On 1/28/25 15:16, Christophe Leroy wrote:
Le 28/01/2025 à 14:57, Julian Vetter a écrit :
Remove the eieio() calls in _memcpy_fromio, to bring its implementation
closer to the one from lib/iomem_copy.c. These eieio() calls don't seem
to be necessary, because the _memcpy_toio completely omits them. Also
the legacy code from ppc was not doing them.
What do you mean exactly by "legacy code" ?
As far as I can see they were already there before commit 68a64357d15a
("[POWERPC] Merge 32 and 64 bits asm-powerpc/io.h"):
With 'ppc' I was refering to 'include/asm-ppc/io.h'. But you're right,
when going back a bit, in the 'include/asm-powerpc/io.h' there are two
cases, one (eeh_memcpy_fromio) which does the the 'eieio', and a second,
i.e., 'iSeries_memcpy_fromio' which does a byte-wise copy. But in the
ppc code ('include/asm-ppc/io.h') there is a simple memcpy. I was
referring to this one. But my description is not very clear. Sorry for that.
-static inline void eeh_memcpy_fromio(void *dest, const volatile void
__iomem *src,
+static inline void eeh_memcpy_fromio(void *dest, const
+ volatile void __iomem *src,
unsigned long n)
{
- void *vsrc = (void __force *) src;
- void *destsave = dest;
- unsigned long nsave = n;
-
- __asm__ __volatile__ ("sync" : : : "memory");
- while(n && (!EEH_CHECK_ALIGN(vsrc, 4) || !EEH_CHECK_ALIGN(dest, 4))) {
- *((u8 *)dest) = *((volatile u8 *)vsrc);
- __asm__ __volatile__ ("eieio" : : : "memory");
- vsrc++;
- dest++;
- n--;
- }
- while(n > 4) {
- *((u32 *)dest) = *((volatile u32 *)vsrc);
- __asm__ __volatile__ ("eieio" : : : "memory");
- vsrc += 4;
- dest += 4;
- n -= 4;
- }
- while(n) {
- *((u8 *)dest) = *((volatile u8 *)vsrc);
- __asm__ __volatile__ ("eieio" : : : "memory");
- vsrc++;
- dest++;
- n--;
- }
- __asm__ __volatile__ ("sync" : : : "memory");
+ _memcpy_fromio(dest, src, n);
/* Look for ffff's here at dest[n]. Assume that at least 4 bytes
* were copied. Check all four bytes.
*/
- if ((nsave >= 4) &&
- (EEH_POSSIBLE_ERROR((*((u32 *) destsave+nsave-4)), u32))) {
- eeh_check_failure(src, (*((u32 *) destsave+nsave-4)));
- }
+ if (n >= 4 && EEH_POSSIBLE_ERROR(*((u32 *)(dest + n - 4)), u32))
+ eeh_check_failure(src, *((u32 *)(dest + n - 4)));
}
Signed-off-by: Julian Vetter <jul...@outer-limits.org>
---
arch/powerpc/kernel/io.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/powerpc/kernel/io.c b/arch/powerpc/kernel/io.c
index 6af535905984..81e5d54260a1 100644
--- a/arch/powerpc/kernel/io.c
+++ b/arch/powerpc/kernel/io.c
@@ -155,21 +155,18 @@ void _memcpy_fromio(void *dest, const volatile
void __iomem *src,
__asm__ __volatile__ ("sync" : : : "memory");
while(n && (!IO_CHECK_ALIGN(vsrc, 4) || !IO_CHECK_ALIGN(dest,
4))) {
*((u8 *)dest) = *((volatile u8 *)vsrc);
- eieio();
vsrc++;
dest++;
n--;
}
while(n >= 4) {
*((u32 *)dest) = *((volatile u32 *)vsrc);
- eieio();
vsrc += 4;
dest += 4;
n -= 4;
}
while(n) {
*((u8 *)dest) = *((volatile u8 *)vsrc);
- eieio();
vsrc++;
dest++;
n--;
--
2.34.1
