From: Karsten Wiese IRQ_PER_CPU is not used by all architectures. This patch introduces the macros ARCH_HAS_IRQ_PER_CPU and CHECK_IRQ_PER_CPU() to avoid the generation of dead code in __do_IRQ(). ARCH_HAS_IRQ_PER_CPU is defined by architectures using IRQ_PER_CPU in their include/asm_ARCH/irq.h file. Through grepping the tree I found the following architectures currently use IRQ_PER_CPU: cris, ia64, ppc, ppc64 and parisc. Signed-off-by: Karsten Wiese Acked-by: Ingo Molnar Signed-off-by: Andrew Morton --- include/asm-cris/irq.h | 5 +++++ include/asm-ia64/irq.h | 5 +++++ include/asm-parisc/irq.h | 5 +++++ include/asm-ppc/irq.h | 5 +++++ include/asm-ppc64/irq.h | 5 +++++ include/linux/irq.h | 7 ++++++- kernel/irq/handle.c | 2 +- 7 files changed, 32 insertions(+), 2 deletions(-) diff -puN include/asm-cris/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/asm-cris/irq.h --- devel/include/asm-cris/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/asm-cris/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -1,6 +1,11 @@ #ifndef _ASM_IRQ_H #define _ASM_IRQ_H +/* + * IRQ line status macro IRQ_PER_CPU is used + */ +#define ARCH_HAS_IRQ_PER_CPU + #include extern __inline__ int irq_canonicalize(int irq) diff -puN include/asm-ia64/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/asm-ia64/irq.h --- devel/include/asm-ia64/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/asm-ia64/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -14,6 +14,11 @@ #define NR_IRQS 256 #define NR_IRQ_VECTORS NR_IRQS +/* + * IRQ line status macro IRQ_PER_CPU is used + */ +#define ARCH_HAS_IRQ_PER_CPU + static __inline__ int irq_canonicalize (int irq) { diff -puN include/asm-parisc/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/asm-parisc/irq.h --- devel/include/asm-parisc/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/asm-parisc/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -26,6 +26,11 @@ #define NR_IRQS (CPU_IRQ_MAX + 1) +/* + * IRQ line status macro IRQ_PER_CPU is used + */ +#define ARCH_HAS_IRQ_PER_CPU + static __inline__ int irq_canonicalize(int irq) { return (irq == 2) ? 9 : irq; diff -puN include/asm-ppc64/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/asm-ppc64/irq.h --- devel/include/asm-ppc64/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/asm-ppc64/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -33,6 +33,11 @@ #define IRQ_POLARITY_POSITIVE 0x2 /* high level or low->high edge */ #define IRQ_POLARITY_NEGATIVE 0x0 /* low level or high->low edge */ +/* + * IRQ line status macro IRQ_PER_CPU is used + */ +#define ARCH_HAS_IRQ_PER_CPU + #define get_irq_desc(irq) (&irq_desc[(irq)]) /* Define a way to iterate across irqs. */ diff -puN include/asm-ppc/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/asm-ppc/irq.h --- devel/include/asm-ppc/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/asm-ppc/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -19,6 +19,11 @@ #define IRQ_POLARITY_POSITIVE 0x2 /* high level or low->high edge */ #define IRQ_POLARITY_NEGATIVE 0x0 /* low level or high->low edge */ +/* + * IRQ line status macro IRQ_PER_CPU is used + */ +#define ARCH_HAS_IRQ_PER_CPU + #if defined(CONFIG_40x) #include diff -puN include/linux/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq include/linux/irq.h --- devel/include/linux/irq.h~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/include/linux/irq.h 2005-08-21 23:48:36.000000000 -0700 @@ -32,7 +32,12 @@ #define IRQ_WAITING 32 /* IRQ not yet seen - for autodetection */ #define IRQ_LEVEL 64 /* IRQ level triggered */ #define IRQ_MASKED 128 /* IRQ masked - shouldn't be seen again */ -#define IRQ_PER_CPU 256 /* IRQ is per CPU */ +#if defined(ARCH_HAS_IRQ_PER_CPU) +# define IRQ_PER_CPU 256 /* IRQ is per CPU */ +# define CHECK_IRQ_PER_CPU(var) ((var) & IRQ_PER_CPU) +#else +# define CHECK_IRQ_PER_CPU(var) 0 +#endif /* * Interrupt controller descriptor. This is all we need diff -puN kernel/irq/handle.c~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq kernel/irq/handle.c --- devel/kernel/irq/handle.c~check_irq_per_cpu-to-avoid-dead-code-in-__do_irq 2005-08-21 23:48:36.000000000 -0700 +++ devel-akpm/kernel/irq/handle.c 2005-08-21 23:48:36.000000000 -0700 @@ -111,7 +111,7 @@ fastcall unsigned int __do_IRQ(unsigned unsigned int status; kstat_this_cpu.irqs[irq]++; - if (desc->status & IRQ_PER_CPU) { + if (CHECK_IRQ_PER_CPU(desc->status)) { irqreturn_t action_ret; /* _