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

[Khem Raj]

On Wed, Feb 16, 2011 at 3:50 PM, Kirill A. Shutemov
<kirill at shutemov.name> wrote:
> On Thu, Feb 17, 2011 at 12:06:48AM +0100, maximilian attems wrote:
>> 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 <steve.langasek at canonical.com> -----
>>
>> Date: Wed, 16 Feb 2011 22:05:42 -0000
>> From: Steve Langasek <steve.langasek at canonical.com>
>> 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 ?


>
>>       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__ */
>>
>> _______________________________________________
>> klibc mailing list
>> klibc at zytor.com
>> http://www.zytor.com/mailman/listinfo/klibc
>
> --
>  Kirill A. Shutemov
>
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