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recordmcount: arm: Implement make_nop

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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.

Link: http://lkml.kernel.org/r/20161018234200.5804-1-sboyd@codeaurora.org

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Stephen Boyd 2016-10-18 16:42:00 -07:00 committed by Steven Rostedt
parent 8d414bd2f7
commit 9648dc1577
1 changed files with 65 additions and 0 deletions
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65
scripts/recordmcount.c
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@ -213,6 +213,59 @@ static int make_nop_x86(void *map, size_t const offset)
return 0;
}
static unsigned char ideal_nop4_arm_le[4] = { 0x00, 0x00, 0xa0, 0xe1 }; /* mov r0, r0 */
static unsigned char ideal_nop4_arm_be[4] = { 0xe1, 0xa0, 0x00, 0x00 }; /* mov r0, r0 */
static unsigned char *ideal_nop4_arm;
static unsigned char bl_mcount_arm_le[4] = { 0xfe, 0xff, 0xff, 0xeb }; /* bl */
static unsigned char bl_mcount_arm_be[4] = { 0xeb, 0xff, 0xff, 0xfe }; /* bl */
static unsigned char *bl_mcount_arm;
static unsigned char push_arm_le[4] = { 0x04, 0xe0, 0x2d, 0xe5 }; /* push {lr} */
static unsigned char push_arm_be[4] = { 0xe5, 0x2d, 0xe0, 0x04 }; /* push {lr} */
static unsigned char *push_arm;
static unsigned char ideal_nop2_thumb_le[2] = { 0x00, 0xbf }; /* nop */
static unsigned char ideal_nop2_thumb_be[2] = { 0xbf, 0x00 }; /* nop */
static unsigned char *ideal_nop2_thumb;
static unsigned char push_bl_mcount_thumb_le[6] = { 0x00, 0xb5, 0xff, 0xf7, 0xfe, 0xff }; /* push {lr}, bl */
static unsigned char push_bl_mcount_thumb_be[6] = { 0xb5, 0x00, 0xf7, 0xff, 0xff, 0xfe }; /* push {lr}, bl */
static unsigned char *push_bl_mcount_thumb;
static int make_nop_arm(void *map, size_t const offset)
{
char *ptr;
int cnt = 1;
int nop_size;
size_t off = offset;
ptr = map + offset;
if (memcmp(ptr, bl_mcount_arm, 4) == 0) {
if (memcmp(ptr - 4, push_arm, 4) == 0) {
off -= 4;
cnt = 2;
}
ideal_nop = ideal_nop4_arm;
nop_size = 4;
} else if (memcmp(ptr - 2, push_bl_mcount_thumb, 6) == 0) {
cnt = 3;
nop_size = 2;
off -= 2;
ideal_nop = ideal_nop2_thumb;
} else
return -1;
/* Convert to nop */
ulseek(fd_map, off, SEEK_SET);
do {
uwrite(fd_map, ideal_nop, nop_size);
} while (--cnt > 0);
return 0;
}
static unsigned char ideal_nop4_arm64[4] = {0x1f, 0x20, 0x03, 0xd5};
static int make_nop_arm64(void *map, size_t const offset)
{
@ -430,6 +483,11 @@ do_file(char const *const fname)
w2 = w2rev;
w8 = w8rev;
}
ideal_nop4_arm = ideal_nop4_arm_le;
bl_mcount_arm = bl_mcount_arm_le;
push_arm = push_arm_le;
ideal_nop2_thumb = ideal_nop2_thumb_le;
push_bl_mcount_thumb = push_bl_mcount_thumb_le;
break;
case ELFDATA2MSB:
if (*(unsigned char const *)&endian != 0) {
@ -438,6 +496,11 @@ do_file(char const *const fname)
w2 = w2rev;
w8 = w8rev;
}
ideal_nop4_arm = ideal_nop4_arm_be;
bl_mcount_arm = bl_mcount_arm_be;
push_arm = push_arm_be;
ideal_nop2_thumb = ideal_nop2_thumb_be;
push_bl_mcount_thumb = push_bl_mcount_thumb_be;
break;
} /* end switch */
if (memcmp(ELFMAG, ehdr->e_ident, SELFMAG) != 0
@ -463,6 +526,8 @@ 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;
break;
case EM_AARCH64:
reltype = R_AARCH64_ABS64;