entry-common.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2
 3#ifndef _ASM_ARM64_ENTRY_COMMON_H
 4#define _ASM_ARM64_ENTRY_COMMON_H
 5
 6#include <linux/thread_info.h>
 7
 8#include <asm/cpufeature.h>
 9#include <asm/daifflags.h>
10#include <asm/fpsimd.h>
11#include <asm/mte.h>
12#include <asm/stacktrace.h>
13
14#define ARCH_EXIT_TO_USER_MODE_WORK (_TIF_MTE_ASYNC_FAULT | _TIF_FOREIGN_FPSTATE)
15
16static __always_inline void arch_exit_to_user_mode_work(struct pt_regs *regs,
17							unsigned long ti_work)
18{
19	if (ti_work & _TIF_MTE_ASYNC_FAULT) {
20		clear_thread_flag(TIF_MTE_ASYNC_FAULT);
21		send_sig_fault(SIGSEGV, SEGV_MTEAERR, (void __user *)NULL, current);
22	}
23
24	if (ti_work & _TIF_FOREIGN_FPSTATE)
25		fpsimd_restore_current_state();
26}
27
28#define arch_exit_to_user_mode_work arch_exit_to_user_mode_work
29
30static inline bool arch_irqentry_exit_need_resched(void)
31{
32	/*
33	 * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
34	 * priority masking is used the GIC irqchip driver will clear DAIF.IF
35	 * using gic_arch_enable_irqs() for normal IRQs. If anything is set in
36	 * DAIF we must have handled an NMI, so skip preemption.
37	 */
38	if (system_uses_irq_prio_masking() && read_sysreg(daif))
39		return false;
40
41	/*
42	 * Preempting a task from an IRQ means we leave copies of PSTATE
43	 * on the stack. cpufeature's enable calls may modify PSTATE, but
44	 * resuming one of these preempted tasks would undo those changes.
45	 *
46	 * Only allow a task to be preempted once cpufeatures have been
47	 * enabled.
48	 */
49	if (!system_capabilities_finalized())
50		return false;
51
52	return true;
53}
54
55#define arch_irqentry_exit_need_resched arch_irqentry_exit_need_resched
56
57#endif /* _ASM_ARM64_ENTRY_COMMON_H */