* [PATCH v2 1/2] lib/zstd: add fallback aliases for disabled BMI2 variants
2026-08-30 22:20 [PATCH v2 0/2] zstd: use x86 feature infrastructure for BMI2 dispatch Usama Arif
@ 2026-08-30 22:20 ` Usama Arif
2026-08-30 22:20 ` [PATCH v2 2/2] zstd: use cpu_feature_enabled() for in-kernel BMI2 dispatch Usama Arif
1 sibling, 0 replies; 5+ messages in thread
From: Usama Arif @ 2026-08-30 22:20 UTC (permalink / raw)
To: dsterba, linux-kernel, terrelln, terrelln, linux-crypto, yosry,
ebiggers, torvalds
Cc: hannes, nphamcs, chengming.zhou, shakeel.butt, kernel-team,
Usama Arif
When dynamic BMI2 dispatch is disabled, the BMI2-specific functions are
not compiled and each selector is conditionally compiled to avoid naming
them.
The selector-level preprocessor guards will be replaced with a predicate
that becomes constant false when dynamic BMI2 dispatch is disabled.
Although the compiler eliminates an `if (0)` branch, it must still parse
and resolve the BMI2 function referenced by it.
Add aliases from the unavailable BMI2 function names to their default
implementations. These aliases make the names valid without emitting
BMI2-specific code. The selectors remain unchanged in this patch, so the
aliases are not used yet and there is no code-generation change.
Signed-off-by: Usama Arif <usama.arif@linux.dev>
---
lib/zstd/common/entropy_common.c | 4 ++++
lib/zstd/common/fse_decompress.c | 2 ++
lib/zstd/compress/zstd_compress_sequences.c | 4 ++++
lib/zstd/decompress/huf_decompress.c | 4 ++++
lib/zstd/decompress/zstd_decompress_block.c | 12 ++++++++++++
5 files changed, 26 insertions(+)
diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
index 6cdd82233fb59..15a7c14ae8040 100644
--- a/lib/zstd/common/entropy_common.c
+++ b/lib/zstd/common/entropy_common.c
@@ -202,6 +202,8 @@ BMI2_TARGET_ATTRIBUTE static size_t FSE_readNCount_body_bmi2(
{
return FSE_readNCount_body(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
}
+#else
+#define FSE_readNCount_body_bmi2 FSE_readNCount_body_default
#endif
size_t FSE_readNCount_bmi2(
@@ -323,6 +325,8 @@ static BMI2_TARGET_ATTRIBUTE size_t HUF_readStats_body_bmi2(BYTE* huffWeight, si
{
return HUF_readStats_body(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize, 1);
}
+#else
+#define HUF_readStats_body_bmi2 HUF_readStats_body_default
#endif
size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
diff --git a/lib/zstd/common/fse_decompress.c b/lib/zstd/common/fse_decompress.c
index 15081d8dc607c..8d9c43b928833 100644
--- a/lib/zstd/common/fse_decompress.c
+++ b/lib/zstd/common/fse_decompress.c
@@ -300,6 +300,8 @@ BMI2_TARGET_ATTRIBUTE static size_t FSE_decompress_wksp_body_bmi2(void* dst, siz
{
return FSE_decompress_wksp_body(dst, dstCapacity, cSrc, cSrcSize, maxLog, workSpace, wkspSize, 1);
}
+#else
+#define FSE_decompress_wksp_body_bmi2 FSE_decompress_wksp_body_default
#endif
size_t FSE_decompress_wksp_bmi2(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, unsigned maxLog, void* workSpace, size_t wkspSize, int bmi2)
diff --git a/lib/zstd/compress/zstd_compress_sequences.c b/lib/zstd/compress/zstd_compress_sequences.c
index 256980c9d85ad..64abcdf2c5714 100644
--- a/lib/zstd/compress/zstd_compress_sequences.c
+++ b/lib/zstd/compress/zstd_compress_sequences.c
@@ -415,6 +415,10 @@ ZSTD_encodeSequences_bmi2(
sequences, nbSeq, longOffsets);
}
+#else
+
+#define ZSTD_encodeSequences_bmi2 ZSTD_encodeSequences_default
+
#endif
size_t ZSTD_encodeSequences(
diff --git a/lib/zstd/decompress/huf_decompress.c b/lib/zstd/decompress/huf_decompress.c
index ac8b87f48f847..5663ae524cd83 100644
--- a/lib/zstd/decompress/huf_decompress.c
+++ b/lib/zstd/decompress/huf_decompress.c
@@ -700,6 +700,8 @@ size_t HUF_decompress4X1_usingDTable_internal_bmi2(void* dst, size_t dstSize, vo
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X1_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
+#else
+#define HUF_decompress4X1_usingDTable_internal_bmi2 HUF_decompress4X1_usingDTable_internal_default
#endif
static
@@ -1503,6 +1505,8 @@ size_t HUF_decompress4X2_usingDTable_internal_bmi2(void* dst, size_t dstSize, vo
size_t cSrcSize, HUF_DTable const* DTable) {
return HUF_decompress4X2_usingDTable_internal_body(dst, dstSize, cSrc, cSrcSize, DTable);
}
+#else
+#define HUF_decompress4X2_usingDTable_internal_bmi2 HUF_decompress4X2_usingDTable_internal_default
#endif
static
diff --git a/lib/zstd/decompress/zstd_decompress_block.c b/lib/zstd/decompress/zstd_decompress_block.c
index 710eb0ffd5a37..9c4215e435014 100644
--- a/lib/zstd/decompress/zstd_decompress_block.c
+++ b/lib/zstd/decompress/zstd_decompress_block.c
@@ -622,6 +622,8 @@ BMI2_TARGET_ATTRIBUTE static void ZSTD_buildFSETable_body_bmi2(ZSTD_seqSymbol* d
ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue,
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
}
+#else
+#define ZSTD_buildFSETable_body_bmi2 ZSTD_buildFSETable_body_default
#endif
void ZSTD_buildFSETable(ZSTD_seqSymbol* dt,
@@ -1934,6 +1936,16 @@ ZSTD_decompressSequencesLong_bmi2(ZSTD_DCtx* dctx,
}
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
+#else
+
+#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
+#define ZSTD_decompressSequences_bmi2 ZSTD_decompressSequences_default
+#define ZSTD_decompressSequencesSplitLitBuffer_bmi2 ZSTD_decompressSequencesSplitLitBuffer_default
+#endif
+#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
+#define ZSTD_decompressSequencesLong_bmi2 ZSTD_decompressSequencesLong_default
+#endif
+
#endif /* DYNAMIC_BMI2 */
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
--
2.53.0-Meta
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v2 2/2] zstd: use cpu_feature_enabled() for in-kernel BMI2 dispatch
2026-08-30 22:20 [PATCH v2 0/2] zstd: use x86 feature infrastructure for BMI2 dispatch Usama Arif
2026-08-30 22:20 ` [PATCH v2 1/2] lib/zstd: add fallback aliases for disabled BMI2 variants Usama Arif
@ 2026-08-30 22:20 ` Usama Arif
2026-08-30 23:06 ` Linus Torvalds
1 sibling, 1 reply; 5+ messages in thread
From: Usama Arif @ 2026-08-30 22:20 UTC (permalink / raw)
To: dsterba, linux-kernel, terrelln, terrelln, linux-crypto, yosry,
ebiggers, torvalds
Cc: hannes, nphamcs, chengming.zhou, shakeel.butt, kernel-team,
Usama Arif
Zstd's dynamic BMI2 implementation probes CPUID when a compression or
decompression context is initialized, stores the result in the context,
and tests that value at every dispatch site. In normal kernel builds this
bypasses the x86 feature policy and uses ordinary runtime branches instead
of allowing x86 alternatives to resolve the feature check at boot.
Add ZSTD_USE_BMI2() and use it at every runtime BMI2/default selector. For
normal x86 kernel objects, the predicate expands directly to
cpu_feature_enabled(X86_FEATURE_BMI2). When dynamic BMI2 dispatch is not
available it is false; other builds retain the caller-provided flag. Keep
the existing HUF conditional layout because DYNAMIC_BMI2 also controls
whether target-attributed variants are emitted.
Keep the BMI2 members in the context structures so their layouts do not
change. Skip Zstd's private CPUID probes in normal x86 kernel objects and
make the context accessors return zero there; the selectors ignore that
value and consult the x86 feature policy directly. The x86 preboot
decompressor is built outside lib/zstd/Makefile, so it retains the existing
CPUID-backed dispatch.
A 4 KiB zstd-generic crypto_acomp benchmark in a one-vCPU KVM guest gave
these median results:
Before After Change
Compression 16,634 ns/op 13,394 ns/op -19.5%
Decompression 3,480 ns/op 963 ns/op -72.3%
Signed-off-by: Usama Arif <usama.arif@linux.dev>
---
lib/zstd/Makefile | 1 +
lib/zstd/common/compiler.h | 8 ++++++++
lib/zstd/common/entropy_common.c | 12 +++++------
lib/zstd/common/fse_decompress.c | 7 ++++---
lib/zstd/compress/huf_compress.c | 7 ++++++-
lib/zstd/compress/zstd_compress.c | 12 +++++++----
lib/zstd/compress/zstd_compress_internal.h | 9 +++++++++
lib/zstd/compress/zstd_compress_sequences.c | 8 +++++---
lib/zstd/compress/zstd_compress_superblock.c | 2 +-
lib/zstd/decompress/huf_decompress.c | 19 +++++++++---------
lib/zstd/decompress/zstd_decompress.c | 4 ++++
lib/zstd/decompress/zstd_decompress_block.c | 20 ++++++++-----------
.../decompress/zstd_decompress_internal.h | 2 +-
13 files changed, 71 insertions(+), 40 deletions(-)
diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
index be218b5e0ed59..4da67e1f7c247 100644
--- a/lib/zstd/Makefile
+++ b/lib/zstd/Makefile
@@ -11,6 +11,7 @@
obj-$(CONFIG_ZSTD_COMPRESS) += zstd_compress.o
obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
obj-$(CONFIG_ZSTD_COMMON) += zstd_common.o
+ccflags-$(CONFIG_X86) += -DZSTD_USE_KERNEL_CPU_FEATURES
zstd_compress-y := \
zstd_compress_module.o \
diff --git a/lib/zstd/common/compiler.h b/lib/zstd/common/compiler.h
index dc9bd15e174e9..e14102557ded3 100644
--- a/lib/zstd/common/compiler.h
+++ b/lib/zstd/common/compiler.h
@@ -96,6 +96,14 @@
*/
#define BMI2_TARGET_ATTRIBUTE TARGET_ATTRIBUTE("lzcnt,bmi,bmi2")
+#if !DYNAMIC_BMI2
+# define ZSTD_USE_BMI2(bmi2) 0
+#elif defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+# define ZSTD_USE_BMI2(bmi2) cpu_feature_enabled(X86_FEATURE_BMI2)
+#else
+# define ZSTD_USE_BMI2(bmi2) (bmi2)
+#endif
+
/* prefetch
* can be disabled, by declaring NO_PREFETCH build macro */
#if ( (__GNUC__ >= 4) || ( (__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) ) )
diff --git a/lib/zstd/common/entropy_common.c b/lib/zstd/common/entropy_common.c
index 15a7c14ae8040..9cdbe0d3a2b2f 100644
--- a/lib/zstd/common/entropy_common.c
+++ b/lib/zstd/common/entropy_common.c
@@ -13,6 +13,10 @@
* You may select, at your option, one of the above-listed licenses.
****************************************************************** */
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
+
/* *************************************
* Dependencies
***************************************/
@@ -210,11 +214,9 @@ size_t FSE_readNCount_bmi2(
short* normalizedCounter, unsigned* maxSVPtr, unsigned* tableLogPtr,
const void* headerBuffer, size_t hbSize, int bmi2)
{
-#if DYNAMIC_BMI2
- if (bmi2) {
+ if (ZSTD_USE_BMI2(bmi2)) {
return FSE_readNCount_body_bmi2(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
}
-#endif
(void)bmi2;
return FSE_readNCount_body_default(normalizedCounter, maxSVPtr, tableLogPtr, headerBuffer, hbSize);
}
@@ -335,11 +337,9 @@ size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, U32* rankStats,
void* workSpace, size_t wkspSize,
int flags)
{
-#if DYNAMIC_BMI2
- if (flags & HUF_flags_bmi2) {
+ if (ZSTD_USE_BMI2(flags & HUF_flags_bmi2)) {
return HUF_readStats_body_bmi2(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
}
-#endif
(void)flags;
return HUF_readStats_body_default(huffWeight, hwSize, rankStats, nbSymbolsPtr, tableLogPtr, src, srcSize, workSpace, wkspSize);
}
diff --git a/lib/zstd/common/fse_decompress.c b/lib/zstd/common/fse_decompress.c
index 8d9c43b928833..763c11d0541f5 100644
--- a/lib/zstd/common/fse_decompress.c
+++ b/lib/zstd/common/fse_decompress.c
@@ -13,6 +13,9 @@
* You may select, at your option, one of the above-listed licenses.
****************************************************************** */
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
/* **************************************************************
* Includes
@@ -306,11 +309,9 @@ BMI2_TARGET_ATTRIBUTE static size_t FSE_decompress_wksp_body_bmi2(void* dst, siz
size_t FSE_decompress_wksp_bmi2(void* dst, size_t dstCapacity, const void* cSrc, size_t cSrcSize, unsigned maxLog, void* workSpace, size_t wkspSize, int bmi2)
{
-#if DYNAMIC_BMI2
- if (bmi2) {
+ if (ZSTD_USE_BMI2(bmi2)) {
return FSE_decompress_wksp_body_bmi2(dst, dstCapacity, cSrc, cSrcSize, maxLog, workSpace, wkspSize);
}
-#endif
(void)bmi2;
return FSE_decompress_wksp_body_default(dst, dstCapacity, cSrc, cSrcSize, maxLog, workSpace, wkspSize);
}
diff --git a/lib/zstd/compress/huf_compress.c b/lib/zstd/compress/huf_compress.c
index 0b229f5d2ae22..5d8c90f9263c2 100644
--- a/lib/zstd/compress/huf_compress.c
+++ b/lib/zstd/compress/huf_compress.c
@@ -13,6 +13,10 @@
* You may select, at your option, one of the above-listed licenses.
****************************************************************** */
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
+
/* **************************************************************
* Compiler specifics
****************************************************************/
@@ -1138,9 +1142,10 @@ HUF_compress1X_usingCTable_internal(void* dst, size_t dstSize,
const void* src, size_t srcSize,
const HUF_CElt* CTable, const int flags)
{
- if (flags & HUF_flags_bmi2) {
+ if (ZSTD_USE_BMI2(flags & HUF_flags_bmi2)) {
return HUF_compress1X_usingCTable_internal_bmi2(dst, dstSize, src, srcSize, CTable);
}
+ (void)flags;
return HUF_compress1X_usingCTable_internal_default(dst, dstSize, src, srcSize, CTable);
}
diff --git a/lib/zstd/compress/zstd_compress.c b/lib/zstd/compress/zstd_compress.c
index c41a747413e01..8295ce44b1d7a 100644
--- a/lib/zstd/compress/zstd_compress.c
+++ b/lib/zstd/compress/zstd_compress.c
@@ -102,7 +102,9 @@ static void ZSTD_initCCtx(ZSTD_CCtx* cctx, ZSTD_customMem memManager)
assert(cctx != NULL);
ZSTD_memset(cctx, 0, sizeof(*cctx));
cctx->customMem = memManager;
+#if !defined(ZSTD_USE_KERNEL_CPU_FEATURES)
cctx->bmi2 = ZSTD_cpuSupportsBmi2();
+#endif
{ size_t const err = ZSTD_CCtx_reset(cctx, ZSTD_reset_parameters);
assert(!ZSTD_isError(err));
(void)err;
@@ -142,7 +144,9 @@ ZSTD_CCtx* ZSTD_initStaticCCtx(void* workspace, size_t workspaceSize)
cctx->blockState.nextCBlock = (ZSTD_compressedBlockState_t*)ZSTD_cwksp_reserve_object(&cctx->workspace, sizeof(ZSTD_compressedBlockState_t));
cctx->tmpWorkspace = ZSTD_cwksp_reserve_object(&cctx->workspace, TMP_WORKSPACE_SIZE);
cctx->tmpWkspSize = TMP_WORKSPACE_SIZE;
+#if !defined(ZSTD_USE_KERNEL_CPU_FEATURES)
cctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid());
+#endif
return cctx;
}
@@ -4042,7 +4046,7 @@ ZSTD_compressSeqStore_singleBlock(ZSTD_CCtx* zc,
op + ZSTD_blockHeaderSize, dstCapacity - ZSTD_blockHeaderSize,
srcSize,
zc->tmpWorkspace, zc->tmpWkspSize /* statically allocated in resetCCtx */,
- zc->bmi2);
+ ZSTD_CCtx_get_bmi2(zc));
FORWARD_IF_ERROR(cSeqsSize, "ZSTD_entropyCompressSeqStore failed!");
if (!zc->isFirstBlock &&
@@ -4332,7 +4336,7 @@ ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
dst, dstCapacity,
srcSize,
zc->tmpWorkspace, zc->tmpWkspSize /* statically allocated in resetCCtx */,
- zc->bmi2);
+ ZSTD_CCtx_get_bmi2(zc));
if (frame &&
/* We don't want to emit our first block as a RLE even if it qualifies because
@@ -6796,7 +6800,7 @@ ZSTD_compressSequences_internal(ZSTD_CCtx* cctx,
op + ZSTD_blockHeaderSize /* Leave space for block header */, dstCapacity - ZSTD_blockHeaderSize,
blockSize,
cctx->tmpWorkspace, cctx->tmpWkspSize /* statically allocated in resetCCtx */,
- cctx->bmi2);
+ ZSTD_CCtx_get_bmi2(cctx));
FORWARD_IF_ERROR(compressedSeqsSize, "Compressing sequences of block failed");
DEBUGLOG(5, "Compressed sequences size: %zu", compressedSeqsSize);
@@ -7321,7 +7325,7 @@ ZSTD_compressSequencesAndLiterals_internal(ZSTD_CCtx* cctx,
&cctx->blockState.prevCBlock->entropy, &cctx->blockState.nextCBlock->entropy,
&cctx->appliedParams,
cctx->tmpWorkspace, cctx->tmpWkspSize /* statically allocated in resetCCtx */,
- cctx->bmi2);
+ ZSTD_CCtx_get_bmi2(cctx));
FORWARD_IF_ERROR(compressedSeqsSize, "Compressing sequences of block failed");
/* note: the spec forbids for any compressed block to be larger than maximum block size */
if (compressedSeqsSize > cctx->blockSizeMax) compressedSeqsSize = 0;
diff --git a/lib/zstd/compress/zstd_compress_internal.h b/lib/zstd/compress/zstd_compress_internal.h
index b109783858763..0b8ec69c081ef 100644
--- a/lib/zstd/compress/zstd_compress_internal.h
+++ b/lib/zstd/compress/zstd_compress_internal.h
@@ -537,6 +537,15 @@ struct ZSTD_CCtx_s {
size_t extSeqBufCapacity;
};
+MEM_STATIC int ZSTD_CCtx_get_bmi2(const struct ZSTD_CCtx_s *cctx) {
+#if !defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+ return cctx->bmi2;
+#else
+ (void)cctx;
+ return 0;
+#endif
+}
+
typedef enum { ZSTD_dtlm_fast, ZSTD_dtlm_full } ZSTD_dictTableLoadMethod_e;
typedef enum { ZSTD_tfp_forCCtx, ZSTD_tfp_forCDict } ZSTD_tableFillPurpose_e;
diff --git a/lib/zstd/compress/zstd_compress_sequences.c b/lib/zstd/compress/zstd_compress_sequences.c
index 64abcdf2c5714..450219bbe28bc 100644
--- a/lib/zstd/compress/zstd_compress_sequences.c
+++ b/lib/zstd/compress/zstd_compress_sequences.c
@@ -9,6 +9,10 @@
* You may select, at your option, one of the above-listed licenses.
*/
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
+
/*-*************************************
* Dependencies
***************************************/
@@ -429,15 +433,13 @@ size_t ZSTD_encodeSequences(
SeqDef const* sequences, size_t nbSeq, int longOffsets, int bmi2)
{
DEBUGLOG(5, "ZSTD_encodeSequences: dstCapacity = %u", (unsigned)dstCapacity);
-#if DYNAMIC_BMI2
- if (bmi2) {
+ if (ZSTD_USE_BMI2(bmi2)) {
return ZSTD_encodeSequences_bmi2(dst, dstCapacity,
CTable_MatchLength, mlCodeTable,
CTable_OffsetBits, ofCodeTable,
CTable_LitLength, llCodeTable,
sequences, nbSeq, longOffsets);
}
-#endif
(void)bmi2;
return ZSTD_encodeSequences_default(dst, dstCapacity,
CTable_MatchLength, mlCodeTable,
diff --git a/lib/zstd/compress/zstd_compress_superblock.c b/lib/zstd/compress/zstd_compress_superblock.c
index dc12d64e935c4..fada5979c3b84 100644
--- a/lib/zstd/compress/zstd_compress_superblock.c
+++ b/lib/zstd/compress/zstd_compress_superblock.c
@@ -684,6 +684,6 @@ size_t ZSTD_compressSuperBlock(ZSTD_CCtx* zc,
&zc->appliedParams,
dst, dstCapacity,
src, srcSize,
- zc->bmi2, lastBlock,
+ ZSTD_CCtx_get_bmi2(zc), lastBlock,
zc->tmpWorkspace, zc->tmpWkspSize /* statically allocated in resetCCtx */);
}
diff --git a/lib/zstd/decompress/huf_decompress.c b/lib/zstd/decompress/huf_decompress.c
index 5663ae524cd83..c4fc0a8c7a46f 100644
--- a/lib/zstd/decompress/huf_decompress.c
+++ b/lib/zstd/decompress/huf_decompress.c
@@ -13,6 +13,10 @@
* You may select, at your option, one of the above-listed licenses.
****************************************************************** */
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
+
/* **************************************************************
* Dependencies
****************************************************************/
@@ -113,9 +117,10 @@ typedef size_t (*HUF_DecompressUsingDTableFn)(void *dst, size_t dstSize,
static size_t fn(void* dst, size_t dstSize, void const* cSrc, \
size_t cSrcSize, HUF_DTable const* DTable, int flags) \
{ \
- if (flags & HUF_flags_bmi2) { \
+ if (ZSTD_USE_BMI2(flags & HUF_flags_bmi2)) { \
return fn##_bmi2(dst, dstSize, cSrc, cSrcSize, DTable); \
} \
+ (void)flags; \
return fn##_default(dst, dstSize, cSrc, cSrcSize, DTable); \
}
@@ -899,18 +904,16 @@ static size_t HUF_decompress4X1_usingDTable_internal(void* dst, size_t dstSize,
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X1_usingDTable_internal_default;
HUF_DecompressFastLoopFn loopFn = HUF_decompress4X1_usingDTable_internal_fast_c_loop;
-#if DYNAMIC_BMI2
- if (flags & HUF_flags_bmi2) {
+ if (ZSTD_USE_BMI2(flags & HUF_flags_bmi2)) {
fallbackFn = HUF_decompress4X1_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X1_usingDTable_internal_fast_asm_loop;
}
# endif
- } else {
+ } else if (DYNAMIC_BMI2) {
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
-#endif
#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
if (!(flags & HUF_flags_disableAsm)) {
@@ -1723,18 +1726,16 @@ static size_t HUF_decompress4X2_usingDTable_internal(void* dst, size_t dstSize,
HUF_DecompressUsingDTableFn fallbackFn = HUF_decompress4X2_usingDTable_internal_default;
HUF_DecompressFastLoopFn loopFn = HUF_decompress4X2_usingDTable_internal_fast_c_loop;
-#if DYNAMIC_BMI2
- if (flags & HUF_flags_bmi2) {
+ if (ZSTD_USE_BMI2(flags & HUF_flags_bmi2)) {
fallbackFn = HUF_decompress4X2_usingDTable_internal_bmi2;
# if ZSTD_ENABLE_ASM_X86_64_BMI2
if (!(flags & HUF_flags_disableAsm)) {
loopFn = HUF_decompress4X2_usingDTable_internal_fast_asm_loop;
}
# endif
- } else {
+ } else if (DYNAMIC_BMI2) {
return fallbackFn(dst, dstSize, cSrc, cSrcSize, DTable);
}
-#endif
#if ZSTD_ENABLE_ASM_X86_64_BMI2 && defined(__BMI2__)
if (!(flags & HUF_flags_disableAsm)) {
diff --git a/lib/zstd/decompress/zstd_decompress.c b/lib/zstd/decompress/zstd_decompress.c
index bb009554e3a61..107b4e42e4ee8 100644
--- a/lib/zstd/decompress/zstd_decompress.c
+++ b/lib/zstd/decompress/zstd_decompress.c
@@ -260,7 +260,11 @@ static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx)
dctx->oversizedDuration = 0;
dctx->isFrameDecompression = 1;
#if DYNAMIC_BMI2
+# if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+ dctx->bmi2 = 0;
+# else
dctx->bmi2 = ZSTD_cpuSupportsBmi2();
+# endif
#endif
dctx->ddictSet = NULL;
ZSTD_DCtx_resetParameters(dctx);
diff --git a/lib/zstd/decompress/zstd_decompress_block.c b/lib/zstd/decompress/zstd_decompress_block.c
index 9c4215e435014..424de08fce82e 100644
--- a/lib/zstd/decompress/zstd_decompress_block.c
+++ b/lib/zstd/decompress/zstd_decompress_block.c
@@ -12,6 +12,10 @@
/* zstd_decompress_block :
* this module takes care of decompressing _compressed_ block */
+#if defined(ZSTD_USE_KERNEL_CPU_FEATURES)
+#include <asm/cpufeature.h>
+#endif
+
/*-*******************************************************
* Dependencies
*********************************************************/
@@ -631,13 +635,11 @@ void ZSTD_buildFSETable(ZSTD_seqSymbol* dt,
const U32* baseValue, const U8* nbAdditionalBits,
unsigned tableLog, void* wksp, size_t wkspSize, int bmi2)
{
-#if DYNAMIC_BMI2
- if (bmi2) {
+ if (ZSTD_USE_BMI2(bmi2)) {
ZSTD_buildFSETable_body_bmi2(dt, normalizedCounter, maxSymbolValue,
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
return;
}
-#endif
(void)bmi2;
ZSTD_buildFSETable_body_default(dt, normalizedCounter, maxSymbolValue,
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
@@ -1955,11 +1957,9 @@ ZSTD_decompressSequences(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize,
const ZSTD_longOffset_e isLongOffset)
{
DEBUGLOG(5, "ZSTD_decompressSequences");
-#if DYNAMIC_BMI2
- if (ZSTD_DCtx_get_bmi2(dctx)) {
+ if (ZSTD_USE_BMI2(ZSTD_DCtx_get_bmi2(dctx))) {
return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
-#endif
return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
static size_t
@@ -1968,11 +1968,9 @@ ZSTD_decompressSequencesSplitLitBuffer(ZSTD_DCtx* dctx, void* dst, size_t maxDst
const ZSTD_longOffset_e isLongOffset)
{
DEBUGLOG(5, "ZSTD_decompressSequencesSplitLitBuffer");
-#if DYNAMIC_BMI2
- if (ZSTD_DCtx_get_bmi2(dctx)) {
+ if (ZSTD_USE_BMI2(ZSTD_DCtx_get_bmi2(dctx))) {
return ZSTD_decompressSequencesSplitLitBuffer_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
-#endif
return ZSTD_decompressSequencesSplitLitBuffer_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
@@ -1991,11 +1989,9 @@ ZSTD_decompressSequencesLong(ZSTD_DCtx* dctx,
const ZSTD_longOffset_e isLongOffset)
{
DEBUGLOG(5, "ZSTD_decompressSequencesLong");
-#if DYNAMIC_BMI2
- if (ZSTD_DCtx_get_bmi2(dctx)) {
+ if (ZSTD_USE_BMI2(ZSTD_DCtx_get_bmi2(dctx))) {
return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
-#endif
return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset);
}
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
diff --git a/lib/zstd/decompress/zstd_decompress_internal.h b/lib/zstd/decompress/zstd_decompress_internal.h
index 2a225d1811c4f..401f2b526bbce 100644
--- a/lib/zstd/decompress/zstd_decompress_internal.h
+++ b/lib/zstd/decompress/zstd_decompress_internal.h
@@ -204,7 +204,7 @@ struct ZSTD_DCtx_s
}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) {
-#if DYNAMIC_BMI2
+#if DYNAMIC_BMI2 && !defined(ZSTD_USE_KERNEL_CPU_FEATURES)
return dctx->bmi2;
#else
(void)dctx;
--
2.53.0-Meta
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