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| author | Adhemerval Zanella Netto <adhemerval.zanella@linaro.org> | 2022-11-17 15:13:08 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2022-11-21 11:25:35 -0300 |
| commit | 59aa41585f668b70b86a8e2617057da08f3291cc (patch) | |
| tree | 5b13f629a5e2cd85ebbd5e8250cc63a030d3db5d | |
| parent | eb4181e9f4a512de37dad4ba623c921671584dea (diff) | |
| download | glibc-59aa41585f668b70b86a8e2617057da08f3291cc.tar.gz glibc-59aa41585f668b70b86a8e2617057da08f3291cc.tar.xz glibc-59aa41585f668b70b86a8e2617057da08f3291cc.zip | |
i386: Avoid rely on linker optimization to avoid relocation
lld does not implement all the linker optimization to avoid the GOT relocation as done by binutils (bfd/elf32-i386.c:elf_i386_convert_load_reloc). The current 'movl main@GOT(%ebx), %eax' will then create a GOT relocation when building with lld, which make static-pie status to not being able to start the provided main function. The change uses a __wrap_main local symbol, which in turn calls main (similar as used by aarch64 and s390x). Checked on i686-linux-gnu with binutils and lld. Reviewed-by: Fangrui Song <maskray@google.com>
| -rw-r--r-- | sysdeps/i386/start.S | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/sysdeps/i386/start.S b/sysdeps/i386/start.S index 4ec04bdfd7..23e4f2b012 100644 --- a/sysdeps/i386/start.S +++ b/sysdeps/i386/start.S @@ -98,11 +98,10 @@ ENTRY (_start) pushl main@GOT(%ebx) # else /* Avoid relocation in static PIE since _start is called before - it is relocated. Don't use "leal main@GOTOFF(%ebx), %eax" - since main may be in a shared object. Linker will convert - "movl main@GOT(%ebx), %eax" to "leal main@GOTOFF(%ebx), %eax" + it is relocated. This also avoid rely on linker optimization to + transform 'movl main@GOT(%ebx), %eax' to 'leal main@GOTOFF(%ebx)' if main is defined locally. */ - movl main@GOT(%ebx), %eax + leal __wrap_main@GOTOFF(%ebx), %eax pushl %eax # endif @@ -130,6 +129,12 @@ ENTRY (_start) 1: movl (%esp), %ebx ret #endif + +#if defined PIC && !defined SHARED +__wrap_main: + _CET_ENDBR + jmp main@PLT +#endif END (_start) /* To fulfill the System V/i386 ABI we need this symbol. Yuck, it's so |