diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2018-06-13 15:38:55 +0200 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2018-06-13 15:53:03 +0200 |
| commit | 8459c35d8b739f06f0bcbf2f5e50c982a17a50c8 (patch) | |
| tree | 00b59a2887c737a4227d384ef2a7618d65117f20 /src/crypto/chacha20poly1305.h | |
| parent | d563cc4eaf2a772ea9286ee36163c5e1d916af56 (diff) | |
chacha20poly1305: use slow crypto on -rt kernels
In rt kernels, spinlocks call schedule(), which means preemption can't
be disabled. The FPU disables preemption. Hence, we can either
restructure things to move the calls to kernel_fpu_begin/end to be
really close to the actual crypto routines, or we can do the slower
lazier solution of just not using the FPU at all on -rt kernels. This
patch goes with the latter lazy solution.
The reason why we don't place the calls to kernel_fpu_begin/end close to
the crypto routines in the first place is that they're very expensive,
as it usually involves a call to XSAVE. So on sane kernels, we benefit
from only having to call it once.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'src/crypto/chacha20poly1305.h')
| -rw-r--r-- | src/crypto/chacha20poly1305.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/crypto/chacha20poly1305.h b/src/crypto/chacha20poly1305.h index 39919cd..f19bf52 100644 --- a/src/crypto/chacha20poly1305.h +++ b/src/crypto/chacha20poly1305.h @@ -56,7 +56,7 @@ bool __must_check xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t static inline bool chacha20poly1305_init_simd(void) { bool have_simd = false; -#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) +#if defined(CONFIG_X86_64) && !defined(CONFIG_UML) && !defined(CONFIG_PREEMPT_RT_BASE) have_simd = irq_fpu_usable(); if (have_simd) kernel_fpu_begin(); |