Messages in this thread Patch in this message | | | Date | Wed, 12 Apr 2023 11:32:13 -0700 | Subject | [PATCH 2/2] start_kernel: omit prevent_tail_call_optimization for newer toolchains | From | ndesaulniers@google ... |
| |
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.
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- init/main.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/init/main.c b/init/main.c index 213baf7b8cb1..c8503d02dfa6 100644 --- a/init/main.c +++ b/init/main.c @@ -1152,7 +1152,12 @@ 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. */ -- 2.40.0.577.gac1e443424-goog
| |