[PATCH 20/27] x86/fpu: Inline copy_user_to_fpregs_zeroing()

Sebastian Andrzej Siewior
2019-04-03T16:43:26Z

Start refactoring __fpu__restore_sig() by inlining
copy_user_to_fpregs_zeroing(). The orignal function remains and will be
used to restore from userland memory if possible.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/kernel/fpu/signal.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index c98c7bca13bc0..f733425c66d8d 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -337,11 +337,29 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
kfree(tmp);
return err;
} else {
+ int ret;
+
/*
* For 64-bit frames and 32-bit fsave frames, restore the user
* state to the registers directly (with exceptions handled).
*/
- if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {
+ if (use_xsave()) {
+ if ((unsigned long)buf_fx % 64 || fx_only) {
+ u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE;
+ copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+ ret = copy_user_to_fxregs(buf_fx);
+ } else {
+ u64 init_bv = xfeatures_mask & ~xfeatures;
+ if (unlikely(init_bv))
+ copy_kernel_to_xregs(&init_fpstate.xsave, init_bv);
+ ret = copy_user_to_xregs(buf_fx, xfeatures);
+ }
+ } else if (use_fxsr()) {
+ ret = copy_user_to_fxregs(buf_fx);
+ } else
+ ret = copy_user_to_fregs(buf_fx);
+
+ if (ret) {
fpu__clear(fpu);
return -1;
}
--
2.20.1