diff options
Diffstat (limited to 'arch/arm64/kernel/probes')
| -rw-r--r-- | arch/arm64/kernel/probes/kprobes.c | 21 | ||||
| -rw-r--r-- | arch/arm64/kernel/probes/kprobes_trampoline.S | 78 |
2 files changed, 22 insertions, 77 deletions
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 70b91a8c6bb3..327855a11df2 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -371,6 +371,21 @@ static struct break_hook kprobes_break_ss_hook = { .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). @@ -396,11 +411,6 @@ int __init arch_populate_kprobe_blacklist(void) 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) { @@ -420,6 +430,7 @@ int __init arch_init_kprobes(void) { register_kernel_break_hook(&kprobes_break_hook); register_kernel_break_hook(&kprobes_break_ss_hook); + register_kernel_break_hook(&kretprobes_break_hook); return 0; } diff --git a/arch/arm64/kernel/probes/kprobes_trampoline.S b/arch/arm64/kernel/probes/kprobes_trampoline.S index 9a6499bed58b..a362f3dbb3d1 100644 --- a/arch/arm64/kernel/probes/kprobes_trampoline.S +++ b/arch/arm64/kernel/probes/kprobes_trampoline.S @@ -4,83 +4,17 @@ */ #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) |