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Commit f860c90b authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Ralf Baechle
Browse files

[MIPS] csum_partial and copy in parallel 



Implement optimized asm version of csum_partial_copy_nocheck,
csum_partial_copy_from_user and csum_and_copy_to_user which can do
calculate and copy in parallel, based on memcpy.S.

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 61e84f99

arch/mips/kernel/mips_ksyms.c

+2 −0
Original line number Diff line number Diff line
@@ -46,5 +46,7 @@ EXPORT_SYMBOL(__strnlen_user_nocheck_asm); 
EXPORT_SYMBOL(__strnlen_user_asm);



EXPORT_SYMBOL(csum_partial);

EXPORT_SYMBOL(csum_partial_copy_nocheck);

EXPORT_SYMBOL(__csum_partial_copy_user);



EXPORT_SYMBOL(invalid_pte_table);

arch/mips/lib/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 
# Makefile for MIPS-specific library files..

#



lib-y	+= csum_partial.o csum_partial_copy.o memcpy.o promlib.o \

lib-y	+= csum_partial.o memcpy.o promlib.o \

	   strlen_user.o strncpy_user.o strnlen_user.o uncached.o



obj-y	+= iomap.o

arch/mips/lib/csum_partial.S

+442 −0
Original line number Diff line number Diff line
@@ -8,7 +8,9 @@ 
 * Copyright (C) 1998, 1999 Ralf Baechle

 * Copyright (C) 1999 Silicon Graphics, Inc.

 */

#include <linux/errno.h>

#include <asm/asm.h>

#include <asm/asm-offsets.h>

#include <asm/regdef.h>



#ifdef CONFIG_64BIT
@@ -271,3 +273,443 @@ small_csumcpy: 
	jr	ra

	.set	noreorder

	END(csum_partial)





/*

 * checksum and copy routines based on memcpy.S

 *

 *	csum_partial_copy_nocheck(src, dst, len, sum)

 *	__csum_partial_copy_user(src, dst, len, sum, errp)

 *

 * See "Spec" in memcpy.S for details.  Unlike __copy_user, all

 * function in this file use the standard calling convention.

 */



#define src a0

#define dst a1

#define len a2

#define psum a3

#define sum v0

#define odd t8

#define errptr t9



/*

 * The exception handler for loads requires that:

 *  1- AT contain the address of the byte just past the end of the source

 *     of the copy,

 *  2- src_entry <= src < AT, and

 *  3- (dst - src) == (dst_entry - src_entry),

 * The _entry suffix denotes values when __copy_user was called.

 *

 * (1) is set up up by __csum_partial_copy_from_user and maintained by

 *	not writing AT in __csum_partial_copy

 * (2) is met by incrementing src by the number of bytes copied

 * (3) is met by not doing loads between a pair of increments of dst and src

 *

 * The exception handlers for stores stores -EFAULT to errptr and return.

 * These handlers do not need to overwrite any data.

 */



#define EXC(inst_reg,addr,handler)		\

9:	inst_reg, addr;				\

	.section __ex_table,"a";		\

	PTR	9b, handler;			\

	.previous



#ifdef USE_DOUBLE



#define LOAD   ld

#define LOADL  ldl

#define LOADR  ldr

#define STOREL sdl

#define STORER sdr

#define STORE  sd

#define ADD    daddu

#define SUB    dsubu

#define SRL    dsrl

#define SLL    dsll

#define SLLV   dsllv

#define SRLV   dsrlv

#define NBYTES 8

#define LOG_NBYTES 3



#else



#define LOAD   lw

#define LOADL  lwl

#define LOADR  lwr

#define STOREL swl

#define STORER swr

#define STORE  sw

#define ADD    addu

#define SUB    subu

#define SRL    srl

#define SLL    sll

#define SLLV   sllv

#define SRLV   srlv

#define NBYTES 4

#define LOG_NBYTES 2



#endif /* USE_DOUBLE */



#ifdef CONFIG_CPU_LITTLE_ENDIAN

#define LDFIRST LOADR

#define LDREST  LOADL

#define STFIRST STORER

#define STREST  STOREL

#define SHIFT_DISCARD SLLV

#define SHIFT_DISCARD_REVERT SRLV

#else

#define LDFIRST LOADL

#define LDREST  LOADR

#define STFIRST STOREL

#define STREST  STORER

#define SHIFT_DISCARD SRLV

#define SHIFT_DISCARD_REVERT SLLV

#endif



#define FIRST(unit) ((unit)*NBYTES)

#define REST(unit)  (FIRST(unit)+NBYTES-1)



#define ADDRMASK (NBYTES-1)



	.set	noat



LEAF(__csum_partial_copy_user)

	PTR_ADDU	AT, src, len	/* See (1) above. */

#ifdef CONFIG_64BIT

	move	errptr, a4

#else

	lw	errptr, 16(sp)

#endif

FEXPORT(csum_partial_copy_nocheck)

	move	sum, zero

	move	odd, zero

	/*

	 * Note: dst & src may be unaligned, len may be 0

	 * Temps

	 */

	/*

	 * The "issue break"s below are very approximate.

	 * Issue delays for dcache fills will perturb the schedule, as will

	 * load queue full replay traps, etc.

	 *

	 * If len < NBYTES use byte operations.

	 */

	sltu	t2, len, NBYTES

	and	t1, dst, ADDRMASK

	bnez	t2, copy_bytes_checklen

	 and	t0, src, ADDRMASK

	andi	odd, dst, 0x1			/* odd buffer? */

	bnez	t1, dst_unaligned

	 nop

	bnez	t0, src_unaligned_dst_aligned

	/*

	 * use delay slot for fall-through

	 * src and dst are aligned; need to compute rem

	 */

both_aligned:

	 SRL	t0, len, LOG_NBYTES+3    # +3 for 8 units/iter

	beqz	t0, cleanup_both_aligned # len < 8*NBYTES

	 nop

	SUB	len, 8*NBYTES		# subtract here for bgez loop

	.align	4

1:

EXC(	LOAD	t0, UNIT(0)(src),	l_exc)

EXC(	LOAD	t1, UNIT(1)(src),	l_exc_copy)

EXC(	LOAD	t2, UNIT(2)(src),	l_exc_copy)

EXC(	LOAD	t3, UNIT(3)(src),	l_exc_copy)

EXC(	LOAD	t4, UNIT(4)(src),	l_exc_copy)

EXC(	LOAD	t5, UNIT(5)(src),	l_exc_copy)

EXC(	LOAD	t6, UNIT(6)(src),	l_exc_copy)

EXC(	LOAD	t7, UNIT(7)(src),	l_exc_copy)

	SUB	len, len, 8*NBYTES

	ADD	src, src, 8*NBYTES

EXC(	STORE	t0, UNIT(0)(dst),	s_exc)

	ADDC(sum, t0)

EXC(	STORE	t1, UNIT(1)(dst),	s_exc)

	ADDC(sum, t1)

EXC(	STORE	t2, UNIT(2)(dst),	s_exc)

	ADDC(sum, t2)

EXC(	STORE	t3, UNIT(3)(dst),	s_exc)

	ADDC(sum, t3)

EXC(	STORE	t4, UNIT(4)(dst),	s_exc)

	ADDC(sum, t4)

EXC(	STORE	t5, UNIT(5)(dst),	s_exc)

	ADDC(sum, t5)

EXC(	STORE	t6, UNIT(6)(dst),	s_exc)

	ADDC(sum, t6)

EXC(	STORE	t7, UNIT(7)(dst),	s_exc)

	ADDC(sum, t7)

	bgez	len, 1b

	 ADD	dst, dst, 8*NBYTES

	ADD	len, 8*NBYTES		# revert len (see above)



	/*

	 * len == the number of bytes left to copy < 8*NBYTES

	 */

cleanup_both_aligned:

#define rem t7

	beqz	len, done

	 sltu	t0, len, 4*NBYTES

	bnez	t0, less_than_4units

	 and	rem, len, (NBYTES-1)	# rem = len % NBYTES

	/*

	 * len >= 4*NBYTES

	 */

EXC(	LOAD	t0, UNIT(0)(src),	l_exc)

EXC(	LOAD	t1, UNIT(1)(src),	l_exc_copy)

EXC(	LOAD	t2, UNIT(2)(src),	l_exc_copy)

EXC(	LOAD	t3, UNIT(3)(src),	l_exc_copy)

	SUB	len, len, 4*NBYTES

	ADD	src, src, 4*NBYTES

EXC(	STORE	t0, UNIT(0)(dst),	s_exc)

	ADDC(sum, t0)

EXC(	STORE	t1, UNIT(1)(dst),	s_exc)

	ADDC(sum, t1)

EXC(	STORE	t2, UNIT(2)(dst),	s_exc)

	ADDC(sum, t2)

EXC(	STORE	t3, UNIT(3)(dst),	s_exc)

	ADDC(sum, t3)

	beqz	len, done

	 ADD	dst, dst, 4*NBYTES

less_than_4units:

	/*

	 * rem = len % NBYTES

	 */

	beq	rem, len, copy_bytes

	 nop

1:

EXC(	LOAD	t0, 0(src),		l_exc)

	ADD	src, src, NBYTES

	SUB	len, len, NBYTES

EXC(	STORE	t0, 0(dst),		s_exc)

	ADDC(sum, t0)

	bne	rem, len, 1b

	 ADD	dst, dst, NBYTES



	/*

	 * src and dst are aligned, need to copy rem bytes (rem < NBYTES)

	 * A loop would do only a byte at a time with possible branch

	 * mispredicts.  Can't do an explicit LOAD dst,mask,or,STORE

	 * because can't assume read-access to dst.  Instead, use

	 * STREST dst, which doesn't require read access to dst.

	 *

	 * This code should perform better than a simple loop on modern,

	 * wide-issue mips processors because the code has fewer branches and

	 * more instruction-level parallelism.

	 */

#define bits t2

	beqz	len, done

	 ADD	t1, dst, len	# t1 is just past last byte of dst

	li	bits, 8*NBYTES

	SLL	rem, len, 3	# rem = number of bits to keep

EXC(	LOAD	t0, 0(src),		l_exc)

	SUB	bits, bits, rem	# bits = number of bits to discard

	SHIFT_DISCARD t0, t0, bits

EXC(	STREST	t0, -1(t1),		s_exc)

	SHIFT_DISCARD_REVERT t0, t0, bits

	.set reorder

	ADDC(sum, t0)

	b	done

	.set noreorder

dst_unaligned:

	/*

	 * dst is unaligned

	 * t0 = src & ADDRMASK

	 * t1 = dst & ADDRMASK; T1 > 0

	 * len >= NBYTES

	 *

	 * Copy enough bytes to align dst

	 * Set match = (src and dst have same alignment)

	 */

#define match rem

EXC(	LDFIRST	t3, FIRST(0)(src),	l_exc)

	ADD	t2, zero, NBYTES

EXC(	LDREST	t3, REST(0)(src),	l_exc_copy)

	SUB	t2, t2, t1	# t2 = number of bytes copied

	xor	match, t0, t1

EXC(	STFIRST t3, FIRST(0)(dst),	s_exc)

	SLL	t4, t1, 3		# t4 = number of bits to discard

	SHIFT_DISCARD t3, t3, t4

	/* no SHIFT_DISCARD_REVERT to handle odd buffer properly */

	ADDC(sum, t3)

	beq	len, t2, done

	 SUB	len, len, t2

	ADD	dst, dst, t2

	beqz	match, both_aligned

	 ADD	src, src, t2



src_unaligned_dst_aligned:

	SRL	t0, len, LOG_NBYTES+2    # +2 for 4 units/iter

	beqz	t0, cleanup_src_unaligned

	 and	rem, len, (4*NBYTES-1)   # rem = len % 4*NBYTES

1:

/*

 * Avoid consecutive LD*'s to the same register since some mips

 * implementations can't issue them in the same cycle.

 * It's OK to load FIRST(N+1) before REST(N) because the two addresses

 * are to the same unit (unless src is aligned, but it's not).

 */

EXC(	LDFIRST	t0, FIRST(0)(src),	l_exc)

EXC(	LDFIRST	t1, FIRST(1)(src),	l_exc_copy)

	SUB     len, len, 4*NBYTES

EXC(	LDREST	t0, REST(0)(src),	l_exc_copy)

EXC(	LDREST	t1, REST(1)(src),	l_exc_copy)

EXC(	LDFIRST	t2, FIRST(2)(src),	l_exc_copy)

EXC(	LDFIRST	t3, FIRST(3)(src),	l_exc_copy)

EXC(	LDREST	t2, REST(2)(src),	l_exc_copy)

EXC(	LDREST	t3, REST(3)(src),	l_exc_copy)

	ADD	src, src, 4*NBYTES

#ifdef CONFIG_CPU_SB1

	nop				# improves slotting

#endif

EXC(	STORE	t0, UNIT(0)(dst),	s_exc)

	ADDC(sum, t0)

EXC(	STORE	t1, UNIT(1)(dst),	s_exc)

	ADDC(sum, t1)

EXC(	STORE	t2, UNIT(2)(dst),	s_exc)

	ADDC(sum, t2)

EXC(	STORE	t3, UNIT(3)(dst),	s_exc)

	ADDC(sum, t3)

	bne	len, rem, 1b

	 ADD	dst, dst, 4*NBYTES



cleanup_src_unaligned:

	beqz	len, done

	 and	rem, len, NBYTES-1  # rem = len % NBYTES

	beq	rem, len, copy_bytes

	 nop

1:

EXC(	LDFIRST t0, FIRST(0)(src),	l_exc)

EXC(	LDREST	t0, REST(0)(src),	l_exc_copy)

	ADD	src, src, NBYTES

	SUB	len, len, NBYTES

EXC(	STORE	t0, 0(dst),		s_exc)

	ADDC(sum, t0)

	bne	len, rem, 1b

	 ADD	dst, dst, NBYTES



copy_bytes_checklen:

	beqz	len, done

	 nop

copy_bytes:

	/* 0 < len < NBYTES  */

#ifdef CONFIG_CPU_LITTLE_ENDIAN

#define SHIFT_START 0

#define SHIFT_INC 8

#else

#define SHIFT_START 8*(NBYTES-1)

#define SHIFT_INC -8

#endif

	move	t2, zero	# partial word

	li	t3, SHIFT_START	# shift

/* use l_exc_copy here to return correct sum on fault */

#define COPY_BYTE(N)			\

EXC(	lbu	t0, N(src), l_exc_copy);	\

	SUB	len, len, 1;		\

EXC(	sb	t0, N(dst), s_exc);	\

	SLLV	t0, t0, t3;		\

	addu	t3, SHIFT_INC;		\

	beqz	len, copy_bytes_done;	\

	 or	t2, t0



	COPY_BYTE(0)

	COPY_BYTE(1)

#ifdef USE_DOUBLE

	COPY_BYTE(2)

	COPY_BYTE(3)

	COPY_BYTE(4)

	COPY_BYTE(5)

#endif

EXC(	lbu	t0, NBYTES-2(src), l_exc_copy)

	SUB	len, len, 1

EXC(	sb	t0, NBYTES-2(dst), s_exc)

	SLLV	t0, t0, t3

	or	t2, t0

copy_bytes_done:

	ADDC(sum, t2)

done:

	/* fold checksum */

#ifdef USE_DOUBLE

	dsll32	v1, sum, 0

	daddu	sum, v1

	sltu	v1, sum, v1

	dsra32	sum, sum, 0

	addu	sum, v1

#endif

	sll	v1, sum, 16

	addu	sum, v1

	sltu	v1, sum, v1

	srl	sum, sum, 16

	addu	sum, v1



	/* odd buffer alignment? */

	beqz	odd, 1f

	 nop

	sll	v1, sum, 8

	srl	sum, sum, 8

	or	sum, v1

	andi	sum, 0xffff

1:

	.set reorder

	ADDC(sum, psum)

	jr	ra

	.set noreorder



l_exc_copy:

	/*

	 * Copy bytes from src until faulting load address (or until a

	 * lb faults)

	 *

	 * When reached by a faulting LDFIRST/LDREST, THREAD_BUADDR($28)

	 * may be more than a byte beyond the last address.

	 * Hence, the lb below may get an exception.

	 *

	 * Assumes src < THREAD_BUADDR($28)

	 */

	LOAD	t0, TI_TASK($28)

	 li	t2, SHIFT_START

	LOAD	t0, THREAD_BUADDR(t0)

1:

EXC(	lbu	t1, 0(src),	l_exc)

	ADD	src, src, 1

	sb	t1, 0(dst)	# can't fault -- we're copy_from_user

	SLLV	t1, t1, t2

	addu	t2, SHIFT_INC

	ADDC(sum, t1)

	bne	src, t0, 1b

	 ADD	dst, dst, 1

l_exc:

	LOAD	t0, TI_TASK($28)

	 nop

	LOAD	t0, THREAD_BUADDR(t0)	# t0 is just past last good address

	 nop

	SUB	len, AT, t0		# len number of uncopied bytes

	/*

	 * Here's where we rely on src and dst being incremented in tandem,

	 *   See (3) above.

	 * dst += (fault addr - src) to put dst at first byte to clear

	 */

	ADD	dst, t0			# compute start address in a1

	SUB	dst, src

	/*

	 * Clear len bytes starting at dst.  Can't call __bzero because it

	 * might modify len.  An inefficient loop for these rare times...

	 */

	beqz	len, done

	 SUB	src, len, 1

1:	sb	zero, 0(dst)

	ADD	dst, dst, 1

	bnez	src, 1b

	 SUB	src, src, 1

	li	v1, -EFAULT

	b	done

	 sw	v1, (errptr)



s_exc:

	li	v0, -1 /* invalid checksum */

	li	v1, -EFAULT

	jr	ra

	 sw	v1, (errptr)

	END(__csum_partial_copy_user)

arch/mips/lib/csum_partial_copy.c

deleted100644 → 0
+0 −52
Original line number Diff line number Diff line 
/*

 * This file is subject to the terms and conditions of the GNU General Public

 * License.  See the file "COPYING" in the main directory of this archive

 * for more details.

 *

 * Copyright (C) 1994, 1995 Waldorf Electronics GmbH

 * Copyright (C) 1998, 1999 Ralf Baechle

 */

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/types.h>

#include <asm/byteorder.h>

#include <asm/string.h>

#include <asm/uaccess.h>

#include <net/checksum.h>



/*

 * copy while checksumming, otherwise like csum_partial

 */

__wsum csum_partial_copy_nocheck(const void *src,

	void *dst, int len, __wsum sum)

{

	/*

	 * It's 2:30 am and I don't feel like doing it real ...

	 * This is lots slower than the real thing (tm)

	 */

	sum = csum_partial(src, len, sum);

	memcpy(dst, src, len);



	return sum;

}



EXPORT_SYMBOL(csum_partial_copy_nocheck);



/*

 * Copy from userspace and compute checksum.  If we catch an exception

 * then zero the rest of the buffer.

 */

__wsum csum_partial_copy_from_user (const void __user *src,

	void *dst, int len, __wsum sum, int *err_ptr)

{

	int missing;



	might_sleep();

	missing = copy_from_user(dst, src, len);

	if (missing) {

		memset(dst + len - missing, 0, missing);

		*err_ptr = -EFAULT;

	}



	return csum_partial(dst, len, sum);

}

include/asm-mips/checksum.h

+19 −12
Original line number Diff line number Diff line
@@ -29,31 +29,38 @@ 
 */

__wsum csum_partial(const void *buff, int len, __wsum sum);



__wsum __csum_partial_copy_user(const void *src, void *dst,

				int len, __wsum sum, int *err_ptr);



/*

 * this is a new version of the above that records errors it finds in *errp,

 * but continues and zeros the rest of the buffer.

 */

__wsum csum_partial_copy_from_user(const void __user *src,

					 void *dst, int len,

					 __wsum sum, int *errp);

static inline

__wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len,

				   __wsum sum, int *err_ptr)

{

	might_sleep();

	return __csum_partial_copy_user((__force void *)src, dst,

					len, sum, err_ptr);

}



/*

 * Copy and checksum to user

 */

#define HAVE_CSUM_COPY_USER

static inline __wsum csum_and_copy_to_user (const void *src, void __user *dst,

						  int len, __wsum sum,

						  int *err_ptr)

static inline

__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,

			     __wsum sum, int *err_ptr)

{

	might_sleep();

	sum = csum_partial(src, len, sum);



	if (copy_to_user(dst, src, len)) {

	if (access_ok(VERIFY_WRITE, dst, len))

		return __csum_partial_copy_user(src, (__force void *)dst,

						len, sum, err_ptr);

	if (len)

		*err_ptr = -EFAULT;

		return (__force __wsum)-1;

	}



	return sum;

	return (__force __wsum)-1; /* invalid checksum */

}



/*