LXR linux/arch/x86/xen/xen-asm

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Asm versions of Xen pv-ops, suitable for direct use.
   4 *
   5 * We only bother with direct forms (ie, vcpu in pda) of the
   6 * operations here; the indirect forms are better handled in C.
   7 */
   8
   9#include <asm/errno.h>
  10#include <asm/percpu.h>
  11#include <asm/processor-flags.h>
  12#include <asm/segment.h>
  13#include <asm/asm-offsets.h>
  14#include <asm/thread_info.h>
  15
  16#include <xen/interface/xen.h>
  17
  18#include <linux/init.h>
  19#include <linux/linkage.h>
  20
  21.macro xen_pv_trap name
  22ENTRY(xen_\name)
  23        pop %rcx
  24        pop %r11
  25        jmp  \name
  26END(xen_\name)
  27.endm
  28
  29xen_pv_trap divide_error
  30xen_pv_trap debug
  31xen_pv_trap xendebug
  32xen_pv_trap int3
  33xen_pv_trap xenint3
  34xen_pv_trap xennmi
  35xen_pv_trap overflow
  36xen_pv_trap bounds
  37xen_pv_trap invalid_op
  38xen_pv_trap device_not_available
  39xen_pv_trap double_fault
  40xen_pv_trap coprocessor_segment_overrun
  41xen_pv_trap invalid_TSS
  42xen_pv_trap segment_not_present
  43xen_pv_trap stack_segment
  44xen_pv_trap general_protection
  45xen_pv_trap page_fault
  46xen_pv_trap spurious_interrupt_bug
  47xen_pv_trap coprocessor_error
  48xen_pv_trap alignment_check
  49#ifdef CONFIG_X86_MCE
  50xen_pv_trap machine_check
  51#endif /* CONFIG_X86_MCE */
  52xen_pv_trap simd_coprocessor_error
  53#ifdef CONFIG_IA32_EMULATION
  54xen_pv_trap entry_INT80_compat
  55#endif
  56xen_pv_trap hypervisor_callback
  57
  58        __INIT
  59ENTRY(xen_early_idt_handler_array)
  60        i = 0
  61        .rept NUM_EXCEPTION_VECTORS
  62        pop %rcx
  63        pop %r11
  64        jmp early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE
  65        i = i + 1
  66        .fill xen_early_idt_handler_array + i*XEN_EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc
  67        .endr
  68END(xen_early_idt_handler_array)
  69        __FINIT
  70
  71hypercall_iret = hypercall_page + __HYPERVISOR_iret * 32
  72/*
  73 * Xen64 iret frame:
  74 *
  75 *      ss
  76 *      rsp
  77 *      rflags
  78 *      cs
  79 *      rip             <-- standard iret frame
  80 *
  81 *      flags
  82 *
  83 *      rcx             }
  84 *      r11             }<-- pushed by hypercall page
  85 * rsp->rax             }
  86 */
  87ENTRY(xen_iret)
  88        pushq $0
  89        jmp hypercall_iret
  90
  91ENTRY(xen_sysret64)
  92        /*
  93         * We're already on the usermode stack at this point, but
  94         * still with the kernel gs, so we can easily switch back
  95         */
  96        movq %rsp, PER_CPU_VAR(rsp_scratch)
  97        movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
  98
  99        pushq $__USER_DS
 100        pushq PER_CPU_VAR(rsp_scratch)
 101        pushq %r11
 102        pushq $__USER_CS
 103        pushq %rcx
 104
 105        pushq $VGCF_in_syscall
 106        jmp hypercall_iret
 107
 108/*
 109 * Xen handles syscall callbacks much like ordinary exceptions, which
 110 * means we have:
 111 * - kernel gs
 112 * - kernel rsp
 113 * - an iret-like stack frame on the stack (including rcx and r11):
 114 *      ss
 115 *      rsp
 116 *      rflags
 117 *      cs
 118 *      rip
 119 *      r11
 120 * rsp->rcx
 121 */
 122
 123/* Normal 64-bit system call target */
 124ENTRY(xen_syscall_target)
 125        popq %rcx
 126        popq %r11
 127
 128        /*
 129         * Neither Xen nor the kernel really knows what the old SS and
 130         * CS were.  The kernel expects __USER_DS and __USER_CS, so
 131         * report those values even though Xen will guess its own values.
 132         */
 133        movq $__USER_DS, 4*8(%rsp)
 134        movq $__USER_CS, 1*8(%rsp)
 135
 136        jmp entry_SYSCALL_64_after_hwframe
 137ENDPROC(xen_syscall_target)
 138
 139#ifdef CONFIG_IA32_EMULATION
 140
 141/* 32-bit compat syscall target */
 142ENTRY(xen_syscall32_target)
 143        popq %rcx
 144        popq %r11
 145
 146        /*
 147         * Neither Xen nor the kernel really knows what the old SS and
 148         * CS were.  The kernel expects __USER32_DS and __USER32_CS, so
 149         * report those values even though Xen will guess its own values.
 150         */
 151        movq $__USER32_DS, 4*8(%rsp)
 152        movq $__USER32_CS, 1*8(%rsp)
 153
 154        jmp entry_SYSCALL_compat_after_hwframe
 155ENDPROC(xen_syscall32_target)
 156
 157/* 32-bit compat sysenter target */
 158ENTRY(xen_sysenter_target)
 159        mov 0*8(%rsp), %rcx
 160        mov 1*8(%rsp), %r11
 161        mov 5*8(%rsp), %rsp
 162        jmp entry_SYSENTER_compat
 163ENDPROC(xen_sysenter_target)
 164
 165#else /* !CONFIG_IA32_EMULATION */
 166
 167ENTRY(xen_syscall32_target)
 168ENTRY(xen_sysenter_target)
 169        lea 16(%rsp), %rsp      /* strip %rcx, %r11 */
 170        mov $-ENOSYS, %rax
 171        pushq $0
 172        jmp hypercall_iret
 173ENDPROC(xen_syscall32_target)
 174ENDPROC(xen_sysenter_target)
 175
 176#endif  /* CONFIG_IA32_EMULATION */
 177