In similar spirit to x86 and arm64 support, add a make_nop_arm()
to replace calls to mcount with a "nop" in sections that aren't
traced.
Cc: Russell King <li...@arm.linux.org.uk>
Cc: Rabin Vincent <ra...@rab.in>
Signed-off-by: Stephen Boyd <sb...@codeaurora.org>
---
scripts/recordmcount.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
scripts/recordmcount.h | 3 ++-
2 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index e167592793a7..0b16d14c54fb 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -206,6 +206,52 @@ static int make_nop_x86(void *map, size_t const offset)
return 0;
}
+/*
+ * Indicates if ARM is using __gnu_mcount_nc or mcount style and if
+ * we should replace it with a pop or a nop respectively.
+ */
+static int uses_altmcount;
+
+static unsigned char ideal_nop4_arm_arm[4] = { 0x00, 0x40, 0xbd, 0xe8 };
+static unsigned char ideal_nop4_arm_thumb[4] = { 0x5d, 0xf8, 0x04, 0xeb };
+static unsigned char ideal_nop4_arm_arm_be[4] = { 0xe8, 0xbd, 0x40, 0x00 };
+static unsigned char ideal_nop4_arm_thumb_be[4] = { 0xf8, 0x5d, 0xeb, 0x04 };
+static unsigned char ideal_nop4_arm_old[4] = { 0x00, 0x00, 0xa0, 0xe1 };
+static unsigned char ideal_nop4_arm_old_be[4] = { 0xe1, 0xa0, 0x00, 0x00 };
+
+static unsigned char bl_gnu_mcount_nc_arm[4] = { 0xfe, 0xff, 0xff, 0xeb };
+static unsigned char bl_gnu_mcount_nc_thumb[4] = { 0xff, 0xf7, 0xfe, 0xff };
+static unsigned char bl_gnu_mcount_nc_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe };
+static unsigned char bl_gnu_mcount_nc_thumb_be[4] = { 0xf7, 0xff, 0xff, 0xfe };
+
+static int make_nop_arm(void *map, size_t const offset)
+{
+ uint32_t *ptr;
+
+ ptr = map + offset;
+ if (memcmp(ptr, bl_gnu_mcount_nc_arm, 4) == 0) {
+ if (uses_altmcount)
+ ideal_nop = ideal_nop4_arm_arm;
+ else
+ ideal_nop = ideal_nop4_arm_old;
+ } else if (memcmp(ptr, bl_gnu_mcount_nc_arm_be, 4) == 0) {
+ if (uses_altmcount)
+ ideal_nop = ideal_nop4_arm_arm_be;
+ else
+ ideal_nop = ideal_nop4_arm_old_be;
+ } else if (memcmp(ptr, bl_gnu_mcount_nc_thumb, 4) == 0)
+ ideal_nop = ideal_nop4_arm_thumb;
+ else if (memcmp(ptr, bl_gnu_mcount_nc_thumb_be, 4) == 0)
+ ideal_nop = ideal_nop4_arm_thumb_be;
+ else
+ return -1;
+
+ /* Convert to nop */
+ ulseek(fd_map, offset, SEEK_SET);
+ uwrite(fd_map, ideal_nop, 4);
+ return 0;
+}
+
static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
static int make_nop_arm64(void *map, size_t const offset)
{
@@ -454,6 +500,9 @@ do_file(char const *const fname)
break;
case EM_ARM: reltype = R_ARM_ABS32;
altmcount = "__gnu_mcount_nc";
+ make_nop = make_nop_arm;
+ rel_type_nop = R_ARM_NONE;
+ ideal_nop = ideal_nop4_arm_arm;
break;
case EM_AARCH64:
reltype = R_AARCH64_ABS64;
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index b9897e2be404..890f5211745f 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -266,7 +266,8 @@ static unsigned get_mcountsym(Elf_Sym const *const sym0,
if (symname[0] == '.')
++symname; /* ppc64 hack */
if (strcmp(mcount, symname) == 0 ||
- (altmcount && strcmp(altmcount, symname) == 0) ||
+ (altmcount && strcmp(altmcount, symname) == 0 &&
+ (uses_altmcount = 1)) ||
(strcmp(fentry, symname) == 0))
mcountsym = Elf_r_sym(relp);
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
