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linux/arch/x86/um/asm/processor.h
Johannes Berg 5bef0a153b um: Implement cpu_relax() as ndelay(1) for time-travel
In time-travel mode, cpu_relax() currently does actual CPU relax,
but that doesn't affect the simulation. Ideally, we wouldn't run
anything that uses it in simulation, but if we actually have virtio
devices combined with the same simulation it's possible. Implement
cpu_relax() as ndelay(1) in this case, using time_travel_ndelay(1)
directly to catch errors if this is used erroneously in builds that
don't set CONFIG_UML_TIME_TRAVEL_SUPPORT.

While at it, convert it to an __always_inline and also add that to
rep_nop() like the original does now.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2020-03-29 23:29:56 +02:00

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997 B
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __UM_PROCESSOR_H
#define __UM_PROCESSOR_H
#include <linux/time-internal.h>
/* include faultinfo structure */
#include <sysdep/faultinfo.h>
#ifdef CONFIG_X86_32
# include "processor_32.h"
#else
# include "processor_64.h"
#endif
#define KSTK_EIP(tsk) KSTK_REG(tsk, HOST_IP)
#define KSTK_ESP(tsk) KSTK_REG(tsk, HOST_SP)
#define KSTK_EBP(tsk) KSTK_REG(tsk, HOST_BP)
#define ARCH_IS_STACKGROW(address) \
(address + 65536 + 32 * sizeof(unsigned long) >= UPT_SP(&current->thread.regs.regs))
#include <asm/user.h>
/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
static __always_inline void rep_nop(void)
{
__asm__ __volatile__("rep;nop": : :"memory");
}
static __always_inline void cpu_relax(void)
{
if (time_travel_mode == TT_MODE_INFCPU ||
time_travel_mode == TT_MODE_EXTERNAL)
time_travel_ndelay(1);
else
rep_nop();
}
#define task_pt_regs(t) (&(t)->thread.regs)
#include <asm/processor-generic.h>
#endif