From 63474dc4ac7ed3848a4786b9592dd061901f606d Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Tue, 6 Mar 2018 17:58:15 -0600 Subject: objtool: Fix 32-bit build Fix the objtool build when cross-compiling a 64-bit kernel on a 32-bit host. This also simplifies read_retpoline_hints() a bit and makes its implementation similar to most of the other annotation reading functions. Reported-by: Sven Joachim Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: b5bc2231b8ad ("objtool: Add retpoline validation") Link: http://lkml.kernel.org/r/2ca46c636c23aa9c9d57d53c75de4ee3ddf7a7df.1520380691.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 27 +++++++-------------------- 1 file changed, 7 insertions(+), 20 deletions(-) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 46c1d239cc1b..92b6a2c21631 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1116,42 +1116,29 @@ static int read_unwind_hints(struct objtool_file *file) static int read_retpoline_hints(struct objtool_file *file) { - struct section *sec, *relasec; + struct section *sec; struct instruction *insn; struct rela *rela; - int i; - sec = find_section_by_name(file->elf, ".discard.retpoline_safe"); + sec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe"); if (!sec) return 0; - relasec = sec->rela; - if (!relasec) { - WARN("missing .rela.discard.retpoline_safe section"); - return -1; - } - - if (sec->len % sizeof(unsigned long)) { - WARN("retpoline_safe size mismatch: %d %ld", sec->len, sizeof(unsigned long)); - return -1; - } - - for (i = 0; i < sec->len / sizeof(unsigned long); i++) { - rela = find_rela_by_dest(sec, i * sizeof(unsigned long)); - if (!rela) { - WARN("can't find rela for retpoline_safe[%d]", i); + list_for_each_entry(rela, &sec->rela_list, list) { + if (rela->sym->type != STT_SECTION) { + WARN("unexpected relocation symbol type in %s", sec->name); return -1; } insn = find_insn(file, rela->sym->sec, rela->addend); if (!insn) { - WARN("can't find insn for retpoline_safe[%d]", i); + WARN("bad .discard.retpoline_safe entry"); return -1; } if (insn->type != INSN_JUMP_DYNAMIC && insn->type != INSN_CALL_DYNAMIC) { - WARN_FUNC("retpoline_safe hint not a indirect jump/call", + WARN_FUNC("retpoline_safe hint not an indirect jump/call", insn->sec, insn->offset); return -1; } -- cgit v1.2.3 From 3c1f05835cbf9fdfe60b81c718d82ceb94b6c55e Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 22 Mar 2018 13:00:37 -0500 Subject: objtool: Add Clang support Since the ORC unwinder was made the default on x86_64, Clang-built defconfig kernels have triggered some new objtool warnings: drivers/gpu/drm/i915/i915_gpu_error.o: warning: objtool: i915_error_printf()+0x6c: return with modified stack frame drivers/gpu/drm/i915/intel_display.o: warning: objtool: pipe_config_err()+0xa6: return with modified stack frame The problem is that objtool has never seen clang-built binaries before. Shockingly enough, objtool is apparently able to follow the code flow mostly fine, except for one instruction sequence. Instead of a LEAVE instruction, clang restores RSP and RBP the long way: 67c: 48 89 ec mov %rbp,%rsp 67f: 5d pop %rbp Teach objtool about this new code sequence. Reported-and-test-by: Matthias Kaehlcke Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Matthias Kaehlcke Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/fce88ce81c356eedcae7f00ed349cfaddb3363cc.1521741586.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar --- tools/objtool/check.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'tools/objtool/check.c') diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 92b6a2c21631..5409f6f6c48d 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1386,6 +1386,17 @@ static int update_insn_state(struct instruction *insn, struct insn_state *state) state->vals[op->dest.reg].offset = -state->stack_size; } + else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP && + cfa->base == CFI_BP) { + + /* + * mov %rbp, %rsp + * + * Restore the original stack pointer (Clang). + */ + state->stack_size = -state->regs[CFI_BP].offset; + } + else if (op->dest.reg == cfa->base) { /* mov %reg, %rsp */ -- cgit v1.2.3