762 lines
21 KiB
C
762 lines
21 KiB
C
/*
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* FP/SIMD context switching and fault handling
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*
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* Copyright (C) 2012 ARM Ltd.
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* Author: Catalin Marinas <catalin.marinas@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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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/bug.h>
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#include <linux/compat.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/linkage.h>
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#include <linux/irqflags.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/ptrace.h>
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#include <linux/sched/signal.h>
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#include <linux/sched/task_stack.h>
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#include <linux/signal.h>
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#include <linux/slab.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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#include <asm/sigcontext.h>
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#include <asm/sysreg.h>
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#include <asm/traps.h>
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#define FPEXC_IOF (1 << 0)
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#define FPEXC_DZF (1 << 1)
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#define FPEXC_OFF (1 << 2)
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#define FPEXC_UFF (1 << 3)
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#define FPEXC_IXF (1 << 4)
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#define FPEXC_IDF (1 << 7)
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/*
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* (Note: in this discussion, statements about FPSIMD apply equally to SVE.)
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*
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* In order to reduce the number of times the FPSIMD state is needlessly saved
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* and restored, we need to keep track of two things:
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* (a) for each task, we need to remember which CPU was the last one to have
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* the task's FPSIMD state loaded into its FPSIMD registers;
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* (b) for each CPU, we need to remember which task's userland FPSIMD state has
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* been loaded into its FPSIMD registers most recently, or whether it has
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* been used to perform kernel mode NEON in the meantime.
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*
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* For (a), we add a 'cpu' field to struct fpsimd_state, which gets updated to
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* the id of the current CPU every time the state is loaded onto a CPU. For (b),
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* we add the per-cpu variable 'fpsimd_last_state' (below), which contains the
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* address of the userland FPSIMD state of the task that was loaded onto the CPU
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* the most recently, or NULL if kernel mode NEON has been performed after that.
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*
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* With this in place, we no longer have to restore the next FPSIMD state right
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* when switching between tasks. Instead, we can defer this check to userland
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* resume, at which time we verify whether the CPU's fpsimd_last_state and the
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* task's fpsimd_state.cpu are still mutually in sync. If this is the case, we
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* can omit the FPSIMD restore.
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*
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* As an optimization, we use the thread_info flag TIF_FOREIGN_FPSTATE to
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* indicate whether or not the userland FPSIMD state of the current task is
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* present in the registers. The flag is set unless the FPSIMD registers of this
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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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* variable points to the task's fpsimd_state, the TIF_FOREIGN_FPSTATE flag is
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* cleared, otherwise it is set;
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*
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* - the task returns to userland; if TIF_FOREIGN_FPSTATE is set, the task's
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* userland FPSIMD state is copied from memory to the registers, the task's
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* fpsimd_state.cpu field is set to the id of the current CPU, the current
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* CPU's fpsimd_last_state pointer is set to this task's fpsimd_state and the
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* TIF_FOREIGN_FPSTATE flag is cleared;
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*
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* - the task executes an ordinary syscall; upon return to userland, the
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* TIF_FOREIGN_FPSTATE flag will still be cleared, so no FPSIMD state is
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* restored;
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*
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* - the task executes a syscall which executes some NEON instructions; this is
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* preceded by a call to kernel_neon_begin(), which copies the task's FPSIMD
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* register contents to memory, clears the fpsimd_last_state per-cpu variable
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* and sets the TIF_FOREIGN_FPSTATE flag;
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*
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* - the task gets preempted after kernel_neon_end() is called; as we have not
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* returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so
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* whatever is in the FPSIMD registers is not saved to memory, but discarded.
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*/
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static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
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/*
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* Call __sve_free() directly only if you know task can't be scheduled
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* or preempted.
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*/
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static void __sve_free(struct task_struct *task)
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{
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kfree(task->thread.sve_state);
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task->thread.sve_state = NULL;
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}
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static void sve_free(struct task_struct *task)
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{
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WARN_ON(test_tsk_thread_flag(task, TIF_SVE));
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__sve_free(task);
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}
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/* Offset of FFR in the SVE register dump */
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static size_t sve_ffr_offset(int vl)
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{
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return SVE_SIG_FFR_OFFSET(sve_vq_from_vl(vl)) - SVE_SIG_REGS_OFFSET;
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}
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static void *sve_pffr(struct task_struct *task)
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{
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return (char *)task->thread.sve_state +
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sve_ffr_offset(task->thread.sve_vl);
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}
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static void change_cpacr(u64 val, u64 mask)
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{
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u64 cpacr = read_sysreg(CPACR_EL1);
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u64 new = (cpacr & ~mask) | val;
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if (new != cpacr)
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write_sysreg(new, CPACR_EL1);
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}
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static void sve_user_disable(void)
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{
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change_cpacr(0, CPACR_EL1_ZEN_EL0EN);
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}
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static void sve_user_enable(void)
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{
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change_cpacr(CPACR_EL1_ZEN_EL0EN, CPACR_EL1_ZEN_EL0EN);
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}
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/*
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* TIF_SVE controls whether a task can use SVE without trapping while
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* in userspace, and also the way a task's FPSIMD/SVE state is stored
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* in thread_struct.
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*
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* The kernel uses this flag to track whether a user task is actively
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* using SVE, and therefore whether full SVE register state needs to
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* be tracked. If not, the cheaper FPSIMD context handling code can
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* be used instead of the more costly SVE equivalents.
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*
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* * TIF_SVE set:
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*
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* The task can execute SVE instructions while in userspace without
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* trapping to the kernel.
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*
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* When stored, Z0-Z31 (incorporating Vn in bits[127:0] or the
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* corresponding Zn), P0-P15 and FFR are encoded in in
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* task->thread.sve_state, formatted appropriately for vector
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* length task->thread.sve_vl.
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*
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* task->thread.sve_state must point to a valid buffer at least
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* sve_state_size(task) bytes in size.
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*
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* During any syscall, the kernel may optionally clear TIF_SVE and
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* discard the vector state except for the FPSIMD subset.
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*
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* * TIF_SVE clear:
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*
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* An attempt by the user task to execute an SVE instruction causes
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* do_sve_acc() to be called, which does some preparation and then
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* sets TIF_SVE.
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*
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* When stored, FPSIMD registers V0-V31 are encoded in
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* task->fpsimd_state; bits [max : 128] for each of Z0-Z31 are
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* logically zero but not stored anywhere; P0-P15 and FFR are not
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* stored and have unspecified values from userspace's point of
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* view. For hygiene purposes, the kernel zeroes them on next use,
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* but userspace is discouraged from relying on this.
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*
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* task->thread.sve_state does not need to be non-NULL, valid or any
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* particular size: it must not be dereferenced.
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*
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* * FPSR and FPCR are always stored in task->fpsimd_state irrespctive of
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* whether TIF_SVE is clear or set, since these are not vector length
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* dependent.
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*/
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/*
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* Update current's FPSIMD/SVE registers from thread_struct.
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*
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* This function should be called only when the FPSIMD/SVE state in
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* thread_struct is known to be up to date, when preparing to enter
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* userspace.
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*
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* Softirqs (and preemption) must be disabled.
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*/
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static void task_fpsimd_load(void)
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{
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WARN_ON(!in_softirq() && !irqs_disabled());
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if (system_supports_sve() && test_thread_flag(TIF_SVE))
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sve_load_state(sve_pffr(current),
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¤t->thread.fpsimd_state.fpsr,
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sve_vq_from_vl(current->thread.sve_vl) - 1);
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else
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fpsimd_load_state(¤t->thread.fpsimd_state);
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if (system_supports_sve()) {
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/* Toggle SVE trapping for userspace if needed */
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if (test_thread_flag(TIF_SVE))
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sve_user_enable();
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else
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sve_user_disable();
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/* Serialised by exception return to user */
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}
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}
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/*
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* Ensure current's FPSIMD/SVE storage in thread_struct is up to date
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* with respect to the CPU registers.
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*
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* Softirqs (and preemption) must be disabled.
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*/
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static void task_fpsimd_save(void)
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{
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WARN_ON(!in_softirq() && !irqs_disabled());
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if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) {
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if (system_supports_sve() && test_thread_flag(TIF_SVE)) {
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if (WARN_ON(sve_get_vl() != current->thread.sve_vl)) {
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/*
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* Can't save the user regs, so current would
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* re-enter user with corrupt state.
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* There's no way to recover, so kill it:
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*/
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force_signal_inject(
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SIGKILL, 0, current_pt_regs(), 0);
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return;
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}
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sve_save_state(sve_pffr(current),
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¤t->thread.fpsimd_state.fpsr);
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} else
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fpsimd_save_state(¤t->thread.fpsimd_state);
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}
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}
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#define ZREG(sve_state, vq, n) ((char *)(sve_state) + \
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(SVE_SIG_ZREG_OFFSET(vq, n) - SVE_SIG_REGS_OFFSET))
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/*
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* Transfer the FPSIMD state in task->thread.fpsimd_state to
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* task->thread.sve_state.
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*
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* Task can be a non-runnable task, or current. In the latter case,
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* softirqs (and preemption) must be disabled.
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* task->thread.sve_state must point to at least sve_state_size(task)
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* bytes of allocated kernel memory.
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* task->thread.fpsimd_state must be up to date before calling this function.
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*/
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static void fpsimd_to_sve(struct task_struct *task)
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{
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unsigned int vq;
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void *sst = task->thread.sve_state;
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struct fpsimd_state const *fst = &task->thread.fpsimd_state;
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unsigned int i;
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if (!system_supports_sve())
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return;
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vq = sve_vq_from_vl(task->thread.sve_vl);
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for (i = 0; i < 32; ++i)
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memcpy(ZREG(sst, vq, i), &fst->vregs[i],
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sizeof(fst->vregs[i]));
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}
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#ifdef CONFIG_ARM64_SVE
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/*
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* Return how many bytes of memory are required to store the full SVE
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* state for task, given task's currently configured vector length.
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*/
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size_t sve_state_size(struct task_struct const *task)
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{
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return SVE_SIG_REGS_SIZE(sve_vq_from_vl(task->thread.sve_vl));
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}
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/*
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* Ensure that task->thread.sve_state is allocated and sufficiently large.
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*
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* This function should be used only in preparation for replacing
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* task->thread.sve_state with new data. The memory is always zeroed
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* here to prevent stale data from showing through: this is done in
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* the interest of testability and predictability: except in the
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* do_sve_acc() case, there is no ABI requirement to hide stale data
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* written previously be task.
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*/
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void sve_alloc(struct task_struct *task)
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{
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if (task->thread.sve_state) {
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memset(task->thread.sve_state, 0, sve_state_size(current));
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return;
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}
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/* This is a small allocation (maximum ~8KB) and Should Not Fail. */
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task->thread.sve_state =
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kzalloc(sve_state_size(task), GFP_KERNEL);
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/*
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* If future SVE revisions can have larger vectors though,
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* this may cease to be true:
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*/
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BUG_ON(!task->thread.sve_state);
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}
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/*
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* Called from the put_task_struct() path, which cannot get here
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* unless dead_task is really dead and not schedulable.
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*/
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void fpsimd_release_task(struct task_struct *dead_task)
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{
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__sve_free(dead_task);
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}
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#endif /* CONFIG_ARM64_SVE */
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/*
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* Trapped SVE access
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*
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* Storage is allocated for the full SVE state, the current FPSIMD
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* register contents are migrated across, and TIF_SVE is set so that
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* the SVE access trap will be disabled the next time this task
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* reaches ret_to_user.
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*
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* TIF_SVE should be clear on entry: otherwise, task_fpsimd_load()
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* would have disabled the SVE access trap for userspace during
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* ret_to_user, making an SVE access trap impossible in that case.
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*/
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asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs)
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{
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/* Even if we chose not to use SVE, the hardware could still trap: */
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if (unlikely(!system_supports_sve()) || WARN_ON(is_compat_task())) {
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force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
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return;
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}
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sve_alloc(current);
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local_bh_disable();
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task_fpsimd_save();
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fpsimd_to_sve(current);
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/* Force ret_to_user to reload the registers: */
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fpsimd_flush_task_state(current);
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set_thread_flag(TIF_FOREIGN_FPSTATE);
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if (test_and_set_thread_flag(TIF_SVE))
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WARN_ON(1); /* SVE access shouldn't have trapped */
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local_bh_enable();
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}
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/*
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* Trapped FP/ASIMD access.
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*/
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asmlinkage void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
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{
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/* TODO: implement lazy context saving/restoring */
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WARN_ON(1);
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}
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/*
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* Raise a SIGFPE for the current process.
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*/
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asmlinkage void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
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{
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siginfo_t info;
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unsigned int si_code = 0;
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if (esr & FPEXC_IOF)
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si_code = FPE_FLTINV;
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else if (esr & FPEXC_DZF)
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si_code = FPE_FLTDIV;
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else if (esr & FPEXC_OFF)
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si_code = FPE_FLTOVF;
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else if (esr & FPEXC_UFF)
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si_code = FPE_FLTUND;
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else if (esr & FPEXC_IXF)
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si_code = FPE_FLTRES;
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memset(&info, 0, sizeof(info));
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info.si_signo = SIGFPE;
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info.si_code = si_code;
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info.si_addr = (void __user *)instruction_pointer(regs);
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send_sig_info(SIGFPE, &info, current);
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}
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void fpsimd_thread_switch(struct task_struct *next)
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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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* Save the current FPSIMD state to memory, but only if whatever is in
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* the registers is in fact the most recent userland FPSIMD state of
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* 'current'.
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*/
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if (current->mm)
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task_fpsimd_save();
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if (next->mm) {
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/*
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* If we are switching to a task whose most recent userland
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* FPSIMD state is already in the registers of *this* cpu,
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* we can skip loading the state from memory. Otherwise, set
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* the TIF_FOREIGN_FPSTATE flag so the state will be loaded
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* upon the next return to userland.
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*/
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struct fpsimd_state *st = &next->thread.fpsimd_state;
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if (__this_cpu_read(fpsimd_last_state) == st
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&& st->cpu == smp_processor_id())
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clear_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
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else
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set_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
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}
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}
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void fpsimd_flush_thread(void)
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{
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int vl;
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if (!system_supports_fpsimd())
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return;
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local_bh_disable();
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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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if (system_supports_sve()) {
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clear_thread_flag(TIF_SVE);
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sve_free(current);
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/*
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* Reset the task vector length as required.
|
|
* This is where we ensure that all user tasks have a valid
|
|
* vector length configured: no kernel task can become a user
|
|
* task without an exec and hence a call to this function.
|
|
* If a bug causes this to go wrong, we make some noise and
|
|
* try to fudge thread.sve_vl to a safe value here.
|
|
*/
|
|
vl = current->thread.sve_vl;
|
|
|
|
if (vl == 0)
|
|
vl = SVE_VL_MIN;
|
|
|
|
if (WARN_ON(!sve_vl_valid(vl)))
|
|
vl = SVE_VL_MIN;
|
|
|
|
current->thread.sve_vl = vl;
|
|
}
|
|
|
|
set_thread_flag(TIF_FOREIGN_FPSTATE);
|
|
|
|
local_bh_enable();
|
|
}
|
|
|
|
/*
|
|
* Save the userland FPSIMD state of 'current' to memory, but only if the state
|
|
* currently held in the registers does in fact belong to 'current'
|
|
*
|
|
* Currently, SVE tasks can't exist, so just WARN in that case.
|
|
* Subsequent patches will add full SVE support here.
|
|
*/
|
|
void fpsimd_preserve_current_state(void)
|
|
{
|
|
if (!system_supports_fpsimd())
|
|
return;
|
|
|
|
local_bh_disable();
|
|
|
|
if (!test_thread_flag(TIF_FOREIGN_FPSTATE))
|
|
fpsimd_save_state(¤t->thread.fpsimd_state);
|
|
|
|
WARN_ON_ONCE(test_and_clear_thread_flag(TIF_SVE));
|
|
|
|
local_bh_enable();
|
|
}
|
|
|
|
/*
|
|
* Load the userland FPSIMD state of 'current' from memory, but only if the
|
|
* FPSIMD state already held in the registers is /not/ the most recent FPSIMD
|
|
* state of 'current'
|
|
*/
|
|
void fpsimd_restore_current_state(void)
|
|
{
|
|
if (!system_supports_fpsimd())
|
|
return;
|
|
|
|
local_bh_disable();
|
|
|
|
if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
|
|
struct fpsimd_state *st = ¤t->thread.fpsimd_state;
|
|
|
|
task_fpsimd_load();
|
|
__this_cpu_write(fpsimd_last_state, st);
|
|
st->cpu = smp_processor_id();
|
|
}
|
|
|
|
local_bh_enable();
|
|
}
|
|
|
|
/*
|
|
* Load an updated userland FPSIMD state for 'current' from memory and set the
|
|
* flag that indicates that the FPSIMD register contents are the most recent
|
|
* FPSIMD state of 'current'
|
|
*/
|
|
void fpsimd_update_current_state(struct fpsimd_state *state)
|
|
{
|
|
if (!system_supports_fpsimd())
|
|
return;
|
|
|
|
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);
|
|
st->cpu = smp_processor_id();
|
|
}
|
|
|
|
local_bh_enable();
|
|
}
|
|
|
|
/*
|
|
* Invalidate live CPU copies of task t's FPSIMD state
|
|
*/
|
|
void fpsimd_flush_task_state(struct task_struct *t)
|
|
{
|
|
t->thread.fpsimd_state.cpu = NR_CPUS;
|
|
}
|
|
|
|
#ifdef CONFIG_KERNEL_MODE_NEON
|
|
|
|
DEFINE_PER_CPU(bool, kernel_neon_busy);
|
|
EXPORT_PER_CPU_SYMBOL(kernel_neon_busy);
|
|
|
|
/*
|
|
* Kernel-side NEON support functions
|
|
*/
|
|
|
|
/*
|
|
* 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;
|
|
|
|
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);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
#ifdef CONFIG_EFI
|
|
|
|
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;
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* __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_EFI */
|
|
|
|
#endif /* CONFIG_KERNEL_MODE_NEON */
|
|
|
|
#ifdef CONFIG_CPU_PM
|
|
static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
|
|
unsigned long cmd, void *v)
|
|
{
|
|
switch (cmd) {
|
|
case CPU_PM_ENTER:
|
|
if (current->mm)
|
|
task_fpsimd_save();
|
|
this_cpu_write(fpsimd_last_state, NULL);
|
|
break;
|
|
case CPU_PM_EXIT:
|
|
if (current->mm)
|
|
set_thread_flag(TIF_FOREIGN_FPSTATE);
|
|
break;
|
|
case CPU_PM_ENTER_FAILED:
|
|
default:
|
|
return NOTIFY_DONE;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block fpsimd_cpu_pm_notifier_block = {
|
|
.notifier_call = fpsimd_cpu_pm_notifier,
|
|
};
|
|
|
|
static void __init fpsimd_pm_init(void)
|
|
{
|
|
cpu_pm_register_notifier(&fpsimd_cpu_pm_notifier_block);
|
|
}
|
|
|
|
#else
|
|
static inline void fpsimd_pm_init(void) { }
|
|
#endif /* CONFIG_CPU_PM */
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static int fpsimd_cpu_dead(unsigned int cpu)
|
|
{
|
|
per_cpu(fpsimd_last_state, cpu) = NULL;
|
|
return 0;
|
|
}
|
|
|
|
static inline void fpsimd_hotplug_init(void)
|
|
{
|
|
cpuhp_setup_state_nocalls(CPUHP_ARM64_FPSIMD_DEAD, "arm64/fpsimd:dead",
|
|
NULL, fpsimd_cpu_dead);
|
|
}
|
|
|
|
#else
|
|
static inline void fpsimd_hotplug_init(void) { }
|
|
#endif
|
|
|
|
/*
|
|
* FP/SIMD support code initialisation.
|
|
*/
|
|
static int __init fpsimd_init(void)
|
|
{
|
|
if (elf_hwcap & HWCAP_FP) {
|
|
fpsimd_pm_init();
|
|
fpsimd_hotplug_init();
|
|
} else {
|
|
pr_notice("Floating-point is not implemented\n");
|
|
}
|
|
|
|
if (!(elf_hwcap & HWCAP_ASIMD))
|
|
pr_notice("Advanced SIMD is not implemented\n");
|
|
|
|
return 0;
|
|
}
|
|
late_initcall(fpsimd_init);
|