linux-kernel - [RFC PATCH 3/6] arm64: remove __dma_*

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Date:   Mon,  6 Dec 2021 12:47:12 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     linux-kernel@...r.kernel.org
Cc:     ardb@...nel.org, bp@...en8.de, broonie@...nel.org,
        catalin.marinas@....com, dave.hansen@...ux.intel.com,
        jpoimboe@...hat.com, jslaby@...e.cz,
        linux-arm-kernel@...ts.infradead.org, mark.rutland@....com,
        maz@...nel.org, mingo@...hat.com, peterz@...radead.org,
        tabba@...gle.com, tglx@...utronix.de, will@...nel.org
Subject: [RFC PATCH 3/6] arm64: remove __dma_*_area() aliases

The __dma_inv_area() and __dma_clean_area() aliases make cache.S harder
to navigate, but don't gain us anything in practice.

For clarity, let's remove them along with their redundant comments. The
only users are __dma_map_area() and __dma_unmap_area(), which need to be
position independent, and can call __pi_dcache_inval_poc() and
__pi_dcache_clean_poc() directly.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@....com>
Cc: Ard Biesheuvel <ardb@...nel.org>
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Fuad Tabba <tabba@...gle.com>
Cc: Marc Zyngier <maz@...nel.org>
Cc: Will Deacon <will@...nel.org>
---
 arch/arm64/mm/cache.S | 24 +++---------------------
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 5051b3c1a4f1..7d0563db4201 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -140,15 +140,7 @@ SYM_FUNC_END(dcache_clean_pou)
  *	- start   - kernel start address of region
  *	- end     - kernel end address of region
  */
-SYM_FUNC_START_LOCAL(__dma_inv_area)
 SYM_FUNC_START_PI(dcache_inval_poc)
-	/* FALLTHROUGH */
-
-/*
- *	__dma_inv_area(start, end)
- *	- start   - virtual start address of region
- *	- end     - virtual end address of region
- */
 	dcache_line_size x2, x3
 	sub	x3, x2, #1
 	tst	x1, x3				// end cache line aligned?
@@ -167,7 +159,6 @@ SYM_FUNC_START_PI(dcache_inval_poc)
 	dsb	sy
 	ret
 SYM_FUNC_END_PI(dcache_inval_poc)
-SYM_FUNC_END(__dma_inv_area)
 
 /*
  *	dcache_clean_poc(start, end)
@@ -178,19 +169,10 @@ SYM_FUNC_END(__dma_inv_area)
  *	- start   - virtual start address of region
  *	- end     - virtual end address of region
  */
-SYM_FUNC_START_LOCAL(__dma_clean_area)
 SYM_FUNC_START_PI(dcache_clean_poc)
-	/* FALLTHROUGH */
-
-/*
- *	__dma_clean_area(start, end)
- *	- start   - virtual start address of region
- *	- end     - virtual end address of region
- */
 	dcache_by_line_op cvac, sy, x0, x1, x2, x3
 	ret
 SYM_FUNC_END_PI(dcache_clean_poc)
-SYM_FUNC_END(__dma_clean_area)
 
 /*
  *	dcache_clean_pop(start, end)
@@ -232,8 +214,8 @@ SYM_FUNC_END_PI(__dma_flush_area)
 SYM_FUNC_START_PI(__dma_map_area)
 	add	x1, x0, x1
 	cmp	w2, #DMA_FROM_DEVICE
-	b.eq	__dma_inv_area
-	b	__dma_clean_area
+	b.eq	__pi_dcache_inval_poc
+	b	__pi_dcache_clean_poc
 SYM_FUNC_END_PI(__dma_map_area)
 
 /*
@@ -245,6 +227,6 @@ SYM_FUNC_END_PI(__dma_map_area)
 SYM_FUNC_START_PI(__dma_unmap_area)
 	add	x1, x0, x1
 	cmp	w2, #DMA_TO_DEVICE
-	b.ne	__dma_inv_area
+	b.ne	__pi_dcache_inval_poc
 	ret
 SYM_FUNC_END_PI(__dma_unmap_area)
-- 
2.30.2