Patchwork [v2] PowerPC: kernel: compiling issue, make additional room in exception vector area

login
register
mail settings
Submitter Chen Gang
Date April 25, 2013, 11:51 a.m.
Message ID <517918AB.4020508@asianux.com>
Download mbox | patch
Permalink /patch/239501/
State Rejected
Headers show

Comments

Chen Gang - April 25, 2013, 11:51 a.m.
When CONFIG_KVM_BOOK3S_64_PR is enabled,
MASKABLE_EXCEPTION_PSERIES(0x900 ...) will includes __KVMTEST, it will
exceed 0x980 which STD_EXCEPTION_HV(0x980 ...) will use, it will cause
compiling issue.

The related errors:
arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
arch/powerpc/kernel/exceptions-64s.S:258: Error: attempt to move .org backwards
make[1]: *** [arch/powerpc/kernel/head_64.o] Error 1

The position 0x900 and 0x980 are solid, so can not move the position
to make room larger. The final solution is to jump to another area to
execute the related code.


Signed-off-by: Chen Gang <gang.chen@asianux.com>
---
 arch/powerpc/kernel/exceptions-64s.S |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)
Chen Gang - April 25, 2013, 11:58 a.m.
Hello Mike:

This patch can pass compiling with Mike's config file, under my
cross-compiling environments, but does not run under the real machine,
please try it.

Welcome other members to help check this patch whether valid.

Thanks.


On 2013年04月25日 19:51, Chen Gang wrote:
> 
> When CONFIG_KVM_BOOK3S_64_PR is enabled,
> MASKABLE_EXCEPTION_PSERIES(0x900 ...) will includes __KVMTEST, it will
> exceed 0x980 which STD_EXCEPTION_HV(0x980 ...) will use, it will cause
> compiling issue.
> 
> The related errors:
> arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
> arch/powerpc/kernel/exceptions-64s.S:258: Error: attempt to move .org backwards
> make[1]: *** [arch/powerpc/kernel/head_64.o] Error 1
> 
> The position 0x900 and 0x980 are solid, so can not move the position
> to make room larger. The final solution is to jump to another area to
> execute the related code.
> 
> 
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
>  arch/powerpc/kernel/exceptions-64s.S |   12 +++++++++++-
>  1 files changed, 11 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index e789ee7..8997de2 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -254,7 +254,11 @@ hardware_interrupt_hv:
>  	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
>  	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
>  
> -	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
> +	. = 0x900
> +	.globl decrementer_pSeries
> +decrementer_pSeries:
> +	b	decrementer_pSeries_0
> +
>  	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
>  
>  	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
> @@ -536,6 +540,12 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
>  #endif
>  
>  	.align	7
> +	/* moved from 0x900 */
> +decrementer_pSeries_0:
> +	_MASKABLE_EXCEPTION_PSERIES(0x900, decrementer,
> +				    EXC_STD, SOFTEN_TEST_PR)
> +
> +	.align	7
>  	/* moved from 0xe00 */
>  	STD_EXCEPTION_HV_OOL(0xe02, h_data_storage)
>  	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0xe02)
>
Michael Neuling - April 25, 2013, 11:16 p.m.
Chen Gang <gang.chen@asianux.com> wrote:

> 
> When CONFIG_KVM_BOOK3S_64_PR is enabled,
> MASKABLE_EXCEPTION_PSERIES(0x900 ...) will includes __KVMTEST, it will
> exceed 0x980 which STD_EXCEPTION_HV(0x980 ...) will use, it will cause
> compiling issue.
> 
> The related errors:
> arch/powerpc/kernel/exceptions-64s.S: Assembler messages:
> arch/powerpc/kernel/exceptions-64s.S:258: Error: attempt to move .org backwards
> make[1]: *** [arch/powerpc/kernel/head_64.o] Error 1
> 
> The position 0x900 and 0x980 are solid, so can not move the position
> to make room larger. The final solution is to jump to another area to
> execute the related code.
> 
> 
> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> ---
>  arch/powerpc/kernel/exceptions-64s.S |   12 +++++++++++-
>  1 files changed, 11 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index e789ee7..8997de2 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -254,7 +254,11 @@ hardware_interrupt_hv:
>  	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
>  	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
>  
> -	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
> +	. = 0x900
> +	.globl decrementer_pSeries
> +decrementer_pSeries:
> +	b	decrementer_pSeries_0
> +

Unfortunately you can't do this ether as we need to save the CFAR[1]
before it's overwritten by any branch. MASKABLE_EXCEPTION_PSERIES does
this.

CFAR is the Come From Register.  It saves the location of the last
branch and is hence overwritten by any branch.

Thanks for trying.

Mikey

>  	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
>  
>  	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
> @@ -536,6 +540,12 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
>  #endif
>  
>  	.align	7
> +	/* moved from 0x900 */
> +decrementer_pSeries_0:
> +	_MASKABLE_EXCEPTION_PSERIES(0x900, decrementer,
> +				    EXC_STD, SOFTEN_TEST_PR)
> +
> +	.align	7
>  	/* moved from 0xe00 */
>  	STD_EXCEPTION_HV_OOL(0xe02, h_data_storage)
>  	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0xe02)
> -- 
> 1.7.7.6
> 
>
Chen Gang - April 26, 2013, 1:06 a.m.
On 2013年04月26日 07:16, Michael Neuling wrote:
>> > diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
>> > index e789ee7..8997de2 100644
>> > --- a/arch/powerpc/kernel/exceptions-64s.S
>> > +++ b/arch/powerpc/kernel/exceptions-64s.S
>> > @@ -254,7 +254,11 @@ hardware_interrupt_hv:
>> >  	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
>> >  	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
>> >  
>> > -	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
>> > +	. = 0x900
>> > +	.globl decrementer_pSeries
>> > +decrementer_pSeries:
>> > +	b	decrementer_pSeries_0
>> > +
> Unfortunately you can't do this ether as we need to save the CFAR[1]
> before it's overwritten by any branch. MASKABLE_EXCEPTION_PSERIES does
> this.
> 

Thanks for your checking.

> CFAR is the Come From Register.  It saves the location of the last
> branch and is hence overwritten by any branch.
> 

Do we process it just like others done (e.g. 0x300, 0xe00, 0xe20 ...) ?
	. = 0x900
	.globl decrementer_pSeries
decrementer_pSeries:
 	HMT_MEDIUM_PPR_DISCARD
	SET_SCRATCH0(r13)
	b decrementer_pSeries_0

	...


> Thanks for trying.
> 

Not at all, before get fixed by other members, I should continue trying.

Patch

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index e789ee7..8997de2 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -254,7 +254,11 @@  hardware_interrupt_hv:
 	STD_EXCEPTION_PSERIES(0x800, 0x800, fp_unavailable)
 	KVM_HANDLER_PR(PACA_EXGEN, EXC_STD, 0x800)
 
-	MASKABLE_EXCEPTION_PSERIES(0x900, 0x900, decrementer)
+	. = 0x900
+	.globl decrementer_pSeries
+decrementer_pSeries:
+	b	decrementer_pSeries_0
+
 	STD_EXCEPTION_HV(0x980, 0x982, hdecrementer)
 
 	MASKABLE_EXCEPTION_PSERIES(0xa00, 0xa00, doorbell_super)
@@ -536,6 +540,12 @@  ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_206)
 #endif
 
 	.align	7
+	/* moved from 0x900 */
+decrementer_pSeries_0:
+	_MASKABLE_EXCEPTION_PSERIES(0x900, decrementer,
+				    EXC_STD, SOFTEN_TEST_PR)
+
+	.align	7
 	/* moved from 0xe00 */
 	STD_EXCEPTION_HV_OOL(0xe02, h_data_storage)
 	KVM_HANDLER_SKIP(PACA_EXGEN, EXC_HV, 0xe02)