diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-11-10 11:01:08 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-12-11 09:09:46 +0100 |
| commit | aa93e2ad7464ffb90155a5ffdde963816f86d5dc (patch) | |
| tree | 345b322a089c1ca16e708ed1123555d729c5bc82 /arch/x86/mm | |
| parent | 16e617d05ef0c521d000c989796412ce713f28c9 (diff) | |
x86/entry_32: Remove .fixup usage
Where possible, push the .fixup into code, at the tail of functions.
This is hard for macros since they're used in multiple functions,
therefore introduce a new extable handler to pop zeros.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.245184699@infradead.org
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/extable.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 5cd2a88930a9..fb0c4752df1a 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -99,6 +99,18 @@ static bool ex_handler_clear_fs(const struct exception_table_entry *fixup, return ex_handler_default(fixup, regs); } +static bool ex_handler_pop_zero(const struct exception_table_entry *fixup, + struct pt_regs *regs) +{ + /* + * Typically used for when "pop %seg" traps, in which case we'll clear + * the stack slot and re-try the instruction, which will then succeed + * to pop zero. + */ + *((unsigned long *)regs->sp) = 0; + return ex_handler_default(fixup, regs); +} + int ex_get_fixup_type(unsigned long ip) { const struct exception_table_entry *e = search_exception_tables(ip); @@ -156,6 +168,8 @@ int fixup_exception(struct pt_regs *regs, int trapnr, unsigned long error_code, case EX_TYPE_WRMSR_IN_MCE: ex_handler_msr_mce(regs, true); break; + case EX_TYPE_POP_ZERO: + return ex_handler_pop_zero(e, regs); } BUG(); } |