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| author | Rabin Vincent <rabin@rab.in> | 2011-05-11 22:53:51 +0530 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2011-05-25 19:56:33 -0400 |
| commit | 9905ce8ad7b79dddd23c7b4753d0b2cdb65bde3c (patch) | |
| tree | 72f06d11cf99b20d7e91a1bb65be8a7f20756c65 /scripts/recordmcount.h | |
| parent | 4d7a2fa876d1a615649761dc465708d0a062249a (diff) | |
| download | lwn-9905ce8ad7b79dddd23c7b4753d0b2cdb65bde3c.tar.gz lwn-9905ce8ad7b79dddd23c7b4753d0b2cdb65bde3c.zip | |
ftrace/recordmcount: Avoid STT_FUNC symbols as base on ARM
While find_secsym_ndx often finds the unamed local STT_SECTION, if a
section has only one function in it, the ARM toolchain generates the
STT_FUNC symbol before the STT_SECTION, and recordmcount finds this
instead.
This is problematic on ARM because in ARM ELFs, "if a [STT_FUNC] symbol
addresses a Thumb instruction, its value is the address of the
instruction with bit zero set (in a relocatable object, the section
offset with bit zero set)". This leads to incorrect mcount addresses
being recorded.
Fix this by not using STT_FUNC symbols as the base on ARM.
Signed-off-by: Rabin Vincent <rabin@rab.in>
Link: http://lkml.kernel.org/r/1305134631-31617-1-git-send-email-rabin@rab.in
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'scripts/recordmcount.h')
| -rw-r--r-- | scripts/recordmcount.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h index 4be60364a405..f40a6af6bf40 100644 --- a/scripts/recordmcount.h +++ b/scripts/recordmcount.h @@ -43,6 +43,7 @@ #undef ELF_R_INFO #undef Elf_r_info #undef ELF_ST_BIND +#undef ELF_ST_TYPE #undef fn_ELF_R_SYM #undef fn_ELF_R_INFO #undef uint_t @@ -76,6 +77,7 @@ # define ELF_R_INFO ELF64_R_INFO # define Elf_r_info Elf64_r_info # define ELF_ST_BIND ELF64_ST_BIND +# define ELF_ST_TYPE ELF64_ST_TYPE # define fn_ELF_R_SYM fn_ELF64_R_SYM # define fn_ELF_R_INFO fn_ELF64_R_INFO # define uint_t uint64_t @@ -108,6 +110,7 @@ # define ELF_R_INFO ELF32_R_INFO # define Elf_r_info Elf32_r_info # define ELF_ST_BIND ELF32_ST_BIND +# define ELF_ST_TYPE ELF32_ST_TYPE # define fn_ELF_R_SYM fn_ELF32_R_SYM # define fn_ELF_R_INFO fn_ELF32_R_INFO # define uint_t uint32_t @@ -427,6 +430,11 @@ static unsigned find_secsym_ndx(unsigned const txtndx, if (txtndx == w2(symp->st_shndx) /* avoid STB_WEAK */ && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) { + /* function symbols on ARM have quirks, avoid them */ + if (w2(ehdr->e_machine) == EM_ARM + && ELF_ST_TYPE(symp->st_info) == STT_FUNC) + continue; + *recvalp = _w(symp->st_value); return symp - sym0; } |