Messages in this thread | | | From | Nick Desaulniers <> | Date | Tue, 22 Mar 2022 10:09:18 -0700 | Subject | Re: [RFC PATCH v2 2/8] tools/nolibc: Remove .global _start from the entry point code |
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On Tue, Mar 22, 2022 at 3:21 AM Ammar Faizi <ammarfaizi2@gnuweeb.org> wrote: > > Building with clang yields the following error: > ``` > <inline asm>:3:1: error: _start changed binding to STB_GLOBAL > .global _start > ^ > 1 error generated. > ``` > Make sure only specify one between `.global _start` and `.weak _start`. > Removing `.global _start`.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Yes, symbols should either be `.weak` or `.global`. The warning from Clang's integrated assembler is meant to flush out funny business.
I assume there's a good reason _why_ _start is weak and not strong? Then again, I'm not familiar with nolibc.
> > Cc: llvm@lists.linux.dev > Cc: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org> > --- > > @@ Changelog: > > Link RFC v1: https://lore.kernel.org/llvm/20220320093750.159991-3-ammarfaizi2@gnuweeb.org > RFC v1 -> RFC v2: > - Remove all `.global _start` for all build (GCC and Clang) instead of > removing all `.weak _start` for clang build (Comment from Willy). > --- > tools/include/nolibc/arch-aarch64.h | 1 - > tools/include/nolibc/arch-arm.h | 1 - > tools/include/nolibc/arch-i386.h | 1 - > tools/include/nolibc/arch-mips.h | 1 - > tools/include/nolibc/arch-riscv.h | 1 - > tools/include/nolibc/arch-x86_64.h | 1 - > 6 files changed, 6 deletions(-) > > diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h > index 87d9e434820c..2dbd80d633cb 100644 > --- a/tools/include/nolibc/arch-aarch64.h > +++ b/tools/include/nolibc/arch-aarch64.h > @@ -184,7 +184,6 @@ struct sys_stat_struct { > /* startup code */ > asm(".section .text\n" > ".weak _start\n" > - ".global _start\n" > "_start:\n" > "ldr x0, [sp]\n" // argc (x0) was in the stack > "add x1, sp, 8\n" // argv (x1) = sp > diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h > index 001a3c8c9ad5..1191395b5acd 100644 > --- a/tools/include/nolibc/arch-arm.h > +++ b/tools/include/nolibc/arch-arm.h > @@ -177,7 +177,6 @@ struct sys_stat_struct { > /* startup code */ > asm(".section .text\n" > ".weak _start\n" > - ".global _start\n" > "_start:\n" > #if defined(__THUMBEB__) || defined(__THUMBEL__) > /* We enter here in 32-bit mode but if some previous functions were in > diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h > index d7e4d53325a3..125a691fc631 100644 > --- a/tools/include/nolibc/arch-i386.h > +++ b/tools/include/nolibc/arch-i386.h > @@ -176,7 +176,6 @@ struct sys_stat_struct { > */ > asm(".section .text\n" > ".weak _start\n" > - ".global _start\n" > "_start:\n" > "pop %eax\n" // argc (first arg, %eax) > "mov %esp, %ebx\n" // argv[] (second arg, %ebx) > diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h > index c9a6aac87c6d..1a124790c99f 100644 > --- a/tools/include/nolibc/arch-mips.h > +++ b/tools/include/nolibc/arch-mips.h > @@ -192,7 +192,6 @@ struct sys_stat_struct { > asm(".section .text\n" > ".weak __start\n" > ".set nomips16\n" > - ".global __start\n" > ".set noreorder\n" > ".option pic0\n" > ".ent __start\n" > diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h > index bc10b7b5706d..511d67fc534e 100644 > --- a/tools/include/nolibc/arch-riscv.h > +++ b/tools/include/nolibc/arch-riscv.h > @@ -185,7 +185,6 @@ struct sys_stat_struct { > /* startup code */ > asm(".section .text\n" > ".weak _start\n" > - ".global _start\n" > "_start:\n" > ".option push\n" > ".option norelax\n" > diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h > index a7b70ea51b68..84c174181425 100644 > --- a/tools/include/nolibc/arch-x86_64.h > +++ b/tools/include/nolibc/arch-x86_64.h > @@ -199,7 +199,6 @@ struct sys_stat_struct { > */ > asm(".section .text\n" > ".weak _start\n" > - ".global _start\n" > "_start:\n" > "pop %rdi\n" // argc (first arg, %rdi) > "mov %rsp, %rsi\n" // argv[] (second arg, %rsi) > -- > Ammar Faizi >
-- Thanks, ~Nick Desaulniers
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