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| author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2015-12-26 13:48:02 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2016-02-24 15:57:25 +0100 |
| commit | 6ad1fe5d9077a1ab40bf74b61994d2e770b00b14 (patch) | |
| tree | 88cfed6d43d89bb5e21c7e8ea9c32e54baa88fac /arch/arm64/include | |
| parent | arm64: add support for module PLTs (diff) | |
| download | linux-6ad1fe5d9077a1ab40bf74b61994d2e770b00b14.tar.xz linux-6ad1fe5d9077a1ab40bf74b61994d2e770b00b14.zip | |
arm64: avoid R_AARCH64_ABS64 relocations for Image header fields
Unfortunately, the current way of using the linker to emit build time
constants into the Image header will no longer work once we switch to
the use of PIE executables. The reason is that such constants are emitted
into the binary using R_AARCH64_ABS64 relocations, which are resolved at
runtime, not at build time, and the places targeted by those relocations
will contain zeroes before that.
So refactor the endian swapping linker script constant generation code so
that it emits the upper and lower 32-bit words separately.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index bb7b72734c24..ba5aff6c830e 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -215,4 +215,15 @@ lr .req x30 // link register .size __pi_##x, . - x; \ ENDPROC(x) + /* + * Emit a 64-bit absolute little endian symbol reference in a way that + * ensures that it will be resolved at build time, even when building a + * PIE binary. This requires cooperation from the linker script, which + * must emit the lo32/hi32 halves individually. + */ + .macro le64sym, sym + .long \sym\()_lo32 + .long \sym\()_hi32 + .endm + #endif /* __ASM_ASSEMBLER_H */ |