* 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
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)
projects / kernel / kernel-generic.git / commitdiff