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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-08-22 12:06:21 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-08-29 11:05:01 +0200
commit7f79695cc1b6aa6d80a861780d9f8ce75d3dddcb (patch)
treedd34f15ed90df7e9920e29b753aa2ff0cf6feff3 /arch/s390/crypto
parent0eab11c7e0d30de14a15ccd8269eef238321a8e1 (diff)
s390/fpu: improve kernel_fpu_[begin|end]
In case of nested user of the FPU or vector registers in the kernel the current code uses the mask of the FPU/vector registers of the previous contexts to decide which registers to save and restore. E.g. if the previous context used KERNEL_VXR_V0V7 and the next context wants to use KERNEL_VXR_V24V31 the first 8 vector registers are stored to the FPU state structure. But this is not necessary as the next context does not use these registers. Rework the FPU/vector register save and restore code. The new code does a few things differently: 1) A lowcore field is used instead of a per-cpu variable. 2) The kernel_fpu_end function now has two parameters just like kernel_fpu_begin. The register flags are required by both functions to save / restore the minimal register set. 3) The inline functions kernel_fpu_begin/kernel_fpu_end now do the update of the register masks. If the user space FPU registers have already been stored neither save_fpu_regs nor the __kernel_fpu_begin/__kernel_fpu_end functions have to be called for the first context. In this case kernel_fpu_begin adds 7 instructions and kernel_fpu_end adds 4 instructions. 3) The inline assemblies in __kernel_fpu_begin / __kernel_fpu_end to save / restore the vector registers are simplified a bit. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/crypto')
-rw-r--r--arch/s390/crypto/crc32-vx.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/crypto/crc32-vx.c b/arch/s390/crypto/crc32-vx.c
index 2bad9d837029..992e630c227b 100644
--- a/arch/s390/crypto/crc32-vx.c
+++ b/arch/s390/crypto/crc32-vx.c
@@ -67,7 +67,7 @@ u32 crc32c_le_vgfm_16(u32 crc, unsigned char const *buf, size_t size);
\
kernel_fpu_begin(&vxstate, KERNEL_VXR_LOW); \
crc = ___crc32_vx(crc, data, aligned); \
- kernel_fpu_end(&vxstate); \
+ kernel_fpu_end(&vxstate, KERNEL_VXR_LOW); \
\
if (remaining) \
crc = ___crc32_sw(crc, data + aligned, remaining); \