The patch titled
kprobe: kprobe-booster against 2.6.16-rc5 for i386
has been removed from the -mm tree. Its filename is
kprobe-kprobe-booster-against-2616-rc5-for.patch
This patch was dropped because it is obsolete
------------------------------------------------------
Subject: kprobe: kprobe-booster against 2.6.16-rc5 for i386
From: Masami Hiramatsu <hiramatu@xxxxxxxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <hiramatu@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/kprobes.c | 92 ++++++++++++++++++++++++++++++++++-
include/asm-i386/kprobes.h | 6 ++
2 files changed, 96 insertions(+), 2 deletions(-)
diff -puN arch/i386/kernel/kprobes.c~kprobe-kprobe-booster-against-2616-rc5-for arch/i386/kernel/kprobes.c
--- devel/arch/i386/kernel/kprobes.c~kprobe-kprobe-booster-against-2616-rc5-for 2006-02-27 18:40:05.000000000 -0800
+++ devel-akpm/arch/i386/kernel/kprobes.c 2006-02-27 18:40:05.000000000 -0800
@@ -41,6 +41,49 @@ void jprobe_return_end(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
+/* insert a jmp code */
+static inline void set_jmp_op(void *from, void *to)
+{
+ struct __arch_jmp_op {
+ char op;
+ long raddr;
+ } __attribute__((packed)) *jop;
+ jop = (struct __arch_jmp_op *)from;
+ jop->raddr = (long)(to) - ((long)(from) + 5);
+ jop->op = RELATIVEJUMP_INSTRUCTION;
+}
+
+/*
+ * returns non-zero if opcodes can be boosted.
+ */
+static inline int can_boost(kprobe_opcode_t opcode)
+{
+ switch (opcode & 0xf0 ) {
+ case 0x70:
+ return 0; /* can't boost conditional jump */
+ case 0x90:
+ /* can't boost call and pushf */
+ return opcode != 0x9a && opcode != 0x9c;
+ case 0xc0:
+ /* can't boost undefined opcodes and soft-interruptions */
+ return (0xc1 < opcode && opcode < 0xc6) ||
+ (0xc7 < opcode && opcode < 0xcc) || opcode == 0xcf;
+ case 0xd0:
+ /* can boost AA* and XLAT */
+ return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
+ case 0xe0:
+ /* can boost in/out and (may be) jmps */
+ return (0xe3 < opcode && opcode != 0xe8);
+ case 0xf0:
+ /* clear and set flags can be boost */
+ return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
+ default:
+ /* currently, can't boost 2 bytes opcodes */
+ return opcode != 0x0f;
+ }
+}
+
+
/*
* returns non-zero if opcode modifies the interrupt flag.
*/
@@ -65,6 +108,11 @@ int __kprobes arch_prepare_kprobe(struct
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
p->opcode = *p->addr;
+ if (can_boost(p->opcode)) {
+ p->ainsn.boostable = 0;
+ } else {
+ p->ainsn.boostable = -1;
+ }
return 0;
}
@@ -158,6 +206,9 @@ static int __kprobes kprobe_handler(stru
kprobe_opcode_t *addr = NULL;
unsigned long *lp;
struct kprobe_ctlblk *kcb;
+#ifdef CONFIG_PREEMPT
+ unsigned pre_preempt_count = preempt_count();
+#endif /* CONFIG_PREEMPT */
/*
* We don't want to be preempted for the entire
@@ -252,6 +303,21 @@ static int __kprobes kprobe_handler(stru
/* handler has already set things up, so skip ss setup */
return 1;
+ if (p->ainsn.boostable == 1 &&
+#ifdef CONFIG_PREEMPT
+ !(pre_preempt_count()) && /*
+ * This enables booster when the direct
+ * execution path aren't preempted.
+ */
+#endif /* CONFIG_PREEMPT */
+ !p->post_handler && !p->break_handler ) {
+ /* Boost up -- we can execute copied instructions directly */
+ reset_current_kprobe();
+ regs->eip = (unsigned long)p->ainsn.insn;
+ preempt_enable_no_resched();
+ return 1;
+ }
+
ss_probe:
prepare_singlestep(p, regs);
kcb->kprobe_status = KPROBE_HIT_SS;
@@ -357,6 +423,8 @@ int __kprobes trampoline_probe_handler(s
* 2) If the single-stepped instruction was a call, the return address
* that is atop the stack is the address following the copied instruction.
* We need to make it the address following the original instruction.
+ *
+ * This function also checks instruction size for preparing direct execution.
*/
static void __kprobes resume_execution(struct kprobe *p,
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
@@ -377,6 +445,7 @@ static void __kprobes resume_execution(s
case 0xca:
case 0xea: /* jmp absolute -- eip is correct */
/* eip is already adjusted, no more changes required */
+ p->ainsn.boostable = 1;
goto no_change;
case 0xe8: /* call relative - Fix return addr */
*tos = orig_eip + (*tos - copy_eip);
@@ -384,18 +453,37 @@ static void __kprobes resume_execution(s
case 0xff:
if ((p->ainsn.insn[1] & 0x30) == 0x10) {
/* call absolute, indirect */
- /* Fix return addr; eip is correct. */
+ /*
+ * Fix return addr; eip is correct.
+ * But this is not boostable
+ */
*tos = orig_eip + (*tos - copy_eip);
goto no_change;
} else if (((p->ainsn.insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */
((p->ainsn.insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */
- /* eip is correct. */
+ /* eip is correct. And this is boostable */
+ p->ainsn.boostable = 1;
goto no_change;
}
default:
break;
}
+ if (p->ainsn.boostable == 0) {
+ if ((regs->eip > copy_eip) &&
+ (regs->eip - copy_eip) + 5 < MAX_INSN_SIZE) {
+ /*
+ * These instructions can be executed directly if it
+ * jumps back to correct address.
+ */
+ set_jmp_op((void *)regs->eip,
+ (void *)orig_eip + (regs->eip - copy_eip));
+ p->ainsn.boostable = 1;
+ } else {
+ p->ainsn.boostable = -1;
+ }
+ }
+
regs->eip = orig_eip + (regs->eip - copy_eip);
no_change:
diff -puN include/asm-i386/kprobes.h~kprobe-kprobe-booster-against-2616-rc5-for include/asm-i386/kprobes.h
--- devel/include/asm-i386/kprobes.h~kprobe-kprobe-booster-against-2616-rc5-for 2006-02-27 18:40:05.000000000 -0800
+++ devel-akpm/include/asm-i386/kprobes.h 2006-02-27 18:40:05.000000000 -0800
@@ -34,6 +34,7 @@ struct pt_regs;
typedef u8 kprobe_opcode_t;
#define BREAKPOINT_INSTRUCTION 0xcc
+#define RELATIVEJUMP_INSTRUCTION 0xe9
#define MAX_INSN_SIZE 16
#define MAX_STACK_SIZE 64
#define MIN_STACK_SIZE(ADDR) (((MAX_STACK_SIZE) < \
@@ -51,6 +52,11 @@ void kretprobe_trampoline(void);
struct arch_specific_insn {
/* copy of the original instruction */
kprobe_opcode_t *insn;
+ /*
+ * If this flag is not 0, this kprobe can be boost when its
+ * post_handler and break_handler is not set.
+ */
+ int boostable;
};
struct prev_kprobe {
_
Patches currently in -mm which might be from hiramatu@xxxxxxxxxxxxxxxxx are
origin.patch
-
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