Re: [PATCH v3 13/18] arm64: __clean_dcache_area_poc to take end parameter instead of size

Mark Rutland
2021-05-20T16:18:42Z

On Thu, May 20, 2021 at 01:44:01PM +0100, Fuad Tabba wrote:
> To be consistent with other functions with similar names and
> functionality in cacheflush.h, cache.S, and cachetlb.rst, change
> to specify the range in terms of start and end, as opposed to
> start and size.
>
> Because the code is shared with __dma_clean_area, it changes the
> parameters for that as well. However, __dma_clean_area is local to
> cache.S, so no other users are affected.
>
> No functional change intended.
>
> Reported-by: Will Deacon <will@kernel.org>
> Signed-off-by: Fuad Tabba <tabba@google.com>

One minor comment below, with that addressed:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
> arch/arm64/include/asm/cacheflush.h | 2 +-
> arch/arm64/kernel/efi-entry.S | 5 +++--
> arch/arm64/mm/cache.S | 16 +++++++---------
> 3 files changed, 11 insertions(+), 12 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
> index 695f88864784..3255878d6f30 100644
> --- a/arch/arm64/include/asm/cacheflush.h
> +++ b/arch/arm64/include/asm/cacheflush.h
> @@ -60,7 +60,7 @@ extern void __flush_icache_range(unsigned long start, unsigned long end);
> extern void invalidate_icache_range(unsigned long start, unsigned long end);
> extern void __flush_dcache_area(unsigned long start, unsigned long end);
> extern void __inval_dcache_area(unsigned long start, unsigned long end);
> -extern void __clean_dcache_area_poc(void *addr, size_t len);
> +extern void __clean_dcache_area_poc(unsigned long start, unsigned long end);
> extern void __clean_dcache_area_pop(void *addr, size_t len);
> extern void __clean_dcache_area_pou(void *addr, size_t len);
> extern long __flush_cache_user_range(unsigned long start, unsigned long end);
> diff --git a/arch/arm64/kernel/efi-entry.S b/arch/arm64/kernel/efi-entry.S
> index 0073b24b5d25..72e6a580290a 100644
> --- a/arch/arm64/kernel/efi-entry.S
> +++ b/arch/arm64/kernel/efi-entry.S
> @@ -28,6 +28,7 @@ SYM_CODE_START(efi_enter_kernel)
> * stale icache entries from before relocation.
> */
> ldr w1, =kernel_size
> + add x1, x0, x1
> bl __clean_dcache_area_poc
> ic ialluis
>
> @@ -36,7 +37,7 @@ SYM_CODE_START(efi_enter_kernel)
> * so that we can safely disable the MMU and caches.
> */
> adr x0, 0f
> - ldr w1, 3f
> + adr x1, 3f
> bl __clean_dcache_area_poc
> 0:
> /* Turn off Dcache and MMU */
> @@ -65,4 +66,4 @@ SYM_CODE_START(efi_enter_kernel)
> mov x3, xzr
> br x19
> SYM_CODE_END(efi_enter_kernel)
> -3: .long . - 0b
> +3:

Now that we're using this label for code rather than data, could we
please move this before the SYM_CODE_END()? It looks a bit out-of-place
sitting after the function now that it has no associated data, and it
shouldn't have a functional impact either way.

Mark.

> diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
> index 35abc8d77c4e..9a9c44bb26d2 100644
> --- a/arch/arm64/mm/cache.S
> +++ b/arch/arm64/mm/cache.S
> @@ -178,24 +178,23 @@ SYM_FUNC_END_PI(__inval_dcache_area)
> SYM_FUNC_END(__dma_inv_area)
>
> /*
> - * __clean_dcache_area_poc(kaddr, size)
> + * __clean_dcache_area_poc(start, end)
> *
> - * Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
> + * Ensure that any D-cache lines for the interval [start, end)
> * are cleaned to the PoC.
> *
> - * - kaddr - kernel address
> - * - size - size in question
> + * - start - virtual start address of region
> + * - end - virtual end address of region
> */
> SYM_FUNC_START_LOCAL(__dma_clean_area)
> SYM_FUNC_START_PI(__clean_dcache_area_poc)
> /* FALLTHROUGH */
>
> /*
> - * __dma_clean_area(start, size)
> + * __dma_clean_area(start, end)
> * - start - virtual start address of region
> - * - size - size in question
> + * - end - virtual end address of region
> */
> - add x1, x0, x1
> dcache_by_line_op cvac, sy, x0, x1, x2, x3
> ret
> SYM_FUNC_END_PI(__clean_dcache_area_poc)
> @@ -211,10 +210,10 @@ SYM_FUNC_END(__dma_clean_area)
> * - size - size in question
> */
> SYM_FUNC_START_PI(__clean_dcache_area_pop)
> + add x1, x0, x1
> alternative_if_not ARM64_HAS_DCPOP
> b __clean_dcache_area_poc
> alternative_else_nop_endif
> - add x1, x0, x1
> dcache_by_line_op cvap, sy, x0, x1, x2, x3
> ret
> SYM_FUNC_END_PI(__clean_dcache_area_pop)
> @@ -243,7 +242,6 @@ SYM_FUNC_START_PI(__dma_map_area)
> add x1, x0, x1
> cmp w2, #DMA_FROM_DEVICE
> b.eq __dma_inv_area
> - sub x1, x1, x0
> b __dma_clean_area
> SYM_FUNC_END_PI(__dma_map_area)
>
> --
> 2.31.1.751.gd2f1c929bd-goog