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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2015-10-08 19:02:04 (GMT)
committerCatalin Marinas <catalin.marinas@arm.com>2015-10-12 15:20:12 (GMT)
commite8f3010f7326c00368dbc057bd052bec80dfc072 (patch)
tree111ad1d750410588ecd346fc257c05565963f0fd /arch/arm64/kernel/head.S
parent207918461eb0aca720fddec5da79bc71c133b9f1 (diff)
downloadlinux-e8f3010f7326c00368dbc057bd052bec80dfc072.tar.xz
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/head.S')
-rw-r--r--arch/arm64/kernel/head.S14
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 90d09ed..28a81e9 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -120,8 +120,8 @@ efi_head:
#endif
#ifdef CONFIG_EFI
- .globl stext_offset
- .set stext_offset, stext - efi_head
+ .globl __efistub_stext_offset
+ .set __efistub_stext_offset, stext - efi_head
.align 3
pe_header:
.ascii "PE"
@@ -144,8 +144,8 @@ optional_header:
.long _end - stext // SizeOfCode
.long 0 // SizeOfInitializedData
.long 0 // SizeOfUninitializedData
- .long efi_stub_entry - efi_head // AddressOfEntryPoint
- .long stext_offset // BaseOfCode
+ .long __efistub_entry - efi_head // AddressOfEntryPoint
+ .long __efistub_stext_offset // BaseOfCode
extra_header_fields:
.quad 0 // ImageBase
@@ -162,7 +162,7 @@ extra_header_fields:
.long _end - efi_head // SizeOfImage
// Everything before the kernel image is considered part of the header
- .long stext_offset // SizeOfHeaders
+ .long __efistub_stext_offset // SizeOfHeaders
.long 0 // CheckSum
.short 0xa // Subsystem (EFI application)
.short 0 // DllCharacteristics
@@ -207,9 +207,9 @@ section_table:
.byte 0
.byte 0 // end of 0 padding of section name
.long _end - stext // VirtualSize
- .long stext_offset // VirtualAddress
+ .long __efistub_stext_offset // VirtualAddress
.long _edata - stext // SizeOfRawData
- .long stext_offset // PointerToRawData
+ .long __efistub_stext_offset // PointerToRawData
.long 0 // PointerToRelocations (0 for executables)
.long 0 // PointerToLineNumbers (0 for executables)