeof(struct lbr_entry);
                pmu->task_ctx_cache = create_lbr_kmem_cache(size, 0);
        }

        x86_pmu.lbr_from = MSR_ARCH_LBR_FROM_0;
        x86_pmu.lbr_to = MSR_ARCH_LBR_TO_0;
        x86_pmu.lbr_info = MSR_ARCH_LBR_INFO_0;

        /* LBR callstack requires both CPL and Branch Filtering support */
        if (!x86_pmu.lbr_cpl ||
            !x86_pmu.lbr_filter ||
            !x86_pmu.lbr_call_stack)
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_CALL_STACK_SHIFT] = LBR_NOT_SUPP;

        if (!x86_pmu.lbr_cpl) {
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_USER_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_KERNEL_SHIFT] = LBR_NOT_SUPP;
        } else if (!x86_pmu.lbr_filter) {
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_RETURN_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_ANY_CALL_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_IND_CALL_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_COND_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_IND_JUMP_SHIFT] = LBR_NOT_SUPP;
                arch_lbr_ctl_map[PERF_SAMPLE_BRANCH_CALL_SHIFT] = LBR_NOT_SUPP;
        }

        x86_pmu.lbr_ctl_mask = ARCH_LBR_CTL_MASK;
        x86_pmu.lbr_ctl_map  = arch_lbr_ctl_map;

        if (!x86_pmu.lbr_cpl && !x86_pmu.lbr_filter)
                x86_pmu.lbr_ctl_map = NULL;

        x86_pmu.lbr_reset = intel_pmu_arch_lbr_reset;
        if (arch_lbr_xsave) {
                x86_pmu.lbr_save = intel_pmu_arch_lbr_xsaves;
                x86_pmu.lbr_restore = intel_pmu_arch_lbr_xrstors;
                x86_pmu.lbr_read = intel_pmu_arch_lbr_read_xsave;
                pr_cont("XSAVE ");
        } else {
                x86_pmu.lbr_save = intel_pmu_arch_lbr_save;
                x86_pmu.lbr_restore = intel_pmu_arch_lbr_restore;
                x86_pmu.lbr_read = intel_pmu_arch_lbr_read;
        }

        pr_cont("Architectural LBR, ");

        return;

clear_arch_lbr:
        clear_cpu_cap(&boot_cpu_data, X86_FEATURE_ARCH_LBR);
}

/**
 * x86_perf_get_lbr - get the LBR records information
 *
 * @lbr: the caller's memory to store the LBR records information
 *
 * Returns: 0 indicates the LBR info has been successfully obtained
 */
int x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
{
        int lbr_fmt = x86_pmu.intel_cap.lbr_format;

        lbr->nr = x86_pmu.lbr_nr;
        lbr->from = x86_pmu.lbr_from;
        lbr->to = x86_pmu.lbr_to;
        lbr->info = (lbr_fmt == LBR_FORMAT_INFO) ? x86_pmu.lbr_info : 0;

        return 0;
}
EXPORT_SYMBOL_GPL(x86_perf_get_lbr);

struct event_constraint vlbr_constraint =
        __EVENT_CONSTRAINT(INTEL_FIXED_VLBR_EVENT, (1ULL << INTEL_PMC_IDX_FIXED_VLBR),
                          FIXED_EVENT_FLAGS, 1, 0, PERF_X86_EVENT_LBR_SELECT);