Messages in this thread Patch in this message | | | Date | Fri, 8 Feb 2019 09:00:07 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH v10 12/25] arm64: irqflags: Use ICC_PMR_EL1 for interrupt masking |
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On Fri, Feb 08, 2019 at 09:36:48AM +0000, Julien Thierry wrote: > Hi Nathan, > > On 08/02/2019 04:35, Nathan Chancellor wrote: > > On Thu, Jan 31, 2019 at 02:58:50PM +0000, Julien Thierry wrote: > > [...] > > > > > Hi Julien, > > > > This patch introduced a slew of Clang warnings: > > > > In file included from arch/arm64/kernel/signal.c:21: > > In file included from include/linux/compat.h:10: > > In file included from include/linux/time.h:6: > > In file included from include/linux/seqlock.h:36: > > In file included from include/linux/spinlock.h:54: > > In file included from include/linux/irqflags.h:16: > > arch/arm64/include/asm/irqflags.h:50:10: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths] > > : "r" (GIC_PRIO_IRQON) > > ^ > > arch/arm64/include/asm/ptrace.h:39:25: note: expanded from macro 'GIC_PRIO_IRQON' > > #define GIC_PRIO_IRQON 0xf0 > > ^ > > arch/arm64/include/asm/irqflags.h:46:44: note: use constraint modifier "w" > > "msr_s " __stringify(SYS_ICC_PMR_EL1) ",%0\n" > > ^~ > > %w0 > > I'm not sure I get the relevance of this kind of warnings from Clang. > Had it been an output operand I could understand the concern of having a > variable too small to store the register value. But here it's an input > operand being place in a wider register... > > > arch/arm64/include/asm/alternative.h:286:29: note: expanded from macro 'ALTERNATIVE' > > _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1) > > ^ > > arch/arm64/include/asm/alternative.h:88:30: note: expanded from macro '_ALTERNATIVE_CFG' > > __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg), 0) > > ^ > > arch/arm64/include/asm/alternative.h:76:2: note: expanded from macro '__ALTERNATIVE_CFG' > > newinstr "\n" \ > > ^ > > In file included from arch/arm64/kernel/signal.c:21: > > In file included from include/linux/compat.h:10: > > In file included from include/linux/time.h:6: > > In file included from include/linux/seqlock.h:36: > > In file included from include/linux/spinlock.h:54: > > In file included from include/linux/irqflags.h:16: > > arch/arm64/include/asm/irqflags.h:61:10: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths] > > : "r" (GIC_PRIO_IRQOFF) > > ^ > > arch/arm64/include/asm/ptrace.h:40:26: note: expanded from macro 'GIC_PRIO_IRQOFF' > > #define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) > > ^ > > arch/arm64/include/asm/irqflags.h:58:45: note: use constraint modifier "w" > > "msr_s " __stringify(SYS_ICC_PMR_EL1) ", %0", > > ^ > > arch/arm64/include/asm/irqflags.h:94:10: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths] > > : "r" (GIC_PRIO_IRQOFF) > > ^ > > arch/arm64/include/asm/ptrace.h:40:26: note: expanded from macro 'GIC_PRIO_IRQOFF' > > #define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80) > > ^ > > arch/arm64/include/asm/irqflags.h:91:18: note: use constraint modifier "w" > > "csel %0, %0, %2, eq", > > ^~ > > %w2 > > arch/arm64/include/asm/alternative.h:286:29: note: expanded from macro 'ALTERNATIVE' > > _ALTERNATIVE_CFG(oldinstr, newinstr, __VA_ARGS__, 1) > > ^ > > arch/arm64/include/asm/alternative.h:88:30: note: expanded from macro '_ALTERNATIVE_CFG' > > __ALTERNATIVE_CFG(oldinstr, newinstr, feature, IS_ENABLED(cfg), 0) > > ^ > > arch/arm64/include/asm/alternative.h:76:2: note: expanded from macro '__ALTERNATIVE_CFG' > > newinstr "\n" \ > > ^ > > 3 warnings generated. > > > > > > I am not sure if they should be fixed with Clang's suggestion of a > > constraint modifier or a cast like commit 1b57ec8c7527 ("arm64: io: > > Ensure value passed to __iormb() is held in a 64-bit register"), hence > > this message. > > > > Clang's suggestion would not work as MSR instructions do not operate on > 32-bit general purpose registers. Seeing that PMR is a 32-bit register, > I'd avoid adding UL for the GIC_PRIO_IRQ* constants. > > So I'd recommend just casting the the asm inline operands to unsigned > long. This should only affect the 3 locations > arch/arm64/include/asm/irqflags.h. > > Does the following patch work for you?
Hi Julien,
Yes it does, thank you for the quick response and fix!
Nathan
> > Thanks, > > -- > Julien Thierry > > > --> > > From e839dec632bbf440efe8314751138ba46324078c Mon Sep 17 00:00:00 2001 > From: Julien Thierry <julien.thierry@arm.com> > Date: Fri, 8 Feb 2019 09:21:58 +0000 > Subject: [PATCH] arm64: irqflags: Fix clang build warnings > > Clang complains when passing asm operands that are smaller than the > registers they are mapped to: > > arch/arm64/include/asm/irqflags.h:50:10: warning: value size does not > match register size specified by the constraint and modifier > [-Wasm-operand-widths] > : "r" (GIC_PRIO_IRQON) > > Fix it by casting the affected input operands to a type of the correct > size. > > Reported-by: Nathan Chancellor <natechancellor@gmail.com> > Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
> --- > arch/arm64/include/asm/irqflags.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h > index d4597b2..43d8366 100644 > --- a/arch/arm64/include/asm/irqflags.h > +++ b/arch/arm64/include/asm/irqflags.h > @@ -47,7 +47,7 @@ static inline void arch_local_irq_enable(void) > "dsb sy", > ARM64_HAS_IRQ_PRIO_MASKING) > : > - : "r" (GIC_PRIO_IRQON) > + : "r" ((unsigned long) GIC_PRIO_IRQON) > : "memory"); > } > > @@ -58,7 +58,7 @@ static inline void arch_local_irq_disable(void) > "msr_s " __stringify(SYS_ICC_PMR_EL1) ", %0", > ARM64_HAS_IRQ_PRIO_MASKING) > : > - : "r" (GIC_PRIO_IRQOFF) > + : "r" ((unsigned long) GIC_PRIO_IRQOFF) > : "memory"); > } > > @@ -91,7 +91,7 @@ static inline unsigned long arch_local_save_flags(void) > "csel %0, %0, %2, eq", > ARM64_HAS_IRQ_PRIO_MASKING) > : "=&r" (flags), "+r" (daif_bits) > - : "r" (GIC_PRIO_IRQOFF) > + : "r" ((unsigned long) GIC_PRIO_IRQOFF) > : "memory"); > > return flags; > -- > 1.9.1 > >
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