[PATCH] ARM: proc-v7: fix Thumb annotation of cpu_v7_hvc_switch_mm

[Dave.Martin@arm.com (Dave Martin)]

On Tue, Jun 19, 2018 at 06:29:19PM +0200, Ard Biesheuvel wrote:
> Due to what appears to be a copy/paste error, the opening ENTRY()
> of cpu_v7_hvc_switch_mm() lacks a matching ENDPROC(), and instead,
> the one for cpu_v7_smc_switch_mm() is duplicated.
> 
> Given that it is ENDPROC() that emits the Thumb annotation, the
> cpu_v7_hvc_switch_mm() routine will be called in ARM mode on a
> Thumb2 kernel, resulting in the following splat:
> 
>   Internal error: Oops - undefined instruction: 0 [#1] SMP THUMB2
>   Modules linked in:
>   CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-rc1-00030-g4d28ad89189d-dirty #488
>   Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
>   PC is at cpu_v7_hvc_switch_mm+0x12/0x18
>   LR is at flush_old_exec+0x31b/0x570
>   pc : [<c0316efe>]    lr : [<c04117c7>]    psr: 00000013
>   sp : ee899e50  ip : 00000000  fp : 00000001
>   r10: eda28f34  r9 : eda31800  r8 : c12470e0
>   r7 : eda1fc00  r6 : eda53000  r5 : 00000000  r4 : ee88c000
>   r3 : c0316eec  r2 : 00000001  r1 : eda53000  r0 : 6da6c000
>   Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> 
> Note the 'ISA ARM' in the last line.
> 
> Fix this by using the correct name in ENDPROC().
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  arch/arm/mm/proc-v7.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
> index 6fe52819e014..339eb17c9808 100644
> --- a/arch/arm/mm/proc-v7.S
> +++ b/arch/arm/mm/proc-v7.S
> @@ -112,7 +112,7 @@ ENTRY(cpu_v7_hvc_switch_mm)
>  	hvc	#0
>  	ldmfd	sp!, {r0 - r3}
>  	b	cpu_v7_switch_mm
> -ENDPROC(cpu_v7_smc_switch_mm)
> +ENDPROC(cpu_v7_hvc_switch_mm)

FWIW,

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

(I'll have a think about whether we can flag these mismatches up at
build time...)

Cheers
---Dave