Ping! (Warning 2: is this architecture still maintained?) -- Steve On Fri, 18 Sep 2020 15:25:07 -0400 Steven Rostedt <roste****@goodm*****> wrote: > From: Steven Rostedt (VMware) <roste****@goodm*****> > > In a conversation on #linux-rt, it was asked if the irq disabling and > enabling functions were a compiler barrier, and reads wont happen outside > these functions from where they were in the call. > > I stated that they most definitely need to be, otherwise we would have bugs > all over the place if not. And just to confirm, I looked at the > implementation on x86 which had "memory" as a constraint to the asm, and > that is a compiler barrier. As that was just one arch, I looked at others, > and all the other archs do the same but one. H8300 seems to fail here. And > that is most definitely a bug. > > Add the compiler barrier to the enabling and disabling of interrupts on > H8300. As this is a really critical bug, I'm starting to wonder how much > this arch is really used. Let's see how quickly this patch gets added to > the arch, and if it is not applied or responded to within a month, I think > we can safely state that this arch is not maintained. > > Reported-by: Vlastimil Babka <vbabk****@suse*****> > Signed-off-by: Steven Rostedt (VMware) <roste****@goodm*****> > --- > diff --git a/arch/h8300/include/asm/irqflags.h b/arch/h8300/include/asm/irqflags.h > index 48756b7f405e..477cb9d7785f 100644 > --- a/arch/h8300/include/asm/irqflags.h > +++ b/arch/h8300/include/asm/irqflags.h > @@ -15,12 +15,12 @@ static inline h8300flags arch_local_save_flags(void) > > static inline void arch_local_irq_disable(void) > { > - __asm__ volatile ("orc #0xc0,ccr"); > + __asm__ volatile ("orc #0xc0,ccr" : : : "memory"); > } > > static inline void arch_local_irq_enable(void) > { > - __asm__ volatile ("andc #0x3f,ccr"); > + __asm__ volatile ("andc #0x3f,ccr" : : : "memory"); > } > > static inline h8300flags arch_local_irq_save(void) > @@ -28,13 +28,13 @@ static inline h8300flags arch_local_irq_save(void) > h8300flags flags; > > __asm__ volatile ("stc ccr,%w0\n\t" > - "orc #0xc0,ccr" : "=r" (flags)); > + "orc #0xc0,ccr" : "=r" (flags) : : "memory"); > return flags; > } > > static inline void arch_local_irq_restore(h8300flags flags) > { > - __asm__ volatile ("ldc %w0,ccr" : : "r" (flags) : "cc"); > + __asm__ volatile ("ldc %w0,ccr" : : "r" (flags) : "memory", "cc"); > } > > static inline int arch_irqs_disabled_flags(unsigned long flags) > @@ -55,13 +55,13 @@ static inline h8300flags arch_local_save_flags(void) > > static inline void arch_local_irq_disable(void) > { > - __asm__ volatile ("orc #0x80,ccr\n\t"); > + __asm__ volatile ("orc #0x80,ccr\n\t" : : : "memory"); > } > > static inline void arch_local_irq_enable(void) > { > __asm__ volatile ("andc #0x7f,ccr\n\t" > - "andc #0xf0,exr\n\t"); > + "andc #0xf0,exr\n\t" : : : "memory"); > } > > static inline h8300flags arch_local_irq_save(void) > @@ -71,7 +71,7 @@ static inline h8300flags arch_local_irq_save(void) > __asm__ volatile ("stc ccr,%w0\n\t" > "stc exr,%x0\n\t" > "orc #0x80,ccr\n\t" > - : "=r" (flags)); > + : "=r" (flags) : : "memory"); > return flags; > } > > @@ -79,7 +79,7 @@ static inline void arch_local_irq_restore(h8300flags flags) > { > __asm__ volatile ("ldc %w0,ccr\n\t" > "ldc %x0,exr" > - : : "r" (flags) : "cc"); > + : : "r" (flags) : "memory", "cc"); > } > > static inline int arch_irqs_disabled_flags(h8300flags flags)
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