Messages in this thread | | | Date | Mon, 16 May 2022 17:41:40 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] objtool: fix objtool regression on x32 systems |
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On Mon, May 16, 2022 at 11:06:36AM -0400, Mikulas Patocka wrote: > The patch 4abff6d48dbc ("objtool: Fix code relocs vs weak symbols") makes > the kernel unbootable. The patch c087c6e7b551 ("objtool: Fix type of > reloc::addend") attempts to fix it by replacing 'int' with 'long'. > > However, we may be running on a system with x32 ABI and 'long' on x32 is > 32-bit, thus the patch c087c6e7b551 doesn't really change anything and we > still end up with miscompiled kernel. This patch replaces 'long' with > 'long long', so that the 64-bit kernel is correctly compiled on a x32 > system.
Hurmph.. you're building a 64bit kernel on a x32 hosted machine? And this is the *only* thing that goes sideways?
I suspect quite a bit of objtool assumes LP64 and won't quite work right on ILP32 and we've just been lucky so far.
> Index: linux-2.6/tools/objtool/elf.c > =================================================================== > --- linux-2.6.orig/tools/objtool/elf.c 2022-05-16 16:20:49.000000000 +0200 > +++ linux-2.6/tools/objtool/elf.c 2022-05-16 16:22:21.000000000 +0200 > @@ -546,7 +546,7 @@ static struct section *elf_create_reloc_ > int reltype); > > int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, > - unsigned int type, struct symbol *sym, long addend) > + unsigned int type, struct symbol *sym, long long addend) > { > struct reloc *reloc; > > Index: linux-2.6/tools/objtool/include/objtool/elf.h > =================================================================== > --- linux-2.6.orig/tools/objtool/include/objtool/elf.h 2022-05-16 16:07:54.000000000 +0200 > +++ linux-2.6/tools/objtool/include/objtool/elf.h 2022-05-16 16:22:45.000000000 +0200 > @@ -73,7 +73,7 @@ struct reloc { > struct symbol *sym; > unsigned long offset; > unsigned int type; > - long addend; > + long long addend; > int idx; > bool jump_table_start; > }; > @@ -135,7 +135,7 @@ struct elf *elf_open_read(const char *na > struct section *elf_create_section(struct elf *elf, const char *name, unsigned int sh_flags, size_t entsize, int nr); > > int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset, > - unsigned int type, struct symbol *sym, long addend); > + unsigned int type, struct symbol *sym, long long addend); > int elf_add_reloc_to_insn(struct elf *elf, struct section *sec, > unsigned long offset, unsigned int type, > struct section *insn_sec, unsigned long insn_off); >
I think I much prefer s64 there instead of 'long long'. But really I think all of objtool needs a bit of an audit to see what types need be used.
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