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authorMasami Hiramatsu <hiramatu@sdl.hitachi.co.jp>2006-06-26 03:25:19 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 12:58:22 -0400
commit585deacaca3e7bfc63580623f0344d1fa9c47f11 (patch)
treef0006846255aa002c74e97a2c32be6063f8de990
parent6ae7440e6b7a46f4c119c60580aa9384c1b463f7 (diff)
[PATCH] kprobe: boost 2byte-opcodes on i386
Previous kprobe-booster patch has not handled any 2byte opcodes and prefixes. I checked whole IA32 opcode map and classified it. This patch enables kprobe to boost those 2byte opcodes and prefixes. Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com> Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Yumiko Sugita <sugita@sdl.hitachi.co.jp> Cc: Satoshi Oshima <soshima@redhat.com> Cc: Hideo Aoki <haoki@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/i386/kernel/kprobes.c79
1 files changed, 65 insertions, 14 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index 395a9a6dff88..37f86234bdd7 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -57,34 +57,85 @@ static __always_inline void set_jmp_op(void *from, void *to)
57/* 57/*
58 * returns non-zero if opcodes can be boosted. 58 * returns non-zero if opcodes can be boosted.
59 */ 59 */
60static __always_inline int can_boost(kprobe_opcode_t opcode) 60static __always_inline int can_boost(kprobe_opcode_t *opcodes)
61{ 61{
62 switch (opcode & 0xf0 ) { 62#define W(row,b0,b1,b2,b3,b4,b5,b6,b7,b8,b9,ba,bb,bc,bd,be,bf) \
63 (((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
64 (b4##UL << 0x4)|(b5##UL << 0x5)|(b6##UL << 0x6)|(b7##UL << 0x7) | \
65 (b8##UL << 0x8)|(b9##UL << 0x9)|(ba##UL << 0xa)|(bb##UL << 0xb) | \
66 (bc##UL << 0xc)|(bd##UL << 0xd)|(be##UL << 0xe)|(bf##UL << 0xf)) \
67 << (row % 32))
68 /*
69 * Undefined/reserved opcodes, conditional jump, Opcode Extension
70 * Groups, and some special opcodes can not be boost.
71 */
72 static const unsigned long twobyte_is_boostable[256 / 32] = {
73 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
74 /* ------------------------------- */
75 W(0x00, 0,0,1,1,0,0,1,0,1,1,0,0,0,0,0,0)| /* 00 */
76 W(0x10, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 10 */
77 W(0x20, 1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0)| /* 20 */
78 W(0x30, 0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 30 */
79 W(0x40, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)| /* 40 */
80 W(0x50, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0), /* 50 */
81 W(0x60, 1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1)| /* 60 */
82 W(0x70, 0,0,0,0,1,1,1,1,0,0,0,0,0,0,1,1), /* 70 */
83 W(0x80, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)| /* 80 */
84 W(0x90, 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1), /* 90 */
85 W(0xa0, 1,1,0,1,1,1,0,0,1,1,0,1,1,1,0,1)| /* a0 */
86 W(0xb0, 1,1,1,1,1,1,1,1,0,0,0,1,1,1,1,1), /* b0 */
87 W(0xc0, 1,1,0,0,0,0,0,0,1,1,1,1,1,1,1,1)| /* c0 */
88 W(0xd0, 0,1,1,1,0,1,0,0,1,1,0,1,1,1,0,1), /* d0 */
89 W(0xe0, 0,1,1,0,0,1,0,0,1,1,0,1,1,1,0,1)| /* e0 */
90 W(0xf0, 0,1,1,1,0,1,0,0,1,1,1,0,1,1,1,0) /* f0 */
91 /* ------------------------------- */
92 /* 0 1 2 3 4 5 6 7 8 9 a b c d e f */
93 };
94#undef W
95 kprobe_opcode_t opcode;
96 kprobe_opcode_t *orig_opcodes = opcodes;
97retry:
98 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
99 return 0;
100 opcode = *(opcodes++);
101
102 /* 2nd-byte opcode */
103 if (opcode == 0x0f) {
104 if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
105 return 0;
106 return test_bit(*opcodes, twobyte_is_boostable);
107 }
108
109 switch (opcode & 0xf0) {
110 case 0x60:
111 if (0x63 < opcode && opcode < 0x67)
112 goto retry; /* prefixes */
113 /* can't boost Address-size override and bound */
114 return (opcode != 0x62 && opcode != 0x67);
63 case 0x70: 115 case 0x70:
64 return 0; /* can't boost conditional jump */ 116 return 0; /* can't boost conditional jump */
65 case 0x90:
66 /* can't boost call and pushf */
67 return opcode != 0x9a && opcode != 0x9c;
68 case 0xc0: 117 case 0xc0:
69 /* can't boost undefined opcodes and soft-interruptions */ 118 /* can't boost software-interruptions */
70 return (0xc1 < opcode && opcode < 0xc6) || 119 return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf;
71 (0xc7 < opcode && opcode < 0xcc) || opcode == 0xcf;
72 case 0xd0: 120 case 0xd0:
73 /* can boost AA* and XLAT */ 121 /* can boost AA* and XLAT */
74 return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7); 122 return (opcode == 0xd4 || opcode == 0xd5 || opcode == 0xd7);
75 case 0xe0: 123 case 0xe0:
76 /* can boost in/out and (may be) jmps */ 124 /* can boost in/out and absolute jmps */
77 return (0xe3 < opcode && opcode != 0xe8); 125 return ((opcode & 0x04) || opcode == 0xea);
78 case 0xf0: 126 case 0xf0:
127 if ((opcode & 0x0c) == 0 && opcode != 0xf1)
128 goto retry; /* lock/rep(ne) prefix */
79 /* clear and set flags can be boost */ 129 /* clear and set flags can be boost */
80 return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe)); 130 return (opcode == 0xf5 || (0xf7 < opcode && opcode < 0xfe));
81 default: 131 default:
82 /* currently, can't boost 2 bytes opcodes */ 132 if (opcode == 0x26 || opcode == 0x36 || opcode == 0x3e)
83 return opcode != 0x0f; 133 goto retry; /* prefixes */
134 /* can't boost CS override and call */
135 return (opcode != 0x2e && opcode != 0x9a);
84 } 136 }
85} 137}
86 138
87
88/* 139/*
89 * returns non-zero if opcode modifies the interrupt flag. 140 * returns non-zero if opcode modifies the interrupt flag.
90 */ 141 */
@@ -109,7 +160,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
109 160
110 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t)); 161 memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
111 p->opcode = *p->addr; 162 p->opcode = *p->addr;
112 if (can_boost(p->opcode)) { 163 if (can_boost(p->addr)) {
113 p->ainsn.boostable = 0; 164 p->ainsn.boostable = 0;
114 } else { 165 } else {
115 p->ainsn.boostable = -1; 166 p->ainsn.boostable = -1;