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authorChen Jun <chenjun102@huawei.com>2021-02-22 13:58:40 +0000
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-03-02 17:27:18 -0500
commit999340d51174ce4141dd723105d4cef872b13ee9 (patch)
treece1bec2d1cefe4c2969d7fb23ce71de5e076d3d5
parentfe07bfda2fb9cdef8a4d4008a409bb02f35f1bd8 (diff)
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>
-rw-r--r--scripts/recordmcount.c2
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.