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619b6e18fc
tmp_suning_uos_patched/arch/mips/lib/csum_partial.S
Maciej W. Rozycki 619b6e18fc [MIPS] R4000/R4400 daddiu erratum workaround 
This complements the generic R4000/R4400 errata workaround code and adds 
bits for the daddiu problem.  In most places it just modifies handwritten 
assembly code so that the assembler is allowed to use a temporary register 
as daddiu may now be treated as a macro that expands to a sequence of li 
and daddu.  It is the AT register or, where AT is unavailable or used 
explicitly for another purpose, an explicitly-named register is selected, 
using the .set at=<reg> feature added recently to gas.  This feature is 
only used if CONFIG_CPU_DADDI_WORKAROUNDS has been set, so if the 
workaround remains disabled, the required version of binutils stays 
unchanged.

 Similarly, daddiu instructions put in branch delay slots in noreorder 
fragments are now taken out of them and the assembler is allowed to 
reorder them itself as possible (which it does making the whole idea of 
scheduling them into delay slots manually questionable).

 Also in the very few places where such a simple conversion was not 
possible, a handcoded longer sequence is implemented.

 Other than that there are changes to code responsible for building the 
TLB fault and page clear/copy handlers to avoid daddiu as appropriate.  
These are only effective if the erratum is verified to be present at the 
run time.

 Finally there is a trivial update to __delay(), because it uses daddiu in 
a branch delay slot.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2008-01-29 10:14:55 +00:00

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/*
* 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.
*
* Quick'n'dirty IP checksum ...
*
* Copyright (C) 1998, 1999 Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2007 Maciej W. Rozycki
*/
#include <linux/errno.h>
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/regdef.h>
#ifdef CONFIG_64BIT
/*
* As we are sharing code base with the mips32 tree (which use the o32 ABI
* register definitions). We need to redefine the register definitions from
* the n64 ABI register naming to the o32 ABI register naming.
*/
#undef t0
#undef t1
#undef t2
#undef t3
#define t0 $8
#define t1 $9
#define t2 $10
#define t3 $11
#define t4 $12
#define t5 $13
#define t6 $14
#define t7 $15
#define USE_DOUBLE
#endif
#ifdef USE_DOUBLE
#define LOAD ld
#define ADD daddu
#define NBYTES 8
#else
#define LOAD lw
#define ADD addu
#define NBYTES 4
#endif /* USE_DOUBLE */
#define UNIT(unit) ((unit)*NBYTES)
#define ADDC(sum,reg) \
.set push; \
.set noat; \
ADD sum, reg; \
sltu v1, sum, reg; \
ADD sum, v1; \
.set pop
#define CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3) \
LOAD _t0, (offset + UNIT(0))(src); \
LOAD _t1, (offset + UNIT(1))(src); \
LOAD _t2, (offset + UNIT(2))(src); \
LOAD _t3, (offset + UNIT(3))(src); \
ADDC(sum, _t0); \
ADDC(sum, _t1); \
ADDC(sum, _t2); \
ADDC(sum, _t3)
#ifdef USE_DOUBLE
#define CSUM_BIGCHUNK(src, offset, sum, _t0, _t1, _t2, _t3) \
CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3)
#else
#define CSUM_BIGCHUNK(src, offset, sum, _t0, _t1, _t2, _t3) \
CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3); \
CSUM_BIGCHUNK1(src, offset + 0x10, sum, _t0, _t1, _t2, _t3)
#endif
/*
* a0: source address
* a1: length of the area to checksum
* a2: partial checksum
*/
#define src a0
#define sum v0
.text
.set noreorder
.align 5
LEAF(csum_partial)
move sum, zero
move t7, zero
sltiu t8, a1, 0x8
bnez t8, small_csumcpy /* < 8 bytes to copy */
move t2, a1
andi t7, src, 0x1 /* odd buffer? */
hword_align:
beqz t7, word_align
andi t8, src, 0x2
lbu t0, (src)
LONG_SUBU a1, a1, 0x1
#ifdef __MIPSEL__
sll t0, t0, 8
#endif
ADDC(sum, t0)
PTR_ADDU src, src, 0x1
andi t8, src, 0x2
word_align:
beqz t8, dword_align
sltiu t8, a1, 56
lhu t0, (src)
LONG_SUBU a1, a1, 0x2
ADDC(sum, t0)
sltiu t8, a1, 56
PTR_ADDU src, src, 0x2
dword_align:
bnez t8, do_end_words
move t8, a1
andi t8, src, 0x4
beqz t8, qword_align
andi t8, src, 0x8
lw t0, 0x00(src)
LONG_SUBU a1, a1, 0x4
ADDC(sum, t0)
PTR_ADDU src, src, 0x4
andi t8, src, 0x8
qword_align:
beqz t8, oword_align
andi t8, src, 0x10
#ifdef USE_DOUBLE
ld t0, 0x00(src)
LONG_SUBU a1, a1, 0x8
ADDC(sum, t0)
#else
lw t0, 0x00(src)
lw t1, 0x04(src)
LONG_SUBU a1, a1, 0x8
ADDC(sum, t0)
ADDC(sum, t1)
#endif
PTR_ADDU src, src, 0x8
andi t8, src, 0x10
oword_align:
beqz t8, begin_movement
LONG_SRL t8, a1, 0x7
#ifdef USE_DOUBLE
ld t0, 0x00(src)
ld t1, 0x08(src)
ADDC(sum, t0)
ADDC(sum, t1)
#else
CSUM_BIGCHUNK1(src, 0x00, sum, t0, t1, t3, t4)
#endif
LONG_SUBU a1, a1, 0x10
PTR_ADDU src, src, 0x10
LONG_SRL t8, a1, 0x7
begin_movement:
beqz t8, 1f
andi t2, a1, 0x40
move_128bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x40, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x60, sum, t0, t1, t3, t4)
LONG_SUBU t8, t8, 0x01
.set reorder /* DADDI_WAR */
PTR_ADDU src, src, 0x80
bnez t8, move_128bytes
.set noreorder
1:
beqz t2, 1f
andi t2, a1, 0x20
move_64bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
PTR_ADDU src, src, 0x40
1:
beqz t2, do_end_words
andi t8, a1, 0x1c
move_32bytes:
CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
andi t8, a1, 0x1c
PTR_ADDU src, src, 0x20
do_end_words:
beqz t8, small_csumcpy
andi t2, a1, 0x3
LONG_SRL t8, t8, 0x2
end_words:
lw t0, (src)
LONG_SUBU t8, t8, 0x1
ADDC(sum, t0)
.set reorder /* DADDI_WAR */
PTR_ADDU src, src, 0x4
bnez t8, end_words
.set noreorder
/* unknown src alignment and < 8 bytes to go */
small_csumcpy:
move a1, t2
andi t0, a1, 4
beqz t0, 1f
andi t0, a1, 2
/* Still a full word to go */
ulw t1, (src)
PTR_ADDIU src, 4
ADDC(sum, t1)
1: move t1, zero
beqz t0, 1f
andi t0, a1, 1
/* Still a halfword to go */
ulhu t1, (src)
PTR_ADDIU src, 2
1: beqz t0, 1f
sll t1, t1, 16
lbu t2, (src)
nop
#ifdef __MIPSEB__
sll t2, t2, 8
#endif
or t1, t2
1: ADDC(sum, t1)
/* fold checksum */
.set push
.set noat
#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 t7, 1f
nop
sll v1, sum, 8
srl sum, sum, 8
or sum, v1
andi sum, 0xffff
.set pop
1:
.set reorder
/* Add the passed partial csum. */
ADDC(sum, a2)
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)
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
.set noat
#else
.set at=v1
#endif
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)
.set reorder /* DADDI_WAR */
ADD dst, dst, 8*NBYTES
bgez len, 1b
.set noreorder
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)
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
beqz len, done
.set noreorder
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)
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
bne rem, len, 1b
.set noreorder
/*
* 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)
.set reorder /* DADDI_WAR */
ADD dst, dst, 4*NBYTES
bne len, rem, 1b
.set noreorder
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)
.set reorder /* DADDI_WAR */
ADD dst, dst, NBYTES
bne len, rem, 1b
.set noreorder
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 */
.set push
.set noat
#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
.set pop
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)
.set reorder /* DADDI_WAR */
ADD dst, dst, 1
bne src, t0, 1b
.set noreorder
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...
*/
.set reorder /* DADDI_WAR */
SUB src, len, 1
beqz len, done
.set noreorder
1: sb zero, 0(dst)
ADD dst, dst, 1
.set push
.set noat
#ifndef CONFIG_CPU_DADDI_WORKAROUNDS
bnez src, 1b
SUB src, src, 1
#else
li v1, 1
bnez src, 1b
SUB src, src, v1
#endif
li v1, -EFAULT
b done
sw v1, (errptr)
s_exc:
li v0, -1 /* invalid checksum */
li v1, -EFAULT
jr ra
sw v1, (errptr)
.set pop
END(__csum_partial_copy_user)
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