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Re: [patch] libffi EABI sys_cacheflush
- From: Steven Newbury <s_j_newbury at yahoo dot co dot uk>
- To: David Daney <ddaney at avtrex dot com>
- Cc: java-patches at gcc dot gnu dot org
- Date: Sun, 5 Aug 2007 13:35:36 +0100 (BST)
- Subject: Re: [patch] libffi EABI sys_cacheflush
--- David Daney <ddaney@avtrex.com> wrote:
> Steven Newbury wrote:
> > The existing code in FFI_INIT_TRAMPOLINE calls sys_cacheflush using only
> the
> > OABI syscall interface ie. the syscall number is encoded in the swi
> > instruction.
> >
> > This patch passes the syscall number in r7 and calls "swi 0" as is needed
> by
> > the EABI Linux syscall ABI.
> >
> > 2007-08-03 Steven Newbury <s_j_newbury@yahoo.co.uk>
> >
> > * src/arm/ffi.c (FFI_INIT_TRAMPOLINE): Use EABI syscall ABI for
> > sys_cacheflush.
> >
> An alternative would be to call the __clear_cache() function provided by
> libgcc, or even better implement __builtin___clear_cache for arm and use
> that.
Now that I've tested it, I've discovered that the patch I sent doesn't actually
work; #ifdef's inside macros are not a good idea..
As David suggested:
Use __clear_cache from libgcc for cache flushing. This function uses the
appropriate EABI/OABI ABI for the cache flush operation.
2007-08-05 Steven Newbury <s_j_newbury@yahoo.co.uk>
* src/arm/ffi.c (FFI_INIT_TRAMPOLINE): Use __clear_cache instead of
directly using the sys_cacheflush syscall.
Steve
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http://uk.answers.yahoo.com/ --- libffi/src/arm/ffi.c~ 2007-08-05 13:30:27.683858627 +0100
+++ libffi/src/arm/ffi.c 2007-08-05 13:30:27.683858627 +0100
@@ -257,12 +257,7 @@
*(unsigned int*) &__tramp[8] = 0xe59ff000; /* ldr pc, [pc] */ \
*(unsigned int*) &__tramp[12] = __ctx; \
*(unsigned int*) &__tramp[16] = __fun; \
- register unsigned long _beg __asm ("a1") = (unsigned long) (&__tramp[0]); \
- register unsigned long _end __asm ("a2") = (unsigned long) (&__tramp[19]); \
- register unsigned long _flg __asm ("a3") = 0; \
- __asm __volatile ("swi 0x9f0002 @ sys_cacheflush" \
- : "=r" (_beg) \
- : "0" (_beg), "r" (_end), "r" (_flg)); \
+ __clear_cache((&__tramp[0]), (&__tramp[19])); \
})