[PATCH] arm: fix compilation of entry-common.S for older CPUs

[PATCH] arm: fix compilation of entry-common.S for older CPUs

[Dmitry Artamonow]

Commit 181f817eaaca4c1f introduced some new code to entry-common.S
Sadly, this new code uses 'bx' instruction which is available only on
ARMv5 and higher CPUs. This causes following compilation errors when
building kernel for StrongARM (ARMv4):

arch/arm/kernel/entry-common.S: Assembler messages:
arch/arm/kernel/entry-common.S:129: Error: selected processor does not
 support `bx ip'
arch/arm/kernel/entry-common.S:138: Error: selected processor does not
 support `bx ip'

Fix these errors by using 'mov pc' instead of 'bx'.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
---
 arch/arm/kernel/entry-common.S |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

Please note that I haven't tested this change on hardware as I don't
have needed toolchain (GCC 4.4+).

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 807cfeb..825db52 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -126,7 +126,7 @@ ENTRY(__gnu_mcount_nc)
 	cmp r0, r2
 	bne gnu_trace
 	ldmia sp!, {r0-r3, ip, lr}
-	bx ip
+	mov pc, ip
 
 gnu_trace:
 	ldr r1, [sp, #20]			@ lr of instrumented routine
@@ -135,7 +135,7 @@ gnu_trace:
 	mov lr, pc
 	mov pc, r2
 	ldmia sp!, {r0-r3, ip, lr}
-	bx ip
+	mov pc, ip
 
 ENTRY(mcount)
 	stmdb sp!, {r0-r3, lr}
-- 
1.6.3.4

[PATCH] arm: fix compilation of entry-common.S for older CPUs

[Uwe Kleine-König]

Hello,

On Fri, Sep 18, 2009 at 06:55:45PM +0400, Dmitry Artamonow wrote:
> Commit 181f817eaaca4c1f introduced some new code to entry-common.S
> Sadly, this new code uses 'bx' instruction which is available only on
> ARMv5 and higher CPUs. This causes following compilation errors when
> building kernel for StrongARM (ARMv4):
> 
> arch/arm/kernel/entry-common.S: Assembler messages:
> arch/arm/kernel/entry-common.S:129: Error: selected processor does not
>  support `bx ip'
> arch/arm/kernel/entry-common.S:138: Error: selected processor does not
>  support `bx ip'
> 
> Fix these errors by using 'mov pc' instead of 'bx'.
> 
> Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Acked-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>

I wonder if newer glibc's have the same problem as the code is taken
more or less from there ...

Thanks
Uwe

-- 
Pengutronix e.K.                              | Uwe Kleine-K?nig            |
Industrial Linux Solutions                    | http://www.pengutronix.de/  |

[PATCH] arm: fix compilation of entry-common.S for older CPUs

[Dmitry Artamonow]

On 18:27 Fri 18 Sep     , Uwe Kleine-K?nig wrote:
> Hello,
> 
> On Fri, Sep 18, 2009 at 06:55:45PM +0400, Dmitry Artamonow wrote:
> > Commit 181f817eaaca4c1f introduced some new code to entry-common.S
> > Sadly, this new code uses 'bx' instruction which is available only on
> > ARMv5 and higher CPUs. This causes following compilation errors when
> > building kernel for StrongARM (ARMv4):
> > 
> > arch/arm/kernel/entry-common.S: Assembler messages:
> > arch/arm/kernel/entry-common.S:129: Error: selected processor does not
> >  support `bx ip'
> > arch/arm/kernel/entry-common.S:138: Error: selected processor does not
> >  support `bx ip'
> > 
> > Fix these errors by using 'mov pc' instead of 'bx'.
> > 
> > Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
> Acked-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
> 
> I wonder if newer glibc's have the same problem as the code is taken
> more or less from there ...
> 
> Thanks
> Uwe

Russell, are you ok with this fix? Should I submit patch to your patch
tracker?

(It seems that first time around patch didn't get through to you, due to your
server being picky about SMTP servers without matching reverse DNS, so
in case you haven't seen the patch on the list, I'm attaching it here again)

-- 
Best regards,
Dmitry "MAD" Artamonow

[PATCH] arm: fix compilation of entry-common.S for older CPUs

[Russell King - ARM Linux]

On Mon, Sep 28, 2009 at 11:41:22PM +0400, Dmitry Artamonow wrote:
> Russell, are you ok with this fix? Should I submit patch to your patch
> tracker?

Yes please.

[PATCH] arm: fix compilation of entry-common.S for older CPUs

[Dmitry Artamonow]

Commit 181f817eaaca4c1f introduced some new code to entry-common.S
Sadly, this new code uses 'bx' instruction which is available only on
ARMv5 and higher CPUs. This causes following compilation errors when
building kernel for StrongARM (ARMv4):

arch/arm/kernel/entry-common.S: Assembler messages:
arch/arm/kernel/entry-common.S:129: Error: selected processor does not
 support `bx ip'
arch/arm/kernel/entry-common.S:138: Error: selected processor does not
 support `bx ip'

Fix these errors by using 'mov pc' instead of 'bx'.

Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
---
 arch/arm/kernel/entry-common.S |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

Please note that I haven't tested this change on hardware as I don't
have needed toolchain (GCC 4.4+).

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 807cfeb..825db52 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -126,7 +126,7 @@ ENTRY(__gnu_mcount_nc)
 	cmp r0, r2
 	bne gnu_trace
 	ldmia sp!, {r0-r3, ip, lr}
-	bx ip
+	mov pc, ip
 
 gnu_trace:
 	ldr r1, [sp, #20]			@ lr of instrumented routine
@@ -135,7 +135,7 @@ gnu_trace:
 	mov lr, pc
 	mov pc, r2
 	ldmia sp!, {r0-r3, ip, lr}
-	bx ip
+	mov pc, ip
 
 ENTRY(mcount)
 	stmdb sp!, {r0-r3, lr}
-- 
1.6.3.4


--envbJBWh7q8WU6mo--