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-rw-r--r--tools/objtool/arch/x86/decode.c27
-rw-r--r--tools/objtool/arch/x86/special.c2
-rw-r--r--tools/objtool/check.c61
-rw-r--r--tools/objtool/include/objtool/arch.h3
4 files changed, 76 insertions, 17 deletions
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 33d861c04ebd..687c5eafb49a 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -189,6 +189,15 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
op2 = ins.opcode.bytes[1];
op3 = ins.opcode.bytes[2];
+ /*
+ * XXX hack, decoder is buggered and thinks 0xea is 7 bytes long.
+ */
+ if (op1 == 0xea) {
+ insn->len = 1;
+ insn->type = INSN_BUG;
+ return 0;
+ }
+
if (ins.rex_prefix.nbytes) {
rex = ins.rex_prefix.bytes[0];
rex_w = X86_REX_W(rex) >> 3;
@@ -522,7 +531,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
case INAT_PFX_REPNE:
if (modrm == 0xca)
/* eretu/erets */
- insn->type = INSN_CONTEXT_SWITCH;
+ insn->type = INSN_SYSRET;
break;
default:
if (modrm == 0xca)
@@ -535,11 +544,15 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
insn->type = INSN_JUMP_CONDITIONAL;
- } else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
- op2 == 0x35) {
+ } else if (op2 == 0x05 || op2 == 0x34) {
+
+ /* syscall, sysenter */
+ insn->type = INSN_SYSCALL;
+
+ } else if (op2 == 0x07 || op2 == 0x35) {
- /* sysenter, sysret */
- insn->type = INSN_CONTEXT_SWITCH;
+ /* sysret, sysexit */
+ insn->type = INSN_SYSRET;
} else if (op2 == 0x0b || op2 == 0xb9) {
@@ -676,7 +689,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
case 0xca: /* retf */
case 0xcb: /* retf */
- insn->type = INSN_CONTEXT_SWITCH;
+ insn->type = INSN_SYSRET;
break;
case 0xe0: /* loopne */
@@ -721,7 +734,7 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
} else if (modrm_reg == 5) {
/* jmpf */
- insn->type = INSN_CONTEXT_SWITCH;
+ insn->type = INSN_SYSRET;
} else if (modrm_reg == 6) {
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 403e587676f1..06ca4a2659a4 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -126,7 +126,7 @@ struct reloc *arch_find_switch_table(struct objtool_file *file,
* indicates a rare GCC quirk/bug which can leave dead
* code behind.
*/
- if (reloc_type(text_reloc) == R_X86_64_PC32) {
+ if (!file->ignore_unreachables && reloc_type(text_reloc) == R_X86_64_PC32) {
WARN_INSN(insn, "ignoring unreachables due to jump table quirk");
file->ignore_unreachables = true;
}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 4a1f6c3169b3..b21b12ec88d9 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -225,7 +225,9 @@ static bool is_rust_noreturn(const struct symbol *func)
str_ends_with(func->name, "_4core9panicking14panic_nounwind") ||
str_ends_with(func->name, "_4core9panicking18panic_bounds_check") ||
str_ends_with(func->name, "_4core9panicking19assert_failed_inner") ||
+ str_ends_with(func->name, "_4core9panicking30panic_null_pointer_dereference") ||
str_ends_with(func->name, "_4core9panicking36panic_misaligned_pointer_dereference") ||
+ str_ends_with(func->name, "_7___rustc17rust_begin_unwind") ||
strstr(func->name, "_4core9panicking13assert_failed") ||
strstr(func->name, "_4core9panicking11panic_const24panic_const_") ||
(strstr(func->name, "_4core5slice5index24slice_") &&
@@ -3505,6 +3507,34 @@ next_orig:
return next_insn_same_sec(file, alt_group->orig_group->last_insn);
}
+static bool skip_alt_group(struct instruction *insn)
+{
+ struct instruction *alt_insn = insn->alts ? insn->alts->insn : NULL;
+
+ /* ANNOTATE_IGNORE_ALTERNATIVE */
+ if (insn->alt_group && insn->alt_group->ignore)
+ return true;
+
+ /*
+ * For NOP patched with CLAC/STAC, only follow the latter to avoid
+ * impossible code paths combining patched CLAC with unpatched STAC
+ * or vice versa.
+ *
+ * ANNOTATE_IGNORE_ALTERNATIVE could have been used here, but Linus
+ * requested not to do that to avoid hurting .s file readability
+ * around CLAC/STAC alternative sites.
+ */
+
+ if (!alt_insn)
+ return false;
+
+ /* Don't override ASM_{CLAC,STAC}_UNSAFE */
+ if (alt_insn->alt_group && alt_insn->alt_group->ignore)
+ return false;
+
+ return alt_insn->type == INSN_CLAC || alt_insn->type == INSN_STAC;
+}
+
/*
* Follow the branch starting at the given instruction, and recursively follow
* any other branches (jumps). Meanwhile, track the frame pointer state at
@@ -3625,7 +3655,7 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
}
}
- if (insn->alt_group && insn->alt_group->ignore)
+ if (skip_alt_group(insn))
return 0;
if (handle_insn_ops(insn, next_insn, &state))
@@ -3684,14 +3714,20 @@ static int validate_branch(struct objtool_file *file, struct symbol *func,
break;
- case INSN_CONTEXT_SWITCH:
- if (func) {
- if (!next_insn || !next_insn->hint) {
- WARN_INSN(insn, "unsupported instruction in callable function");
- return 1;
- }
- break;
+ case INSN_SYSCALL:
+ if (func && (!next_insn || !next_insn->hint)) {
+ WARN_INSN(insn, "unsupported instruction in callable function");
+ return 1;
+ }
+
+ break;
+
+ case INSN_SYSRET:
+ if (func && (!next_insn || !next_insn->hint)) {
+ WARN_INSN(insn, "unsupported instruction in callable function");
+ return 1;
}
+
return 0;
case INSN_STAC:
@@ -3886,6 +3922,12 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
WARN_INSN(insn, "RET before UNTRAIN");
return 1;
+ case INSN_SYSCALL:
+ break;
+
+ case INSN_SYSRET:
+ return 0;
+
case INSN_NOP:
if (insn->retpoline_safe)
return 0;
@@ -3895,6 +3937,9 @@ static int validate_unret(struct objtool_file *file, struct instruction *insn)
break;
}
+ if (insn->dead_end)
+ return 0;
+
if (!next) {
WARN_INSN(insn, "teh end!");
return 1;
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index 089a1acc48a8..01ef6f415adf 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -19,7 +19,8 @@ enum insn_type {
INSN_CALL,
INSN_CALL_DYNAMIC,
INSN_RETURN,
- INSN_CONTEXT_SWITCH,
+ INSN_SYSCALL,
+ INSN_SYSRET,
INSN_BUG,
INSN_NOP,
INSN_STAC,
generated by cgit (git 2.34.1) at 2025-05-18 17:07:46 +0000