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| author | Dave Martin <Dave.Martin@arm.com> | 2018-04-06 14:55:59 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2018-05-25 12:27:55 +0100 |
| commit | d179761519d9fe57ece975eaf8eec131547b9da3 (patch) | |
| tree | bd860f7853ffbd233d846625bb059d638a9da158 /arch | |
| parent | ceda9fff70e8b5939fa8882d1c497e55472a727f (diff) | |
| download | linux-d179761519d9fe57ece975eaf8eec131547b9da3.tar.bz2 | |
arm64: fpsimd: Generalise context saving for non-task contexts
In preparation for allowing non-task (i.e., KVM vcpu) FPSIMD
contexts to be handled by the fpsimd common code, this patch adapts
task_fpsimd_save() to save back the currently loaded context,
removing the explicit dependency on current.
The relevant storage to write back to in memory is now found by
examining the fpsimd_last_state percpu struct.
fpsimd_save() does nothing unless TIF_FOREIGN_FPSTATE is clear, and
fpsimd_last_state is updated under local_bh_disable() or
local_irq_disable() everywhere that TIF_FOREIGN_FPSTATE is cleared:
thus, fpsimd_save() will write back to the correct storage for the
loaded context.
No functional change.
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 9d853732f9f4..2d9a9e8ed826 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -270,13 +270,16 @@ static void task_fpsimd_load(void) } /* - * Ensure current's FPSIMD/SVE storage in thread_struct is up to date - * with respect to the CPU registers. + * Ensure FPSIMD/SVE storage in memory for the loaded context is up to + * date with respect to the CPU registers. * * Softirqs (and preemption) must be disabled. */ -static void task_fpsimd_save(void) +static void fpsimd_save(void) { + struct user_fpsimd_state *st = __this_cpu_read(fpsimd_last_state.st); + /* set by fpsimd_bind_to_cpu() */ + WARN_ON(!in_softirq() && !irqs_disabled()); if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { @@ -291,10 +294,9 @@ static void task_fpsimd_save(void) return; } - sve_save_state(sve_pffr(current), - ¤t->thread.uw.fpsimd_state.fpsr); + sve_save_state(sve_pffr(current), &st->fpsr); } else - fpsimd_save_state(¤t->thread.uw.fpsimd_state); + fpsimd_save_state(st); } } @@ -598,7 +600,7 @@ int sve_set_vector_length(struct task_struct *task, if (task == current) { local_bh_disable(); - task_fpsimd_save(); + fpsimd_save(); set_thread_flag(TIF_FOREIGN_FPSTATE); } @@ -837,7 +839,7 @@ asmlinkage void do_sve_acc(unsigned int esr, struct pt_regs *regs) local_bh_disable(); - task_fpsimd_save(); + fpsimd_save(); fpsimd_to_sve(current); /* Force ret_to_user to reload the registers: */ @@ -898,7 +900,7 @@ void fpsimd_thread_switch(struct task_struct *next) * 'current'. */ if (current->mm) - task_fpsimd_save(); + fpsimd_save(); if (next->mm) { /* @@ -980,7 +982,7 @@ void fpsimd_preserve_current_state(void) return; local_bh_disable(); - task_fpsimd_save(); + fpsimd_save(); local_bh_enable(); } @@ -1121,7 +1123,7 @@ void kernel_neon_begin(void) /* Save unsaved task fpsimd state, if any: */ if (current->mm) - task_fpsimd_save(); + fpsimd_save(); /* Invalidate any task state remaining in the fpsimd regs: */ fpsimd_flush_cpu_state(); @@ -1244,7 +1246,7 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self, switch (cmd) { case CPU_PM_ENTER: if (current->mm) - task_fpsimd_save(); + fpsimd_save(); fpsimd_flush_cpu_state(); break; case CPU_PM_EXIT: |