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| author | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-06-10 05:30:17 -0300 |
|---|---|---|
| committer | André Fabian Silva Delgado <emulatorman@parabola.nu> | 2016-06-10 05:30:17 -0300 |
| commit | d635711daa98be86d4c7fd01499c34f566b54ccb (patch) | |
| tree | aa5cc3760a27c3d57146498cb82fa549547de06c /arch/x86/boot/compressed/head_32.S | |
| parent | c91265cd0efb83778f015b4d4b1129bd2cfd075e (diff) | |
Linux-libre 4.6.2-gnu
Diffstat (limited to 'arch/x86/boot/compressed/head_32.S')
| -rw-r--r-- | arch/x86/boot/compressed/head_32.S | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S index 8ef964ddc..0256064da 100644 --- a/arch/x86/boot/compressed/head_32.S +++ b/arch/x86/boot/compressed/head_32.S @@ -31,6 +31,34 @@ #include <asm/asm-offsets.h> #include <asm/bootparam.h> +/* + * The 32-bit x86 assembler in binutils 2.26 will generate R_386_GOT32X + * relocation to get the symbol address in PIC. When the compressed x86 + * kernel isn't built as PIC, the linker optimizes R_386_GOT32X + * relocations to their fixed symbol addresses. However, when the + * compressed x86 kernel is loaded at a different address, it leads + * to the following load failure: + * + * Failed to allocate space for phdrs + * + * during the decompression stage. + * + * If the compressed x86 kernel is relocatable at run-time, it should be + * compiled with -fPIE, instead of -fPIC, if possible and should be built as + * Position Independent Executable (PIE) so that linker won't optimize + * R_386_GOT32X relocation to its fixed symbol address. Older + * linkers generate R_386_32 relocations against locally defined symbols, + * _bss, _ebss, _got and _egot, in PIE. It isn't wrong, just less + * optimal than R_386_RELATIVE. But the x86 kernel fails to properly handle + * R_386_32 relocations when relocating the kernel. To generate + * R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as + * hidden: + */ + .hidden _bss + .hidden _ebss + .hidden _got + .hidden _egot + __HEAD ENTRY(startup_32) #ifdef CONFIG_EFI_STUB |