kernel-fxtec-pro1x/arch/x86/include/asm/irqflags.h
H. Peter Anvin ab94fcf528 x86: allow "=rm" in native_save_fl()
This is a partial revert of f1f029c7bf.

"=rm" is allowed in this context, because "pop" is explicitly defined
to adjust the stack pointer *before* it evaluates its effective
address, if it has one.  Thus, we do end up writing to the correct
address even if we use an on-stack memory argument.

The original reporter for f1f029c7bf was
apparently using a broken x86 simulator.

[ Impact: performance ]

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Gabe Black <spamforgabe@umich.edu>
2009-08-25 16:47:16 -07:00

216 lines
4.1 KiB
C

#ifndef _X86_IRQFLAGS_H_
#define _X86_IRQFLAGS_H_
#include <asm/processor-flags.h>
#ifndef __ASSEMBLY__
/*
* Interrupt control:
*/
static inline unsigned long native_save_fl(void)
{
unsigned long flags;
/*
* "=rm" is safe here, because "pop" adjusts the stack before
* it evaluates its effective address -- this is part of the
* documented behavior of the "pop" instruction.
*/
asm volatile("# __raw_save_flags\n\t"
"pushf ; pop %0"
: "=rm" (flags)
: /* no input */
: "memory");
return flags;
}
static inline void native_restore_fl(unsigned long flags)
{
asm volatile("push %0 ; popf"
: /* no output */
:"g" (flags)
:"memory", "cc");
}
static inline void native_irq_disable(void)
{
asm volatile("cli": : :"memory");
}
static inline void native_irq_enable(void)
{
asm volatile("sti": : :"memory");
}
static inline void native_safe_halt(void)
{
asm volatile("sti; hlt": : :"memory");
}
static inline void native_halt(void)
{
asm volatile("hlt": : :"memory");
}
#endif
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#else
#ifndef __ASSEMBLY__
static inline unsigned long __raw_local_save_flags(void)
{
return native_save_fl();
}
static inline void raw_local_irq_restore(unsigned long flags)
{
native_restore_fl(flags);
}
static inline void raw_local_irq_disable(void)
{
native_irq_disable();
}
static inline void raw_local_irq_enable(void)
{
native_irq_enable();
}
/*
* Used in the idle loop; sti takes one instruction cycle
* to complete:
*/
static inline void raw_safe_halt(void)
{
native_safe_halt();
}
/*
* Used when interrupts are already enabled or to
* shutdown the processor:
*/
static inline void halt(void)
{
native_halt();
}
/*
* For spinlocks, etc:
*/
static inline unsigned long __raw_local_irq_save(void)
{
unsigned long flags = __raw_local_save_flags();
raw_local_irq_disable();
return flags;
}
#else
#define ENABLE_INTERRUPTS(x) sti
#define DISABLE_INTERRUPTS(x) cli
#ifdef CONFIG_X86_64
#define SWAPGS swapgs
/*
* Currently paravirt can't handle swapgs nicely when we
* don't have a stack we can rely on (such as a user space
* stack). So we either find a way around these or just fault
* and emulate if a guest tries to call swapgs directly.
*
* Either way, this is a good way to document that we don't
* have a reliable stack. x86_64 only.
*/
#define SWAPGS_UNSAFE_STACK swapgs
#define PARAVIRT_ADJUST_EXCEPTION_FRAME /* */
#define INTERRUPT_RETURN iretq
#define USERGS_SYSRET64 \
swapgs; \
sysretq;
#define USERGS_SYSRET32 \
swapgs; \
sysretl
#define ENABLE_INTERRUPTS_SYSEXIT32 \
swapgs; \
sti; \
sysexit
#else
#define INTERRUPT_RETURN iret
#define ENABLE_INTERRUPTS_SYSEXIT sti; sysexit
#define GET_CR0_INTO_EAX movl %cr0, %eax
#endif
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_PARAVIRT */
#ifndef __ASSEMBLY__
#define raw_local_save_flags(flags) \
do { (flags) = __raw_local_save_flags(); } while (0)
#define raw_local_irq_save(flags) \
do { (flags) = __raw_local_irq_save(); } while (0)
static inline int raw_irqs_disabled_flags(unsigned long flags)
{
return !(flags & X86_EFLAGS_IF);
}
static inline int raw_irqs_disabled(void)
{
unsigned long flags = __raw_local_save_flags();
return raw_irqs_disabled_flags(flags);
}
#else
#ifdef CONFIG_X86_64
#define ARCH_LOCKDEP_SYS_EXIT call lockdep_sys_exit_thunk
#define ARCH_LOCKDEP_SYS_EXIT_IRQ \
TRACE_IRQS_ON; \
sti; \
SAVE_REST; \
LOCKDEP_SYS_EXIT; \
RESTORE_REST; \
cli; \
TRACE_IRQS_OFF;
#else
#define ARCH_LOCKDEP_SYS_EXIT \
pushl %eax; \
pushl %ecx; \
pushl %edx; \
call lockdep_sys_exit; \
popl %edx; \
popl %ecx; \
popl %eax;
#define ARCH_LOCKDEP_SYS_EXIT_IRQ
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
# define TRACE_IRQS_ON call trace_hardirqs_on_thunk;
# define TRACE_IRQS_OFF call trace_hardirqs_off_thunk;
#else
# define TRACE_IRQS_ON
# define TRACE_IRQS_OFF
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
# define LOCKDEP_SYS_EXIT ARCH_LOCKDEP_SYS_EXIT
# define LOCKDEP_SYS_EXIT_IRQ ARCH_LOCKDEP_SYS_EXIT_IRQ
# else
# define LOCKDEP_SYS_EXIT
# define LOCKDEP_SYS_EXIT_IRQ
# endif
#endif /* __ASSEMBLY__ */
#endif