[PATCH] ppc64: fix memcpy_to/from_io

From: Benjamin Herrenschmidt (benh_at_kernel.crashing.org)
Date: 07/30/04

  • Next message: Andrea Arcangeli: "Re: [cleanup] do_general_protection doesn't disable irq" 
    To: Andrew Morton <akpm@osdl.org>
Date:	Fri, 30 Jul 2004 14:22:19 +1000

    Hi !

    The ppc64 implementation of memcpy_to/from_io was bogus (used memcpy
    which uses cache hints and thus is broken on non cacheable IO space).

    This re-implements them with some simple/gross C code doing 32 bits
    accesses when aligned and bytes accesses when not.

    Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

    ===== include/asm-ppc64/eeh.h 1.12 vs ? (writable without lock!) =====
    --- 1.12/include/asm-ppc64/eeh.h 2004-07-02 15:23:45 +10:00
    +++ ?/include/asm-ppc64/eeh.h 2004-07-30 14:19:48 +10:00
    @@ -180,26 +180,95 @@
             out_be64(vaddr, val);
     }
     
    +#define EEH_CHECK_ALIGN(v,a) \
    + ((((unsigned long)(v)) & ((a) - 1)) == 0)
    +
     static inline void eeh_memset_io(void *addr, int c, unsigned long n) {
             void *vaddr = (void *)IO_TOKEN_TO_ADDR(addr);
    - memset(vaddr, c, n);
    + u32 lc = c;
    + lc |= lc << 8;
    + lc |= lc << 16;
    +
    + while(n && !EEH_CHECK_ALIGN(vaddr, 4)) {
    + *((volatile u8 *)vaddr) = c;
    + vaddr = (void *)((unsigned long)vaddr + 1);
    + n--;
    + }
    + while(n >= 4) {
    + *((volatile u32 *)vaddr) = lc;
    + vaddr = (void *)((unsigned long)vaddr + 4);
    + n -= 4;
    + }
    + while(n) {
    + *((volatile u8 *)vaddr) = c;
    + vaddr = (void *)((unsigned long)vaddr + 1);
    + n--;
    + }
    + __asm__ __volatile__ ("sync" : : : "memory");
     }
     static inline void eeh_memcpy_fromio(void *dest, void *src, unsigned long n) {
             void *vsrc = (void *)IO_TOKEN_TO_ADDR(src);
    - memcpy(dest, vsrc, n);
    + void *vsrcsave = vsrc, *destsave = dest, *srcsave = src;
    + unsigned long nsave = n;
    +
    + while(n && (!EEH_CHECK_ALIGN(vsrc, 4) || !EEH_CHECK_ALIGN(dest, 4))) {
    + *((u8 *)dest) = *((volatile u8 *)vsrc);
    + __asm__ __volatile__ ("eieio" : : : "memory");
    + vsrc = (void *)((unsigned long)vsrc + 1);
    + dest = (void *)((unsigned long)dest + 1);
    + n--;
    + }
    + while(n > 4) {
    + *((u32 *)dest) = *((volatile u32 *)vsrc);
    + __asm__ __volatile__ ("eieio" : : : "memory");
    + vsrc = (void *)((unsigned long)vsrc + 4);
    + dest = (void *)((unsigned long)dest + 4);
    + n -= 4;
    + }
    + while(n) {
    + *((u8 *)dest) = *((volatile u8 *)vsrc);
    + __asm__ __volatile__ ("eieio" : : : "memory");
    + vsrc = (void *)((unsigned long)vsrc + 1);
    + dest = (void *)((unsigned long)dest + 1);
    + n--;
    + }
    + __asm__ __volatile__ ("sync" : : : "memory");
    +
             /* Look for ffff's here at dest[n]. Assume that at least 4 bytes
              * were copied. Check all four bytes.
              */
    - if ((n >= 4) &&
    - (EEH_POSSIBLE_ERROR(src, vsrc, (*((u32 *) dest+n-4)), u32))) {
    - eeh_check_failure(src, (*((u32 *) dest+n-4)));
    + if ((nsave >= 4) &&
    + (EEH_POSSIBLE_ERROR(srcsave, vsrcsave, (*((u32 *) destsave+nsave-4)),
    + u32))) {
    + eeh_check_failure(srcsave, (*((u32 *) destsave+nsave-4)));
             }
     }
     
     static inline void eeh_memcpy_toio(void *dest, void *src, unsigned long n) {
             void *vdest = (void *)IO_TOKEN_TO_ADDR(dest);
    - memcpy(vdest, src, n);
    +
    + while(n && (!EEH_CHECK_ALIGN(vdest, 4) || !EEH_CHECK_ALIGN(src, 4))) {
    + *((volatile u8 *)vdest) = *((u8 *)src);
    + src = (void *)((unsigned long)src + 1);
    + vdest = (void *)((unsigned long)vdest + 1);
    + n--;
    + }
    + while(n > 4) {
    + *((volatile u32 *)vdest) = *((volatile u32 *)src);
    + src = (void *)((unsigned long)src + 4);
    + vdest = (void *)((unsigned long)vdest + 4);
    + n-=4;
    + }
    + while(n) {
    + *((volatile u8 *)vdest) = *((u8 *)src);
    + src = (void *)((unsigned long)src + 1);
    + vdest = (void *)((unsigned long)vdest + 1);
    + n--;
    + }
    + __asm__ __volatile__ ("sync" : : : "memory");
     }
    +
    +#undef EEH_CHECK_ALIGN
     
     #define MAX_ISA_PORT 0x10000
     extern unsigned long io_page_mask;

    -
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