[PATCH 2/3] btrfs: Patch the kernel zstd

[Nick Terrell <terrelln@fb.com>]

Applies patches to the upstream kernel zstd needed to compile in grub.
* Replace kernel headers with "kerncompat.h".
* Replace the unaligned memory access functions.
* Add fallthrough statements for newer gcc versions.
* Rename a variable from "byte" because of a conflicting typedef.
* Remove the module code.
* Switch the memcpy() in ZSTD_copy8() to __builtin_memcpy().

Signed-off-by: Nick Terrell <terrelln@fb.com>
---
 grub-core/lib/zstd/bitstream.h      |  6 ++++
 grub-core/lib/zstd/decompress.c     | 56 ++++++------------------------
 grub-core/lib/zstd/error_private.h  |  3 +-
 grub-core/lib/zstd/fse.h            |  2 +-
 grub-core/lib/zstd/fse_decompress.c |  3 --
 grub-core/lib/zstd/huf.h            |  2 +-
 grub-core/lib/zstd/huf_decompress.c |  3 --
 grub-core/lib/zstd/kerncompat.h     | 69 +++++++++++++++++++++++++++++++++++++
 grub-core/lib/zstd/mem.h            | 42 ++++++++++++----------
 grub-core/lib/zstd/xxhash.c         | 22 ++----------
 grub-core/lib/zstd/xxhash.h         |  2 +-
 grub-core/lib/zstd/zstd.h           |  2 +-
 grub-core/lib/zstd/zstd_common.c    |  2 +-
 grub-core/lib/zstd/zstd_internal.h  | 12 ++++---
 14 files changed, 124 insertions(+), 102 deletions(-)
 create mode 100644 grub-core/lib/zstd/kerncompat.h

diff --git a/grub-core/lib/zstd/bitstream.h b/grub-core/lib/zstd/bitstream.h
index a826b99e1..92a6c3fb9 100644
--- a/grub-core/lib/zstd/bitstream.h
+++ b/grub-core/lib/zstd/bitstream.h
@@ -51,6 +51,7 @@
 *  Dependencies
 ******************************************/
 #include "error_private.h" /* error codes and messages */
+#include "kerncompat.h"
 #include "mem.h"	   /* unaligned access routines */

 /*=========================================
@@ -259,10 +260,15 @@ ZSTD_STATIC size_t BIT_initDStream(BIT_DStream_t *bitD, const void *srcBuffer, s
 		bitD->bitContainer = *(const BYTE *)(bitD->start);
 		switch (srcSize) {
 		case 7: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[6]) << (sizeof(bitD->bitContainer) * 8 - 16);
+			/* fallthrough */
 		case 6: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[5]) << (sizeof(bitD->bitContainer) * 8 - 24);
+			/* fallthrough */
 		case 5: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[4]) << (sizeof(bitD->bitContainer) * 8 - 32);
+			/* fallthrough */
 		case 4: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[3]) << 24;
+			/* fallthrough */
 		case 3: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[2]) << 16;
+			/* fallthrough */
 		case 2: bitD->bitContainer += (size_t)(((const BYTE *)(srcBuffer))[1]) << 8;
 		default:;
 		}
diff --git a/grub-core/lib/zstd/decompress.c b/grub-core/lib/zstd/decompress.c
index b17846725..e7af8df09 100644
--- a/grub-core/lib/zstd/decompress.c
+++ b/grub-core/lib/zstd/decompress.c
@@ -33,9 +33,6 @@
 #include "huf.h"
 #include "mem.h" /* low level memory routines */
 #include "zstd_internal.h"
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/string.h> /* memcpy, memmove, memset */

 #define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)

@@ -123,6 +120,7 @@ size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx)
 	return 0;
 }

+static
 ZSTD_DCtx *ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
 {
 	ZSTD_DCtx *dctx;
@@ -391,6 +389,7 @@ typedef struct {

 /*! ZSTD_getcBlockSize() :
 *   Provides the size of compressed block from block header `src` */
+static
 size_t ZSTD_getcBlockSize(const void *src, size_t srcSize, blockProperties_t *bpPtr)
 {
 	if (srcSize < ZSTD_blockHeaderSize)
@@ -429,6 +428,7 @@ static size_t ZSTD_setRleBlock(void *dst, size_t dstCapacity, const void *src, s

 /*! ZSTD_decodeLiteralsBlock() :
 	@return : nb of bytes read from src (< srcSize ) */
+static
 size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
 {
 	if (srcSize < MIN_CBLOCK_SIZE)
@@ -791,6 +791,7 @@ static size_t ZSTD_buildSeqTable(FSE_DTable *DTableSpace, const FSE_DTable **DTa
 	}
 }

+static
 size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx *dctx, int *nbSeqPtr, const void *src, size_t srcSize)
 {
 	const BYTE *const istart = (const BYTE *const)src;
@@ -1494,11 +1495,12 @@ size_t ZSTD_insertBlock(ZSTD_DCtx *dctx, const void *blockStart, size_t blockSiz
 	return blockSize;
 }

-size_t ZSTD_generateNxBytes(void *dst, size_t dstCapacity, BYTE byte, size_t length)
+static
+size_t ZSTD_generateNxBytes(void *dst, size_t dstCapacity, BYTE value, size_t length)
 {
 	if (length > dstCapacity)
 		return ERROR(dstSize_tooSmall);
-	memset(dst, byte, length);
+	memset(dst, value, length);
 	return length;
 }

@@ -1768,6 +1770,7 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx *dctx, void *dst, size_t dstCapacity, c
 			return 0;
 		}
 		dctx->expected = 0; /* not necessary to copy more */
+		/* fallthrough */

 	case ZSTDds_decodeFrameHeader:
 		memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
@@ -2376,6 +2379,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
 			zds->stage = zdss_read;
 		}
 		/* pass-through */
+		/* fallthrough */

 		case zdss_read: {
 			size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
@@ -2404,6 +2408,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
 			zds->stage = zdss_load;
 			/* pass-through */
 		}
+		/* fallthrough */

 		case zdss_load: {
 			size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
@@ -2436,6 +2441,7 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
 				/* pass-through */
 			}
 		}
+		/* fallthrough */

 		case zdss_flush: {
 			size_t const toFlushSize = zds->outEnd - zds->outStart;
@@ -2486,43 +2492,3 @@ size_t ZSTD_decompressStream(ZSTD_DStream *zds, ZSTD_outBuffer *output, ZSTD_inB
 		return nextSrcSizeHint;
 	}
 }
-
-EXPORT_SYMBOL(ZSTD_DCtxWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDCtx);
-EXPORT_SYMBOL(ZSTD_decompressDCtx);
-EXPORT_SYMBOL(ZSTD_decompress_usingDict);
-
-EXPORT_SYMBOL(ZSTD_DDictWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDDict);
-EXPORT_SYMBOL(ZSTD_decompress_usingDDict);
-
-EXPORT_SYMBOL(ZSTD_DStreamWorkspaceBound);
-EXPORT_SYMBOL(ZSTD_initDStream);
-EXPORT_SYMBOL(ZSTD_initDStream_usingDDict);
-EXPORT_SYMBOL(ZSTD_resetDStream);
-EXPORT_SYMBOL(ZSTD_decompressStream);
-EXPORT_SYMBOL(ZSTD_DStreamInSize);
-EXPORT_SYMBOL(ZSTD_DStreamOutSize);
-
-EXPORT_SYMBOL(ZSTD_findFrameCompressedSize);
-EXPORT_SYMBOL(ZSTD_getFrameContentSize);
-EXPORT_SYMBOL(ZSTD_findDecompressedSize);
-
-EXPORT_SYMBOL(ZSTD_isFrame);
-EXPORT_SYMBOL(ZSTD_getDictID_fromDict);
-EXPORT_SYMBOL(ZSTD_getDictID_fromDDict);
-EXPORT_SYMBOL(ZSTD_getDictID_fromFrame);
-
-EXPORT_SYMBOL(ZSTD_getFrameParams);
-EXPORT_SYMBOL(ZSTD_decompressBegin);
-EXPORT_SYMBOL(ZSTD_decompressBegin_usingDict);
-EXPORT_SYMBOL(ZSTD_copyDCtx);
-EXPORT_SYMBOL(ZSTD_nextSrcSizeToDecompress);
-EXPORT_SYMBOL(ZSTD_decompressContinue);
-EXPORT_SYMBOL(ZSTD_nextInputType);
-
-EXPORT_SYMBOL(ZSTD_decompressBlock);
-EXPORT_SYMBOL(ZSTD_insertBlock);
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_DESCRIPTION("Zstd Decompressor");
diff --git a/grub-core/lib/zstd/error_private.h b/grub-core/lib/zstd/error_private.h
index 1a60b31f7..02e6736ea 100644
--- a/grub-core/lib/zstd/error_private.h
+++ b/grub-core/lib/zstd/error_private.h
@@ -22,8 +22,7 @@
 /* ****************************************
 *  Dependencies
 ******************************************/
-#include <linux/types.h> /* size_t */
-#include <linux/zstd.h>  /* enum list */
+#include "zstd.h"

 /* ****************************************
 *  Compiler-specific
diff --git a/grub-core/lib/zstd/fse.h b/grub-core/lib/zstd/fse.h
index 7460ab04b..b39639745 100644
--- a/grub-core/lib/zstd/fse.h
+++ b/grub-core/lib/zstd/fse.h
@@ -43,7 +43,7 @@
 /*-*****************************************
 *  Dependencies
 ******************************************/
-#include <linux/types.h> /* size_t, ptrdiff_t */
+#include "kerncompat.h"

 /*-*****************************************
 *  FSE_PUBLIC_API : control library symbols visibility
diff --git a/grub-core/lib/zstd/fse_decompress.c b/grub-core/lib/zstd/fse_decompress.c
index a84300e5a..35b05e3c0 100644
--- a/grub-core/lib/zstd/fse_decompress.c
+++ b/grub-core/lib/zstd/fse_decompress.c
@@ -47,9 +47,6 @@
 ****************************************************************/
 #include "bitstream.h"
 #include "fse.h"
-#include <linux/compiler.h>
-#include <linux/kernel.h>
-#include <linux/string.h> /* memcpy, memset */

 /* **************************************************************
 *  Error Management
diff --git a/grub-core/lib/zstd/huf.h b/grub-core/lib/zstd/huf.h
index 2143da28d..2b2ac96c2 100644
--- a/grub-core/lib/zstd/huf.h
+++ b/grub-core/lib/zstd/huf.h
@@ -41,7 +41,7 @@
 #define HUF_H_298734234

 /* *** Dependencies *** */
-#include <linux/types.h> /* size_t */
+#include "kerncompat.h"

 /* ***   Tool functions *** */
 #define HUF_BLOCKSIZE_MAX (128 * 1024) /**< maximum input size for a single block compressed with HUF_compress */
diff --git a/grub-core/lib/zstd/huf_decompress.c b/grub-core/lib/zstd/huf_decompress.c
index 652648204..fdad9cf98 100644
--- a/grub-core/lib/zstd/huf_decompress.c
+++ b/grub-core/lib/zstd/huf_decompress.c
@@ -48,9 +48,6 @@
 #include "bitstream.h" /* BIT_* */
 #include "fse.h"       /* header compression */
 #include "huf.h"
-#include <linux/compiler.h>
-#include <linux/kernel.h>
-#include <linux/string.h> /* memcpy, memset */

 /* **************************************************************
 *  Error Management
diff --git a/grub-core/lib/zstd/kerncompat.h b/grub-core/lib/zstd/kerncompat.h
new file mode 100644
index 000000000..219749d7b
--- /dev/null
+++ b/grub-core/lib/zstd/kerncompat.h
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef KERNCOMPAT_H
+#define KERNCOMPAT_H
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <include/grub/types.h>
+
+#define get_unaligned_le16(p) grub_le_to_cpu16(grub_get_unaligned16((p)))
+#define get_unaligned_be16(p) grub_be_to_cpu16(grub_get_unaligned16((p)))
+#define get_unaligned_16(p) grub_get_unaligned16((p))
+#define put_unaligned_le16(val,p) grub_set_unaligned16((p), grub_cpu_to_le16((val)))
+#define put_unaligned_be16(val,p) grub_set_unaligned16((p), grub_cpu_to_be16((val)))
+#define put_unaligned_16(val,p) grub_set_unaligned16((p), (val))
+
+#define get_unaligned_le32(p) grub_le_to_cpu32(grub_get_unaligned32((p)))
+#define get_unaligned_be32(p) grub_be_to_cpu32(grub_get_unaligned32((p)))
+#define get_unaligned_32(p) grub_get_unaligned32((p))
+#define put_unaligned_le32(val,p) grub_set_unaligned32((p), grub_cpu_to_le32((val)))
+#define put_unaligned_be32(val,p) grub_set_unaligned32((p), grub_cpu_to_be32((val)))
+#define put_unaligned_32(val,p) grub_set_unaligned32((p), (val))
+
+#define get_unaligned_le64(p) grub_le_to_cpu64(grub_get_unaligned64((p)))
+#define get_unaligned_be64(p) grub_be_to_cpu64(grub_get_unaligned64((p)))
+#define get_unaligned_64(p) grub_get_unaligned64((p))
+#define put_unaligned_le64(val,p) grub_set_unaligned64((p), grub_cpu_to_le64((val)))
+#define put_unaligned_be64(val,p) grub_set_unaligned64((p), grub_cpu_to_be64((val)))
+#define put_unaligned_64(val,p) grub_set_unaligned64((p), (val))
+
+#ifndef noinline
+#	define noinline
+#endif
+
+#ifndef __always_inline
+#	ifdef __GNUC__
+#		define __always_inline inline __attribute__((__always_inline__))
+#	else
+#		define __always_inline inline
+#	endif
+#endif
+
+#define __ALIGN_KERNEL(x, a)		__ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
+#define __ALIGN_KERNEL_MASK(x, mask)	(((x) + (mask)) & ~(mask))
+#define ALIGN(x, a)		__ALIGN_KERNEL((x), (a))
+#define __ALIGN_MASK(x, mask)	__ALIGN_KERNEL_MASK((x), (mask))
+#define PTR_ALIGN(p, a)		((typeof(p))ALIGN((unsigned long)(p), (a)))
+
+#endif /* KERNCOMPAT_H */
diff --git a/grub-core/lib/zstd/mem.h b/grub-core/lib/zstd/mem.h
index 3a0f34c87..0e0ede37c 100644
--- a/grub-core/lib/zstd/mem.h
+++ b/grub-core/lib/zstd/mem.h
@@ -20,9 +20,7 @@
 /*-****************************************
 *  Dependencies
 ******************************************/
-#include <asm/unaligned.h>
-#include <linux/string.h> /* memcpy */
-#include <linux/types.h>  /* size_t, ptrdiff_t */
+#include "kerncompat.h"

 /*-****************************************
 *  Compiler specifics
@@ -32,15 +30,15 @@
 /*-**************************************************************
 *  Basic Types
 *****************************************************************/
-typedef uint8_t BYTE;
-typedef uint16_t U16;
-typedef int16_t S16;
-typedef uint32_t U32;
-typedef int32_t S32;
-typedef uint64_t U64;
-typedef int64_t S64;
-typedef ptrdiff_t iPtrDiff;
-typedef uintptr_t uPtrDiff;
+#include <include/grub/types.h>
+typedef grub_uint8_t BYTE;
+typedef grub_uint16_t U16;
+typedef grub_int16_t S16;
+typedef grub_uint32_t U32;
+typedef grub_int32_t S32;
+typedef grub_uint64_t U64;
+typedef grub_int64_t S64;
+typedef grub_size_t uPtrDiff;

 /*-**************************************************************
 *  Memory I/O
@@ -56,19 +54,25 @@ ZSTD_STATIC unsigned ZSTD_64bits(void) { return sizeof(size_t) == 8; }

 ZSTD_STATIC unsigned ZSTD_isLittleEndian(void) { return ZSTD_LITTLE_ENDIAN; }

-ZSTD_STATIC U16 ZSTD_read16(const void *memPtr) { return get_unaligned((const U16 *)memPtr); }
+ZSTD_STATIC U16 ZSTD_read16(const void *memPtr) { return get_unaligned_16(memPtr); }

-ZSTD_STATIC U32 ZSTD_read32(const void *memPtr) { return get_unaligned((const U32 *)memPtr); }
+ZSTD_STATIC U32 ZSTD_read32(const void *memPtr) { return get_unaligned_32(memPtr); }

-ZSTD_STATIC U64 ZSTD_read64(const void *memPtr) { return get_unaligned((const U64 *)memPtr); }
+ZSTD_STATIC U64 ZSTD_read64(const void *memPtr) { return get_unaligned_64(memPtr); }

-ZSTD_STATIC size_t ZSTD_readST(const void *memPtr) { return get_unaligned((const size_t *)memPtr); }
+ZSTD_STATIC size_t ZSTD_readST(const void *memPtr)
+{
+	if (ZSTD_32bits())
+		return get_unaligned_32(memPtr);
+	else
+		return get_unaligned_64(memPtr);
+}

-ZSTD_STATIC void ZSTD_write16(void *memPtr, U16 value) { put_unaligned(value, (U16 *)memPtr); }
+ZSTD_STATIC void ZSTD_write16(void *memPtr, U16 value) { put_unaligned_16(value, memPtr); }

-ZSTD_STATIC void ZSTD_write32(void *memPtr, U32 value) { put_unaligned(value, (U32 *)memPtr); }
+ZSTD_STATIC void ZSTD_write32(void *memPtr, U32 value) { put_unaligned_32(value, memPtr); }

-ZSTD_STATIC void ZSTD_write64(void *memPtr, U64 value) { put_unaligned(value, (U64 *)memPtr); }
+ZSTD_STATIC void ZSTD_write64(void *memPtr, U64 value) { put_unaligned_64(value, memPtr); }

 /*=== Little endian r/w ===*/

diff --git a/grub-core/lib/zstd/xxhash.c b/grub-core/lib/zstd/xxhash.c
index aa61e2a38..d5bd26097 100644
--- a/grub-core/lib/zstd/xxhash.c
+++ b/grub-core/lib/zstd/xxhash.c
@@ -38,13 +38,8 @@
  * - xxHash source repository: https://github.com/Cyan4973/xxHash
  */

-#include <asm/unaligned.h>
-#include <linux/errno.h>
-#include <linux/compiler.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/string.h>
-#include <linux/xxhash.h>
+#include "kerncompat.h"
+#include "xxhash.h"

 /*-*************************************
  * Macros
@@ -80,13 +75,11 @@ void xxh32_copy_state(struct xxh32_state *dst, const struct xxh32_state *src)
 {
 	memcpy(dst, src, sizeof(*dst));
 }
-EXPORT_SYMBOL(xxh32_copy_state);

 void xxh64_copy_state(struct xxh64_state *dst, const struct xxh64_state *src)
 {
 	memcpy(dst, src, sizeof(*dst));
 }
-EXPORT_SYMBOL(xxh64_copy_state);

 /*-***************************
  * Simple Hash Functions
@@ -151,7 +144,6 @@ uint32_t xxh32(const void *input, const size_t len, const uint32_t seed)

 	return h32;
 }
-EXPORT_SYMBOL(xxh32);

 static uint64_t xxh64_round(uint64_t acc, const uint64_t input)
 {
@@ -234,7 +226,6 @@ uint64_t xxh64(const void *input, const size_t len, const uint64_t seed)

 	return h64;
 }
-EXPORT_SYMBOL(xxh64);

 /*-**************************************************
  * Advanced Hash Functions
@@ -251,7 +242,6 @@ void xxh32_reset(struct xxh32_state *statePtr, const uint32_t seed)
 	state.v4 = seed - PRIME32_1;
 	memcpy(statePtr, &state, sizeof(state));
 }
-EXPORT_SYMBOL(xxh32_reset);

 void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
 {
@@ -265,7 +255,6 @@ void xxh64_reset(struct xxh64_state *statePtr, const uint64_t seed)
 	state.v4 = seed - PRIME64_1;
 	memcpy(statePtr, &state, sizeof(state));
 }
-EXPORT_SYMBOL(xxh64_reset);

 int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)
 {
@@ -334,7 +323,6 @@ int xxh32_update(struct xxh32_state *state, const void *input, const size_t len)

 	return 0;
 }
-EXPORT_SYMBOL(xxh32_update);

 uint32_t xxh32_digest(const struct xxh32_state *state)
 {
@@ -372,7 +360,6 @@ uint32_t xxh32_digest(const struct xxh32_state *state)

 	return h32;
 }
-EXPORT_SYMBOL(xxh32_digest);

 int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)
 {
@@ -439,7 +426,6 @@ int xxh64_update(struct xxh64_state *state, const void *input, const size_t len)

 	return 0;
 }
-EXPORT_SYMBOL(xxh64_update);

 uint64_t xxh64_digest(const struct xxh64_state *state)
 {
@@ -494,7 +480,3 @@ uint64_t xxh64_digest(const struct xxh64_state *state)

 	return h64;
 }
-EXPORT_SYMBOL(xxh64_digest);
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_DESCRIPTION("xxHash");
diff --git a/grub-core/lib/zstd/xxhash.h b/grub-core/lib/zstd/xxhash.h
index 9e1f42cb5..b089a4abd 100644
--- a/grub-core/lib/zstd/xxhash.h
+++ b/grub-core/lib/zstd/xxhash.h
@@ -75,7 +75,7 @@
 #ifndef XXHASH_H
 #define XXHASH_H

-#include <linux/types.h>
+#include "kerncompat.h"

 /*-****************************
  * Simple Hash Functions
diff --git a/grub-core/lib/zstd/zstd.h b/grub-core/lib/zstd/zstd.h
index 249575e24..302581446 100644
--- a/grub-core/lib/zstd/zstd.h
+++ b/grub-core/lib/zstd/zstd.h
@@ -18,7 +18,7 @@
 #define ZSTD_H

 /* ======   Dependency   ======*/
-#include <linux/types.h>   /* size_t */
+#include <stddef.h>


 /*-*****************************************************************************
diff --git a/grub-core/lib/zstd/zstd_common.c b/grub-core/lib/zstd/zstd_common.c
index a282624ee..db6327744 100644
--- a/grub-core/lib/zstd/zstd_common.c
+++ b/grub-core/lib/zstd/zstd_common.c
@@ -17,9 +17,9 @@
 /*-*************************************
 *  Dependencies
 ***************************************/
+#include "kerncompat.h"
 #include "error_private.h"
 #include "zstd_internal.h" /* declaration of ZSTD_isError, ZSTD_getErrorName, ZSTD_getErrorCode, ZSTD_getErrorString, ZSTD_versionNumber */
-#include <linux/kernel.h>

 /*=**************************************************************
 *  Custom allocator
diff --git a/grub-core/lib/zstd/zstd_internal.h b/grub-core/lib/zstd/zstd_internal.h
index 1a79fab9e..990f4f13f 100644
--- a/grub-core/lib/zstd/zstd_internal.h
+++ b/grub-core/lib/zstd/zstd_internal.h
@@ -28,10 +28,8 @@
 ***************************************/
 #include "error_private.h"
 #include "mem.h"
-#include <linux/compiler.h>
-#include <linux/kernel.h>
-#include <linux/xxhash.h>
-#include <linux/zstd.h>
+#include "xxhash.h"
+#include "zstd.h"

 /*-*************************************
 *  shared macros
@@ -127,7 +125,11 @@ static const U32 OF_defaultNormLog = OF_DEFAULTNORMLOG;
 *  Shared functions to include for inlining
 *********************************************/
 ZSTD_STATIC void ZSTD_copy8(void *dst, const void *src) {
-	memcpy(dst, src, 8);
+	/* When compiled in freestanding mode, the compiler can't inline memcpy()
+	 * unless explicitly told that it is allowed to. This is a major pessimization
+	 * for zstd, since ZSTD_wildcopy() is hot.
+	 */
+	__builtin_memcpy(dst, src, 8);
 }
 /*! ZSTD_wildcopy() :
 *   custom version of memcpy(), can copy up to 7 bytes too many (8 bytes if length==0) */
--
2.16.2