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Commit f892b7d4 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Sam Ravnborg
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kbuild: make better section mismatch reports on i386, arm and mips 



On i386, ARM and MIPS, warn_sec_mismatch() sometimes fails to show
usefull symbol name.  This is because empty 'refsym' due to 0 r_addend
value.  This patch is to adjust r_addend value, consulting with
apply_relocate() routine in kernel code.

Without this patch:
  MODPOST vmlinux
WARNING: init/built-in.o - Section mismatch: reference to .init.text: from .text between 'rest_init' (at offset 0xf4) and 'try_name'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text: from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap'

With this patch:
  MODPOST vmlinux
WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a39) and 'cache_reap'
WARNING: mm/built-in.o - Section mismatch: reference to .init.text:set_up_list3s from .text between 'kmem_cache_create' (at offset 0x18a6b) and 'cache_reap'

Now modpost can detect "kernel_init" name (and whitelist it) and show
"set_up_list3s" name.

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent 25601209

scripts/mod/modpost.c

+79 −0
Original line number Diff line number Diff line
@@ -384,6 +384,7 @@ static int parse_elf(struct elf_info *info, const char *filename) 
		sechdrs[i].sh_size   = TO_NATIVE(sechdrs[i].sh_size);

		sechdrs[i].sh_link   = TO_NATIVE(sechdrs[i].sh_link);

		sechdrs[i].sh_name   = TO_NATIVE(sechdrs[i].sh_name);

		sechdrs[i].sh_info   = TO_NATIVE(sechdrs[i].sh_info);

	}

	/* Find symbol table. */

	for (i = 1; i < hdr->e_shnum; i++) {
@@ -773,6 +774,8 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr, 
	for (sym = elf->symtab_start; sym < elf->symtab_stop; sym++) {

		if (sym->st_shndx != relsym->st_shndx)

			continue;

		if (ELF_ST_TYPE(sym->st_info) == STT_SECTION)

			continue;

		if (sym->st_value == addr)

			return sym;

	}
@@ -910,6 +913,68 @@ static void warn_sec_mismatch(const char *modname, const char *fromsec, 
	}

}



static void addend_386_rel(struct elf_info *elf, int section, Elf_Rela *r)

{

	Elf_Shdr *sechdrs = elf->sechdrs;

	unsigned int r_typ;

	unsigned int *location;



	r_typ = ELF_R_TYPE(r->r_info);

	location = (void *)elf->hdr +

		sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;

	switch (r_typ) {

	case R_386_32:

		r->r_addend = TO_NATIVE(*location);

		break;

	case R_386_PC32:

		r->r_addend = TO_NATIVE(*location) + 4;

		break;

	}

}



static void addend_arm_rel(struct elf_info *elf, int section, Elf_Rela *r)

{

	Elf_Shdr *sechdrs = elf->sechdrs;

	unsigned int r_typ;

	unsigned int *location;



	r_typ = ELF_R_TYPE(r->r_info);

	location = (void *)elf->hdr +

		sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;

	switch (r_typ) {

	case R_ARM_ABS32:

		r->r_addend = TO_NATIVE(*location);

		break;

	case R_ARM_PC24:

		r->r_addend = ((TO_NATIVE(*location) & 0x00ffffff) << 2) + 8;

		break;

	}

}



static int addend_mips_rel(struct elf_info *elf, int section, Elf_Rela *r)

{

	Elf_Shdr *sechdrs = elf->sechdrs;

	unsigned int r_typ;

	unsigned int *location;

	unsigned int inst;



	r_typ = ELF_R_TYPE(r->r_info);

	if (r_typ == R_MIPS_HI16)

		return 1;	/* skip this */

	location = (void *)elf->hdr +

		sechdrs[sechdrs[section].sh_info].sh_offset + r->r_offset;

	inst = TO_NATIVE(*location);

	switch (r_typ) {

	case R_MIPS_LO16:

		r->r_addend = ((inst & 0xffff) ^ 0x8000) - 0x8000;

		break;

	case R_MIPS_26:

		r->r_addend = (inst & 0x03ffffff) << 2;

		break;

	}

	return 0;

}



/**

 * A module includes a number of sections that are discarded

 * either when loaded or when used as built-in.
@@ -953,8 +1018,11 @@ static void check_sec_ref(struct module *mod, const char *modname, 
				r.r_offset = TO_NATIVE(rela->r_offset);

#if KERNEL_ELFCLASS == ELFCLASS64

				if (hdr->e_machine == EM_MIPS) {

					unsigned int r_typ;

					r_sym = ELF64_MIPS_R_SYM(rela->r_info);

					r_sym = TO_NATIVE(r_sym);

					r_typ = ELF64_MIPS_R_TYPE(rela->r_info);

					r.r_info = ELF64_R_INFO(r_sym, r_typ);

				} else {

					r.r_info = TO_NATIVE(rela->r_info);

					r_sym = ELF_R_SYM(r.r_info);
@@ -987,8 +1055,11 @@ static void check_sec_ref(struct module *mod, const char *modname, 
				r.r_offset = TO_NATIVE(rel->r_offset);

#if KERNEL_ELFCLASS == ELFCLASS64

				if (hdr->e_machine == EM_MIPS) {

					unsigned int r_typ;

					r_sym = ELF64_MIPS_R_SYM(rel->r_info);

					r_sym = TO_NATIVE(r_sym);

					r_typ = ELF64_MIPS_R_TYPE(rel->r_info);

					r.r_info = ELF64_R_INFO(r_sym, r_typ);

				} else {

					r.r_info = TO_NATIVE(rel->r_info);

					r_sym = ELF_R_SYM(r.r_info);
@@ -998,6 +1069,14 @@ static void check_sec_ref(struct module *mod, const char *modname, 
				r_sym = ELF_R_SYM(r.r_info);

#endif

				r.r_addend = 0;

				if (hdr->e_machine == EM_386)

					addend_386_rel(elf, i, &r);

				else if (hdr->e_machine == EM_ARM)

					addend_arm_rel(elf, i, &r);

				else if (hdr->e_machine == EM_MIPS) {

					if (addend_mips_rel(elf, i, &r))

						continue;

				}

				sym = elf->symtab_start + r_sym;

				/* Skip special sections */

				if (sym->st_shndx >= SHN_LORESERVE)

scripts/mod/modpost.h

+3 −0
Original line number Diff line number Diff line
@@ -60,6 +60,9 @@ typedef union 
#define ELF64_MIPS_R_SYM(i) \

  ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_sym)



#define ELF64_MIPS_R_TYPE(i) \

  ((__extension__ (_Elf64_Mips_R_Info_union)(i)).r_info_fields.r_type1)



#if KERNEL_ELFDATA != HOST_ELFDATA



static inline void __endian(const void *src, void *dest, unsigned int size)