@@ -42,6 +42,7 @@
#ifndef EM_AARCH64
#define EM_AARCH64 183
+#define R_AARCH64_NONE 0
#define R_AARCH64_ABS64 257
#endif
@@ -160,6 +161,22 @@ static int make_nop_x86(void *map, size_t const offset)
return 0;
}
+static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
+static int make_nop_arm64(void *map, size_t const offset)
+{
+ uint32_t *ptr;
+
+ ptr = map + offset;
+ /* bl <_mcount> is 0x94000000 before relocation */
+ if (*ptr != 0x94000000)
+ return -1;
+
+ /* Convert to nop */
+ ulseek(fd_map, offset, SEEK_SET);
+ uwrite(fd_map, ideal_nop, 4);
+ return 0;
+}
+
/*
* Get the whole file as a programming convenience in order to avoid
* malloc+lseek+read+free of many pieces. If successful, then mmap
@@ -353,7 +370,12 @@ do_file(char const *const fname)
altmcount = "__gnu_mcount_nc";
break;
case EM_AARCH64:
- reltype = R_AARCH64_ABS64; gpfx = '_'; break;
+ reltype = R_AARCH64_ABS64;
+ make_nop = make_nop_arm64;
+ rel_type_nop = R_AARCH64_NONE;
+ ideal_nop = ideal_nop4_arm64;
+ gpfx = '_';
+ break;
case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break;
case EM_METAG: reltype = R_METAG_ADDR32;
altmcount = "_mcount_wrapper";
This is a note to let you know that I have just added a patch titled recordmcount: arm64: Replace the ignored mcount call into nop to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue This patch is scheduled to be released in version 4.2.8-ckt1. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 4.2.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From b88c1d09987d3b3b9b0ed037e9b66f46f2afc0e6 Mon Sep 17 00:00:00 2001 From: Li Bin <huawei.libin@huawei.com> Date: Fri, 30 Oct 2015 16:31:04 +0800 Subject: recordmcount: arm64: Replace the ignored mcount call into nop commit 2ee8a74f2a5da913637f75a19a0da0e7a08c0f86 upstream. By now, the recordmcount only records the function that in following sections: .text/.ref.text/.sched.text/.spinlock.text/.irqentry.text/ .kprobes.text/.text.unlikely For the function that not in these sections, the call mcount will be in place and not be replaced when kernel boot up. And it will bring performance overhead, such as do_mem_abort (in .exception.text section). This patch make the call mcount to nop for this case in recordmcount. Link: http://lkml.kernel.org/r/1446019445-14421-1-git-send-email-huawei.libin@huawei.com Link: http://lkml.kernel.org/r/1446193864-24593-4-git-send-email-huawei.libin@huawei.com Cc: <lkp@intel.com> Cc: <catalin.marinas@arm.com> Cc: <takahiro.akashi@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Li Bin <huawei.libin@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- scripts/recordmcount.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) -- 1.9.1