[PATCH] arm64: Fix flush_icache_range prototype

[PATCH] arm64: Fix flush_icache_range prototype

[Marc Zyngier]

flush_icache_range can return -EFAULT, and yet its prototype
has void as a return type. Fix it by aligning it to that of
__flush_cache_user_range.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
 arch/arm64/include/asm/cacheflush.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 76d1cc85d5b1..377fa6b5d67f 100644
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -65,7 +65,7 @@
  *		- kaddr  - page address
  *		- size   - region size
  */
-extern void flush_icache_range(unsigned long start, unsigned long end);
+extern long flush_icache_range(unsigned long start, unsigned long end);
 extern void __flush_dcache_area(void *addr, size_t len);
 extern void __inval_dcache_area(void *addr, size_t len);
 extern void __clean_dcache_area_poc(void *addr, size_t len);
-- 
2.11.0

[PATCH] arm64: Fix flush_icache_range prototype

[Will Deacon]

On Mon, Oct 23, 2017 at 01:54:14PM +0100, Marc Zyngier wrote:
> flush_icache_range can return -EFAULT, and yet its prototype
> has void as a return type. Fix it by aligning it to that of
> __flush_cache_user_range.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/include/asm/cacheflush.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
> index 76d1cc85d5b1..377fa6b5d67f 100644
> --- a/arch/arm64/include/asm/cacheflush.h
> +++ b/arch/arm64/include/asm/cacheflush.h
> @@ -65,7 +65,7 @@
>   *		- kaddr  - page address
>   *		- size   - region size
>   */
> -extern void flush_icache_range(unsigned long start, unsigned long end);
> +extern long flush_icache_range(unsigned long start, unsigned long end);

Oh blimey, I hadn't realised that. However, this is used in the core code,
which expects a void return type and I'd like to avoid the risk of compiler
warnings complaining that the returned value is not used. I don't think
there's a problem with leaving this as void, since the PCS already says
that x0 is caller saved and this is out-of-line asm.

It just means that we silently handle userspace addresses, rather than
trigger a panic in the absence of software-PAN.

Will