From 59aa41585f668b70b86a8e2617057da08f3291cc Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Netto Date: Thu, 17 Nov 2022 15:13:08 -0300 Subject: 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 --- sysdeps/i386/start.S | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'sysdeps/i386') diff --git a/sysdeps/i386/start.S b/sysdeps/i386/start.S index 4ec04bd..23e4f2b 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 -- cgit v1.1