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arm64: kprobes: Remove redundant kprobe_step_ctx 

The kprobe_step_ctx (kcb->ss_ctx) has ss_pending and match_addr, but
those are redundant because those can be replaced by KPROBE_HIT_SS and
&cur_kprobe->ainsn.api.insn[1] respectively.
To simplify the code, remove the kprobe_step_ctx.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201103134900.337243-2-jean-philippe@linaro.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Masami Hiramatsu 2020-11-03 14:49:04 +01:00 committed by Catalin Marinas
parent f8394f232b
commit ba090f9caf
2 changed files with 12 additions and 48 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/arm64/include/asm/kprobes.h
View File

@ -28,18 +28,11 @@ struct prev_kprobe {
unsigned int status;
};
/* Single step context for kprobe */
struct kprobe_step_ctx {
unsigned long ss_pending;
unsigned long match_addr;
};
/* per-cpu kprobe control block */
struct kprobe_ctlblk {
unsigned int kprobe_status;
unsigned long saved_irqflag;
struct prev_kprobe prev_kprobe;
struct kprobe_step_ctx ss_ctx;
};
void arch_remove_kprobe(struct kprobe *);

53
arch/arm64/kernel/probes/kprobes.c
View File

@ -34,7 +34,7 @@ DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void __kprobes
post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
@ -68,7 +68,7 @@ static void __kprobes arch_simulate_insn(struct kprobe *p, struct pt_regs *regs)
p->ainsn.api.handler((u32)p->opcode, (long)p->addr, regs);
/* single step simulated, now go for post processing */
post_kprobe_handler(kcb, regs);
post_kprobe_handler(p, kcb, regs);
}
int __kprobes arch_prepare_kprobe(struct kprobe *p)
@ -177,19 +177,6 @@ static void __kprobes kprobes_restore_local_irqflag(struct kprobe_ctlblk *kcb,
regs->pstate |= kcb->saved_irqflag;
}
static void __kprobes
set_ss_context(struct kprobe_ctlblk *kcb, unsigned long addr)
{
kcb->ss_ctx.ss_pending = true;
kcb->ss_ctx.match_addr = addr + sizeof(kprobe_opcode_t);
}
static void __kprobes clear_ss_context(struct kprobe_ctlblk *kcb)
{
kcb->ss_ctx.ss_pending = false;
kcb->ss_ctx.match_addr = 0;
}
static void __kprobes setup_singlestep(struct kprobe *p,
struct pt_regs *regs,
struct kprobe_ctlblk *kcb, int reenter)
@ -209,7 +196,6 @@ static void __kprobes setup_singlestep(struct kprobe *p,
/* prepare for single stepping */
slot = (unsigned long)p->ainsn.api.insn;
set_ss_context(kcb, slot); /* mark pending ss */
kprobes_save_local_irqflag(kcb, regs);
instruction_pointer_set(regs, slot);
} else {
@ -243,13 +229,8 @@ static int __kprobes reenter_kprobe(struct kprobe *p,
}
static void __kprobes
post_kprobe_handler(struct kprobe_ctlblk *kcb, struct pt_regs *regs)
post_kprobe_handler(struct kprobe *cur, struct kprobe_ctlblk *kcb, struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
if (!cur)
return;
/* return addr restore if non-branching insn */
if (cur->ainsn.api.restore != 0)
instruction_pointer_set(regs, cur->ainsn.api.restore);
@ -364,33 +345,23 @@ static void __kprobes kprobe_handler(struct pt_regs *regs)
*/
}
static int __kprobes
kprobe_ss_hit(struct kprobe_ctlblk *kcb, unsigned long addr)
{
if ((kcb->ss_ctx.ss_pending)
&& (kcb->ss_ctx.match_addr == addr)) {
clear_ss_context(kcb); /* clear pending ss */
return DBG_HOOK_HANDLED;
}
/* not ours, kprobes should ignore it */
return DBG_HOOK_ERROR;
}
static int __kprobes
kprobe_breakpoint_ss_handler(struct pt_regs *regs, unsigned int esr)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
int retval;
unsigned long addr = instruction_pointer(regs);
struct kprobe *cur = kprobe_running();
/* return error if this is not our step */
retval = kprobe_ss_hit(kcb, instruction_pointer(regs));
if (retval == DBG_HOOK_HANDLED) {
if (cur && (kcb->kprobe_status == KPROBE_HIT_SS)
&& ((unsigned long)&cur->ainsn.api.insn[1] == addr)) {
kprobes_restore_local_irqflag(kcb, regs);
post_kprobe_handler(kcb, regs);
post_kprobe_handler(cur, kcb, regs);
return DBG_HOOK_HANDLED;
}
return retval;
/* not ours, kprobes should ignore it */
return DBG_HOOK_ERROR;
}
static struct break_hook kprobes_break_ss_hook = {