--- /dev/null
+/*
+ * Optimized memory copy routines.
+ *
+ * Copyright (C) 2004 Randolph Chung <tausq@debian.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * Portions derived from the GNU C Library
+ * Copyright (C) 1991, 1997, 2003 Free Software Foundation, Inc.
+ *
+ * Several strategies are tried to try to get the best performance for various
+ * conditions. In the optimal case, we copy 64-bytes in an unrolled loop using
+ * fp regs. This is followed by loops that copy 32- or 16-bytes at a time using
+ * general registers. Unaligned copies are handled either by aligning the
+ * destination and then using shift-and-write method, or in a few cases by
+ * falling back to a byte-at-a-time copy.
+ *
+ * I chose to implement this in C because it is easier to maintain and debug,
+ * and in my experiments it appears that the C code generated by gcc (3.3/3.4
+ * at the time of writing) is fairly optimal. Unfortunately some of the
+ * semantics of the copy routine (exception handling) is difficult to express
+ * in C, so we have to play some tricks to get it to work.
+ *
+ * All the loads and stores are done via explicit asm() code in order to use
+ * the right space registers.
+ *
+ * Testing with various alignments and buffer sizes shows that this code is
+ * often >10x faster than a simple byte-at-a-time copy, even for strangely
+ * aligned operands. It is interesting to note that the glibc version
+ * of memcpy (written in C) is actually quite fast already. This routine is
+ * able to beat it by 30-40% for aligned copies because of the loop unrolling,
+ * but in some cases the glibc version is still slightly faster. This lends
+ * more credibility that gcc can generate very good code as long as we are
+ * careful.
+ *
+ * TODO:
+ * - cache prefetching needs more experimentation to get optimal settings
+ * - try not to use the post-increment address modifiers; they create additional
+ * interlocks
+ * - replace byte-copy loops with stybs sequences
+ */
+
+#ifdef __KERNEL__
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/compiler.h>
+#include <asm/uaccess.h>
+#define s_space "%%sr1"
+#define d_space "%%sr2"
+#else
+#include "memcpy.h"
+#define s_space "%%sr0"
+#define d_space "%%sr0"
+#define pa_memcpy new2_copy
+#endif
+
+DECLARE_PER_CPU(struct exception_data, exception_data);
+
+#define preserve_branch(label) do { \
+ volatile int dummy; \
+ /* The following branch is never taken, it's just here to */ \
+ /* prevent gcc from optimizing away our exception code. */ \
+ if (unlikely(dummy != dummy)) \
+ goto label; \
+} while (0)
+
+#define get_user_space() (segment_eq(get_fs(), KERNEL_DS) ? 0 : mfsp(3))
+#define get_kernel_space() (0)
+
+#define MERGE(w0, sh_1, w1, sh_2) ({ \
+ unsigned int _r; \
+ asm volatile ( \
+ "mtsar %3\n" \
+ "shrpw %1, %2, %%sar, %0\n" \
+ : "=r"(_r) \
+ : "r"(w0), "r"(w1), "r"(sh_2) \
+ ); \
+ _r; \
+})
+#define THRESHOLD 16
+
+#ifdef DEBUG_MEMCPY
+#define DPRINTF(fmt, args...) do { printk(KERN_DEBUG "%s:%d:%s ", __FILE__, __LINE__, __FUNCTION__ ); printk(KERN_DEBUG fmt, ##args ); } while (0)
+#else
+#define DPRINTF(fmt, args...)
+#endif
+
+#ifndef __LP64__
+#define EXC_WORD ".word"
+#else
+#define EXC_WORD ".dword"
+#endif
+
+#define def_load_ai_insn(_insn,_sz,_tt,_s,_a,_t,_e) \
+ __asm__ __volatile__ ( \
+ "1:\t" #_insn ",ma " #_sz "(" _s ",%1), %0\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t" EXC_WORD "\t1b\n" \
+ "\t" EXC_WORD "\t" #_e "\n" \
+ "\t.previous\n" \
+ : _tt(_t), "+r"(_a) \
+ : "1"(_a) \
+ : "r8")
+
+#define def_store_ai_insn(_insn,_sz,_tt,_s,_a,_t,_e) \
+ __asm__ __volatile__ ( \
+ "1:\t" #_insn ",ma %1, " #_sz "(" _s ",%0)\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t" EXC_WORD "\t1b\n" \
+ "\t" EXC_WORD "\t" #_e "\n" \
+ "\t.previous\n" \
+ : "+r"(_a) \
+ : _tt(_t), "0"(_a) \
+ : "r8")
+
+#define ldbma(_s, _a, _t, _e) def_load_ai_insn(ldbs,1,"=r",_s,_a,_t,_e)
+#define stbma(_s, _t, _a, _e) def_store_ai_insn(stbs,1,"r",_s,_a,_t,_e)
+#define ldwma(_s, _a, _t, _e) def_load_ai_insn(ldw,4,"=r",_s,_a,_t,_e)
+#define stwma(_s, _t, _a, _e) def_store_ai_insn(stw,4,"r",_s,_a,_t,_e)
+#define flddma(_s, _a, _t, _e) def_load_ai_insn(fldd,8,"=f",_s,_a,_t,_e)
+#define fstdma(_s, _t, _a, _e) def_store_ai_insn(fstd,8,"f",_s,_a,_t,_e)
+
+#define def_load_insn(_insn,_tt,_s,_o,_a,_t,_e) \
+ __asm__ __volatile__ ( \
+ "1:\t" #_insn " " #_o "(" _s ",%1), %0\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t" EXC_WORD "\t1b\n" \
+ "\t" EXC_WORD "\t" #_e "\n" \
+ "\t.previous\n" \
+ : _tt(_t) \
+ : "r"(_a) \
+ : "r8")
+
+#define def_store_insn(_insn,_tt,_s,_t,_o,_a,_e) \
+ __asm__ __volatile__ ( \
+ "1:\t" #_insn " %0, " #_o "(" _s ",%1)\n" \
+ "\t.section __ex_table,\"aw\"\n" \
+ "\t" EXC_WORD "\t1b\n" \
+ "\t" EXC_WORD "\t" #_e "\n" \
+ "\t.previous\n" \
+ : \
+ : _tt(_t), "r"(_a) \
+ : "r8")
+
+#define ldw(_s,_o,_a,_t,_e) def_load_insn(ldw,"=r",_s,_o,_a,_t,_e)
+#define stw(_s,_t,_o,_a,_e) def_store_insn(stw,"r",_s,_t,_o,_a,_e)
+
+#ifdef CONFIG_PREFETCH
+extern inline void prefetch_src(const void *addr)
+{
+ __asm__("ldw 0(" s_space ",%0), %%r0" : : "r" (addr));
+}
+
+extern inline void prefetch_dst(const void *addr)
+{
+ __asm__("ldd 0(" d_space ",%0), %%r0" : : "r" (addr));
+}
+#else
+#define prefetch_src(addr)
+#define prefetch_dst(addr)
+#endif
+
+/* Copy from a not-aligned src to an aligned dst, using shifts. Handles 4 words
+ * per loop. This code is derived from glibc.
+ */
+static inline unsigned long copy_dstaligned(unsigned long dst, unsigned long src, unsigned long len, unsigned long o_dst, unsigned long o_src, unsigned long o_len)
+{
+ /* gcc complains that a2 and a3 may be uninitialized, but actually
+ * they cannot be. Initialize a2/a3 to shut gcc up.
+ */
+ register unsigned int a0, a1, a2 = 0, a3 = 0;
+ int sh_1, sh_2;
+ struct exception_data *d;
+
+ /* prefetch_src((const void *)src); */
+
+ /* Calculate how to shift a word read at the memory operation
+ aligned srcp to make it aligned for copy. */
+ sh_1 = 8 * (src % sizeof(unsigned int));
+ sh_2 = 8 * sizeof(unsigned int) - sh_1;
+
+ /* Make src aligned by rounding it down. */
+ src &= -sizeof(unsigned int);
+
+ switch (len % 4)
+ {
+ case 2:
+ /* a1 = ((unsigned int *) src)[0];
+ a2 = ((unsigned int *) src)[1]; */
+ ldw(s_space, 0, src, a1, cda_ldw_exc);
+ ldw(s_space, 4, src, a2, cda_ldw_exc);
+ src -= 1 * sizeof(unsigned int);
+ dst -= 3 * sizeof(unsigned int);
+ len += 2;
+ goto do1;
+ case 3:
+ /* a0 = ((unsigned int *) src)[0];
+ a1 = ((unsigned int *) src)[1]; */
+ ldw(s_space, 0, src, a0, cda_ldw_exc);
+ ldw(s_space, 4, src, a1, cda_ldw_exc);
+ src -= 0 * sizeof(unsigned int);
+ dst -= 2 * sizeof(unsigned int);
+ len += 1;
+ goto do2;
+ case 0:
+ if (len == 0)
+ return 0;
+ /* a3 = ((unsigned int *) src)[0];
+ a0 = ((unsigned int *) src)[1]; */
+ ldw(s_space, 0, src, a3, cda_ldw_exc);
+ ldw(s_space, 4, src, a0, cda_ldw_exc);
+ src -=-1 * sizeof(unsigned int);
+ dst -= 1 * sizeof(unsigned int);
+ len += 0;
+ goto do3;
+ case 1:
+ /* a2 = ((unsigned int *) src)[0];
+ a3 = ((unsigned int *) src)[1]; */
+ ldw(s_space, 0, src, a2, cda_ldw_exc);
+ ldw(s_space, 4, src, a3, cda_ldw_exc);
+ src -=-2 * sizeof(unsigned int);
+ dst -= 0 * sizeof(unsigned int);
+ len -= 1;
+ if (len == 0)
+ goto do0;
+ goto do4; /* No-op. */
+ }
+
+ do
+ {
+ /* prefetch_src((const void *)(src + 4 * sizeof(unsigned int))); */
+do4:
+ /* a0 = ((unsigned int *) src)[0]; */
+ ldw(s_space, 0, src, a0, cda_ldw_exc);
+ /* ((unsigned int *) dst)[0] = MERGE (a2, sh_1, a3, sh_2); */
+ stw(d_space, MERGE (a2, sh_1, a3, sh_2), 0, dst, cda_stw_exc);
+do3:
+ /* a1 = ((unsigned int *) src)[1]; */
+ ldw(s_space, 4, src, a1, cda_ldw_exc);
+ /* ((unsigned int *) dst)[1] = MERGE (a3, sh_1, a0, sh_2); */
+ stw(d_space, MERGE (a3, sh_1, a0, sh_2), 4, dst, cda_stw_exc);
+do2:
+ /* a2 = ((unsigned int *) src)[2]; */
+ ldw(s_space, 8, src, a2, cda_ldw_exc);
+ /* ((unsigned int *) dst)[2] = MERGE (a0, sh_1, a1, sh_2); */
+ stw(d_space, MERGE (a0, sh_1, a1, sh_2), 8, dst, cda_stw_exc);
+do1:
+ /* a3 = ((unsigned int *) src)[3]; */
+ ldw(s_space, 12, src, a3, cda_ldw_exc);
+ /* ((unsigned int *) dst)[3] = MERGE (a1, sh_1, a2, sh_2); */
+ stw(d_space, MERGE (a1, sh_1, a2, sh_2), 12, dst, cda_stw_exc);
+
+ src += 4 * sizeof(unsigned int);
+ dst += 4 * sizeof(unsigned int);
+ len -= 4;
+ }
+ while (len != 0);
+
+do0:
+ /* ((unsigned int *) dst)[0] = MERGE (a2, sh_1, a3, sh_2); */
+ stw(d_space, MERGE (a2, sh_1, a3, sh_2), 0, dst, cda_stw_exc);
+
+ preserve_branch(handle_load_error);
+ preserve_branch(handle_store_error);
+
+ return 0;
+
+handle_load_error:
+ __asm__ __volatile__ ("cda_ldw_exc:\n");
+ d = &__get_cpu_var(exception_data);
+ DPRINTF("cda_ldw_exc: o_len=%lu fault_addr=%lu o_src=%lu ret=%lu\n",
+ o_len, d->fault_addr, o_src, o_len - d->fault_addr + o_src);
+ return o_len * 4 - d->fault_addr + o_src;
+
+handle_store_error:
+ __asm__ __volatile__ ("cda_stw_exc:\n");
+ d = &__get_cpu_var(exception_data);
+ DPRINTF("cda_stw_exc: o_len=%lu fault_addr=%lu o_dst=%lu ret=%lu\n",
+ o_len, d->fault_addr, o_dst, o_len - d->fault_addr + o_dst);
+ return o_len * 4 - d->fault_addr + o_dst;
+}
+
+
+/* Returns 0 for success, otherwise, returns number of bytes not transferred. */
+unsigned long pa_memcpy(void *dstp, const void *srcp, unsigned long len)
+{
+ register unsigned long src, dst, t1, t2, t3;
+ register char *pcs, *pcd;
+ register unsigned int *pws, *pwd;
+ register double *pds, *pdd;
+ unsigned long ret = 0;
+ unsigned long o_dst, o_src, o_len;
+ struct exception_data *d;
+
+ src = (unsigned long)srcp;
+ dst = (unsigned long)dstp;
+ pcs = (unsigned char *)srcp;
+ pcd = (unsigned char *)dstp;
+
+ o_dst = dst; o_src = src; o_len = len;
+
+ /* prefetch_src((const void *)srcp); */
+
+ if (len < THRESHOLD)
+ goto byte_copy;
+
+ /* Check alignment */
+ t1 = (src ^ dst);
+ if (unlikely(t1 & (sizeof(double)-1)))
+ goto unaligned_copy;
+
+ /* src and dst have same alignment. */
+
+ /* Copy bytes till we are double-aligned. */
+ t2 = src & (sizeof(double) - 1);
+ if (unlikely(t2 != 0)) {
+ t2 = sizeof(double) - t2;
+ while (t2 && len) {
+ /* *pcd++ = *pcs++; */
+ ldbma(s_space, pcs, t3, pmc_load_exc);
+ len--;
+ stbma(d_space, t3, pcd, pmc_store_exc);
+ t2--;
+ }
+ }
+
+ pds = (double *)pcs;
+ pdd = (double *)pcd;
+
+ /* Copy 8 doubles at a time */
+ while (len >= 8*sizeof(double)) {
+ register double r1, r2, r3, r4, r5, r6, r7, r8;
+ /* prefetch_src((char *)pds + L1_CACHE_BYTES); */
+ flddma(s_space, pds, r1, pmc_load_exc);
+ flddma(s_space, pds, r2, pmc_load_exc);
+ flddma(s_space, pds, r3, pmc_load_exc);
+ flddma(s_space, pds, r4, pmc_load_exc);
+ fstdma(d_space, r1, pdd, pmc_store_exc);
+ fstdma(d_space, r2, pdd, pmc_store_exc);
+ fstdma(d_space, r3, pdd, pmc_store_exc);
+ fstdma(d_space, r4, pdd, pmc_store_exc);
+
+#if 0
+ if (L1_CACHE_BYTES <= 32)
+ prefetch_src((char *)pds + L1_CACHE_BYTES);
+#endif
+ flddma(s_space, pds, r5, pmc_load_exc);
+ flddma(s_space, pds, r6, pmc_load_exc);
+ flddma(s_space, pds, r7, pmc_load_exc);
+ flddma(s_space, pds, r8, pmc_load_exc);
+ fstdma(d_space, r5, pdd, pmc_store_exc);
+ fstdma(d_space, r6, pdd, pmc_store_exc);
+ fstdma(d_space, r7, pdd, pmc_store_exc);
+ fstdma(d_space, r8, pdd, pmc_store_exc);
+ len -= 8*sizeof(double);
+ }
+
+ pws = (unsigned int *)pds;
+ pwd = (unsigned int *)pdd;
+
+word_copy:
+ while (len >= 8*sizeof(unsigned int)) {
+ register unsigned int r1,r2,r3,r4,r5,r6,r7,r8;
+ /* prefetch_src((char *)pws + L1_CACHE_BYTES); */
+ ldwma(s_space, pws, r1, pmc_load_exc);
+ ldwma(s_space, pws, r2, pmc_load_exc);
+ ldwma(s_space, pws, r3, pmc_load_exc);
+ ldwma(s_space, pws, r4, pmc_load_exc);
+ stwma(d_space, r1, pwd, pmc_store_exc);
+ stwma(d_space, r2, pwd, pmc_store_exc);
+ stwma(d_space, r3, pwd, pmc_store_exc);
+ stwma(d_space, r4, pwd, pmc_store_exc);
+
+ ldwma(s_space, pws, r5, pmc_load_exc);
+ ldwma(s_space, pws, r6, pmc_load_exc);
+ ldwma(s_space, pws, r7, pmc_load_exc);
+ ldwma(s_space, pws, r8, pmc_load_exc);
+ stwma(d_space, r5, pwd, pmc_store_exc);
+ stwma(d_space, r6, pwd, pmc_store_exc);
+ stwma(d_space, r7, pwd, pmc_store_exc);
+ stwma(d_space, r8, pwd, pmc_store_exc);
+ len -= 8*sizeof(unsigned int);
+ }
+
+ while (len >= 4*sizeof(unsigned int)) {
+ register unsigned int r1,r2,r3,r4;
+ ldwma(s_space, pws, r1, pmc_load_exc);
+ ldwma(s_space, pws, r2, pmc_load_exc);
+ ldwma(s_space, pws, r3, pmc_load_exc);
+ ldwma(s_space, pws, r4, pmc_load_exc);
+ stwma(d_space, r1, pwd, pmc_store_exc);
+ stwma(d_space, r2, pwd, pmc_store_exc);
+ stwma(d_space, r3, pwd, pmc_store_exc);
+ stwma(d_space, r4, pwd, pmc_store_exc);
+ len -= 4*sizeof(unsigned int);
+ }
+
+ pcs = (unsigned char *)pws;
+ pcd = (unsigned char *)pwd;
+
+byte_copy:
+ while (len) {
+ /* *pcd++ = *pcs++; */
+ ldbma(s_space, pcs, t3, pmc_load_exc);
+ stbma(d_space, t3, pcd, pmc_store_exc);
+ len--;
+ }
+
+ return 0;
+
+unaligned_copy:
+ /* possibly we are aligned on a word, but not on a double... */
+ if (likely(t1 & (sizeof(unsigned int)-1)) == 0) {
+ t2 = src & (sizeof(unsigned int) - 1);
+
+ if (unlikely(t2 != 0)) {
+ t2 = sizeof(unsigned int) - t2;
+ while (t2) {
+ /* *pcd++ = *pcs++; */
+ ldbma(s_space, pcs, t3, pmc_load_exc);
+ stbma(d_space, t3, pcd, pmc_store_exc);
+ len--;
+ t2--;
+ }
+ }
+
+ pws = (unsigned int *)pcs;
+ pwd = (unsigned int *)pcd;
+ goto word_copy;
+ }
+
+ /* Align the destination. */
+ if (unlikely((dst & (sizeof(unsigned int) - 1)) != 0)) {
+ t2 = sizeof(unsigned int) - (dst & (sizeof(unsigned int) - 1));
+ while (t2) {
+ /* *pcd++ = *pcs++; */
+ ldbma(s_space, pcs, t3, pmc_load_exc);
+ stbma(d_space, t3, pcd, pmc_store_exc);
+ len--;
+ t2--;
+ }
+ dst = (unsigned long)pcd;
+ src = (unsigned long)pcs;
+ }
+
+ ret = copy_dstaligned(dst, src, len / sizeof(unsigned int),
+ o_dst, o_src, o_len);
+ if (ret)
+ return ret;
+
+ pcs += (len & -sizeof(unsigned int));
+ pcd += (len & -sizeof(unsigned int));
+ len %= sizeof(unsigned int);
+
+ preserve_branch(handle_load_error);
+ preserve_branch(handle_store_error);
+
+ goto byte_copy;
+
+handle_load_error:
+ __asm__ __volatile__ ("pmc_load_exc:\n");
+ d = &__get_cpu_var(exception_data);
+ DPRINTF("pmc_load_exc: o_len=%lu fault_addr=%lu o_src=%lu ret=%lu\n",
+ o_len, d->fault_addr, o_src, o_len - d->fault_addr + o_src);
+ return o_len - d->fault_addr + o_src;
+
+handle_store_error:
+ __asm__ __volatile__ ("pmc_store_exc:\n");
+ d = &__get_cpu_var(exception_data);
+ DPRINTF("pmc_store_exc: o_len=%lu fault_addr=%lu o_dst=%lu ret=%lu\n",
+ o_len, d->fault_addr, o_dst, o_len - d->fault_addr + o_dst);
+ return o_len - d->fault_addr + o_dst;
+}
+
+#ifdef __KERNEL__
+unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len)
+{
+ mtsp(get_kernel_space(), 1);
+ mtsp(get_user_space(), 2);
+ return pa_memcpy((void __force *)dst, src, len);
+}
+
+unsigned long copy_from_user(void *dst, const void __user *src, unsigned long len)
+{
+ mtsp(get_user_space(), 1);
+ mtsp(get_kernel_space(), 2);
+ return pa_memcpy(dst, (void __force *)src, len);
+}
+
+unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len)
+{
+ mtsp(get_user_space(), 1);
+ mtsp(get_user_space(), 2);
+ return pa_memcpy((void __force *)dst, (void __force *)src, len);
+}
+
+
+void * memcpy(void * dst,const void *src, size_t count)
+{
+ mtsp(get_kernel_space(), 1);
+ mtsp(get_kernel_space(), 2);
+ pa_memcpy(dst, src, count);
+ return dst;
+}
+
+void bcopy(const void * srcp, void * destp, size_t count)
+{
+ mtsp(get_kernel_space(), 1);
+ mtsp(get_kernel_space(), 2);
+ pa_memcpy(destp, srcp, count);
+}
+
+EXPORT_SYMBOL(copy_to_user);
+EXPORT_SYMBOL(copy_from_user);
+EXPORT_SYMBOL(copy_in_user);
+EXPORT_SYMBOL(memcpy);
+EXPORT_SYMBOL(bcopy);
+#endif
git://git.onelab.eu / linux-2.6.git / blobdiff