linux/arch/xtensa/include/asm/irqflags.h
Max Filippov 38fef73c21 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 <a.p.zijlstra@chello.nl>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2015-08-17 07:33:39 +03:00

82 lines
2.0 KiB
C

/*
* Xtensa IRQ flags handling functions
*
* 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 - 2005 Tensilica Inc.
* Copyright (C) 2015 Cadence Design Systems Inc.
*/
#ifndef _XTENSA_IRQFLAGS_H
#define _XTENSA_IRQFLAGS_H
#include <linux/types.h>
static inline unsigned long arch_local_save_flags(void)
{
unsigned long flags;
asm volatile("rsr %0, ps" : "=a" (flags));
return flags;
}
static inline unsigned long arch_local_irq_save(void)
{
unsigned long flags;
#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;
}
static inline void arch_local_irq_disable(void)
{
arch_local_irq_save();
}
static inline void arch_local_irq_enable(void)
{
unsigned long flags;
asm volatile("rsil %0, 0" : "=a" (flags) :: "memory");
}
static inline void arch_local_irq_restore(unsigned long flags)
{
asm volatile("wsr %0, ps; rsync"
:: "a" (flags) : "memory");
}
static inline bool arch_irqs_disabled_flags(unsigned long flags)
{
#if XCHAL_EXCM_LEVEL < LOCKLEVEL || (1 << PS_EXCM_BIT) < LOCKLEVEL
#error "XCHAL_EXCM_LEVEL and 1<<PS_EXCM_BIT must be no less than LOCKLEVEL"
#endif
return (flags & (PS_INTLEVEL_MASK | (1 << PS_EXCM_BIT))) >= LOCKLEVEL;
}
static inline bool arch_irqs_disabled(void)
{
return arch_irqs_disabled_flags(arch_local_save_flags());
}
#endif /* _XTENSA_IRQFLAGS_H */