Viewing file:  daifflags.h (3.45 KB) -rw-r--r--
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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2017 ARM Ltd.
*/
#ifndef __ASM_DAIFFLAGS_H
#define __ASM_DAIFFLAGS_H
#include <linux/irqflags.h>
#include <asm/arch_gicv3.h>
#include <asm/barrier.h>
#include <asm/cpufeature.h>
#include <asm/ptrace.h>
#define DAIF_PROCCTX 0
#define DAIF_PROCCTX_NOIRQ (PSR_I_BIT | PSR_F_BIT)
#define DAIF_ERRCTX (PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
#define DAIF_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
/* mask/save/unmask/restore all exceptions, including interrupts. */
static inline void local_daif_mask(void)
{
WARN_ON(system_has_prio_mask_debugging() &&
(read_sysreg_s(SYS_ICC_PMR_EL1) == (GIC_PRIO_IRQOFF |
GIC_PRIO_PSR_I_SET)));
asm volatile(
"msr daifset, #0xf // local_daif_mask\n"
:
:
: "memory");
/* Don't really care for a dsb here, we don't intend to enable IRQs */
if (system_uses_irq_prio_masking())
gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET);
trace_hardirqs_off();
}
static inline unsigned long local_daif_save_flags(void)
{
unsigned long flags;
flags = read_sysreg(daif);
if (system_uses_irq_prio_masking()) {
/* If IRQs are masked with PMR, reflect it in the flags */
if (read_sysreg_s(SYS_ICC_PMR_EL1) != GIC_PRIO_IRQON)
flags |= PSR_I_BIT | PSR_F_BIT;
}
return flags;
}
static inline unsigned long local_daif_save(void)
{
unsigned long flags;
flags = local_daif_save_flags();
local_daif_mask();
return flags;
}
static inline void local_daif_restore(unsigned long flags)
{
bool irq_disabled = flags & PSR_I_BIT;
WARN_ON(system_has_prio_mask_debugging() &&
(read_sysreg(daif) & (PSR_I_BIT | PSR_F_BIT)) != (PSR_I_BIT | PSR_F_BIT));
if (!irq_disabled) {
trace_hardirqs_on();
if (system_uses_irq_prio_masking()) {
gic_write_pmr(GIC_PRIO_IRQON);
pmr_sync();
}
} else if (system_uses_irq_prio_masking()) {
u64 pmr;
if (!(flags & PSR_A_BIT)) {
/*
* If interrupts are disabled but we can take
* asynchronous errors, we can take NMIs
*/
flags &= ~(PSR_I_BIT | PSR_F_BIT);
pmr = GIC_PRIO_IRQOFF;
} else {
pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET;
}
/*
* There has been concern that the write to daif
* might be reordered before this write to PMR.
* From the ARM ARM DDI 0487D.a, section D1.7.1
* "Accessing PSTATE fields":
* Writes to the PSTATE fields have side-effects on
* various aspects of the PE operation. All of these
* side-effects are guaranteed:
* - Not to be visible to earlier instructions in
* the execution stream.
* - To be visible to later instructions in the
* execution stream
*
* Also, writes to PMR are self-synchronizing, so no
* interrupts with a lower priority than PMR is signaled
* to the PE after the write.
*
* So we don't need additional synchronization here.
*/
gic_write_pmr(pmr);
}
write_sysreg(flags, daif);
if (irq_disabled)
trace_hardirqs_off();
}
/*
* Called by synchronous exception handlers to restore the DAIF bits that were
* modified by taking an exception.
*/
static inline void local_daif_inherit(struct pt_regs *regs)
{
unsigned long flags = regs->pstate & DAIF_MASK;
if (interrupts_enabled(regs))
trace_hardirqs_on();
if (system_uses_irq_prio_masking())
gic_write_pmr(regs->pmr_save);
/*
* We can't use local_daif_restore(regs->pstate) here as
* system_has_prio_mask_debugging() won't restore the I bit if it can
* use the pmr instead.
*/
write_sysreg(flags, daif);
}
#endif
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