From 9648dc15772d77b5431cd5c11675d90eee1a4c2f Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Tue, 18 Oct 2016 16:42:00 -0700 Subject: recordmcount: arm: Implement make_nop 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 Acked-by: Rabin Vincent Signed-off-by: Stephen Boyd Signed-off-by: Steven Rostedt --- scripts/recordmcount.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) (limited to 'scripts') diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c index 5423a58..aeb3422 100644 --- a/scripts/recordmcount.c +++ b/scripts/recordmcount.c @@ -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; -- cgit v1.1