kprobes: Cleanup fix_riprel() using insn decoder on x86

Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using the new x86
instruction decoder instead of using comparisons with raw ad hoc numeric
opcodes.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Przemysław Pawełczyk <przemyslaw@pawelczyk.it>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
LKML-Reference: <20090813203436.31965.34374.stgit@localhost.localdomain>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index aa15f3e..16ae961 100644 (file)
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -108,50 +108,6 @@ static const u32 twobyte_is_boostable[256 / 32] = {
        /*      -----------------------------------------------         */
        /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
 };
-static const u32 onebyte_has_modrm[256 / 32] = {
-       /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-       /*      -----------------------------------------------         */
-       W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
-       W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
-       W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
-       W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
-       W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
-       W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
-       W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
-       W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
-       W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
-       W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
-       W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
-       W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
-       W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
-       W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
-       W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
-       W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1)   /* f0 */
-       /*      -----------------------------------------------         */
-       /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
-static const u32 twobyte_has_modrm[256 / 32] = {
-       /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-       /*      -----------------------------------------------         */
-       W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
-       W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
-       W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
-       W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
-       W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
-       W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
-       W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
-       W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
-       W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
-       W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
-       W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
-       W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
-       W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
-       W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
-       W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
-       W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)   /* ff */
-       /*      -----------------------------------------------         */
-       /*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
 #undef W
 
 struct kretprobe_blackpoint kretprobe_blacklist[] = {
@@ -348,68 +304,30 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
 static void __kprobes fix_riprel(struct kprobe *p)
 {
 #ifdef CONFIG_X86_64
-       u8 *insn = p->ainsn.insn;
-       s64 disp;
-       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;
-       }
+       struct insn insn;
+       kernel_insn_init(&insn, p->ainsn.insn);
 
-       /* Skip REX instruction prefix.  */
-       if (is_REX_prefix(insn))
-               ++insn;
-
-       if (*insn == 0x0f) {
-               /* Two-byte opcode.  */
-               ++insn;
-               need_modrm = test_bit(*insn,
-                                     (unsigned long *)twobyte_has_modrm);
-       } else
-               /* One-byte opcode.  */
-               need_modrm = test_bit(*insn,
-                                     (unsigned long *)onebyte_has_modrm);
-
-       if (need_modrm) {
-               u8 modrm = *++insn;
-               if ((modrm & 0xc7) == 0x05) {
-                       /* %rip+disp32 addressing mode */
-                       /* Displacement follows ModRM byte.  */
-                       ++insn;
-                       /*
-                        * 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.
-                        */
-                       disp = (u8 *) p->addr + *((s32 *) insn) -
-                              (u8 *) p->ainsn.insn;
-                       BUG_ON((s64) (s32) disp != disp); /* Sanity check.  */
-                       *(s32 *)insn = (s32) disp;
-               }
+       if (insn_rip_relative(&insn)) {
+               s64 newdisp;
+               u8 *disp;
+               insn_get_displacement(&insn);
+               /*
+                * 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.
+                */
+               newdisp = (u8 *) p->addr + (s64) insn.displacement.value -
+                         (u8 *) p->ainsn.insn;
+               BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check.  */
+               disp = (u8 *) p->ainsn.insn + insn_offset_displacement(&insn);
+               *(s32 *) disp = (s32) newdisp;
        }
 #endif
 }