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-rw-r--r--tools/objtool/arch/x86/decode.c91
1 files changed, 40 insertions, 51 deletions
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index a36c2eba64e7..0e8c8ec4fd4e 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -86,8 +86,8 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
struct insn insn;
int x86_64, sign;
unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0,
- modrm = 0, modrm_mod = 0, modrm_rm = 0, modrm_reg = 0,
- sib = 0;
+ rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0,
+ modrm_reg = 0, sib = 0;
x86_64 = is_x86_64(elf);
if (x86_64 == -1)
@@ -114,6 +114,7 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
rex = insn.rex_prefix.bytes[0];
rex_w = X86_REX_W(rex) >> 3;
rex_r = X86_REX_R(rex) >> 2;
+ rex_x = X86_REX_X(rex) >> 1;
rex_b = X86_REX_B(rex);
}
@@ -217,6 +218,18 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
op->dest.reg = CFI_BP;
break;
}
+
+ if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {
+
+ /* mov reg, %rsp */
+ *type = INSN_STACK;
+ op->src.type = OP_SRC_REG;
+ op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = CFI_SP;
+ break;
+ }
+
/* fallthrough */
case 0x88:
if (!rex_b &&
@@ -269,56 +282,28 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
break;
case 0x8d:
- if (rex == 0x48 && modrm == 0x65) {
+ if (sib == 0x24 && rex_w && !rex_b && !rex_x) {
- /* lea -disp(%rbp), %rsp */
- *type = INSN_STACK;
- op->src.type = OP_SRC_ADD;
- op->src.reg = CFI_BP;
- op->src.offset = insn.displacement.value;
- op->dest.type = OP_DEST_REG;
- op->dest.reg = CFI_SP;
- break;
- }
-
- if (rex == 0x4c && modrm == 0x54 && sib == 0x24 &&
- insn.displacement.value == 8) {
-
- /*
- * lea 0x8(%rsp), %r10
- *
- * Here r10 is the "drap" pointer, used as a stack
- * pointer helper when the stack gets realigned.
- */
+ /* lea disp(%rsp), reg */
*type = INSN_STACK;
op->src.type = OP_SRC_ADD;
op->src.reg = CFI_SP;
- op->src.offset = 8;
+ op->src.offset = insn.displacement.value;
op->dest.type = OP_DEST_REG;
- op->dest.reg = CFI_R10;
- break;
- }
+ op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
- if (rex == 0x4c && modrm == 0x6c && sib == 0x24 &&
- insn.displacement.value == 16) {
+ } else if (rex == 0x48 && modrm == 0x65) {
- /*
- * lea 0x10(%rsp), %r13
- *
- * Here r13 is the "drap" pointer, used as a stack
- * pointer helper when the stack gets realigned.
- */
+ /* lea disp(%rbp), %rsp */
*type = INSN_STACK;
op->src.type = OP_SRC_ADD;
- op->src.reg = CFI_SP;
- op->src.offset = 16;
+ op->src.reg = CFI_BP;
+ op->src.offset = insn.displacement.value;
op->dest.type = OP_DEST_REG;
- op->dest.reg = CFI_R13;
- break;
- }
+ op->dest.reg = CFI_SP;
- if (rex == 0x49 && modrm == 0x62 &&
- insn.displacement.value == -8) {
+ } else if (rex == 0x49 && modrm == 0x62 &&
+ insn.displacement.value == -8) {
/*
* lea -0x8(%r10), %rsp
@@ -332,11 +317,9 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
op->src.offset = -8;
op->dest.type = OP_DEST_REG;
op->dest.reg = CFI_SP;
- break;
- }
- if (rex == 0x49 && modrm == 0x65 &&
- insn.displacement.value == -16) {
+ } else if (rex == 0x49 && modrm == 0x65 &&
+ insn.displacement.value == -16) {
/*
* lea -0x10(%r13), %rsp
@@ -350,7 +333,6 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
op->src.offset = -16;
op->dest.type = OP_DEST_REG;
op->dest.reg = CFI_SP;
- break;
}
break;
@@ -382,20 +364,27 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
case 0x0f:
- if (op2 >= 0x80 && op2 <= 0x8f)
+ if (op2 >= 0x80 && op2 <= 0x8f) {
+
*type = INSN_JUMP_CONDITIONAL;
- else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
- op2 == 0x35)
+
+ } else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
+ op2 == 0x35) {
/* sysenter, sysret */
*type = INSN_CONTEXT_SWITCH;
- else if (op2 == 0x0d || op2 == 0x1f)
+ } else if (op2 == 0x0b || op2 == 0xb9) {
+
+ /* ud2 */
+ *type = INSN_BUG;
+
+ } else if (op2 == 0x0d || op2 == 0x1f) {
/* nopl/nopw */
*type = INSN_NOP;
- else if (op2 == 0xa0 || op2 == 0xa8) {
+ } else if (op2 == 0xa0 || op2 == 0xa8) {
/* push fs/gs */
*type = INSN_STACK;