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| author | Helge Deller <deller@gmx.de> | 2021-11-09 22:25:02 +0100 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2022-03-18 09:10:14 +0100 |
| commit | 9b046d0245cec982c72a65d3ea1b834959a9708b (patch) | |
| tree | d361a9686a4bc99ccc0122014c0800353e357d14 /arch/parisc/kernel/kprobes.c | |
| parent | parisc: Improve CPU socket and core bootup info text (diff) | |
| download | linux-9b046d0245cec982c72a65d3ea1b834959a9708b.tar.xz linux-9b046d0245cec982c72a65d3ea1b834959a9708b.zip | |
parisc: Avoid using hardware single-step in kprobes
This patch changes the kprobe and kretprobe feature to use another
break instruction instead of relying on the hardware single-step
feature.
That way those kprobes now work in qemu as well, because in qemu we
don't emulate yet single-stepping.
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/kernel/kprobes.c')
| -rw-r--r-- | arch/parisc/kernel/kprobes.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/arch/parisc/kernel/kprobes.c b/arch/parisc/kernel/kprobes.c index e2bdb5a5f93e..3343d2fb7889 100644 --- a/arch/parisc/kernel/kprobes.c +++ b/arch/parisc/kernel/kprobes.c @@ -5,6 +5,7 @@ * PA-RISC kprobes implementation * * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org> + * Copyright (c) 2022 Helge Deller <deller@gmx.de> */ #include <linux/types.h> @@ -25,9 +26,14 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p) if (!p->ainsn.insn) return -ENOMEM; - memcpy(p->ainsn.insn, p->addr, - MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); + /* + * Set up new instructions. Second break instruction will + * trigger call of parisc_kprobe_ss_handler(). + */ p->opcode = *p->addr; + p->ainsn.insn[0] = p->opcode; + p->ainsn.insn[1] = PARISC_KPROBES_BREAK_INSN2; + flush_insn_slot(p); return 0; } @@ -73,9 +79,7 @@ static void __kprobes setup_singlestep(struct kprobe *p, { kcb->iaoq[0] = regs->iaoq[0]; kcb->iaoq[1] = regs->iaoq[1]; - regs->iaoq[0] = (unsigned long)p->ainsn.insn; - mtctl(0, 0); - regs->gr[0] |= PSW_R; + instruction_pointer_set(regs, (unsigned long)p->ainsn.insn); } int __kprobes parisc_kprobe_break_handler(struct pt_regs *regs) @@ -165,9 +169,8 @@ int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs) regs->iaoq[0] = kcb->iaoq[1]; break; default: - regs->iaoq[1] = kcb->iaoq[0]; - regs->iaoq[1] += (regs->iaoq[1] - regs->iaoq[0]) + 4; regs->iaoq[0] = kcb->iaoq[1]; + regs->iaoq[1] = regs->iaoq[0] + 4; break; } kcb->kprobe_status = KPROBE_HIT_SSDONE; @@ -191,14 +194,17 @@ static struct kprobe trampoline_p = { static int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) { - unsigned long orig_ret_address; - - orig_ret_address = __kretprobe_trampoline_handler(regs, NULL); - instruction_pointer_set(regs, orig_ret_address); + __kretprobe_trampoline_handler(regs, NULL); return 1; } +void arch_kretprobe_fixup_return(struct pt_regs *regs, + kprobe_opcode_t *correct_ret_addr) +{ + regs->gr[2] = (unsigned long)correct_ret_addr; +} + void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs) { |