diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-09-30 12:43:10 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-10-01 13:57:47 +0200 |
| commit | 24ff652573754fe4c03213ebd26b17e86842feb3 (patch) | |
| tree | e50930aa185cfdae8dffb8d4e2fde79a14c1b5bc /tools | |
| parent | e4e737bb5c170df6135a127739a9e6148ee3da82 (diff) | |
objtool: Teach get_alt_entry() about more relocation types
Occasionally objtool encounters symbol (as opposed to section)
relocations in .altinstructions. Typically they are the alternatives
written by elf_add_alternative() as encountered on a noinstr
validation run on vmlinux after having already ran objtool on the
individual .o files.
Basically this is the counterpart of commit 44f6a7c0755d ("objtool:
Fix seg fault with Clang non-section symbols"), because when these new
assemblers (binutils now also does this) strip the section symbols,
elf_add_reloc_to_insn() is forced to emit symbol based relocations.
As such, teach get_alt_entry() about different relocation types.
Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/YVWUvknIEVNkPvnP@hirez.programming.kicks-ass.net
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/objtool/special.c | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/tools/objtool/special.c b/tools/objtool/special.c index bc925cf19e2d..f58ecc50fb10 100644 --- a/tools/objtool/special.c +++ b/tools/objtool/special.c @@ -58,6 +58,24 @@ void __weak arch_handle_alternative(unsigned short feature, struct special_alt * { } +static bool reloc2sec_off(struct reloc *reloc, struct section **sec, unsigned long *off) +{ + switch (reloc->sym->type) { + case STT_FUNC: + *sec = reloc->sym->sec; + *off = reloc->sym->offset + reloc->addend; + return true; + + case STT_SECTION: + *sec = reloc->sym->sec; + *off = reloc->addend; + return true; + + default: + return false; + } +} + static int get_alt_entry(struct elf *elf, struct special_entry *entry, struct section *sec, int idx, struct special_alt *alt) @@ -91,15 +109,12 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, WARN_FUNC("can't find orig reloc", sec, offset + entry->orig); return -1; } - if (orig_reloc->sym->type != STT_SECTION) { - WARN_FUNC("don't know how to handle non-section reloc symbol %s", + if (!reloc2sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off)) { + WARN_FUNC("don't know how to handle reloc symbol type: %s", sec, offset + entry->orig, orig_reloc->sym->name); return -1; } - alt->orig_sec = orig_reloc->sym->sec; - alt->orig_off = orig_reloc->addend; - if (!entry->group || alt->new_len) { new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new); if (!new_reloc) { @@ -116,8 +131,11 @@ static int get_alt_entry(struct elf *elf, struct special_entry *entry, if (arch_is_retpoline(new_reloc->sym)) return 1; - alt->new_sec = new_reloc->sym->sec; - alt->new_off = (unsigned int)new_reloc->addend; + if (!reloc2sec_off(new_reloc, &alt->new_sec, &alt->new_off)) { + WARN_FUNC("don't know how to handle reloc symbol type: %s", + sec, offset + entry->new, new_reloc->sym->name); + return -1; + } /* _ASM_EXTABLE_EX hack */ if (alt->new_off >= 0x7ffffff0) |