| Message ID | 20200103113953.9571-3-ardb@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | More EFI updates for v5.6 | expand |
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index da04948d75ed..565ee4733579 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -6,6 +6,8 @@ * * ----------------------------------------------------------------------- */ +#pragma GCC visibility push(hidden) + #include <linux/efi.h> #include <linux/pci.h>
Commit c3710de5065d ("efi/libstub/x86: Drop __efi_early() export and efi_config struct") introduced a reference from C code in eboot.c to the startup_32 symbol defined in the .S startup code. This results in a GOT based reference to startup_32, and since GOT entries carry absolute addresses, they need to be fixed up before they can be used. On modern toolchains (binutils 2.26 or later), this reference is relaxed into a R_386_GOTOFF relocation (or the analogous X86_64 one) which never uses the absolute address in the entry, and so we get away with not fixing up the GOT table before calling the EFI entry point. However, GCC 4.6 combined with a binutils of the era (2.24) will produce a true GOT indirected reference, resulting in a wrong value to be returned for the address of startup_32() if the boot code is not running at the address it was linked at. Fortunately, we can easily override this behavior, and force GCC to emit the GOTOFF relocations explicitly, by setting the visibility pragma 'hidden'. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- arch/x86/boot/compressed/eboot.c | 2 ++ 1 file changed, 2 insertions(+)