diff options
Diffstat (limited to 'recipes-kernel/linux/linux-intel/objtool-fix-segfault-with-clang.patch')
| -rw-r--r-- | recipes-kernel/linux/linux-intel/objtool-fix-segfault-with-clang.patch | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-intel/objtool-fix-segfault-with-clang.patch b/recipes-kernel/linux/linux-intel/objtool-fix-segfault-with-clang.patch new file mode 100644 index 00000000..f4b1374f --- /dev/null +++ b/recipes-kernel/linux/linux-intel/objtool-fix-segfault-with-clang.patch @@ -0,0 +1,150 @@ +From 44f6a7c0755d8dd453c70557e11687bb080a6f21 Mon Sep 17 00:00:00 2001 +From: Josh Poimboeuf <jpoimboe@redhat.com> +Date: Mon, 14 Dec 2020 16:04:20 -0600 +Subject: [PATCH] objtool: Fix seg fault with Clang non-section symbols + +The Clang assembler likes to strip section symbols, which means objtool +can't reference some text code by its section. This confuses objtool +greatly, causing it to seg fault. + +The fix is similar to what was done before, for ORC reloc generation: + + e81e07244325 ("objtool: Support Clang non-section symbols in ORC generation") + +Factor out that code into a common helper and use it for static call +reloc generation as well. + +Reported-by: Arnd Bergmann <arnd@kernel.org> +Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> +Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> +Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> +Reviewed-by: Miroslav Benes <mbenes@suse.cz> +Link: https://github.com/ClangBuiltLinux/linux/issues/1207 +Link: https://lkml.kernel.org/r/ba6b6c0f0dd5acbba66e403955a967d9fdd1726a.1607983452.git.jpoimboe@redhat.com + +Upstream-Status: Backport +Signed-off-by: Anuj Mittal <anuj.mittal@intel.com> +--- + tools/objtool/check.c | 11 +++++++++-- + tools/objtool/elf.c | 26 ++++++++++++++++++++++++++ + tools/objtool/elf.h | 2 ++ + tools/objtool/orc_gen.c | 29 +++++------------------------ + 4 files changed, 42 insertions(+), 26 deletions(-) + +diff --git a/tools/objtool/check.c b/tools/objtool/check.c +index c6ab44543c92a..5f8d3eed78a18 100644 +--- a/tools/objtool/check.c ++++ b/tools/objtool/check.c +@@ -467,13 +467,20 @@ static int create_static_call_sections(struct objtool_file *file) + + /* populate reloc for 'addr' */ + reloc = malloc(sizeof(*reloc)); ++ + if (!reloc) { + perror("malloc"); + return -1; + } + memset(reloc, 0, sizeof(*reloc)); +- reloc->sym = insn->sec->sym; +- reloc->addend = insn->offset; ++ ++ insn_to_reloc_sym_addend(insn->sec, insn->offset, reloc); ++ if (!reloc->sym) { ++ WARN_FUNC("static call tramp: missing containing symbol", ++ insn->sec, insn->offset); ++ return -1; ++ } ++ + reloc->type = R_X86_64_PC32; + reloc->offset = idx * sizeof(struct static_call_site); + reloc->sec = reloc_sec; +diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c +index 4e1d7460574b4..be89c741ba9a0 100644 +--- a/tools/objtool/elf.c ++++ b/tools/objtool/elf.c +@@ -262,6 +262,32 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns + return find_reloc_by_dest_range(elf, sec, offset, 1); + } + ++void insn_to_reloc_sym_addend(struct section *sec, unsigned long offset, ++ struct reloc *reloc) ++{ ++ if (sec->sym) { ++ reloc->sym = sec->sym; ++ reloc->addend = offset; ++ return; ++ } ++ ++ /* ++ * The Clang assembler strips section symbols, so we have to reference ++ * the function symbol instead: ++ */ ++ reloc->sym = find_symbol_containing(sec, offset); ++ if (!reloc->sym) { ++ /* ++ * Hack alert. This happens when we need to reference the NOP ++ * pad insn immediately after the function. ++ */ ++ reloc->sym = find_symbol_containing(sec, offset - 1); ++ } ++ ++ if (reloc->sym) ++ reloc->addend = offset - reloc->sym->offset; ++} ++ + static int read_sections(struct elf *elf) + { + Elf_Scn *s = NULL; +diff --git a/tools/objtool/elf.h b/tools/objtool/elf.h +index 807f8c6700974..e6890cc70a25b 100644 +--- a/tools/objtool/elf.h ++++ b/tools/objtool/elf.h +@@ -140,6 +140,8 @@ struct reloc *find_reloc_by_dest(const struct elf *elf, struct section *sec, uns + struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *sec, + unsigned long offset, unsigned int len); + struct symbol *find_func_containing(struct section *sec, unsigned long offset); ++void insn_to_reloc_sym_addend(struct section *sec, unsigned long offset, ++ struct reloc *reloc); + int elf_rebuild_reloc_section(struct elf *elf, struct section *sec); + + #define for_each_sec(file, sec) \ +diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c +index 235663b96adc7..9ce68b385a1b8 100644 +--- a/tools/objtool/orc_gen.c ++++ b/tools/objtool/orc_gen.c +@@ -105,30 +105,11 @@ static int create_orc_entry(struct elf *elf, struct section *u_sec, struct secti + } + memset(reloc, 0, sizeof(*reloc)); + +- if (insn_sec->sym) { +- reloc->sym = insn_sec->sym; +- reloc->addend = insn_off; +- } else { +- /* +- * The Clang assembler doesn't produce section symbols, so we +- * have to reference the function symbol instead: +- */ +- reloc->sym = find_symbol_containing(insn_sec, insn_off); +- if (!reloc->sym) { +- /* +- * Hack alert. This happens when we need to reference +- * the NOP pad insn immediately after the function. +- */ +- reloc->sym = find_symbol_containing(insn_sec, +- insn_off - 1); +- } +- if (!reloc->sym) { +- WARN("missing symbol for insn at offset 0x%lx\n", +- insn_off); +- return -1; +- } +- +- reloc->addend = insn_off - reloc->sym->offset; ++ insn_to_reloc_sym_addend(insn_sec, insn_off, reloc); ++ if (!reloc->sym) { ++ WARN("missing symbol for insn at offset 0x%lx", ++ insn_off); ++ return -1; + } + + reloc->type = R_X86_64_PC32; |