linux-kernel - [PATCH 09/10] ARM: ftrace: add Thumb-2 support to dynamic ftrace

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Date:	Sun, 14 Feb 2010 01:18:37 +0530
From:	Rabin Vincent <rabin@....in>
To:	linux-kernel@...r.kernel.org
Cc:	linux-arm-kernel@...ts.infradead.org, Rabin Vincent <rabin@....in>,
	Catalin Marinas <catalin.marinas@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...hat.com>,
	Abhishek Sagar <sagar.abhishek@...il.com>,
	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Subject: [PATCH 09/10] ARM: ftrace: add Thumb-2 support to dynamic ftrace

Handle the different nop and call instructions for Thumb-2.  Also, we
need to adjust the recorded mcount_loc addresses because they have the
lsb set.

Cc: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Rabin Vincent <rabin@....in>
---
 arch/arm/include/asm/ftrace.h |    4 ++++
 arch/arm/kernel/ftrace.c      |   33 +++++++++++++++++++++++++++++++++
 scripts/recordmcount.pl       |    2 +-
 3 files changed, 38 insertions(+), 1 deletions(-)

diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h
index 4a56a2e..0845f2d 100644
--- a/arch/arm/include/asm/ftrace.h
+++ b/arch/arm/include/asm/ftrace.h
@@ -18,7 +18,11 @@ struct dyn_arch_ftrace {
 
 static inline unsigned long ftrace_call_adjust(unsigned long addr)
 {
+#ifdef CONFIG_THUMB2_KERNEL
+	return addr & ~1;
+#else
 	return addr;
+#endif
 }
 
 extern void ftrace_caller_old(void);
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c
index f09014c..971ac8c 100644
--- a/arch/arm/kernel/ftrace.c
+++ b/arch/arm/kernel/ftrace.c
@@ -18,7 +18,11 @@
 #include <asm/cacheflush.h>
 #include <asm/ftrace.h>
 
+#ifdef CONFIG_THUMB2_KERNEL
+#define	NOP		0xeb04f85d	/* pop.w {lr} */
+#else
 #define	NOP		0xe8bd4000	/* pop {lr} */
+#endif
 
 #ifdef CONFIG_OLD_MCOUNT
 #define OLD_MCOUNT_ADDR	((unsigned long) mcount)
@@ -56,6 +60,34 @@ static unsigned long adjust_address(struct dyn_ftrace *rec, unsigned long addr)
 #endif
 
 /* construct a branch (BL) instruction to addr */
+#ifdef CONFIG_THUMB2_KERNEL
+static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
+{
+	unsigned long s, j1, j2, i1, i2, imm10, imm11;
+	unsigned long first, second;
+	long offset;
+
+	offset = (long)addr - (long)(pc + 4);
+	if (offset < -16777216 || offset > 16777214) {
+		WARN_ON_ONCE(1);
+		return 0;
+	}
+
+	s	= (offset >> 24) & 0x1;
+	i1	= (offset >> 23) & 0x1;
+	i2	= (offset >> 22) & 0x1;
+	imm10	= (offset >> 12) & 0x3ff;
+	imm11	= (offset >>  1) & 0x7ff;
+
+	j1 = (!i1) ^ s;
+	j2 = (!i2) ^ s;
+
+	first = 0xf000 | (s << 10) | imm10;
+	second = 0xd000 | (j1 << 13) | (j2 << 11) | imm11;
+
+	return (second << 16) | first;
+}
+#else
 static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
 {
 	long offset;
@@ -73,6 +105,7 @@ static unsigned long ftrace_call_replace(unsigned long pc, unsigned long addr)
 
 	return 0xeb000000 | offset;
 }
+#endif
 
 static int ftrace_modify_code(unsigned long pc, unsigned long old,
 			      unsigned long new)
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 66c1c4b..88b083b 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -267,7 +267,7 @@ if ($arch eq "x86_64") {
 } elsif ($arch eq "arm") {
     $alignment = 2;
     $section_type = '%progbits';
-    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24)" .
+    $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" .
 			"\\s+(__gnu_mcount_nc|mcount)\$";
 
 } elsif ($arch eq "ia64") {
-- 
1.6.6

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