summaryrefslogtreecommitdiff
path: root/tools
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-24 12:33:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-24 12:33:58 -0700
commita141fd55f26231b5a17f74e504c56d44c3e62e5d (patch)
tree5859552ca39fec7b0808794889d03dff2106c145 /tools
parent16528a3fed5de9228de0dd7a9a4de3f3eb4c982a (diff)
parentf5caf621ee357279e759c0911daf6d55c7d36f03 (diff)
downloadlwn-a141fd55f26231b5a17f74e504c56d44c3e62e5d.tar.gz
lwn-a141fd55f26231b5a17f74e504c56d44c3e62e5d.zip
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar: "Another round of CR3/PCID related fixes (I think this addresses all but one of the known problems with PCID support), an objtool fix plus a Clang fix that (finally) solves all Clang quirks to build a bootable x86 kernel as-is" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/asm: Fix inline asm call constraints for Clang objtool: Handle another GCC stack pointer adjustment bug x86/mm/32: Load a sane CR3 before cpu_init() on secondary CPUs x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier x86/mm/64: Stop using CR3.PCID == 0 in ASID-aware code x86/mm: Factor out CR3-building code
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/Documentation/stack-validation.txt6
-rw-r--r--tools/objtool/arch/x86/decode.c6
-rw-r--r--tools/objtool/check.c43
3 files changed, 35 insertions, 20 deletions
diff --git a/tools/objtool/Documentation/stack-validation.txt b/tools/objtool/Documentation/stack-validation.txt
index 6a1af43862df..3995735a878f 100644
--- a/tools/objtool/Documentation/stack-validation.txt
+++ b/tools/objtool/Documentation/stack-validation.txt
@@ -194,10 +194,10 @@ they mean, and suggestions for how to fix them.
If it's a GCC-compiled .c file, the error may be because the function
uses an inline asm() statement which has a "call" instruction. An
asm() statement with a call instruction must declare the use of the
- stack pointer in its output operand. For example, on x86_64:
+ stack pointer in its output operand. On x86_64, this means adding
+ the ASM_CALL_CONSTRAINT as an output constraint:
- register void *__sp asm("rsp");
- asm volatile("call func" : "+r" (__sp));
+ asm volatile("call func" : ASM_CALL_CONSTRAINT);
Otherwise the stack frame may not get created before the call.
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 0e8c8ec4fd4e..0f22768c0d4d 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -208,14 +208,14 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
break;
case 0x89:
- if (rex == 0x48 && modrm == 0xe5) {
+ if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) {
- /* mov %rsp, %rbp */
+ /* mov %rsp, reg */
*type = INSN_STACK;
op->src.type = OP_SRC_REG;
op->src.reg = CFI_SP;
op->dest.type = OP_DEST_REG;
- op->dest.reg = CFI_BP;
+ op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b];
break;
}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index f744617c9946..a0c518ecf085 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1203,24 +1203,39 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state)
switch (op->src.type) {
case OP_SRC_REG:
- if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP) {
+ if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP &&
+ cfa->base == CFI_SP &&
+ regs[CFI_BP].base == CFI_CFA &&
+ regs[CFI_BP].offset == -cfa->offset) {
+
+ /* mov %rsp, %rbp */
+ cfa->base = op->dest.reg;
+ state->bp_scratch = false;
+ }
- if (cfa->base == CFI_SP &&
- regs[CFI_BP].base == CFI_CFA &&
- regs[CFI_BP].offset == -cfa->offset) {
+ else if (op->src.reg == CFI_SP &&
+ op->dest.reg == CFI_BP && state->drap) {
- /* mov %rsp, %rbp */
- cfa->base = op->dest.reg;
- state->bp_scratch = false;
- }
+ /* drap: mov %rsp, %rbp */
+ regs[CFI_BP].base = CFI_BP;
+ regs[CFI_BP].offset = -state->stack_size;
+ state->bp_scratch = false;
+ }
- else if (state->drap) {
+ else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
- /* drap: mov %rsp, %rbp */
- regs[CFI_BP].base = CFI_BP;
- regs[CFI_BP].offset = -state->stack_size;
- state->bp_scratch = false;
- }
+ /*
+ * mov %rsp, %reg
+ *
+ * This is needed for the rare case where GCC
+ * does:
+ *
+ * mov %rsp, %rax
+ * ...
+ * mov %rax, %rsp
+ */
+ state->vals[op->dest.reg].base = CFI_CFA;
+ state->vals[op->dest.reg].offset = -state->stack_size;
}
else if (op->dest.reg == cfa->base) {