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* [PATCH 0/2] x86/fpu: minor cleanups
       [not found]     ` <20150302174818.GA16886@redhat.com>
@ 2015-03-02 18:32       ` Oleg Nesterov
  2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
  2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
  0 siblings, 2 replies; 12+ messages in thread
From: Oleg Nesterov @ 2015-03-02 18:32 UTC (permalink / raw)
  To: Tavis Ormandy, Borislav Petkov, Ingo Molnar
  Cc: Rik van Riel, Andy Lutomirski, Linus Torvalds, linux-kernel

add lkml/cc's.

On 03/02, Oleg Nesterov wrote:
>
> Btw, why xstateregs_get/set() looks so confusing? The comment says
> "Copy the 48bytes defined by the software first into the xstate" but the
> code uses ->fxsave. Yes, this is the same memory, but still. I'll send
> the cosmetic cleanup.
>
> Or fx_finit()... Again, memset(fx, 0, xstate_size) is correct but only
> because of the current layout. I think this needs a cleanup too.

Of course this is purely cosmetic, but still...

Oleg.


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave
  2015-03-02 18:32       ` [PATCH 0/2] x86/fpu: minor cleanups Oleg Nesterov
@ 2015-03-02 18:32         ` Oleg Nesterov
  2015-03-03 19:23           ` Rik van Riel
                             ` (2 more replies)
  2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
  1 sibling, 3 replies; 12+ messages in thread
From: Oleg Nesterov @ 2015-03-02 18:32 UTC (permalink / raw)
  To: Tavis Ormandy, Borislav Petkov, Ingo Molnar
  Cc: Rik van Riel, Andy Lutomirski, Linus Torvalds, linux-kernel

Cosmetic. xstateregs_get() and xstateregs_set() abuse ->fxsave to access
xsave->i387.sw_reserved. This 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 "struct xsave_struct *"
local.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 arch/x86/kernel/i387.c |   25 +++++++++----------------
 1 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 8e070a6..4b12df8 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -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;
 }
 
-- 
1.5.5.1



^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths
  2015-03-02 18:32       ` [PATCH 0/2] x86/fpu: minor cleanups Oleg Nesterov
  2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
@ 2015-03-02 18:32         ` Oleg Nesterov
  2015-03-03 22:01           ` Rik van Riel
                             ` (2 more replies)
  1 sibling, 3 replies; 12+ messages in thread
From: Oleg Nesterov @ 2015-03-02 18:32 UTC (permalink / raw)
  To: Tavis Ormandy, Borislav Petkov, Ingo Molnar
  Cc: Rik van Riel, Andy Lutomirski, Linus Torvalds, linux-kernel

fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
memory.

And note that both memset()'s look confusing. Yes, offsetof() is 0
for ->fxsave or ->fsave, but it would be more clean to turn them into
a single memset() which nullifies fpu->state.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
 arch/x86/include/asm/fpu-internal.h |    1 -
 arch/x86/kernel/i387.c              |    3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 02f2e08..8809b5a 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -107,7 +107,6 @@ static __always_inline __pure bool use_fxsr(void)
 
 static inline void fx_finit(struct i387_fxsave_struct *fx)
 {
-	memset(fx, 0, xstate_size);
 	fx->cwd = 0x37f;
 	fx->mxcsr = MXCSR_DEFAULT;
 }
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 4b12df8..9b7759f 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -224,11 +224,12 @@ void fpu_finit(struct fpu *fpu)
 		return;
 	}
 
+	memset(fpu->state, 0, xstate_size);
+
 	if (cpu_has_fxsr) {
 		fx_finit(&fpu->state->fxsave);
 	} else {
 		struct i387_fsave_struct *fp = &fpu->state->fsave;
-		memset(fp, 0, xstate_size);
 		fp->cwd = 0xffff037fu;
 		fp->swd = 0xffff0000u;
 		fp->twd = 0xffffffffu;
-- 
1.5.5.1



^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave
  2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
@ 2015-03-03 19:23           ` Rik van Riel
  2015-03-04 10:30           ` Borislav Petkov
  2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Change xstateregs_get()/set() to use -> xsave.i387 " tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: Rik van Riel @ 2015-03-03 19:23 UTC (permalink / raw)
  To: Oleg Nesterov, Tavis Ormandy, Borislav Petkov, Ingo Molnar
  Cc: Andy Lutomirski, Linus Torvalds, linux-kernel

On 03/02/2015 01:32 PM, Oleg Nesterov wrote:
> Cosmetic. xstateregs_get() and xstateregs_set() abuse ->fxsave to access
> xsave->i387.sw_reserved. This 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 "struct xsave_struct *"
> local.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Reviewed-by: Rik van Riel <riel@redhat.com>

-- 
All rights reversed

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths
  2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
@ 2015-03-03 22:01           ` Rik van Riel
  2015-03-04 11:38           ` Borislav Petkov
  2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Factor out memset(xstate, 0) in fpu_finit( ) paths tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: Rik van Riel @ 2015-03-03 22:01 UTC (permalink / raw)
  To: Oleg Nesterov, Tavis Ormandy, Borislav Petkov, Ingo Molnar
  Cc: Andy Lutomirski, Linus Torvalds, linux-kernel

On 03/02/2015 01:32 PM, Oleg Nesterov wrote:
> fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
> alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
> memory.
> 
> And note that both memset()'s look confusing. Yes, offsetof() is 0
> for ->fxsave or ->fsave, but it would be more clean to turn them into
> a single memset() which nullifies fpu->state.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Rik van Riel <riel@redhat.com>

-- 
All rights reversed

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave
  2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
  2015-03-03 19:23           ` Rik van Riel
@ 2015-03-04 10:30           ` Borislav Petkov
  2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Change xstateregs_get()/set() to use -> xsave.i387 " tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: Borislav Petkov @ 2015-03-04 10:30 UTC (permalink / raw)
  To: Oleg Nesterov
  Cc: Tavis Ormandy, Ingo Molnar, Rik van Riel, Andy Lutomirski,
	Linus Torvalds, linux-kernel

On Mon, Mar 02, 2015 at 07:32:37PM +0100, Oleg Nesterov wrote:
> Cosmetic. xstateregs_get() and xstateregs_set() abuse ->fxsave to access
> xsave->i387.sw_reserved. This 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 "struct xsave_struct *"
> local.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

^ permalink raw reply	[flat|nested] 12+ messages in thread

* Re: [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths
  2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
  2015-03-03 22:01           ` Rik van Riel
@ 2015-03-04 11:38           ` Borislav Petkov
  2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Factor out memset(xstate, 0) in fpu_finit( ) paths tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: Borislav Petkov @ 2015-03-04 11:38 UTC (permalink / raw)
  To: Oleg Nesterov
  Cc: Tavis Ormandy, Ingo Molnar, Rik van Riel, Andy Lutomirski,
	Linus Torvalds, linux-kernel

On Mon, Mar 02, 2015 at 07:32:57PM +0100, Oleg Nesterov wrote:
> fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
> alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
> memory.
> 
> And note that both memset()'s look confusing. Yes, offsetof() is 0
> for ->fxsave or ->fsave, but it would be more clean to turn them into
> a single memset() which nullifies fpu->state.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

^ permalink raw reply	[flat|nested] 12+ messages in thread

* [GIT PULL] x86/fpu cleanups
@ 2015-03-09 18:08 Borislav Petkov
  2015-03-10  6:06 ` [PATCH 1/2] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave Borislav Petkov
  0 siblings, 1 reply; 12+ messages in thread
From: Borislav Petkov @ 2015-03-09 18:08 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: Oleg Nesterov, x86-ml, lkml

Hi Ingo,

please pull two more cleanups to the FPU insanity from Oleg.

So this is *not* the urgent stuff - the urgent stuff will come later.
This is the unload-some-more-onto-tip stuff which can be safely queued
for 4.1 and I can forget about it here. :)

Thanks.

---
The following changes since commit ae486033b980346eb6a77240101210cb66924a91:

  Merge tag 'tip_x86_fpu' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/fpu (2015-03-03 12:12:15 +0100)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp.git tags/tip_x86_fpu_2

for you to fetch changes up to 9ed010d31f173be786f0398a64f08bb4a0300c3b:

  x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths (2015-03-04 11:57:46 +0100)

----------------------------------------------------------------
Two more cleanups from Oleg.

----------------------------------------------------------------
Oleg Nesterov (2):
      x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave
      x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths

 arch/x86/include/asm/fpu-internal.h |  1 -
 arch/x86/kernel/i387.c              | 28 +++++++++++-----------------
 2 files changed, 11 insertions(+), 18 deletions(-)

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH 1/2] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave
  2015-03-09 18:08 [GIT PULL] x86/fpu cleanups Borislav Petkov
@ 2015-03-10  6:06 ` Borislav Petkov
  2015-03-10  6:06   ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Borislav Petkov
  0 siblings, 1 reply; 12+ messages in thread
From: Borislav Petkov @ 2015-03-10  6:06 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: X86 ML, LKML

From: Oleg Nesterov <oleg@redhat.com>

This is a cosmetic change: xstateregs_get() and xstateregs_set() abuse
->fxsave to access xsave->i387.sw_reserved. This 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 "struct xsave_struct
*" local.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: <x86@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150302183237.GB23085@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/i387.c | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 8416b5f85806..03cc0add8694 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -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;
 }
 
-- 
2.2.0.33.gc18b867


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths
  2015-03-10  6:06 ` [PATCH 1/2] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave Borislav Petkov
@ 2015-03-10  6:06   ` Borislav Petkov
  0 siblings, 0 replies; 12+ messages in thread
From: Borislav Petkov @ 2015-03-10  6:06 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: X86 ML, LKML

From: Oleg Nesterov <oleg@redhat.com>

fx_finit() has 2 users but only fpu_finit() needs to nullify xstate,
alloc_bootmem_align() in setup_init_fpu_buf() returns zero-filled
memory.

And note that both memset()'s look confusing. Yes, offsetof() is 0
for ->fxsave or ->fsave, but it would be more clean to turn them into
a single memset() which nullifies fpu->state.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tavis Ormandy <taviso@google.com>
Cc: <x86@kernel.org>
Link: http://lkml.kernel.org/r/20150302183257.GC23085@redhat.com
Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/include/asm/fpu-internal.h | 1 -
 arch/x86/kernel/i387.c              | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 61609b963eab..5fa1be21ac2a 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -135,7 +135,6 @@ static __always_inline __pure bool use_fxsr(void)
 
 static inline void fx_finit(struct i387_fxsave_struct *fx)
 {
-	memset(fx, 0, xstate_size);
 	fx->cwd = 0x37f;
 	fx->mxcsr = MXCSR_DEFAULT;
 }
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 03cc0add8694..0f3de6674ae3 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -224,11 +224,12 @@ void fpu_finit(struct fpu *fpu)
 		return;
 	}
 
+	memset(fpu->state, 0, xstate_size);
+
 	if (cpu_has_fxsr) {
 		fx_finit(&fpu->state->fxsave);
 	} else {
 		struct i387_fsave_struct *fp = &fpu->state->fsave;
-		memset(fp, 0, xstate_size);
 		fp->cwd = 0xffff037fu;
 		fp->swd = 0xffff0000u;
 		fp->twd = 0xffffffffu;
-- 
2.2.0.33.gc18b867


^ permalink raw reply	[flat|nested] 12+ messages in thread

* [tip:x86/fpu] x86/fpu: Change xstateregs_get()/set() to use -> xsave.i387 rather than ->fxsave
  2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
  2015-03-03 19:23           ` Rik van Riel
  2015-03-04 10:30           ` Borislav Petkov
@ 2015-03-10 10:08           ` tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: tip-bot for Oleg Nesterov @ 2015-03-10 10:08 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: luto, riel, oleg, bp, hpa, taviso, linux-kernel, mingo, bp,
	torvalds, tglx

Commit-ID:  e7f180dcd8ab48f18b20d7e8a7e9b39192bdf8e0
Gitweb:     http://git.kernel.org/tip/e7f180dcd8ab48f18b20d7e8a7e9b39192bdf8e0
Author:     Oleg Nesterov <oleg@redhat.com>
AuthorDate: Tue, 10 Mar 2015 07:06:24 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 10 Mar 2015 07:14:31 +0100

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

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>
---
 arch/x86/kernel/i387.c | 25 +++++++++----------------
 1 file changed, 9 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 8416b5f..03cc0ad 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -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;
 }
 

^ permalink raw reply	[flat|nested] 12+ messages in thread

* [tip:x86/fpu] x86/fpu: Factor out memset(xstate, 0) in fpu_finit( ) paths
  2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
  2015-03-03 22:01           ` Rik van Riel
  2015-03-04 11:38           ` Borislav Petkov
@ 2015-03-10 10:08           ` tip-bot for Oleg Nesterov
  2 siblings, 0 replies; 12+ messages in thread
From: tip-bot for Oleg Nesterov @ 2015-03-10 10:08 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: torvalds, linux-kernel, tglx, luto, bp, bp, taviso, oleg, hpa,
	mingo, riel

Commit-ID:  1d23c4518b1f3a03c278f23333149245c178d2a6
Gitweb:     http://git.kernel.org/tip/1d23c4518b1f3a03c278f23333149245c178d2a6
Author:     Oleg Nesterov <oleg@redhat.com>
AuthorDate: Tue, 10 Mar 2015 07:06:25 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 10 Mar 2015 07:14:31 +0100

x86/fpu: Factor out memset(xstate, 0) in fpu_finit() paths

fx_finit() has two users but only fpu_finit() needs to clear
xstate, alloc_bootmem_align() in setup_init_fpu_buf() returns
zero-filled memory.

And note that both memset()'s look confusing. Yes, offsetof() is
0 for ->fxsave or ->fsave, but it would be cleaner to turn
them into a single memset() which zeroes fpu->state.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-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/1425967585-4725-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/20150302183257.GC23085@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/fpu-internal.h | 1 -
 arch/x86/kernel/i387.c              | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 61609b9..5fa1be2 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -135,7 +135,6 @@ static __always_inline __pure bool use_fxsr(void)
 
 static inline void fx_finit(struct i387_fxsave_struct *fx)
 {
-	memset(fx, 0, xstate_size);
 	fx->cwd = 0x37f;
 	fx->mxcsr = MXCSR_DEFAULT;
 }
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 03cc0ad..0f3de66 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -224,11 +224,12 @@ void fpu_finit(struct fpu *fpu)
 		return;
 	}
 
+	memset(fpu->state, 0, xstate_size);
+
 	if (cpu_has_fxsr) {
 		fx_finit(&fpu->state->fxsave);
 	} else {
 		struct i387_fsave_struct *fp = &fpu->state->fsave;
-		memset(fp, 0, xstate_size);
 		fp->cwd = 0xffff037fu;
 		fp->swd = 0xffff0000u;
 		fp->twd = 0xffffffffu;

^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2015-03-10 10:08 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-03-09 18:08 [GIT PULL] x86/fpu cleanups Borislav Petkov
2015-03-10  6:06 ` [PATCH 1/2] x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave Borislav Petkov
2015-03-10  6:06   ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Borislav Petkov
     [not found] <CAJ_zFkJkHpU4Y8wrrZjO0VnhzUVqJfyrLmNfRsBRT29bgbDSHg@mail.gmail.com>
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2015-03-02 18:32       ` [PATCH 0/2] x86/fpu: minor cleanups Oleg Nesterov
2015-03-02 18:32         ` [PATCH 1/2] x86/regsets: change xstateregs_get/set to use ->xsave.i387 rather than ->fxsave Oleg Nesterov
2015-03-03 19:23           ` Rik van Riel
2015-03-04 10:30           ` Borislav Petkov
2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Change xstateregs_get()/set() to use -> xsave.i387 " tip-bot for Oleg Nesterov
2015-03-02 18:32         ` [PATCH 2/2] x86/fpu: factor out memset(xstate, 0) in fpu_finit() paths Oleg Nesterov
2015-03-03 22:01           ` Rik van Riel
2015-03-04 11:38           ` Borislav Petkov
2015-03-10 10:08           ` [tip:x86/fpu] x86/fpu: Factor out memset(xstate, 0) in fpu_finit( ) paths tip-bot for Oleg Nesterov

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