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author | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-02-24 15:26:29 +0100 |
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committer | Ard Biesheuvel <ard.biesheuvel@linaro.org> | 2014-05-08 11:31:57 +0200 |
commit | 190f1ca85d071114930dd7abe6b5d103e9d5572f (patch) | |
tree | 27344d61659e775df00892c8a13ae2473aad29b1 /arch/arm64/kernel/fpsimd.c | |
parent | 005f78cd88494457ed38ce817f4e3fe5d372f0cb (diff) | |
download | linux-stable-190f1ca85d071114930dd7abe6b5d103e9d5572f.tar.gz linux-stable-190f1ca85d071114930dd7abe6b5d103e9d5572f.tar.bz2 linux-stable-190f1ca85d071114930dd7abe6b5d103e9d5572f.zip |
arm64: add support for kernel mode NEON in interrupt context
This patch modifies kernel_neon_begin() and kernel_neon_end(), so
they may be called from any context. To address the case where only
a couple of registers are needed, kernel_neon_begin_partial(u32) is
introduced which takes as a parameter the number of bottom 'n' NEON
q-registers required. To mark the end of such a partial section, the
regular kernel_neon_end() should be used.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Diffstat (limited to 'arch/arm64/kernel/fpsimd.c')
-rw-r--r-- | arch/arm64/kernel/fpsimd.c | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 5ae89303c3ab..ad8aebb1cdef 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -218,29 +218,45 @@ 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); + /* * Kernel-side NEON support functions */ -void kernel_neon_begin(void) +void kernel_neon_begin_partial(u32 num_regs) { - /* Avoid using the NEON in interrupt context */ - BUG_ON(in_interrupt()); - preempt_disable(); + if (in_interrupt()) { + struct fpsimd_partial_state *s = this_cpu_ptr( + in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate); - /* - * 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. - */ - 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(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); + } } -EXPORT_SYMBOL(kernel_neon_begin); +EXPORT_SYMBOL(kernel_neon_begin_partial); void kernel_neon_end(void) { - preempt_enable(); + 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(); + } } EXPORT_SYMBOL(kernel_neon_end); |