root/arch/arm64/kernel/probes/kprobes_trampoline.S

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * trampoline entry and return code for kretprobes.
   4  */
   5 
   6 #include <linux/linkage.h>
   7 #include <asm/asm-offsets.h>
   8 #include <asm/assembler.h>
   9 
  10         .text
  11 
  12         .macro  save_all_base_regs
  13         stp x0, x1, [sp, #S_X0]
  14         stp x2, x3, [sp, #S_X2]
  15         stp x4, x5, [sp, #S_X4]
  16         stp x6, x7, [sp, #S_X6]
  17         stp x8, x9, [sp, #S_X8]
  18         stp x10, x11, [sp, #S_X10]
  19         stp x12, x13, [sp, #S_X12]
  20         stp x14, x15, [sp, #S_X14]
  21         stp x16, x17, [sp, #S_X16]
  22         stp x18, x19, [sp, #S_X18]
  23         stp x20, x21, [sp, #S_X20]
  24         stp x22, x23, [sp, #S_X22]
  25         stp x24, x25, [sp, #S_X24]
  26         stp x26, x27, [sp, #S_X26]
  27         stp x28, x29, [sp, #S_X28]
  28         add x0, sp, #S_FRAME_SIZE
  29         stp lr, x0, [sp, #S_LR]
  30         /*
  31          * Construct a useful saved PSTATE
  32          */
  33         mrs x0, nzcv
  34         mrs x1, daif
  35         orr x0, x0, x1
  36         mrs x1, CurrentEL
  37         orr x0, x0, x1
  38         mrs x1, SPSel
  39         orr x0, x0, x1
  40         stp xzr, x0, [sp, #S_PC]
  41         .endm
  42 
  43         .macro  restore_all_base_regs
  44         ldr x0, [sp, #S_PSTATE]
  45         and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
  46         msr nzcv, x0
  47         ldp x0, x1, [sp, #S_X0]
  48         ldp x2, x3, [sp, #S_X2]
  49         ldp x4, x5, [sp, #S_X4]
  50         ldp x6, x7, [sp, #S_X6]
  51         ldp x8, x9, [sp, #S_X8]
  52         ldp x10, x11, [sp, #S_X10]
  53         ldp x12, x13, [sp, #S_X12]
  54         ldp x14, x15, [sp, #S_X14]
  55         ldp x16, x17, [sp, #S_X16]
  56         ldp x18, x19, [sp, #S_X18]
  57         ldp x20, x21, [sp, #S_X20]
  58         ldp x22, x23, [sp, #S_X22]
  59         ldp x24, x25, [sp, #S_X24]
  60         ldp x26, x27, [sp, #S_X26]
  61         ldp x28, x29, [sp, #S_X28]
  62         .endm
  63 
  64 ENTRY(kretprobe_trampoline)
  65         sub sp, sp, #S_FRAME_SIZE
  66 
  67         save_all_base_regs
  68 
  69         mov x0, sp
  70         bl trampoline_probe_handler
  71         /*
  72          * Replace trampoline address in lr with actual orig_ret_addr return
  73          * address.
  74          */
  75         mov lr, x0
  76 
  77         restore_all_base_regs
  78 
  79         add sp, sp, #S_FRAME_SIZE
  80         ret
  81 
  82 ENDPROC(kretprobe_trampoline)