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Message-Id: <1197671876.898.67.camel@brick>
Date: Fri, 14 Dec 2007 14:37:56 -0800
From: Harvey Harrison <harvey.harrison@...il.com>
To: Ingo Molnar <mingo@...e.hu>
Cc: "H. Peter Anvin" <hpa@...or.com>,
LKML <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH] x86: Further reduce kprobes_{32|64}.c
Add X86_32 only static function to X86_64 file and add static
X86_64 functions to X86_32 file. Produces compile warnings
about defined but not used functions for now, will deal with
these in final unified file.
Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
arch/x86/kernel/kprobes_32.c | 85 ++++++++++++++++++++++++++++++++++++++++-
arch/x86/kernel/kprobes_64.c | 61 ++++++++++++++++++++++++++++++
2 files changed, 143 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
index 3e45b51..cebc077 100644
--- a/arch/x86/kernel/kprobes_32.c
+++ b/arch/x86/kernel/kprobes_32.c
@@ -37,13 +37,14 @@
#include <asm/alternative.h>
void jprobe_return_end(void);
+static void __kprobes arch_copy_kprobe(struct kprobe *p);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
struct kretprobe_blackpoint kretprobe_blacklist[] = {
{"__switch_to", }, /* This function switches only current task, but
- doesn't switch kernel stack.*/
+ doesn't switch kernel stack.*/
{NULL, NULL} /* Terminator */
};
const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
@@ -156,7 +157,7 @@ twobyte_has_modrm[256 / sizeof(unsigned long)] = {
#undef RF
/* insert a jmp code */
-static __always_inline void set_jmp_op(void *from, void *to)
+static inline void set_jmp_op(void *from, void *to)
{
struct __arch_jmp_op {
char op;
@@ -170,7 +171,7 @@ static __always_inline void set_jmp_op(void *from, void *to)
/*
* returns non-zero if opcodes can be boosted.
*/
-static __always_inline int can_boost(kprobe_opcode_t *opcodes)
+static inline int can_boost(kprobe_opcode_t *opcodes)
{
kprobe_opcode_t opcode;
kprobe_opcode_t *orig_opcodes = opcodes;
@@ -248,6 +249,84 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}
+/*
+ * Determine if the instruction uses the %rip-relative addressing mode.
+ * If it does, return the address of the 32-bit displacement word.
+ * If not, return null.
+ */
+static s32 __kprobes *is_riprel(u8 *insn)
+{
+ int need_modrm;
+
+ /* Skip legacy instruction prefixes. */
+ while (1) {
+ switch (*insn) {
+ case 0x66:
+ case 0x67:
+ case 0x2e:
+ case 0x3e:
+ case 0x26:
+ case 0x64:
+ case 0x65:
+ case 0x36:
+ case 0xf0:
+ case 0xf3:
+ case 0xf2:
+ ++insn;
+ continue;
+ }
+ break;
+ }
+
+ /* Skip REX instruction prefix. */
+ if ((*insn & 0xf0) == 0x40)
+ ++insn;
+
+ if (*insn == 0x0f) { /* Two-byte opcode. */
+ ++insn;
+ need_modrm = test_bit(*insn, twobyte_has_modrm);
+ } else { /* One-byte opcode. */
+ need_modrm = test_bit(*insn, onebyte_has_modrm);
+ }
+
+ if (need_modrm) {
+ u8 modrm = *++insn;
+ if ((modrm & 0xc7) == 0x05) { /* %rip+disp32 addressing mode */
+ /* Displacement follows ModRM byte. */
+ return (s32 *) ++insn;
+ }
+ }
+
+ /* No %rip-relative addressing mode here. */
+ return NULL;
+}
+
+static void __kprobes arch_copy_kprobe(struct kprobe *p)
+{
+ s32 *ripdisp;
+ memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
+ ripdisp = is_riprel(p->ainsn.insn);
+ if (ripdisp) {
+ /*
+ * The copied instruction uses the %rip-relative
+ * addressing mode. Adjust the displacement for the
+ * difference between the original location of this
+ * instruction and the location of the copy that will
+ * actually be run. The tricky bit here is making sure
+ * that the sign extension happens correctly in this
+ * calculation, since we need a signed 32-bit result to
+ * be sign-extended to 64 bits when it's added to the
+ * %rip value and yield the same 64-bit result that the
+ * sign-extension of the original signed 32-bit
+ * displacement would have given.
+ */
+ s64 disp = (u8 *) p->addr + *ripdisp - (u8 *) p->ainsn.insn;
+ BUG_ON((s64) (s32) disp != disp); /* Sanity check. */
+ *ripdisp = disp;
+ }
+ p->opcode = *p->addr;
+}
+
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c
index 54b2279..6f62a4a 100644
--- a/arch/x86/kernel/kprobes_64.c
+++ b/arch/x86/kernel/kprobes_64.c
@@ -162,6 +162,67 @@ twobyte_has_modrm[256 / sizeof(unsigned long)] = {
#undef R4
#undef RF
+/* 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 *opcodes)
+{
+ kprobe_opcode_t opcode;
+ kprobe_opcode_t *orig_opcodes = opcodes;
+retry:
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE)
+ return 0;
+ opcode = *(opcodes++);
+
+ /* 2nd-byte opcode */
+ if (opcode == 0x0f) {
+ if (opcodes - orig_opcodes > MAX_INSN_SIZE)
+ return 0;
+ return test_bit(*opcodes, twobyte_is_boostable);
+ }
+
+ switch (opcode & 0xf0) {
+ case 0x60:
+ if (0x63 < opcode && opcode < 0x67)
+ goto retry; /* prefixes */
+ /* can't boost Address-size override and bound */
+ return (opcode != 0x62 && opcode != 0x67);
+ case 0x70:
+ return 0; /* can't boost conditional jump */
+ case 0xc0:
+ /* can't boost software-interruptions */
+ return (0xc1 < 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 absolute jmps */
+ return ((opcode & 0x04) || opcode == 0xea);
+ case 0xf0:
+ if ((opcode & 0x0c) == 0 && opcode != 0xf1)
+ goto retry; /* lock/rep(ne) prefix */
+ /* clear and set flags can be boost */
+ return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
+ default:
+ if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
+ goto retry; /* prefixes */
+ /* can't boost CS override and call */
+ return (opcode != 0x2e && opcode != 0x9a);
+ }
+}
+
/*
* returns non-zero if opcode modifies the interrupt flag.
*/
--
1.5.4.rc0.1083.gf568
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