Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave

Browse source 
This is a cosmetic change: xstateregs_get() and xstateregs_set()
abuse ->fxsave to access xsave->i387.sw_reserved.

This practice is correct, ->fxsave and xsave->i387 share the same memory,
but IMHO this looks confusing.

And we can make this code more readable if we add a
"struct xsave_struct *" local variable as well.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425967585-4725-1-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/20150302183237.GB23085@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Oleg Nesterov 2015-03-10 07:06:24 +01:00 committed by Ingo Molnar
parent ae486033b9
commit e7f180dcd8
1 changed files with 9 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
arch/x86/kernel/i387.c
View file

@ -339,6 +339,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
struct xsave_struct *xsave = &target->thread.fpu.state->xsave;
int ret;
if (!cpu_has_xsave)
@ -353,14 +354,12 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
* memory layout in the thread struct, so that we can copy the entire
* xstateregs to the user using one user_regset_copyout().
*/
memcpy(&target->thread.fpu.state->fxsave.sw_reserved,
xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
memcpy(&xsave->i387.sw_reserved,
xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
/*
* Copy the xstate memory layout.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.fpu.state->xsave, 0, -1);
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
return ret;
}
@ -368,8 +367,8 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
struct xsave_struct *xsave = &target->thread.fpu.state->xsave;
int ret;
struct xsave_hdr_struct *xsave_hdr;
if (!cpu_has_xsave)
return -ENODEV;
@ -378,22 +377,16 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
if (ret)
return ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.fpu.state->xsave, 0, -1);
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
/*
* mxcsr reserved bits must be masked to zero for security reasons.
*/
target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask;
xsave_hdr = &target->thread.fpu.state->xsave.xsave_hdr;
xsave_hdr->xstate_bv &= pcntxt_mask;
xsave->i387.mxcsr &= mxcsr_feature_mask;
xsave->xsave_hdr.xstate_bv &= pcntxt_mask;
/*
* These bits must be zero.
*/
memset(xsave_hdr->reserved, 0, 48);
memset(&xsave->xsave_hdr.reserved, 0, 48);
return ret;
}