diff options
| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-10-08 20:02:04 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2015-10-12 16:20:12 +0100 |
| commit | e8f3010f7326c00368dbc057bd052bec80dfc072 (patch) | |
| tree | 111ad1d750410588ecd346fc257c05565963f0fd /arch/arm64/kernel/image.h | |
| parent | 207918461eb0aca720fddec5da79bc71c133b9f1 (diff) | |
arm64/efi: isolate EFI stub from the kernel proper
Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.
So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/image.h')
| -rw-r--r-- | arch/arm64/kernel/image.h | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h index 8fae0756e175..e083af0dd546 100644 --- a/arch/arm64/kernel/image.h +++ b/arch/arm64/kernel/image.h @@ -59,4 +59,31 @@ _kernel_offset_le = DATA_LE64(TEXT_OFFSET); \ _kernel_flags_le = DATA_LE64(__HEAD_FLAGS); +#ifdef CONFIG_EFI + +/* + * The EFI stub has its own symbol namespace prefixed by __efistub_, to + * isolate it from the kernel proper. The following symbols are legally + * accessed by the stub, so provide some aliases to make them accessible. + * Only include data symbols here, or text symbols of functions that are + * guaranteed to be safe when executed at another offset than they were + * linked at. The routines below are all implemented in assembler in a + * position independent manner + */ +__efistub_memcmp = __pi_memcmp; +__efistub_memchr = __pi_memchr; +__efistub_memcpy = __pi_memcpy; +__efistub_memmove = __pi_memmove; +__efistub_memset = __pi_memset; +__efistub_strlen = __pi_strlen; +__efistub_strcmp = __pi_strcmp; +__efistub_strncmp = __pi_strncmp; +__efistub___flush_dcache_area = __pi___flush_dcache_area; + +__efistub__text = _text; +__efistub__end = _end; +__efistub__edata = _edata; + +#endif + #endif /* __ASM_IMAGE_H */ |