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| author | ndesaulniers@google.com <ndesaulniers@google.com> | 2023-04-17 15:00:06 -0700 |
|---|---|---|
| committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-05-16 06:28:24 -0700 |
| commit | dc1d05536f44cee16e46e86316e6718b2c0d8872 (patch) | |
| tree | c63e9b66f55385705504149293da0407fc15303b /init | |
| parent | 514ca14ed5444b911de59ed3381dfd195d99fe4b (diff) | |
| download | lwn-dc1d05536f44cee16e46e86316e6718b2c0d8872.tar.gz lwn-dc1d05536f44cee16e46e86316e6718b2c0d8872.zip | |
start_kernel: Omit prevent_tail_call_optimization() for newer toolchains
prevent_tail_call_optimization() was added in
commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try")
to work around stack canaries getting inserted into functions that would
initialize the stack canary in the first place.
Now that we have no_stack_protector function attribute (gcc-11+,
clang-7+) and use it on start_kernel(), remove the call to
prevent_tail_call_optimization() such that we may one day remove it
outright.
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230412-no_stackp-v2-2-116f9fe4bbe7@google.com
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'init')
| -rw-r--r-- | init/main.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/init/main.c b/init/main.c index c445c1fb19b9..c0b6499c31db 100644 --- a/init/main.c +++ b/init/main.c @@ -1088,7 +1088,13 @@ void start_kernel(void) /* Do the rest non-__init'ed, we're now alive */ arch_call_rest_init(); + /* + * Avoid stack canaries in callers of boot_init_stack_canary for gcc-10 + * and older. + */ +#if !__has_attribute(__no_stack_protector__) prevent_tail_call_optimization(); +#endif } /* Call all constructor functions linked into the kernel. */ |