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authorDavid Brownell <david-b@pacbell.net>2007-02-20 16:58:16 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-02-20 20:10:16 -0500
commitda68d61f89e275260cc993a0d4a39e63700098fb (patch)
tree2b54d5e695cc233045cb854d7e1fc7470cd6d3a6
parent3deac046e2883686a732960050ab74fca0db11fa (diff)
[PATCH] remove modpost false warnings on ARM
This patch stops "modpost" from issuing erroneous modpost warnings on ARM builds, which it's been doing since since maybe last summer. A canonical example would be driver method table entries: WARNING: <path> - Section mismatch: reference to .exit.text:<name>_remove from .data after '$d' (at offset 0x4) That "$d" symbol is generated by tools conformant with ARM ABI specs; in this case it's a symbol **in the middle of** a "<name>_driver" struct. The erroneous warnings appear to be issued because "modpost" whitelists references from "<name>_driver" data into init and exit sections ... but doesn't know should also include those "$d" mapping symbols, which are not otherwise associated with "<name>_driver" symbols. This patch prevents the modpost symbol lookup code from ever returning those mapping symbols, so it will return a whitelisted symbol instead. Then things work as expected. Now to revert various code-bloating "fixes" that got merged because of this modpost bug.... Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Roman Zippel <zippel@linux-m68k.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--scripts/mod/modpost.c36
1 files changed, 28 insertions, 8 deletions
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 569e68410d7a..c4b5398687b8 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -686,6 +686,30 @@ static Elf_Sym *find_elf_symbol(struct elf_info *elf, Elf_Addr addr,
686 return NULL; 686 return NULL;
687} 687}
688 688
689static inline int is_arm_mapping_symbol(const char *str)
690{
691 return str[0] == '$' && strchr("atd", str[1])
692 && (str[2] == '\0' || str[2] == '.');
693}
694
695/*
696 * If there's no name there, ignore it; likewise, ignore it if it's
697 * one of the magic symbols emitted used by current ARM tools.
698 *
699 * Otherwise if find_symbols_between() returns those symbols, they'll
700 * fail the whitelist tests and cause lots of false alarms ... fixable
701 * only by merging __exit and __init sections into __text, bloating
702 * the kernel (which is especially evil on embedded platforms).
703 */
704static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
705{
706 const char *name = elf->strtab + sym->st_name;
707
708 if (!name || !strlen(name))
709 return 0;
710 return !is_arm_mapping_symbol(name);
711}
712
689/* 713/*
690 * Find symbols before or equal addr and after addr - in the section sec. 714 * Find symbols before or equal addr and after addr - in the section sec.
691 * If we find two symbols with equal offset prefer one with a valid name. 715 * If we find two symbols with equal offset prefer one with a valid name.
@@ -714,16 +738,15 @@ static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
714 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name; 738 symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
715 if (strcmp(symsec, sec) != 0) 739 if (strcmp(symsec, sec) != 0)
716 continue; 740 continue;
741 if (!is_valid_name(elf, sym))
742 continue;
717 if (sym->st_value <= addr) { 743 if (sym->st_value <= addr) {
718 if ((addr - sym->st_value) < beforediff) { 744 if ((addr - sym->st_value) < beforediff) {
719 beforediff = addr - sym->st_value; 745 beforediff = addr - sym->st_value;
720 *before = sym; 746 *before = sym;
721 } 747 }
722 else if ((addr - sym->st_value) == beforediff) { 748 else if ((addr - sym->st_value) == beforediff) {
723 /* equal offset, valid name? */ 749 *before = sym;
724 const char *name = elf->strtab + sym->st_name;
725 if (name && strlen(name))
726 *before = sym;
727 } 750 }
728 } 751 }
729 else 752 else
@@ -733,10 +756,7 @@ static void find_symbols_between(struct elf_info *elf, Elf_Addr addr,
733 *after = sym; 756 *after = sym;
734 } 757 }
735 else if ((sym->st_value - addr) == afterdiff) { 758 else if ((sym->st_value - addr) == afterdiff) {
736 /* equal offset, valid name? */ 759 *after = sym;
737 const char *name = elf->strtab + sym->st_name;
738 if (name && strlen(name))
739 *after = sym;
740 } 760 }
741 } 761 }
742 } 762 }