[RFC PATCH -tip v5 14/27] kprobes/x86: Don't call ->break_handler() in x86 kprobes

From: Masami Hiramatsu
Date: Mon Jun 04 2018 - 11:55:46 EST


Don't call ->break_handler() and remove break_handler
related code since that was only used by jprobe which
got removed.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
arch/x86/include/asm/kprobes.h | 2 +-
arch/x86/kernel/kprobes/common.h | 10 ----------
arch/x86/kernel/kprobes/core.c | 7 -------
arch/x86/kernel/kprobes/ftrace.c | 16 ++--------------
4 files changed, 3 insertions(+), 32 deletions(-)

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 06782c2efa04..c8cec1b39b88 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -78,7 +78,7 @@ struct arch_specific_insn {
* boostable = true: This instruction has been boosted: we have
* added a relative jump after the instruction copy in insn,
* so no single-step and fixup are needed (unless there's
- * a post_handler or break_handler).
+ * a post_handler).
*/
bool boostable;
bool if_modifier;
diff --git a/arch/x86/kernel/kprobes/common.h b/arch/x86/kernel/kprobes/common.h
index ae38dccf0c8f..2b949f4fd4d8 100644
--- a/arch/x86/kernel/kprobes/common.h
+++ b/arch/x86/kernel/kprobes/common.h
@@ -105,14 +105,4 @@ static inline unsigned long __recover_optprobed_insn(kprobe_opcode_t *buf, unsig
}
#endif

-#ifdef CONFIG_KPROBES_ON_FTRACE
-extern int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb);
-#else
-static inline int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- return 0;
-}
-#endif
#endif
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 1b2d1acba810..0ac16a0d93e5 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -709,13 +709,6 @@ int kprobe_int3_handler(struct pt_regs *regs)
regs->ip = (unsigned long)addr;
preempt_enable_no_resched();
return 1;
- } else if (kprobe_running()) {
- p = __this_cpu_read(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs)) {
- if (!skip_singlestep(p, regs, kcb))
- setup_singlestep(p, regs, kcb, 0);
- return 1;
- }
} /* else: not a kprobe fault; let the kernel handle it */

preempt_enable_no_resched();
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index 8dc0161cec8f..c8696f2a583f 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -26,7 +26,7 @@
#include "common.h"

static nokprobe_inline
-void __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+void skip_singlestep(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb, unsigned long orig_ip)
{
/*
@@ -43,18 +43,6 @@ void __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
regs->ip = orig_ip;
}

-int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
-{
- if (kprobe_ftrace(p)) {
- __skip_singlestep(p, regs, kcb, 0);
- preempt_enable_no_resched();
- return 1;
- }
- return 0;
-}
-NOKPROBE_SYMBOL(skip_singlestep);
-
/* Ftrace callback handler for kprobes -- called under preepmt disabed */
void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *ops, struct pt_regs *regs)
@@ -80,7 +68,7 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
__this_cpu_write(current_kprobe, p);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
if (!p->pre_handler || !p->pre_handler(p, regs)) {
- __skip_singlestep(p, regs, kcb, orig_ip);
+ skip_singlestep(p, regs, kcb, orig_ip);
preempt_enable_no_resched();
}
/*