From: Guenter Roeck <linux@xxxxxxxxxxxx>
Subject: scripts/kallsyms.c: ignore symbol type 'n'
gcc on aarch64 may emit synbols of type 'n' if the kernel is built with
'-frecord-gcc-switches'. In most cases, those symbols are reported with
nm as
000000000000000e n $d
and with objdump as
0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line
000000000000000e l .GCC.command.line 0000000000000000 $d
Those symbols are detected in is_arm_mapping_symbol() and ignored.
However, if "--prefix-symbols=<prefix>" is configured as well, the
situation is different. For example, in efi/libstub, arm64 images are
built with
'--prefix-alloc-sections=.init --prefix-symbols=__efistub_'.
In combination with '-frecord-gcc-switches', the symbols are now reported
by nm as:
000000000000000e n __efistub_$d
and by objdump as:
0000000000000000 l d .GCC.command.line 0000000000000000 .GCC.command.line
000000000000000e l .GCC.command.line 0000000000000000 __efistub_$d
Those symbols are no longer ignored and included in the base address
calculation. This results in a base address of 000000000000000e, which in
turn causes kallsyms to abort with
kallsyms failure:
relative symbol value 0xffffff900800a000 out of range in relative mode
The problem is seen in little endian arm64 builds with CONFIG_EFI enabled
and with '-frecord-gcc-switches' set in KCFLAGS.
Explicitly ignore symbols of type 'n' since those are clearly debug
symbols.
Link: http://lkml.kernel.org/r/1507136063-3139-1-git-send-email-linux@xxxxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
scripts/kallsyms.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN scripts/kallsyms.c~scripts-kallsyms-ignore-symbol-type-n scripts/kallsyms.c
--- a/scripts/kallsyms.c~scripts-kallsyms-ignore-symbol-type-n
+++ a/scripts/kallsyms.c
@@ -158,7 +158,7 @@ static int read_symbol(FILE *in, struct
else if (str[0] == '$')
return -1;
/* exclude debugging symbols */
- else if (stype == 'N')
+ else if (stype == 'N' || stype == 'n')
return -1;
/* include the type field in the symbol name, so that it gets
_
--
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