[klibc] fwd: fix up ARM assembly to use 'bx lr' in place of 'mov pc, lr'.

On Wed, Feb 16, 2011 at 3:50 PM, Kirill A. Shutemov
[off-list ref] wrote:

On Thu, Feb 17, 2011 at 12:06:48AM +0100, maximilian attems wrote:

quoted

hello vorlon,

got notified of your patch,
will apply next days upstream unless some critiques are voiced on ml.
thanks.

--
maks


----- Forwarded message from Steve Langasek [off-list ref] -----

Date: Wed, 16 Feb 2011 22:05:42 -0000
From: Steve Langasek <redacted>
Subject: [Bug 527720] Re: thumb2 porting issues identified: klibc uses mov.*pc


I've also touched it up to be mergeable with Debian (support v4t builds
with #ifdef).

Confirmed that installing the resulting klibc packages on my beagleboard
gives me a successfully-booting initramfs with klibc; and the
vfork/setjmptest test cases all pass in the klibc package tree.

Fixes: https://bugs.launchpad.net/ubuntu/+source/klibc/+bug/527720

--- klibc-1.5.20.orig/usr/klibc/arch/arm/vfork.S
+++ klibc-1.5.20/usr/klibc/arch/arm/vfork.S

@@ -25,7 +25,11 @@ vfork:

? ? ? ? ?ldrcs ? ? ? ?r3, 1f
? ? ? ? ?mvncs ? ? ? ?r0, #0
? ? ? ? ?strcs ? ? ? ?r2, [r3]
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)

NAK. ARMv4T supports bx intruction. ARMv4 doesn't.

Does ARMv4t support BX lr ?

quoted

? ? ? mov ? ? pc, lr
+#else
+ ? ? bx ? ? ?lr
+#endif

? ? ? .balign 4
?1:

@@ -49,7 +53,11 @@ vfork:

? ? ? str ? ? r2, [r1]
? ? ? neg ? ? r0, r0
?1:
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
? ? ? mov ? ? pc, lr
+#else
+ ? ? bx ? ? ?lr
+#endif

? ? ? .balign 4
?2:

--- klibc-1.5.20.orig/usr/klibc/arch/arm/setjmp.S
+++ klibc-1.5.20/usr/klibc/arch/arm/setjmp.S

@@ -29,7 +29,11 @@

?setjmp:
? ? ? stmia ? r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
? ? ? mov ? ? r0, #0
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
? ? ? mov ? ? pc, lr
+#else
+ ? ? bx ? ? ?lr
+#endif
? ? ? .size setjmp,.-setjmp

? ? ? .text

@@ -39,7 +43,11 @@ setjmp:

?longjmp:
? ? ? ldmia ? r0, {r4, r5, r6, r7, r8, r9, r10, fp, sp, lr}
? ? ? mov ? ? r0, r1
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
? ? ? mov ? ? pc, lr
+#else
+ ? ? bx ? ? ?lr
+#endif
? ? ? .size longjmp,.-longjmp

?#else /* __thumb__ */

@@ -75,7 +83,11 @@ setjmp:

? ? ? mov ? ? r7, sp
? ? ? stmia ? r0!, {r3, r4, r5, r6, r7}
? ? ? mov ? ? r0, #0
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
? ? ? mov ? ? pc, lr
+#else
+ ? ? bx ? ? ?lr
+#endif
? ? ? .size setjmp,.-setjmp

? ? ? .text

@@ -96,7 +108,11 @@ longjmp:

? ? ? mov ? ? r0, r1
? ? ? bne ? ? 1f
? ? ? mov ? ? r0, #1
+#if defined (___ARM_ARCH_4T__) || defined (__ARM_ARCH_4__)
?1: ? mov ? ? pc, r3
+#else
+1: ? bx ? ? ?r3
+#endif
? ? ? .size longjmp,.-longjmp

?#endif /* __thumb__ */

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--
?Kirill A. Shutemov

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