Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=da68d61f89e275260cc993a0d4a39e63700098fb
Commit:     da68d61f89e275260cc993a0d4a39e63700098fb
Parent:     3deac046e2883686a732960050ab74fca0db11fa
Author:     David Brownell <[EMAIL PROTECTED]>
AuthorDate: Tue Feb 20 13:58:16 2007 -0800
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Tue Feb 20 17:10:16 2007 -0800

    [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 <[EMAIL PROTECTED]>
    Acked-by: Rusty Russell <[EMAIL PROTECTED]>
    Cc: Roman Zippel <[EMAIL PROTECTED]>
    Acked-by: Sam Ravnborg <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
 scripts/mod/modpost.c |   36 ++++++++++++++++++++++++++++--------
 1 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 569e684..c4b5398 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,
        return NULL;
 }
 
+static inline int is_arm_mapping_symbol(const char *str)
+{
+       return str[0] == '$' && strchr("atd", str[1])
+              && (str[2] == '\0' || str[2] == '.');
+}
+
+/*
+ * If there's no name there, ignore it; likewise, ignore it if it's
+ * one of the magic symbols emitted used by current ARM tools.
+ *
+ * Otherwise if find_symbols_between() returns those symbols, they'll
+ * fail the whitelist tests and cause lots of false alarms ... fixable
+ * only by merging __exit and __init sections into __text, bloating
+ * the kernel (which is especially evil on embedded platforms).
+ */
+static inline int is_valid_name(struct elf_info *elf, Elf_Sym *sym)
+{
+       const char *name = elf->strtab + sym->st_name;
+
+       if (!name || !strlen(name))
+               return 0;
+       return !is_arm_mapping_symbol(name);
+}
+
 /*
  * Find symbols before or equal addr and after addr - in the section sec.
  * 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,
                symsec = secstrings + elf->sechdrs[sym->st_shndx].sh_name;
                if (strcmp(symsec, sec) != 0)
                        continue;
+               if (!is_valid_name(elf, sym))
+                       continue;
                if (sym->st_value <= addr) {
                        if ((addr - sym->st_value) < beforediff) {
                                beforediff = addr - sym->st_value;
                                *before = sym;
                        }
                        else if ((addr - sym->st_value) == beforediff) {
-                               /* equal offset, valid name? */
-                               const char *name = elf->strtab + sym->st_name;
-                               if (name && strlen(name))
-                                       *before = sym;
+                               *before = sym;
                        }
                }
                else
@@ -733,10 +756,7 @@ static void find_symbols_between(struct elf_info *elf, 
Elf_Addr addr,
                                *after = sym;
                        }
                        else if ((sym->st_value - addr) == afterdiff) {
-                               /* equal offset, valid name? */
-                               const char *name = elf->strtab + sym->st_name;
-                               if (name && strlen(name))
-                                       *after = sym;
+                               *after = sym;
                        }
                }
        }
-
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