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Message-Id: <20161018234200.5804-1-sboyd@codeaurora.org>
Date: Tue, 18 Oct 2016 16:42:00 -0700
From: Stephen Boyd <sboyd@...eaurora.org>
To: "Steven Rostedt (Red Hat)" <rostedt@...dmis.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Andrew Morton <akpm@...ux-foundation.org>,
Russell King <linux@....linux.org.uk>
Subject: [PATCH/RESEND] 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.
Cc: Russell King <linux@....linux.org.uk>
Acked-by: Rabin Vincent <rabin@....in>
Signed-off-by: Stephen Boyd <sboyd@...eaurora.org>
---
scripts/recordmcount.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 5423a58d1b06..aeb34223167c 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;
--
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