arm64: Provide dcache_by_myline_op_nosync helper

dcache_by_myline_op ensures completion of the data cache operations for a
region, while dcache_by_myline_op_nosync only issues them without waiting.
This enables deferred synchronization so completion for multiple regions
can be handled together later.

Cc: Leon Romanovsky <leon@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Tangquan Zheng <zhengtangquan@oppo.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Signed-off-by: Barry Song <baohua@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260228221216.59886-1-21cnbao@gmail.com

2 files changed, 21 insertions, 7 deletions

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index d3d46e5f7188..cdbaad41bddb 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -371,14 +371,13 @@ alternative_endif
  * [start, end) with dcache line size explicitly provided.
  *
  * 	op:		operation passed to dc instruction
- * 	domain:		domain used in dsb instruction
  * 	start:          starting virtual address of the region
  * 	end:            end virtual address of the region
  *	linesz:		dcache line size
  * 	fixup:		optional label to branch to on user fault
  * 	Corrupts:       start, end, tmp
  */
-	.macro dcache_by_myline_op op, domain, start, end, linesz, tmp, fixup
+	.macro dcache_by_myline_op_nosync op, start, end, linesz, tmp, fixup
 	sub	\tmp, \linesz, #1
 	bic	\start, \start, \tmp
 alternative_if ARM64_WORKAROUND_4311569
@@ -412,14 +411,28 @@ alternative_if ARM64_WORKAROUND_4311569
 	cbnz	\start, .Ldcache_op\@
 	.endif
 alternative_else_nop_endif
-	dsb	\domain
 
 	_cond_uaccess_extable .Ldcache_op\@, \fixup
 	.endm
 
 /*
  * Macro to perform a data cache maintenance for the interval
- * [start, end)
+ * [start, end) without waiting for completion
+ *
+ * 	op:		operation passed to dc instruction
+ * 	start:          starting virtual address of the region
+ * 	end:            end virtual address of the region
+ * 	fixup:		optional label to branch to on user fault
+ * 	Corrupts:       start, end, tmp1, tmp2
+ */
+	.macro dcache_by_line_op_nosync op, start, end, tmp1, tmp2, fixup
+	dcache_line_size \tmp1, \tmp2
+	dcache_by_myline_op_nosync \op, \start, \end, \tmp1, \tmp2, \fixup
+	.endm
+
+/*
+ * Macro to perform a data cache maintenance for the interval
+ * [start, end) and wait for completion
  *
  * 	op:		operation passed to dc instruction
  * 	domain:		domain used in dsb instruction
@@ -429,8 +442,8 @@ alternative_else_nop_endif
  * 	Corrupts:       start, end, tmp1, tmp2
  */
 	.macro dcache_by_line_op op, domain, start, end, tmp1, tmp2, fixup
-	dcache_line_size \tmp1, \tmp2
-	dcache_by_myline_op \op, \domain, \start, \end, \tmp1, \tmp2, \fixup
+	dcache_by_line_op_nosync \op, \start, \end, \tmp1, \tmp2, \fixup
+	dsb \domain
 	.endm
 
 /*
diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S
index 413f899e4ac6..6cb4209f5dab 100644
--- a/arch/arm64/kernel/relocate_kernel.S
+++ b/arch/arm64/kernel/relocate_kernel.S
@@ -64,7 +64,8 @@ SYM_CODE_START(arm64_relocate_new_kernel)
 	mov	x19, x13
 	copy_page x13, x12, x1, x2, x3, x4, x5, x6, x7, x8
 	add	x1, x19, #PAGE_SIZE
-	dcache_by_myline_op civac, sy, x19, x1, x15, x20
+	dcache_by_myline_op_nosync civac, x19, x1, x15, x20
+	dsb	sy
 	b	.Lnext
 .Ltest_indirection:
 	tbz	x16, IND_INDIRECTION_BIT, .Ltest_destination