linux-kernel - Re: [PATCH 4/4] ARM: kprobes: make more tests conditional

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Message-ID: <alpine.LFD.2.02.1208221136180.1754@xanadu.home>
Date:	Wed, 22 Aug 2012 11:38:46 -0400 (EDT)
From:	Nicolas Pitre <nicolas.pitre@...aro.org>
To:	Arnd Bergmann <arnd@...db.de>
cc:	Russell King <rmk+kernel@....linux.org.uk>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Jon Medhurst <tixy@...t.co.uk>,
	Leif Lindholm <leif.lindholm@....com>
Subject: Re: [PATCH 4/4] ARM: kprobes: make more tests conditional

On Wed, 22 Aug 2012, Arnd Bergmann wrote:

> On Wednesday 22 August 2012, Nicolas Pitre wrote:
> > On Wed, 22 Aug 2012, Arnd Bergmann wrote:
> > 
> > > The mls instruction is not available in ARMv6K or below, so we
> > > should make the test conditional on at least ARMv7. ldrex/strex
> > > are available in ARMv6K or ARMv7, which we can test by checking
> > > the CONFIG_CPU_32v6K symbol. Just testing for ARMv6 is not enough.
> > 
> > The ldrex/strex instructions are available on ARMv6.  It's only the d 
> > variants (strexd/ldrexd) which are only available from ARMv6k.
> 
> Ok. How is the version below then? I haven't tested this one yet.

In fact, I think the b variants are ARMv6k+ as well.  Only the plain 
(non b non d) variants are available on ARMv6.


> 
> 	Arnd
> 
> 8<---
> From d878ab212cf0ac1957be83ad80dc734ace2b476c Mon Sep 17 00:00:00 2001
> From: Arnd Bergmann <arnd@...db.de>
> Date: Thu, 16 Aug 2012 07:49:31 +0000
> Subject: [PATCH] ARM: kprobes: make more tests conditional
> 
> The mls instruction is not available in ARMv6K or below, so we
> should make the test conditional on at least ARMv7. ldrexd/strexd
> are available in ARMv6K or ARMv7, which we can test by checking
> the CONFIG_CPU_32v6K symbol. Just testing for ARMv6 is not enough.
> 
> /tmp/ccuMTZ8D.s: Assembler messages:
> /tmp/ccuMTZ8D.s:22188: Error: selected processor does not support ARM mode `mls r0,r1,r2,r3'
> /tmp/ccuMTZ8D.s:22222: Error: selected processor does not support ARM mode `mlshi r7,r8,r9,r10'
> /tmp/ccuMTZ8D.s:22252: Error: selected processor does not support ARM mode `mls lr,r1,r2,r13'
> 
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> Cc: Jon Medhurst <tixy@...t.co.uk>
> Cc: Russell King <rmk+kernel@....linux.org.uk>
> Cc: Nicolas Pitre <nicolas.pitre@...aro.org>
> Cc: Leif Lindholm <leif.lindholm@....com>
> ---
>  arch/arm/kernel/kprobes-test-arm.c |    4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm/kernel/kprobes-test-arm.c b/arch/arm/kernel/kprobes-test-arm.c
> index 38c1a3b..fc9f6e0 100644
> --- a/arch/arm/kernel/kprobes-test-arm.c
> +++ b/arch/arm/kernel/kprobes-test-arm.c
> @@ -367,9 +367,11 @@ void kprobe_arm_test_cases(void)
>  	TEST_UNSUPPORTED(".word 0xe0500090 @ undef")
>  	TEST_UNSUPPORTED(".word 0xe05fff9f @ undef")
>  
> +#if __LINUX_ARM_ARCH__ >= 7
>  	TEST_RRR(  "mls		r0, r",1, VAL1,", r",2, VAL2,", r",3,  VAL3,"")
>  	TEST_RRR(  "mlshi	r7, r",8, VAL3,", r",9, VAL1,", r",10, VAL2,"")
>  	TEST_RR(   "mls		lr, r",1, VAL2,", r",2, VAL3,", r13")
> +#endif
>  	TEST_UNSUPPORTED(".word 0xe06f3291 @ mls pc, r1, r2, r3")
>  	TEST_UNSUPPORTED(".word 0xe060329f @ mls r0, pc, r2, r3")
>  	TEST_UNSUPPORTED(".word 0xe0603f91 @ mls r0, r1, pc, r3")
> @@ -456,8 +458,10 @@ void kprobe_arm_test_cases(void)
>  	TEST_UNSUPPORTED(".word	0xe1700090") /* Unallocated space */
>  #if __LINUX_ARM_ARCH__ >= 6
>  	TEST_UNSUPPORTED("ldrex	r2, [sp]")
> +#ifdef CONFIG_CPU_32v6K
>  	TEST_UNSUPPORTED("strexd	r0, r2, r3, [sp]")
>  	TEST_UNSUPPORTED("ldrexd	r2, r3, [sp]")
> +#endif
>  	TEST_UNSUPPORTED("strexb	r0, r2, [sp]")
>  	TEST_UNSUPPORTED("ldrexb	r2, [sp]")
>  	TEST_UNSUPPORTED("strexh	r0, r2, [sp]")
> -- 
> 1.7.10
> 
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