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authorDave Martin <Dave.Martin@arm.com>2017-08-09 11:43:28 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2017-08-09 15:05:59 +0100
commit66c3ec5a712005625437474cf5a04148d7890350 (patch)
tree38274244ae2d7531ce45045cbfb2b64201dd69fb /arch/arm64/include/asm/simd.h
parentarm64: neon: Export kernel_neon_busy to loadable modules (diff)
downloadlinux-dev-66c3ec5a712005625437474cf5a04148d7890350.tar.xz
linux-dev-66c3ec5a712005625437474cf5a04148d7890350.zip
arm64: neon: Forbid when irqs are disabled
Currently, may_use_simd() can return true if IRQs are disabled. If the caller goes ahead and calls kernel_neon_begin(), this can result in use of local_bh_enable() in an unsafe context. In particular, __efi_fpsimd_begin() may do this when calling EFI as part of system shutdown. This patch ensures that callers don't think they can use kernel_neon_begin() in such a context. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to '')
-rw-r--r--arch/arm64/include/asm/simd.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/simd.h b/arch/arm64/include/asm/simd.h
index 5a1a927b74a2..fa8b3fe932e6 100644
--- a/arch/arm64/include/asm/simd.h
+++ b/arch/arm64/include/asm/simd.h
@@ -10,6 +10,7 @@
#define __ASM_SIMD_H
#include <linux/compiler.h>
+#include <linux/irqflags.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
#include <linux/types.h>
@@ -40,7 +41,8 @@ static __must_check inline bool may_use_simd(void)
* can't migrate to another CPU and spuriously see it become
* false.
*/
- return !in_irq() && !in_nmi() && !raw_cpu_read(kernel_neon_busy);
+ return !in_irq() && !irqs_disabled() && !in_nmi() &&
+ !raw_cpu_read(kernel_neon_busy);
}
#else /* ! CONFIG_KERNEL_MODE_NEON */