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Commit 755efdc3 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Drop the hardware crc32c asm code 



This is already in the arch specific directories in mainline and
shouldn't be copied into btrfs.

Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 709ac06a

fs/btrfs/crc32c.h

+3 −94
Original line number Diff line number Diff line
@@ -18,103 +18,12 @@ 


#ifndef __BTRFS_CRC32C__

#define __BTRFS_CRC32C__

#include <asm/byteorder.h>

#include <linux/crc32c.h>

#include <linux/version.h>



/* #define CONFIG_BTRFS_HW_SUM 1 */



#ifdef CONFIG_BTRFS_HW_SUM

#ifdef CONFIG_X86

/*

 * Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.

 * CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)

 * CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:

 * http://www.intel.com/products/processor/manuals/

 * Intel(R) 64 and IA-32 Architectures Software Developer's Manual

 * Volume 2A: Instruction Set Reference, A-M

 */



#include <asm/cpufeature.h>

#include <asm/processor.h>



#define X86_FEATURE_XMM4_2     (4*32+20) /* Streaming SIMD Extensions-4.2 */

#define cpu_has_xmm4_2         boot_cpu_has(X86_FEATURE_XMM4_2)



#ifdef CONFIG_X86_64

#define REX_PRE	"0x48, "

#define SCALE_F	8

#else

#define REX_PRE

#define SCALE_F	4

#endif



static inline u32 btrfs_crc32c_le_hw_byte(u32 crc, unsigned char const *data,

				   size_t length)

{

	while (length--) {

		__asm__ __volatile__(

			".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"

			:"=S"(crc)

			:"0"(crc), "c"(*data)

		);

		data++;

	}



	return crc;

}



static inline u32 __pure btrfs_crc32c_le_hw(u32 crc, unsigned char const *p,

				     size_t len)

{

	unsigned int iquotient = len / SCALE_F;

	unsigned int iremainder = len % SCALE_F;

#ifdef CONFIG_X86_64

	u64 *ptmp = (u64 *)p;

#else

	u32 *ptmp = (u32 *)p;

#endif



	while (iquotient--) {

		__asm__ __volatile__(

			".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"

			:"=S"(crc)

			:"0"(crc), "c"(*ptmp)

		);

		ptmp++;

	}



	if (iremainder)

		crc = btrfs_crc32c_le_hw_byte(crc, (unsigned char *)ptmp,

					      iremainder);



	return crc;

}

#endif /* CONFIG_BTRFS_HW_SUM */



static inline u32 __btrfs_crc32c(u32 crc, unsigned char const *address,

				 size_t len)

{

#ifdef CONFIG_BTRFS_HW_SUM

	if (cpu_has_xmm4_2)

		return btrfs_crc32c_le_hw(crc, address, len);

#endif

	return crc32c_le(crc, address, len);

}



#else



#define __btrfs_crc32c(seed, data, length) crc32c(seed, data, length)



#endif /* CONFIG_X86 */



/**

 * implementation of crc32c_le() changed in linux-2.6.23,

 * has of v0.13 btrfs-progs is using the latest version.

 * We must workaround older implementations of crc32c_le()

 * found on older kernel versions.

 * this file used to do more for selecting the HW version of crc32c,

 * perhaps it will one day again soon.

 */

#define btrfs_crc32c(seed, data, length) \

	__btrfs_crc32c(seed, (unsigned char const *)data, length)

#define btrfs_crc32c(seed, data, length) crc32c(seed, data, length)

#endif