From 38fef73c21d117cf992fb5ec6e30630e54e13f4f Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Thu, 16 Jul 2015 10:37:31 +0300 Subject: xtensa: implement fake NMI In case perf IRQ is the highest of the medium-level IRQs, and is alone on its level, it may be treated as NMI: - LOCKLEVEL is defined to be one level less than EXCM level, - IRQ masking never lowers current IRQ level, - new fake exception cause code, EXCCAUSE_MAPPED_NMI is assigned to that IRQ; new second level exception handler, do_nmi, assigned to it handles it as NMI, - atomic operations in configurations without s32c1i still need to mask all interrupts. Cc: Peter Zijlstra Acked-by: Peter Zijlstra (Intel) Signed-off-by: Max Filippov --- arch/xtensa/include/asm/atomic.h | 10 +++++----- arch/xtensa/include/asm/cmpxchg.h | 4 ++-- arch/xtensa/include/asm/irqflags.h | 22 +++++++++++++++++++++- arch/xtensa/include/asm/processor.h | 31 +++++++++++++++++++++++++++++-- 4 files changed, 57 insertions(+), 10 deletions(-) (limited to 'arch/xtensa/include') diff --git a/arch/xtensa/include/asm/atomic.h b/arch/xtensa/include/asm/atomic.h index 00b7d46..ebcd1f6 100644 --- a/arch/xtensa/include/asm/atomic.h +++ b/arch/xtensa/include/asm/atomic.h @@ -29,7 +29,7 @@ * * Locking interrupts looks like this: * - * rsil a15, LOCKLEVEL + * rsil a15, TOPLEVEL * * wsr a15, PS * rsync @@ -106,7 +106,7 @@ static inline void atomic_##op(int i, atomic_t * v) \ unsigned int vval; \ \ __asm__ __volatile__( \ - " rsil a15, "__stringify(LOCKLEVEL)"\n"\ + " rsil a15, "__stringify(TOPLEVEL)"\n"\ " l32i %0, %2, 0\n" \ " " #op " %0, %0, %1\n" \ " s32i %0, %2, 0\n" \ @@ -124,7 +124,7 @@ static inline int atomic_##op##_return(int i, atomic_t * v) \ unsigned int vval; \ \ __asm__ __volatile__( \ - " rsil a15,"__stringify(LOCKLEVEL)"\n" \ + " rsil a15,"__stringify(TOPLEVEL)"\n" \ " l32i %0, %2, 0\n" \ " " #op " %0, %0, %1\n" \ " s32i %0, %2, 0\n" \ @@ -272,7 +272,7 @@ static inline void atomic_clear_mask(unsigned int mask, atomic_t *v) unsigned int vval; __asm__ __volatile__( - " rsil a15,"__stringify(LOCKLEVEL)"\n" + " rsil a15,"__stringify(TOPLEVEL)"\n" " l32i %0, %2, 0\n" " xor %1, %4, %3\n" " and %0, %0, %4\n" @@ -306,7 +306,7 @@ static inline void atomic_set_mask(unsigned int mask, atomic_t *v) unsigned int vval; __asm__ __volatile__( - " rsil a15,"__stringify(LOCKLEVEL)"\n" + " rsil a15,"__stringify(TOPLEVEL)"\n" " l32i %0, %2, 0\n" " or %0, %0, %1\n" " s32i %0, %2, 0\n" diff --git a/arch/xtensa/include/asm/cmpxchg.h b/arch/xtensa/include/asm/cmpxchg.h index 370b26f..201e900 100644 --- a/arch/xtensa/include/asm/cmpxchg.h +++ b/arch/xtensa/include/asm/cmpxchg.h @@ -34,7 +34,7 @@ __cmpxchg_u32(volatile int *p, int old, int new) return new; #else __asm__ __volatile__( - " rsil a15, "__stringify(LOCKLEVEL)"\n" + " rsil a15, "__stringify(TOPLEVEL)"\n" " l32i %0, %1, 0\n" " bne %0, %2, 1f\n" " s32i %3, %1, 0\n" @@ -123,7 +123,7 @@ static inline unsigned long xchg_u32(volatile int * m, unsigned long val) #else unsigned long tmp; __asm__ __volatile__( - " rsil a15, "__stringify(LOCKLEVEL)"\n" + " rsil a15, "__stringify(TOPLEVEL)"\n" " l32i %0, %1, 0\n" " s32i %2, %1, 0\n" " wsr a15, ps\n" diff --git a/arch/xtensa/include/asm/irqflags.h b/arch/xtensa/include/asm/irqflags.h index ea36674..8e090c7 100644 --- a/arch/xtensa/include/asm/irqflags.h +++ b/arch/xtensa/include/asm/irqflags.h @@ -6,6 +6,7 @@ * for more details. * * Copyright (C) 2001 - 2005 Tensilica Inc. + * Copyright (C) 2015 Cadence Design Systems Inc. */ #ifndef _XTENSA_IRQFLAGS_H @@ -23,8 +24,27 @@ static inline unsigned long arch_local_save_flags(void) static inline unsigned long arch_local_irq_save(void) { unsigned long flags; - asm volatile("rsil %0, "__stringify(LOCKLEVEL) +#if XTENSA_FAKE_NMI +#if defined(CONFIG_DEBUG_KERNEL) && (LOCKLEVEL | TOPLEVEL) >= XCHAL_DEBUGLEVEL + unsigned long tmp; + + asm volatile("rsr %0, ps\t\n" + "extui %1, %0, 0, 4\t\n" + "bgei %1, "__stringify(LOCKLEVEL)", 1f\t\n" + "rsil %0, "__stringify(LOCKLEVEL)"\n" + "1:" + : "=a" (flags), "=a" (tmp) :: "memory"); +#else + asm volatile("rsr %0, ps\t\n" + "or %0, %0, %1\t\n" + "xsr %0, ps\t\n" + "rsync" + : "=&a" (flags) : "a" (LOCKLEVEL) : "memory"); +#endif +#else + asm volatile("rsil %0, "__stringify(LOCKLEVEL) : "=a" (flags) :: "memory"); +#endif return flags; } diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h index b61bdf0..83e2e4bc 100644 --- a/arch/xtensa/include/asm/processor.h +++ b/arch/xtensa/include/asm/processor.h @@ -1,11 +1,10 @@ /* - * include/asm-xtensa/processor.h - * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 2001 - 2008 Tensilica Inc. + * Copyright (C) 2015 Cadence Design Systems Inc. */ #ifndef _XTENSA_PROCESSOR_H @@ -45,6 +44,14 @@ #define STACK_TOP_MAX STACK_TOP /* + * General exception cause assigned to fake NMI. Fake NMI needs to be handled + * differently from other interrupts, but it uses common kernel entry/exit + * code. + */ + +#define EXCCAUSE_MAPPED_NMI 62 + +/* * General exception cause assigned to debug exceptions. Debug exceptions go * to their own vector, rather than the general exception vectors (user, * kernel, double); and their specific causes are reported via DEBUGCAUSE @@ -65,10 +72,30 @@ #define VALID_DOUBLE_EXCEPTION_ADDRESS 64 +#define XTENSA_INT_LEVEL(intno) _XTENSA_INT_LEVEL(intno) +#define _XTENSA_INT_LEVEL(intno) XCHAL_INT##intno##_LEVEL + +#define XTENSA_INTLEVEL_MASK(level) _XTENSA_INTLEVEL_MASK(level) +#define _XTENSA_INTLEVEL_MASK(level) (XCHAL_INTLEVEL##level##_MASK) + +#define IS_POW2(v) (((v) & ((v) - 1)) == 0) + +#define PROFILING_INTLEVEL XTENSA_INT_LEVEL(XCHAL_PROFILING_INTERRUPT) + /* LOCKLEVEL defines the interrupt level that masks all * general-purpose interrupts. */ +#if defined(CONFIG_XTENSA_VARIANT_HAVE_PERF_EVENTS) && \ + defined(XCHAL_PROFILING_INTERRUPT) && \ + PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \ + XCHAL_EXCM_LEVEL > 1 && \ + IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL)) +#define LOCKLEVEL (XCHAL_EXCM_LEVEL - 1) +#else #define LOCKLEVEL XCHAL_EXCM_LEVEL +#endif +#define TOPLEVEL XCHAL_EXCM_LEVEL +#define XTENSA_FAKE_NMI (LOCKLEVEL < TOPLEVEL) /* WSBITS and WBBITS are the width of the WINDOWSTART and WINDOWBASE * registers -- cgit v1.1