.fn = kprobe_breakpoint_ss_handler,
};
+static int __kprobes
+kretprobe_breakpoint_handler(struct pt_regs *regs, unsigned long esr)
+{
+ if (regs->pc != (unsigned long)__kretprobe_trampoline)
+ return DBG_HOOK_ERROR;
+
+ regs->pc = kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
+ return DBG_HOOK_HANDLED;
+}
+
+static struct break_hook kretprobes_break_hook = {
+ .imm = KRETPROBES_BRK_IMM,
+ .fn = kretprobe_breakpoint_handler,
+};
+
/*
* Provide a blacklist of symbols identifying ranges which cannot be kprobed.
* This blacklist is exposed to userspace via debugfs (kprobes/blacklist).
return ret;
}
-void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
-{
- return (void *)kretprobe_trampoline_handler(regs, (void *)regs->regs[29]);
-}
-
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
{
register_kernel_break_hook(&kprobes_break_hook);
register_kernel_break_hook(&kprobes_break_ss_hook);
+ register_kernel_break_hook(&kretprobes_break_hook);
return 0;
}
*/
#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
+#include <asm/asm-bug.h>
#include <asm/assembler.h>
.text
- .macro save_all_base_regs
- stp x0, x1, [sp, #S_X0]
- stp x2, x3, [sp, #S_X2]
- stp x4, x5, [sp, #S_X4]
- stp x6, x7, [sp, #S_X6]
- stp x8, x9, [sp, #S_X8]
- stp x10, x11, [sp, #S_X10]
- stp x12, x13, [sp, #S_X12]
- stp x14, x15, [sp, #S_X14]
- stp x16, x17, [sp, #S_X16]
- stp x18, x19, [sp, #S_X18]
- stp x20, x21, [sp, #S_X20]
- stp x22, x23, [sp, #S_X22]
- stp x24, x25, [sp, #S_X24]
- stp x26, x27, [sp, #S_X26]
- stp x28, x29, [sp, #S_X28]
- add x0, sp, #PT_REGS_SIZE
- stp lr, x0, [sp, #S_LR]
- /*
- * Construct a useful saved PSTATE
- */
- mrs x0, nzcv
- mrs x1, daif
- orr x0, x0, x1
- mrs x1, CurrentEL
- orr x0, x0, x1
- mrs x1, SPSel
- orr x0, x0, x1
- stp xzr, x0, [sp, #S_PC]
- .endm
-
- .macro restore_all_base_regs
- ldr x0, [sp, #S_PSTATE]
- and x0, x0, #(PSR_N_BIT | PSR_Z_BIT | PSR_C_BIT | PSR_V_BIT)
- msr nzcv, x0
- ldp x0, x1, [sp, #S_X0]
- ldp x2, x3, [sp, #S_X2]
- ldp x4, x5, [sp, #S_X4]
- ldp x6, x7, [sp, #S_X6]
- ldp x8, x9, [sp, #S_X8]
- ldp x10, x11, [sp, #S_X10]
- ldp x12, x13, [sp, #S_X12]
- ldp x14, x15, [sp, #S_X14]
- ldp x16, x17, [sp, #S_X16]
- ldp x18, x19, [sp, #S_X18]
- ldp x20, x21, [sp, #S_X20]
- ldp x22, x23, [sp, #S_X22]
- ldp x24, x25, [sp, #S_X24]
- ldp x26, x27, [sp, #S_X26]
- ldp x28, x29, [sp, #S_X28]
- .endm
-
SYM_CODE_START(__kretprobe_trampoline)
- sub sp, sp, #PT_REGS_SIZE
-
- save_all_base_regs
-
- /* Setup a frame pointer. */
- add x29, sp, #S_FP
-
- mov x0, sp
- bl trampoline_probe_handler
/*
- * Replace trampoline address in lr with actual orig_ret_addr return
- * address.
+ * Trigger a breakpoint exception. The PC will be adjusted by
+ * kretprobe_breakpoint_handler(), and no subsequent instructions will
+ * be executed from the trampoline.
*/
- mov lr, x0
-
- /* The frame pointer (x29) is restored with other registers. */
- restore_all_base_regs
-
- add sp, sp, #PT_REGS_SIZE
- ret
-
+ brk #KRETPROBES_BRK_IMM
+ ASM_BUG()
SYM_CODE_END(__kretprobe_trampoline)