mirror of https://gitee.com/openkylin/linux.git
Merge branch 'for-next/kernel-mode-neon' into for-next/core
* for-next/kernel-mode-neon: arm64: neon/efi: Make EFI fpsimd save/restore variables static arm64: neon: Forbid when irqs are disabled arm64: neon: Export kernel_neon_busy to loadable modules arm64: neon: Temporarily add a kernel_mode_begin_partial() definition arm64: neon: Remove support for nested or hardirq kernel-mode NEON arm64: neon: Allow EFI runtime services to use FPSIMD in irq context arm64: fpsimd: Consistently use __this_cpu_ ops where appropriate arm64: neon: Add missing header guard in <asm/neon.h> arm64: neon: replace generic definition of may_use_simd()
This commit is contained in:
Catalin Marinas
commit
a7ba38d680
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@ -20,7 +20,6 @@ generic-y += rwsem.h
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generic-y += segment.h
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generic-y += serial.h
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generic-y += set_memory.h
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generic-y += simd.h
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generic-y += sizes.h
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generic-y += switch_to.h
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generic-y += trace_clock.h
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@ -3,6 +3,7 @@
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#include <asm/boot.h>
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#include <asm/cpufeature.h>
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#include <asm/fpsimd.h>
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#include <asm/io.h>
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#include <asm/memory.h>
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#include <asm/mmu_context.h>
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@ -21,8 +22,8 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
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#define arch_efi_call_virt_setup() \
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({ \
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kernel_neon_begin(); \
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efi_virtmap_load(); \
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__efi_fpsimd_begin(); \
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})
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#define arch_efi_call_virt(p, f, args...) \
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@ -34,8 +35,8 @@ int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
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#define arch_efi_call_virt_teardown() \
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({ \
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__efi_fpsimd_end(); \
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efi_virtmap_unload(); \
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kernel_neon_end(); \
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})
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#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
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@ -41,16 +41,6 @@ struct fpsimd_state {
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unsigned int cpu;
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};
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/*
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* Struct for stacking the bottom 'n' FP/SIMD registers.
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*/
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struct fpsimd_partial_state {
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u32 fpsr;
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u32 fpcr;
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u32 num_regs;
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__uint128_t vregs[32];
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};
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#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
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/* Masks for extracting the FPSR and FPCR from the FPSCR */
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@ -77,9 +67,9 @@ extern void fpsimd_update_current_state(struct fpsimd_state *state);
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extern void fpsimd_flush_task_state(struct task_struct *target);
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extern void fpsimd_save_partial_state(struct fpsimd_partial_state *state,
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u32 num_regs);
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extern void fpsimd_load_partial_state(struct fpsimd_partial_state *state);
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/* For use by EFI runtime services calls only */
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extern void __efi_fpsimd_begin(void);
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extern void __efi_fpsimd_end(void);
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#endif
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@ -75,59 +75,3 @@
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ldr w\tmpnr, [\state, #16 * 2 + 4]
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fpsimd_restore_fpcr x\tmpnr, \state
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.endm
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.macro fpsimd_save_partial state, numnr, tmpnr1, tmpnr2
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mrs x\tmpnr1, fpsr
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str w\numnr, [\state, #8]
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mrs x\tmpnr2, fpcr
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stp w\tmpnr1, w\tmpnr2, [\state]
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adr x\tmpnr1, 0f
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add \state, \state, x\numnr, lsl #4
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sub x\tmpnr1, x\tmpnr1, x\numnr, lsl #1
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br x\tmpnr1
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stp q30, q31, [\state, #-16 * 30 - 16]
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stp q28, q29, [\state, #-16 * 28 - 16]
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stp q26, q27, [\state, #-16 * 26 - 16]
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stp q24, q25, [\state, #-16 * 24 - 16]
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stp q22, q23, [\state, #-16 * 22 - 16]
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stp q20, q21, [\state, #-16 * 20 - 16]
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stp q18, q19, [\state, #-16 * 18 - 16]
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stp q16, q17, [\state, #-16 * 16 - 16]
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stp q14, q15, [\state, #-16 * 14 - 16]
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stp q12, q13, [\state, #-16 * 12 - 16]
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stp q10, q11, [\state, #-16 * 10 - 16]
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stp q8, q9, [\state, #-16 * 8 - 16]
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stp q6, q7, [\state, #-16 * 6 - 16]
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stp q4, q5, [\state, #-16 * 4 - 16]
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stp q2, q3, [\state, #-16 * 2 - 16]
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stp q0, q1, [\state, #-16 * 0 - 16]
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0:
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.endm
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.macro fpsimd_restore_partial state, tmpnr1, tmpnr2
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ldp w\tmpnr1, w\tmpnr2, [\state]
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msr fpsr, x\tmpnr1
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fpsimd_restore_fpcr x\tmpnr2, x\tmpnr1
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adr x\tmpnr1, 0f
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ldr w\tmpnr2, [\state, #8]
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add \state, \state, x\tmpnr2, lsl #4
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sub x\tmpnr1, x\tmpnr1, x\tmpnr2, lsl #1
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br x\tmpnr1
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ldp q30, q31, [\state, #-16 * 30 - 16]
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ldp q28, q29, [\state, #-16 * 28 - 16]
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ldp q26, q27, [\state, #-16 * 26 - 16]
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ldp q24, q25, [\state, #-16 * 24 - 16]
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ldp q22, q23, [\state, #-16 * 22 - 16]
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ldp q20, q21, [\state, #-16 * 20 - 16]
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ldp q18, q19, [\state, #-16 * 18 - 16]
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ldp q16, q17, [\state, #-16 * 16 - 16]
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ldp q14, q15, [\state, #-16 * 14 - 16]
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ldp q12, q13, [\state, #-16 * 12 - 16]
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ldp q10, q11, [\state, #-16 * 10 - 16]
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ldp q8, q9, [\state, #-16 * 8 - 16]
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ldp q6, q7, [\state, #-16 * 6 - 16]
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ldp q4, q5, [\state, #-16 * 4 - 16]
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ldp q2, q3, [\state, #-16 * 2 - 16]
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ldp q0, q1, [\state, #-16 * 0 - 16]
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0:
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.endm
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@ -8,12 +8,22 @@
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_NEON_H
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#define __ASM_NEON_H
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#include <linux/types.h>
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#include <asm/fpsimd.h>
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#define cpu_has_neon() system_supports_fpsimd()
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#define kernel_neon_begin() kernel_neon_begin_partial(32)
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void kernel_neon_begin_partial(u32 num_regs);
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void kernel_neon_begin(void);
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void kernel_neon_end(void);
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/*
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* Temporary macro to allow the crypto code to compile. Note that the
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* semantics of kernel_neon_begin_partial() are now different from the
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* original as it does not allow being called in an interrupt context.
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*/
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#define kernel_neon_begin_partial(num_regs) kernel_neon_begin()
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#endif /* ! __ASM_NEON_H */
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@ -0,0 +1,56 @@
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/*
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* Copyright (C) 2017 Linaro Ltd. <ard.biesheuvel@linaro.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*/
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#ifndef __ASM_SIMD_H
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#define __ASM_SIMD_H
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#include <linux/compiler.h>
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#include <linux/irqflags.h>
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#include <linux/percpu.h>
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#include <linux/preempt.h>
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#include <linux/types.h>
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#ifdef CONFIG_KERNEL_MODE_NEON
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DECLARE_PER_CPU(bool, kernel_neon_busy);
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/*
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* may_use_simd - whether it is allowable at this time to issue SIMD
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* instructions or access the SIMD register file
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*
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* Callers must not assume that the result remains true beyond the next
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* preempt_enable() or return from softirq context.
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*/
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static __must_check inline bool may_use_simd(void)
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{
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/*
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* The raw_cpu_read() is racy if called with preemption enabled.
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* This is not a bug: kernel_neon_busy is only set when
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* preemption is disabled, so we cannot migrate to another CPU
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* while it is set, nor can we migrate to a CPU where it is set.
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* So, if we find it clear on some CPU then we're guaranteed to
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* find it clear on any CPU we could migrate to.
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*
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* If we are in between kernel_neon_begin()...kernel_neon_end(),
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* the flag will be set, but preemption is also disabled, so we
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* can't migrate to another CPU and spuriously see it become
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* false.
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*/
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return !in_irq() && !irqs_disabled() && !in_nmi() &&
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!raw_cpu_read(kernel_neon_busy);
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}
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#else /* ! CONFIG_KERNEL_MODE_NEON */
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static __must_check inline bool may_use_simd(void) {
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return false;
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}
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#endif /* ! CONFIG_KERNEL_MODE_NEON */
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#endif
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@ -41,27 +41,3 @@ ENTRY(fpsimd_load_state)
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fpsimd_restore x0, 8
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ret
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ENDPROC(fpsimd_load_state)
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#ifdef CONFIG_KERNEL_MODE_NEON
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/*
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* Save the bottom n FP registers.
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*
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* x0 - pointer to struct fpsimd_partial_state
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*/
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ENTRY(fpsimd_save_partial_state)
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fpsimd_save_partial x0, 1, 8, 9
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ret
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ENDPROC(fpsimd_save_partial_state)
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/*
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* Load the bottom n FP registers.
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*
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* x0 - pointer to struct fpsimd_partial_state
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*/
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ENTRY(fpsimd_load_partial_state)
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fpsimd_restore_partial x0, 8, 9
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ret
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ENDPROC(fpsimd_load_partial_state)
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#endif
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|
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@ -17,16 +17,19 @@
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/bottom_half.h>
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#include <linux/cpu.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/percpu.h>
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#include <linux/preempt.h>
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#include <linux/sched/signal.h>
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#include <linux/signal.h>
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#include <linux/hardirq.h>
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#include <asm/fpsimd.h>
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#include <asm/cputype.h>
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#include <asm/simd.h>
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#define FPEXC_IOF (1 << 0)
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#define FPEXC_DZF (1 << 1)
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@ -62,6 +65,13 @@
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* CPU currently contain the most recent userland FPSIMD state of the current
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* task.
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*
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* In order to allow softirq handlers to use FPSIMD, kernel_neon_begin() may
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* save the task's FPSIMD context back to task_struct from softirq context.
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* To prevent this from racing with the manipulation of the task's FPSIMD state
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* from task context and thereby corrupting the state, it is necessary to
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* protect any manipulation of a task's fpsimd_state or TIF_FOREIGN_FPSTATE
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* flag with local_bh_disable() unless softirqs are already masked.
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*
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* For a certain task, the sequence may look something like this:
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* - the task gets scheduled in; if both the task's fpsimd_state.cpu field
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* contains the id of the current CPU, and the CPU's fpsimd_last_state per-cpu
|
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@ -161,9 +171,14 @@ void fpsimd_flush_thread(void)
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{
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if (!system_supports_fpsimd())
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return;
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|
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local_bh_disable();
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|
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memset(¤t->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
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fpsimd_flush_task_state(current);
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set_thread_flag(TIF_FOREIGN_FPSTATE);
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|
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local_bh_enable();
|
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}
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|
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/*
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||||
|
|
@ -174,10 +189,13 @@ void fpsimd_preserve_current_state(void)
|
|||
{
|
||||
if (!system_supports_fpsimd())
|
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return;
|
||||
preempt_disable();
|
||||
|
||||
local_bh_disable();
|
||||
|
||||
if (!test_thread_flag(TIF_FOREIGN_FPSTATE))
|
||||
fpsimd_save_state(¤t->thread.fpsimd_state);
|
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preempt_enable();
|
||||
|
||||
local_bh_enable();
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -189,15 +207,18 @@ void fpsimd_restore_current_state(void)
|
|||
{
|
||||
if (!system_supports_fpsimd())
|
||||
return;
|
||||
preempt_disable();
|
||||
|
||||
local_bh_disable();
|
||||
|
||||
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
|
||||
struct fpsimd_state *st = ¤t->thread.fpsimd_state;
|
||||
|
||||
fpsimd_load_state(st);
|
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this_cpu_write(fpsimd_last_state, st);
|
||||
__this_cpu_write(fpsimd_last_state, st);
|
||||
st->cpu = smp_processor_id();
|
||||
}
|
||||
preempt_enable();
|
||||
|
||||
local_bh_enable();
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -209,15 +230,18 @@ void fpsimd_update_current_state(struct fpsimd_state *state)
|
|||
{
|
||||
if (!system_supports_fpsimd())
|
||||
return;
|
||||
preempt_disable();
|
||||
|
||||
local_bh_disable();
|
||||
|
||||
fpsimd_load_state(state);
|
||||
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
|
||||
struct fpsimd_state *st = ¤t->thread.fpsimd_state;
|
||||
|
||||
this_cpu_write(fpsimd_last_state, st);
|
||||
__this_cpu_write(fpsimd_last_state, st);
|
||||
st->cpu = smp_processor_id();
|
||||
}
|
||||
preempt_enable();
|
||||
|
||||
local_bh_enable();
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -230,51 +254,121 @@ void fpsimd_flush_task_state(struct task_struct *t)
|
|||
|
||||
#ifdef CONFIG_KERNEL_MODE_NEON
|
||||
|
||||
static DEFINE_PER_CPU(struct fpsimd_partial_state, hardirq_fpsimdstate);
|
||||
static DEFINE_PER_CPU(struct fpsimd_partial_state, softirq_fpsimdstate);
|
||||
DEFINE_PER_CPU(bool, kernel_neon_busy);
|
||||
EXPORT_PER_CPU_SYMBOL(kernel_neon_busy);
|
||||
|
||||
/*
|
||||
* Kernel-side NEON support functions
|
||||
*/
|
||||
void kernel_neon_begin_partial(u32 num_regs)
|
||||
|
||||
/*
|
||||
* kernel_neon_begin(): obtain the CPU FPSIMD registers for use by the calling
|
||||
* context
|
||||
*
|
||||
* Must not be called unless may_use_simd() returns true.
|
||||
* Task context in the FPSIMD registers is saved back to memory as necessary.
|
||||
*
|
||||
* A matching call to kernel_neon_end() must be made before returning from the
|
||||
* calling context.
|
||||
*
|
||||
* The caller may freely use the FPSIMD registers until kernel_neon_end() is
|
||||
* called.
|
||||
*/
|
||||
void kernel_neon_begin(void)
|
||||
{
|
||||
if (WARN_ON(!system_supports_fpsimd()))
|
||||
return;
|
||||
if (in_interrupt()) {
|
||||
struct fpsimd_partial_state *s = this_cpu_ptr(
|
||||
in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
|
||||
|
||||
BUG_ON(num_regs > 32);
|
||||
fpsimd_save_partial_state(s, roundup(num_regs, 2));
|
||||
} else {
|
||||
/*
|
||||
* Save the userland FPSIMD state if we have one and if we
|
||||
* haven't done so already. Clear fpsimd_last_state to indicate
|
||||
* that there is no longer userland FPSIMD state in the
|
||||
* registers.
|
||||
*/
|
||||
preempt_disable();
|
||||
if (current->mm &&
|
||||
!test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
|
||||
fpsimd_save_state(¤t->thread.fpsimd_state);
|
||||
this_cpu_write(fpsimd_last_state, NULL);
|
||||
}
|
||||
BUG_ON(!may_use_simd());
|
||||
|
||||
local_bh_disable();
|
||||
|
||||
__this_cpu_write(kernel_neon_busy, true);
|
||||
|
||||
/* Save unsaved task fpsimd state, if any: */
|
||||
if (current->mm && !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
|
||||
fpsimd_save_state(¤t->thread.fpsimd_state);
|
||||
|
||||
/* Invalidate any task state remaining in the fpsimd regs: */
|
||||
__this_cpu_write(fpsimd_last_state, NULL);
|
||||
|
||||
preempt_disable();
|
||||
|
||||
local_bh_enable();
|
||||
}
|
||||
EXPORT_SYMBOL(kernel_neon_begin_partial);
|
||||
EXPORT_SYMBOL(kernel_neon_begin);
|
||||
|
||||
/*
|
||||
* kernel_neon_end(): give the CPU FPSIMD registers back to the current task
|
||||
*
|
||||
* Must be called from a context in which kernel_neon_begin() was previously
|
||||
* called, with no call to kernel_neon_end() in the meantime.
|
||||
*
|
||||
* The caller must not use the FPSIMD registers after this function is called,
|
||||
* unless kernel_neon_begin() is called again in the meantime.
|
||||
*/
|
||||
void kernel_neon_end(void)
|
||||
{
|
||||
bool busy;
|
||||
|
||||
if (!system_supports_fpsimd())
|
||||
return;
|
||||
|
||||
busy = __this_cpu_xchg(kernel_neon_busy, false);
|
||||
WARN_ON(!busy); /* No matching kernel_neon_begin()? */
|
||||
|
||||
preempt_enable();
|
||||
}
|
||||
EXPORT_SYMBOL(kernel_neon_end);
|
||||
|
||||
static DEFINE_PER_CPU(struct fpsimd_state, efi_fpsimd_state);
|
||||
static DEFINE_PER_CPU(bool, efi_fpsimd_state_used);
|
||||
|
||||
/*
|
||||
* EFI runtime services support functions
|
||||
*
|
||||
* The ABI for EFI runtime services allows EFI to use FPSIMD during the call.
|
||||
* This means that for EFI (and only for EFI), we have to assume that FPSIMD
|
||||
* is always used rather than being an optional accelerator.
|
||||
*
|
||||
* These functions provide the necessary support for ensuring FPSIMD
|
||||
* save/restore in the contexts from which EFI is used.
|
||||
*
|
||||
* Do not use them for any other purpose -- if tempted to do so, you are
|
||||
* either doing something wrong or you need to propose some refactoring.
|
||||
*/
|
||||
|
||||
/*
|
||||
* __efi_fpsimd_begin(): prepare FPSIMD for making an EFI runtime services call
|
||||
*/
|
||||
void __efi_fpsimd_begin(void)
|
||||
{
|
||||
if (!system_supports_fpsimd())
|
||||
return;
|
||||
if (in_interrupt()) {
|
||||
struct fpsimd_partial_state *s = this_cpu_ptr(
|
||||
in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
|
||||
fpsimd_load_partial_state(s);
|
||||
} else {
|
||||
preempt_enable();
|
||||
|
||||
WARN_ON(preemptible());
|
||||
|
||||
if (may_use_simd())
|
||||
kernel_neon_begin();
|
||||
else {
|
||||
fpsimd_save_state(this_cpu_ptr(&efi_fpsimd_state));
|
||||
__this_cpu_write(efi_fpsimd_state_used, true);
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL(kernel_neon_end);
|
||||
|
||||
/*
|
||||
* __efi_fpsimd_end(): clean up FPSIMD after an EFI runtime services call
|
||||
*/
|
||||
void __efi_fpsimd_end(void)
|
||||
{
|
||||
if (!system_supports_fpsimd())
|
||||
return;
|
||||
|
||||
if (__this_cpu_xchg(efi_fpsimd_state_used, false))
|
||||
fpsimd_load_state(this_cpu_ptr(&efi_fpsimd_state));
|
||||
else
|
||||
kernel_neon_end();
|
||||
}
|
||||
|
||||
#endif /* CONFIG_KERNEL_MODE_NEON */
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue