diff options
authorWill Deacon <will.deacon@arm.com>2018-12-10 13:39:48 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-26 09:37:03 +0100
commitca5664c3aee9a2e177ebf6e12e476a22b5863400 (patch)
parente107641b0a1273636b0ebe601eaa573001ed0f1d (diff)
arm64: Fix minor issues with the dcache_by_line_op macro
[ Upstream commit 33309ecda0070506c49182530abe7728850ebe78 ] The dcache_by_line_op macro suffers from a couple of small problems: First, the GAS directives that are currently being used rely on assembler behavior that is not documented, and probably not guaranteed to produce the correct behavior going forward. As a result, we end up with some undefined symbols in cache.o: $ nm arch/arm64/mm/cache.o ... U civac ... U cvac U cvap U cvau This is due to the fact that the comparisons used to select the operation type in the dcache_by_line_op macro are comparing symbols not strings, and even though it seems that GAS is doing the right thing here (undefined symbols by the same name are equal to each other), it seems unwise to rely on this. Second, when patching in a DC CVAP instruction on CPUs that support it, the fallback path consists of a DC CVAU instruction which may be affected by CPU errata that require ARM64_WORKAROUND_CLEAN_CACHE. Solve these issues by unrolling the various maintenance routines and using the conditional directives that are documented as operating on strings. To avoid the complexity of nested alternatives, we move the DC CVAP patching to __clean_dcache_area_pop, falling back to a branch to __clean_dcache_area_poc if DCPOP is not supported by the CPU. Reported-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Suggested-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2 files changed, 21 insertions, 12 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index 66aea4aa455d..02d73d83f0de 100644
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -373,27 +373,33 @@ alternative_endif
* size: size of the region
* Corrupts: kaddr, size, tmp1, tmp2
+ .macro __dcache_op_workaround_clean_cache, op, kaddr
+alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
+ dc \op, \kaddr
+ dc civac, \kaddr
+ .endm
.macro dcache_by_line_op op, domain, kaddr, size, tmp1, tmp2
dcache_line_size \tmp1, \tmp2
add \size, \kaddr, \size
sub \tmp2, \tmp1, #1
bic \kaddr, \kaddr, \tmp2
- .if (\op == cvau || \op == cvac)
-alternative_if_not ARM64_WORKAROUND_CLEAN_CACHE
- dc \op, \kaddr
- dc civac, \kaddr
- .elseif (\op == cvap)
-alternative_if ARM64_HAS_DCPOP
- sys 3, c7, c12, 1, \kaddr // dc cvap
- dc cvac, \kaddr
+ .ifc \op, cvau
+ __dcache_op_workaround_clean_cache \op, \kaddr
+ .else
+ .ifc \op, cvac
+ __dcache_op_workaround_clean_cache \op, \kaddr
+ .else
+ .ifc \op, cvap
+ sys 3, c7, c12, 1, \kaddr // dc cvap
dc \op, \kaddr
+ .endif
+ .endif
add \kaddr, \kaddr, \tmp1
cmp \kaddr, \size
b.lo 9998b
diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S
index 91464e7f77cc..c1e8f3c6ffd5 100644
--- a/arch/arm64/mm/cache.S
+++ b/arch/arm64/mm/cache.S
@@ -181,6 +181,9 @@ ENDPROC(__dma_clean_area)
* - size - size in question
+ alternative_if_not ARM64_HAS_DCPOP
+ b __clean_dcache_area_poc
+ alternative_else_nop_endif
dcache_by_line_op cvap, sy, x0, x1, x2, x3