// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 */

#include <linux/ptrace.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/kdev_t.h>
#include <linux/proc_fs.h>
#include <linux/file.h>
#include <linux/sched/mm.h>
#include <linux/sched/debug.h>

#include <asm/arcregs.h>
#include <asm/irqflags.h>

#define ARC_PATH_MAX    256

/*
 * Common routine to print scratch regs (r0-r12) or callee regs (r13-r25)
 *   -Prints 3 regs per line and a CR.
 *   -To continue, callee regs right after scratch, special handling of CR
 */
static noinline void print_reg_file(long *reg_rev, int start_num)
{
        unsigned int i;
        char buf[512];
        int n = 0, len = sizeof(buf);

        for (i = start_num; i < start_num + 13; i++) {
                n += scnprintf(buf + n, len - n, "r%02u: 0x%08lx\t",
                               i, (unsigned long)*reg_rev);

                if (((i + 1) % 3) == 0)
                        n += scnprintf(buf + n, len - n, "\n");

                /* because pt_regs has regs reversed: r12..r0, r25..r13 */
                if (is_isa_arcv2() && start_num == 0)
                        reg_rev++;
                else
                        reg_rev--;
        }

        if (start_num != 0)
                n += scnprintf(buf + n, len - n, "\n\n");

        /* To continue printing callee regs on same line as scratch regs */
        if (start_num == 0)
                pr_info("%s", buf);
        else
                pr_cont("%s\n", buf);
}

static void show_callee_regs(struct callee_regs *cregs)
{
        print_reg_file(&(cregs->r13), 13);
}

static void print_task_path_n_nm(struct task_struct *tsk)
{
        char *path_nm = NULL;
        struct mm_struct *mm;
        struct file *exe_file;
        char buf[ARC_PATH_MAX];

        mm = get_task_mm(tsk);
        if (!mm)
                goto done;

        exe_file = get_mm_exe_file(mm);
        mmput(mm);

        if (exe_file) {
                path_nm = file_path(exe_file, buf, ARC_PATH_MAX-1);
                fput(exe_file);
        }

done:
        pr_info("Path: %s\n", !IS_ERR(path_nm) ? path_nm : "?");
}

static void show_faulting_vma(unsigned long address)
{
        struct vm_area_struct *vma;
        struct mm_struct *active_mm = current->active_mm;

        /* can't use print_vma_addr() yet as it doesn't check for
         * non-inclusive vma
         */
        down_read(&active_mm->mmap_sem);
        vma = find_vma(active_mm, address);

        /* check against the find_vma( ) behaviour which returns the next VMA
         * if the container VMA is not found
         */
        if (vma && (vma->vm_start <= address)) {
                char buf[ARC_PATH_MAX];
                char *nm = "?";

                if (vma->vm_file) {
                        nm = file_path(vma->vm_file, buf, ARC_PATH_MAX-1);
                        if (IS_ERR(nm))
                                nm = "?";
                }
                pr_info("    @off 0x%lx in [%s]\n"
                        "    VMA: 0x%08lx to 0x%08lx\n",
                        vma->vm_start < TASK_UNMAPPED_BASE ?
                                address : address - vma->vm_start,
                        nm, vma->vm_start, vma->vm_end);
        } else
                pr_info("    @No matching VMA found\n");

        up_read(&active_mm->mmap_sem);
}

static void show_ecr_verbose(struct pt_regs *regs)
{
        unsigned int vec, cause_code;
        unsigned long address;

        pr_info("\n[ECR   ]: 0x%08lx => ", regs->event);

        /* For Data fault, this is data address not instruction addr */
        address = current->thread.fault_address;

        vec = regs->ecr_vec;
        cause_code = regs->ecr_cause;

        /* For DTLB Miss or ProtV, display the memory involved too */
        if (vec == ECR_V_DTLB_MISS) {
                pr_cont("Invalid %s @ 0x%08lx by insn @ 0x%08lx\n",
                       (cause_code == 0x01) ? "Read" :
                       ((cause_code == 0x02) ? "Write" : "EX"),
                       address, regs->ret);
        } else if (vec == ECR_V_ITLB_MISS) {
                pr_cont("Insn could not be fetched\n");
        } else if (vec == ECR_V_MACH_CHK) {
                pr_cont("Machine Check (%s)\n", (cause_code == 0x0) ?
                                        "Double Fault" : "Other Fatal Err");

        } else if (vec == ECR_V_PROTV) {
                if (cause_code == ECR_C_PROTV_INST_FETCH)
                        pr_cont("Execute from Non-exec Page\n");
                else if (cause_code == ECR_C_PROTV_MISALIG_DATA &&
                         IS_ENABLED(CONFIG_ISA_ARCOMPACT))
                        pr_cont("Misaligned r/w from 0x%08lx\n", address);
                else
                        pr_cont("%s access not allowed on page\n",
                                (cause_code == 0x01) ? "Read" :
                                ((cause_code == 0x02) ? "Write" : "EX"));
        } else if (vec == ECR_V_INSN_ERR) {
                pr_cont("Illegal Insn\n");
#ifdef CONFIG_ISA_ARCV2
        } else if (vec == ECR_V_MEM_ERR) {
                if (cause_code == 0x00)
                        pr_cont("Bus Error from Insn Mem\n");
                else if (cause_code == 0x10)
                        pr_cont("Bus Error from Data Mem\n");
                else
                        pr_cont("Bus Error, check PRM\n");
        } else if (vec == ECR_V_MISALIGN) {
                pr_cont("Misaligned r/w from 0x%08lx\n", address);
#endif
        } else if (vec == ECR_V_TRAP) {
                if (regs->ecr_param == 5)
                        pr_cont("gcc generated __builtin_trap\n");
        } else {
                pr_cont("Check Programmer's Manual\n");
        }
}

/************************************************************************
 *  API called by rest of kernel
 ***********************************************************************/

void show_regs(struct pt_regs *regs)
{
        struct task_struct *tsk = current;
        struct callee_regs *cregs;

        /*
         * generic code calls us with preemption disabled, but some calls
         * here could sleep, so re-enable to avoid lockdep splat
         */
        preempt_enable();

        print_task_path_n_nm(tsk);
        show_regs_print_info(KERN_INFO);

        show_ecr_verbose(regs);

        pr_info("[EFA   ]: 0x%08lx\n[BLINK ]: %pS\n[ERET  ]: %pS\n",
                current->thread.fault_address,
                (void *)regs->blink, (void *)regs->ret);

        if (user_mode(regs))
                show_faulting_vma(regs->ret); /* faulting code, not data */

        pr_info("[STAT32]: 0x%08lx", regs->status32);

#define STS_BIT(r, bit) r->status32 & STATUS_##bit##_MASK ? #bit" " : ""

#ifdef CONFIG_ISA_ARCOMPACT
        pr_cont(" : %2s%2s%2s%2s%2s%2s%2s\n",
                        (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
                        STS_BIT(regs, DE), STS_BIT(regs, AE),
                        STS_BIT(regs, A2), STS_BIT(regs, A1),
                        STS_BIT(regs, E2), STS_BIT(regs, E1));
#else
        pr_cont(" : %2s%2s%2s%2s\n",
                        STS_BIT(regs, IE),
                        (regs->status32 & STATUS_U_MASK) ? "U " : "K ",
                        STS_BIT(regs, DE), STS_BIT(regs, AE));
#endif
        pr_info("BTA: 0x%08lx\t SP: 0x%08lx\t FP: 0x%08lx\n",
                regs->bta, regs->sp, regs->fp);
        pr_info("LPS: 0x%08lx\tLPE: 0x%08lx\tLPC: 0x%08lx\n",
               regs->lp_start, regs->lp_end, regs->lp_count);

        /* print regs->r0 thru regs->r12
         * Sequential printing was generating horrible code
         */
        print_reg_file(&(regs->r0), 0);

        /* If Callee regs were saved, display them too */
        cregs = (struct callee_regs *)current->thread.callee_reg;
        if (cregs)
                show_callee_regs(cregs);

        preempt_disable();
}

void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
                            unsigned long address)
{
        current->thread.fault_address = address;

        /* Show fault description */
        pr_info("\n%s\n", str);

        /* Caller and Callee regs */
        show_regs(regs);

        /* Show stack trace if this Fatality happened in kernel mode */
        if (!user_mode(regs))
                show_stacktrace(current, regs);
}