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| author | Chen Jun <chenjun102@huawei.com> | 2021-02-22 13:58:40 +0000 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-03-02 17:27:18 -0500 |
| commit | 999340d51174ce4141dd723105d4cef872b13ee9 (patch) | |
| tree | ce1bec2d1cefe4c2969d7fb23ce71de5e076d3d5 /scripts | |
| parent | fe07bfda2fb9cdef8a4d4008a409bb02f35f1bd8 (diff) | |
| download | lwn-999340d51174ce4141dd723105d4cef872b13ee9.tar.gz lwn-999340d51174ce4141dd723105d4cef872b13ee9.zip | |
ftrace: Have recordmcount use w8 to read relp->r_info in arm64_is_fake_mcount
On little endian system, Use aarch64_be(gcc v7.3) downloaded from
linaro.org to build image with CONFIG_CPU_BIG_ENDIAN = y,
CONFIG_FTRACE = y, CONFIG_DYNAMIC_FTRACE = y.
gcc will create symbols of _mcount but recordmcount can not create
mcount_loc for *.o.
aarch64_be-linux-gnu-objdump -r fs/namei.o | grep mcount
00000000000000d0 R_AARCH64_CALL26 _mcount
...
0000000000007190 R_AARCH64_CALL26 _mcount
The reason is than funciton arm64_is_fake_mcount can not work correctly.
A symbol of _mcount in *.o compiled with big endian compiler likes:
00 00 00 2d 00 00 01 1b
w(rp->r_info) will return 0x2d instead of 0x011b. Because w() takes
uint32_t as parameter, which truncates rp->r_info.
Use w8() instead w() to read relp->r_info
Link: https://lkml.kernel.org/r/20210222135840.56250-1-chenjun102@huawei.com
Fixes: ea0eada45632 ("recordmcount: only record relocation of type R_AARCH64_CALL26 on arm64.")
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/recordmcount.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index b9c2ee7ab43f..cce12e1971d8 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -438,7 +438,7 @@ static int arm_is_fake_mcount(Elf32_Rel const *rp) static int arm64_is_fake_mcount(Elf64_Rel const *rp) { - return ELF64_R_TYPE(w(rp->r_info)) != R_AARCH64_CALL26; + return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26; } /* 64-bit EM_MIPS has weird ELF64_Rela.r_info. |