On Tue, 2 Mar 2021 17:30:58 -0500 Steven Rostedt <rost...@goodmis.org> wrote:
> I just realized that I received this patch twice, and thought it was the > same patch! Chen was three days ahead of you, so he get's the credit ;-) > > https://lore.kernel.org/r/20210222135840.56250-1-chenjun...@huawei.com I'm applying this patch (same one here but came earlier). Will, you still OK with your acked-by on it? -- Steve >From 999340d51174ce4141dd723105d4cef872b13ee9 Mon Sep 17 00:00:00 2001 From: Chen Jun <chenjun...@huawei.com> Date: Mon, 22 Feb 2021 13:58:40 +0000 Subject: [PATCH] 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-chenjun...@huawei.com Fixes: ea0eada45632 ("recordmcount: only record relocation of type R_AARCH64_CALL26 on arm64.") Acked-by: Will Deacon <w...@kernel.org> Signed-off-by: Chen Jun <chenjun...@huawei.com> Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> --- scripts/recordmcount.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) 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. -- 2.25.4
