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arm: use bx on thumb2 v3

PATCH New maximilian attems 2 participants 4 messages May 17, 2011 Kbuild

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maximilian attems

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#0 lore raw

PATCH 1/1 arm: use bx on thumb2 v3

Use klibc way to define a system dependent preprocessor
definition: disabled by default and enabled for newer arm.

Based on a patch by vorlon that got tested on his beagleboard, should be functional equivalent.
Fixes: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/527720

Cc Steve Langasek <[email protected]>
Cc Kirill A. Shutemov <[email protected]>
Cc Michael Tokarev <[email protected]>
Signed-off-by maximilian attems <[email protected]>
---
 usr/include/arch/arm/klibc/archconfig.h |    6 +++++-
 usr/include/arch/arm/klibc/asmmacros.h  |    6 ++++++
 usr/include/klibc/sysconfig.h           |    9 +++++++++
 usr/klibc/arch/arm/setjmp.S             |   10 ++++++----
 usr/klibc/arch/arm/vfork.S              |    5 +++--
 5 files changed, 29 insertions(+), 7 deletions(-)
usr/include/arch/arm/klibc/archconfig.h +5 -1
index e34bdb7..36e9ab5 100644
@@ -9,6 +9,10 @@
 #ifndef _KLIBC_ARCHCONFIG_H
 #define _KLIBC_ARCHCONFIG_H
 
-/* All defaults */
+/* newer arm arch support bx instruction */
+#if (!defined(__ARM_ARCH_2__) && !defined(__ARM_ARCH_3__) \
+	&& !defined(__ARM_ARCH_3M__) && !defined(__ARM_ARCH_4__))
+# define _KLIBC_ARM_USE_BX 1
+#endif
 
 #endif				/* _KLIBC_ARCHCONFIG_H */
usr/include/arch/arm/klibc/asmmacros.h +6 -0
index 8a21c94..45bea0e 100644
@@ -27,4 +27,10 @@
 	 (((x) & ~0xf000000f) == 0) || \
 	 (((x) & ~0xc000003f) == 0))
 
+#if _KLIBC_ARM_USE_BX
+# define BX(x) bx	##x
+#else
+# define BX(x) mov	pc, ##x
+#endif
+
 #endif /* _KLIBC_ASMMACROS_H */
usr/include/klibc/sysconfig.h +9 -0
index bf1daf5..a1c37fd 100644
@@ -196,4 +196,13 @@
 # define _KLIBC_SYS_SOCKETCALL 0
 #endif
 
+/*
+ * _KLIBC_ARM_USE_BX
+ *
+ *	This arm architecture supports bx instruction.
+ */
+#ifndef _KLIBC_ARM_USE_BX
+# define _KLIBC_ARM_USE_BX 0
+#endif
+
 #endif /* _KLIBC_SYSCONFIG_H */
usr/klibc/arch/arm/setjmp.S +6 -4
index 2232458..6018bda 100644
@@ -4,6 +4,8 @@
 # setjmp/longjmp for the ARM architecture
 #
 
+#include <klibc/asmmacros.h>
+
 #ifndef	__thumb__
 
 #

@@ -29,7 +31,7 @@
 setjmp:
 	stmia	r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
 	mov	r0, #0
-	mov	pc, lr
+	BX(lr)
 	.size setjmp,.-setjmp
 
 	.text

@@ -39,7 +41,7 @@ setjmp:
 longjmp:
 	ldmia	r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
 	mov	r0, r1
-	mov	pc, lr
+	BX(lr)
 	.size longjmp,.-longjmp
 
 #else /* __thumb__ */

@@ -75,7 +77,7 @@ setjmp:
 	mov	r7, sp
 	stmia	r0!, {r3, r4, r5, r6, r7}
 	mov	r0, #0
-	mov	pc, lr
+	BX(lr)
 	.size setjmp,.-setjmp
 
 	.text

@@ -96,7 +98,7 @@ longjmp:
 	mov	r0, r1
 	bne	1f
 	mov	r0, #1
-1:	mov	pc, r3
+1:	BX(r3)
 	.size longjmp,.-longjmp
 
 #endif /* __thumb__ */
usr/klibc/arch/arm/vfork.S +3 -2
index 3b2d9f7..7130b65 100644
@@ -4,6 +4,7 @@
  * vfork - nasty system call which must not use the stack.
  */
 
+#include <klibc/asmmacros.h>
 #include <asm/unistd.h>
 
 	.type	vfork,#function

@@ -25,7 +26,7 @@ vfork:
         ldrcs	r3, 1f
         mvncs	r0, #0
         strcs	r2, [r3]
-	mov	pc, lr
+	BX(lr)
 
 	.balign 4
 1:

@@ -49,7 +50,7 @@ vfork:
 	str	r2, [r1]
 	neg	r0, r0
 1:
-	mov	pc, lr
+	BX(lr)
 
 	.balign	4
 2:
Signature · 1 line
1.7.2.5
author
#1 lore raw

PATCH 1/1 arm: no usage of ARM_VALID_IMM() anymore

Since bd56c54ae409a2c36d23e61d4075e2d1ffcd1a23 aka klibc 1.4.1 the usage of that macro is gone, so just get rid of it.

Signed-off-by maximilian attems <[email protected]>
---
 usr/include/arch/arm/klibc/asmmacros.h |   20 --------------------
 1 files changed, 0 insertions(+), 20 deletions(-)
usr/include/arch/arm/klibc/asmmacros.h +0 -20
index 8a21c94..b5bade2 100644
@@ -7,24 +7,4 @@
 #ifndef _KLIBC_ASMMACROS_H
 #define _KLIBC_ASMMACROS_H
 
-/* An immediate in ARM can be any 8-bit value rotated by an even number of bits */
-
-#define ARM_VALID_IMM(x)	\
-	((((x) & ~0x000000ff) == 0) || \
-	 (((x) & ~0x000003fc) == 0) || \
-	 (((x) & ~0x00000ff0) == 0) || \
-	 (((x) & ~0x00003fc0) == 0) || \
-	 (((x) & ~0x0000ff00) == 0) || \
-	 (((x) & ~0x0003fc00) == 0) || \
-	 (((x) & ~0x000ff000) == 0) || \
-	 (((x) & ~0x003fc000) == 0) || \
-	 (((x) & ~0x00ff0000) == 0) || \
-	 (((x) & ~0x03fc0000) == 0) || \
-	 (((x) & ~0x0ff00000) == 0) || \
-	 (((x) & ~0x3fc00000) == 0) || \
-	 (((x) & ~0xff000000) == 0) || \
-	 (((x) & ~0xfc000003) == 0) || \
-	 (((x) & ~0xf000000f) == 0) || \
-	 (((x) & ~0xc000003f) == 0))
-
 #endif /* _KLIBC_ASMMACROS_H */
Signature · 1 line
1.7.4.4
#2 lore raw

PATCH 1/1 arm: use bx on thumb2 v3

In reply to maximilian attems
Quoted 40 lines · maximilian attems

Use klibc way to define a system dependent preprocessor
definition: disabled by default and enabled for newer arm.

Based on a patch by vorlon that got tested on his beagleboard, should be functional equivalent.
Fixes: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/527720

Cc Steve Langasek <[email protected]>
Cc Kirill A. Shutemov <[email protected]>
Cc Michael Tokarev <[email protected]>
Signed-off-by maximilian attems <[email protected]>
---
 usr/include/arch/arm/klibc/archconfig.h |    6 +++++-
 usr/include/arch/arm/klibc/asmmacros.h  |    6 ++++++
 usr/include/klibc/sysconfig.h           |    9 +++++++++
 usr/klibc/arch/arm/setjmp.S             |   10 ++++++----
 usr/klibc/arch/arm/vfork.S              |    5 +++--
 5 files changed, 29 insertions(+), 7 deletions(-)
usr/include/arch/arm/klibc/archconfig.h +5 -1
index e34bdb7..36e9ab5 100644
@@ -9,6 +9,10 @@
 #ifndef _KLIBC_ARCHCONFIG_H
 #define _KLIBC_ARCHCONFIG_H
 
-/* All defaults */
+/* newer arm arch support bx instruction */
+#if (!defined(__ARM_ARCH_2__) && !defined(__ARM_ARCH_3__) \
+	&& !defined(__ARM_ARCH_3M__) && !defined(__ARM_ARCH_4__))
+# define _KLIBC_ARM_USE_BX 1
+#endif
 
 #endif				/* _KLIBC_ARCHCONFIG_H */
usr/include/arch/arm/klibc/asmmacros.h +0 -0
index 8a21c94..45bea0e 100644

usr/include/arch/arm/klibc/asmmacros.h line 35

Quoted 9 lines
usr/include/arch/arm/klibc/asmmacros.h +6 -0
@@ -27,4 +27,10 @@
 	 (((x) & ~0xf000000f) == 0) || \
 	 (((x) & ~0xc000003f) == 0))
 
+#if _KLIBC_ARM_USE_BX
+# define BX(x) bx	##x
+#else
+# define BX(x) mov	pc, ##x
+#endif
+

What's the ## for? The C preprocessor collapses whitespace around this operator, so won't this expand to strings like "bxlr" in the _KLIBC_ARM_USE_BX case?

Otherwise this looks OK, though I'm not a klibc expert.

Cheers
---Dave

author
#3 lore raw

PATCH 1/1 arm: use bx on thumb2 v3

Quoted 7 lines · Dave Martin
Quoted 6 lines · maximilian attems
usr/include/arch/arm/klibc/asmmacros.h +0 -0
@@ -27,4 +27,10 @@
 	 (((x) & ~0xf000000f) == 0) || \
 	 (((x) & ~0xc000003f) == 0))
Quoted 10 lines

usr/include/arch/arm/klibc/asmmacros.h line 35

Quoted 6 lines
usr/include/arch/arm/klibc/asmmacros.h +6 -0
+#if _KLIBC_ARM_USE_BX
+# define BX(x) bx	##x
+#else
+# define BX(x) mov	pc, ##x
+#endif
+

What's the ## for? The C preprocessor collapses whitespace around this operator, so won't this expand to strings like "bxlr" in the _KLIBC_ARM_USE_BX case?

good catch, had tested the mov pc, x case on the debian parter box. will just remove them on the merged patch.

Quoted 1 line

Otherwise this looks OK, though I'm not a klibc expert.

thanks for review.

Signature · 1 line
maks