kernel-fxtec-pro1x/arch/mips/include/asm/edac.h

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#ifndef ASM_EDAC_H
#define ASM_EDAC_H
MIPS: Fix microMIPS LL/SC immediate offsets In the microMIPS encoding some memory access instructions have their immediate offset reduced to 12 bits only. That does not match the GCC `R' constraint we use in some places to satisfy the requirement, resulting in build failures like this: {standard input}: Assembler messages: {standard input}:720: Error: macro used $at after ".set noat" {standard input}:720: Warning: macro instruction expanded into multiple instructions Fix the problem by defining a macro, `GCC_OFF12_ASM', that expands to the right constraint depending on whether microMIPS or standard MIPS code is produced. Also apply the fix to where `m' is used as in the worst case this change does nothing, e.g. where the pointer was already in a register such as a function argument and no further offset was requested, and in the best case it avoids an extraneous sequence of up to two instructions to load the high 20 bits of the address in the LL/SC loop. This reduces the risk of lock contention that is the higher the more instructions there are in the critical section between LL and SC. Strictly speaking we could just bulk-replace `R' with `ZC' as the latter constraint adjusts automatically depending on the ISA selected. However it was only introduced with GCC 4.9 and we keep supporing older compilers for the standard MIPS configuration, hence the slightly more complicated approach I chose. The choice of a zero-argument function-like rather than an object-like macro was made so that it does not look like a function call taking the C expression used for the constraint as an argument. This is so as not to confuse the reader or formatting checkers like `checkpatch.pl' and follows previous practice. Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com> Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/8482/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2014-11-15 15:08:48 -07:00
#include <asm/compiler.h>
/* ECC atomic, DMA, SMP and interrupt safe scrub function */
EDAC: Cleanup atomic_scrub mess So first of all, this atomic_scrub() function's naming is bad. It looks like an atomic_t helper. Change it to edac_atomic_scrub(). The bigger problem is that this function is arch-specific and every new arch which doesn't necessarily need that functionality still needs to define it, otherwise EDAC doesn't compile. So instead of doing that and including arch-specific headers, have each arch define an EDAC_ATOMIC_SCRUB symbol which can be used in edac_mc.c for ifdeffery. Much cleaner. And we already are doing this with another symbol - EDAC_SUPPORT. This is also much cleaner than having CONFIG_EDAC enumerate all the arches which need/have EDAC support and drivers. This way I can kill the useless edac.h header in tile too. Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Chris Metcalf <cmetcalf@ezchip.com> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Doug Thompson <dougthompson@xmission.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-edac@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linuxppc-dev@lists.ozlabs.org Cc: "Maciej W. Rozycki" <macro@codesourcery.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Cc: Paul Mackerras <paulus@samba.org> Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: x86@kernel.org Signed-off-by: Borislav Petkov <bp@suse.de>
2015-05-21 11:59:31 -06:00
static inline void edac_atomic_scrub(void *va, u32 size)
{
unsigned long *virt_addr = va;
unsigned long temp;
u32 i;
for (i = 0; i < size / sizeof(unsigned long); i++) {
/*
* Very carefully read and write to memory atomically
* so we are interrupt, DMA and SMP safe.
*
* Intel: asm("lock; addl $0, %0"::"m"(*virt_addr));
*/
__asm__ __volatile__ (
" .set mips2 \n"
EDAC: Cleanup atomic_scrub mess So first of all, this atomic_scrub() function's naming is bad. It looks like an atomic_t helper. Change it to edac_atomic_scrub(). The bigger problem is that this function is arch-specific and every new arch which doesn't necessarily need that functionality still needs to define it, otherwise EDAC doesn't compile. So instead of doing that and including arch-specific headers, have each arch define an EDAC_ATOMIC_SCRUB symbol which can be used in edac_mc.c for ifdeffery. Much cleaner. And we already are doing this with another symbol - EDAC_SUPPORT. This is also much cleaner than having CONFIG_EDAC enumerate all the arches which need/have EDAC support and drivers. This way I can kill the useless edac.h header in tile too. Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Chris Metcalf <cmetcalf@ezchip.com> Acked-by: Ingo Molnar <mingo@kernel.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Doug Thompson <dougthompson@xmission.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-edac@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: linuxppc-dev@lists.ozlabs.org Cc: "Maciej W. Rozycki" <macro@codesourcery.com> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Cc: Paul Mackerras <paulus@samba.org> Cc: "Steven J. Hill" <Steven.Hill@imgtec.com> Cc: x86@kernel.org Signed-off-by: Borislav Petkov <bp@suse.de>
2015-05-21 11:59:31 -06:00
"1: ll %0, %1 # edac_atomic_scrub \n"
" addu %0, $0 \n"
" sc %0, %1 \n"
" beqz %0, 1b \n"
" .set mips0 \n"
: "=&r" (temp), "=" GCC_OFF_SMALL_ASM() (*virt_addr)
: GCC_OFF_SMALL_ASM() (*virt_addr));
virt_addr++;
}
}
#endif