Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1397383 > unrolled thread

[PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-09 23:00 +0200
    Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for  xstate size in signal context Borislav Petkov <bp@suse.de> - 2016-05-10 13:10 +0200
      Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for  xstate size in signal context Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-10 18:10 +0200
        Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for  xstate size in signal context Borislav Petkov <bp@suse.de> - 2016-05-10 18:30 +0200
          Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for  xstate size in signal context Yu-cheng Yu <yu-cheng.yu@intel.com> - 2016-05-10 18:40 +0200

#1397383 — [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

If "xsaves" is enabled, kernel always uses compacted format of xsave area.
But user space still uses standard format of xsave area. Thus, xstate size
in kernel's xsave area is smaller than xstate size in user's xsave area.
The xstate in signal frame should be in standard format for user's signal
handler to access.

In no "xsaves" case, xsave area in both user space and kernel space are in
standard format. Therefore, user's and kernel's xstate sizes are equal.

In "xsaves" case, xsave area in user space is in standard format while
xsave area in kernel space is in compacted format. Therefore, kernel's
xstate size is smaller than user's xstate size.

So here is the problem: currently kernel assumes its own xstate size is
signal frame's xstate size. This is not a problem in no "xsaves" case.
It is an issue in "xsaves" case because kernel's xstate size is smaller
than user's xstate size. In fpu__alloc_mathframe(), a smaller fpstate
buffer is allocated for the standard format xstate in signal frame.
Then kernel saves only part of xstate registers into this smaller
user's fpstate buffer and user will see part of the xstate registers in
signal context. Similar issue happens after returning from signal handler:
kernel will only restore part of xstate registers from user's fpstate
buffer in signal frame.

This patch defines and uses user_xstate_size for xstate size in signal
frame. It's read from returned value in ebx from CPUID leaf 0x0D subleaf
0x0. This is maximum size required by enabled states in XCR0 and may be
different from ecx when states at the end of the xsave area are not
enabled. This value indicates the size required for XSAVE to save all
supported user states in legacy/standard format.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
---
 arch/x86/include/asm/fpu/xstate.h |  1 -
 arch/x86/include/asm/processor.h  |  1 +
 arch/x86/kernel/fpu/init.c        |  5 ++-
 arch/x86/kernel/fpu/signal.c      | 26 ++++++++++----
 arch/x86/kernel/fpu/xstate.c      | 71 ++++++++++++++++++++++++---------------
 5 files changed, 67 insertions(+), 37 deletions(-)

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 38951b0..16df2c4 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -39,7 +39,6 @@
 #define REX_PREFIX
 #endif
 
-extern unsigned int xstate_size;
 extern u64 xfeatures_mask;
 extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
 
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 9264476..132b4ca 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -368,6 +368,7 @@ DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
 #endif	/* X86_64 */
 
 extern unsigned int xstate_size;
+extern unsigned int user_xstate_size;
 
 struct perf_event;
 
diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index 54c86ff..7ea80c2 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -195,7 +195,7 @@ static void __init fpu__init_task_struct_size(void)
 }
 
 /*
- * Set up the xstate_size based on the legacy FPU context size.
+ * Set up the user and kernel xstate_size based on the legacy FPU context size.
  *
  * We set this up first, and later it will be overwritten by
  * fpu__init_system_xstate() if the CPU knows about xstates.
@@ -226,6 +226,9 @@ static void __init fpu__init_system_xstate_size_legacy(void)
 		else
 			xstate_size = sizeof(struct fregs_state);
 	}
+
+	user_xstate_size = xstate_size;
+
 	/*
 	 * Quirk: we don't yet handle the XSAVES* instructions
 	 * correctly, as we don't correctly convert between
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 31c6a60..ee6d662 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -31,7 +31,7 @@ static inline int check_for_xstate(struct fxregs_state __user *buf,
 	/* Check for the first magic field and other error scenarios. */
 	if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
 	    fx_sw->xstate_size < min_xstate_size ||
-	    fx_sw->xstate_size > xstate_size ||
+	    fx_sw->xstate_size > user_xstate_size ||
 	    fx_sw->xstate_size > fx_sw->extended_size)
 		return -1;
 
@@ -88,7 +88,7 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
 	if (!use_xsave())
 		return err;
 
-	err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
+	err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + user_xstate_size));
 
 	/*
 	 * Read the xfeatures which we copied (directly from the cpu or
@@ -125,7 +125,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
 	else
 		err = copy_fregs_to_user((struct fregs_state __user *) buf);
 
-	if (unlikely(err) && __clear_user(buf, xstate_size))
+	if (unlikely(err) && __clear_user(buf, user_xstate_size))
 		err = -EFAULT;
 	return err;
 }
@@ -175,8 +175,19 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 		if (ia32_fxstate)
 			copy_fxregs_to_kernel(&tsk->thread.fpu);
 	} else {
+		/*
+		 * It is a *bug* if kernel uses compacted-format for xsave
+		 * area and we copy it out directly to a signal frame. It
+		 * should have been handled above by saving the registers
+		 * directly.
+		 */
+		if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+			WARN_ONCE(1, "x86/fpu: saving compacted-format xsave area to a signal frame!\n");
+			return -1;
+		}
+
 		fpstate_sanitize_xstate(&tsk->thread.fpu);
-		if (__copy_to_user(buf_fx, xsave, xstate_size))
+		if (__copy_to_user(buf_fx, xsave, user_xstate_size))
 			return -1;
 	}
 
@@ -341,7 +352,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 
 static inline int xstate_sigframe_size(void)
 {
-	return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
+	return use_xsave() ? user_xstate_size + FP_XSTATE_MAGIC2_SIZE :
+			user_xstate_size;
 }
 
 /*
@@ -385,12 +397,12 @@ fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
  */
 void fpu__init_prepare_fx_sw_frame(void)
 {
-	int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
+	int size = user_xstate_size + FP_XSTATE_MAGIC2_SIZE;
 
 	fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
 	fx_sw_reserved.extended_size = size;
 	fx_sw_reserved.xfeatures = xfeatures_mask;
-	fx_sw_reserved.xstate_size = xstate_size;
+	fx_sw_reserved.xstate_size = user_xstate_size;
 
 	if (config_enabled(CONFIG_IA32_EMULATION) ||
 	    config_enabled(CONFIG_X86_32)) {
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index b48ef35..d8aa7d2 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -43,6 +43,8 @@ static unsigned int xstate_offsets[XFEATURE_MAX] = { [ 0 ... XFEATURE_MAX - 1] =
 static unsigned int xstate_sizes[XFEATURE_MAX]   = { [ 0 ... XFEATURE_MAX - 1] = -1};
 static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8];
 
+unsigned int user_xstate_size;
+
 /*
  * Clear all of the X86_FEATURE_* bits that are unavailable
  * when the CPU has no XSAVE support.
@@ -171,7 +173,7 @@ void fpstate_sanitize_xstate(struct fpu *fpu)
 	 */
 	while (xfeatures) {
 		if (xfeatures & 0x1) {
-			int offset = xstate_offsets[feature_bit];
+			int offset = xstate_comp_offsets[feature_bit];
 			int size = xstate_sizes[feature_bit];
 
 			memcpy((void *)fx + offset,
@@ -533,8 +535,9 @@ static void do_extra_xstate_size_checks(void)
 	XSTATE_WARN_ON(paranoid_xstate_size != xstate_size);
 }
 
+
 /*
- * Calculate total size of enabled xstates in XCR0/xfeatures_mask.
+ * Get total size of enabled xstates in XCR0/xfeatures_mask.
  *
  * Note the SDM's wording here.  "sub-function 0" only enumerates
  * the size of the *user* states.  If we use it to size a buffer
@@ -544,34 +547,33 @@ static void do_extra_xstate_size_checks(void)
  * Note that we do not currently set any bits on IA32_XSS so
  * 'XCR0 | IA32_XSS == XCR0' for now.
  */
-static unsigned int __init calculate_xstate_size(void)
+static unsigned int __init get_xsaves_size(void)
 {
 	unsigned int eax, ebx, ecx, edx;
-	unsigned int calculated_xstate_size;
+	/*
+	 * - CPUID function 0DH, sub-function 1:
+	 *    EBX enumerates the size (in bytes) required by
+	 *    the XSAVES instruction for an XSAVE area
+	 *    containing all the state components
+	 *    corresponding to bits currently set in
+	 *    XCR0 | IA32_XSS.
+	 */
+	cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
+	return ebx;
+}
 
-	if (!cpu_has_xsaves) {
-		/*
-		 * - CPUID function 0DH, sub-function 0:
-		 *    EBX enumerates the size (in bytes) required by
-		 *    the XSAVE instruction for an XSAVE area
-		 *    containing all the *user* state components
-		 *    corresponding to bits currently set in XCR0.
-		 */
-		cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
-		calculated_xstate_size = ebx;
-	} else {
-		/*
-		 * - CPUID function 0DH, sub-function 1:
-		 *    EBX enumerates the size (in bytes) required by
-		 *    the XSAVES instruction for an XSAVE area
-		 *    containing all the state components
-		 *    corresponding to bits currently set in
-		 *    XCR0 | IA32_XSS.
-		 */
-		cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
-		calculated_xstate_size = ebx;
-	}
-	return calculated_xstate_size;
+static unsigned int __init get_xsave_size(void)
+{
+	unsigned int eax, ebx, ecx, edx;
+	/*
+	 * - CPUID function 0DH, sub-function 0:
+	 *    EBX enumerates the size (in bytes) required by
+	 *    the XSAVE instruction for an XSAVE area
+	 *    containing all the *user* state components
+	 *    corresponding to bits currently set in XCR0.
+	 */
+	cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
+	return ebx;
 }
 
 /*
@@ -591,7 +593,15 @@ static bool is_supported_xstate_size(unsigned int test_xstate_size)
 static int init_xstate_size(void)
 {
 	/* Recompute the context size for enabled features: */
-	unsigned int possible_xstate_size = calculate_xstate_size();
+	unsigned int possible_xstate_size;
+	unsigned int xsave_size;
+
+	xsave_size = get_xsave_size();
+
+	if (cpu_has_xsaves)
+		possible_xstate_size = get_xsaves_size();
+	else
+		possible_xstate_size = xsave_size;
 
 	/* Ensure we have the space to store all enabled: */
 	if (!is_supported_xstate_size(possible_xstate_size))
@@ -603,6 +613,11 @@ static int init_xstate_size(void)
 	 */
 	xstate_size = possible_xstate_size;
 	do_extra_xstate_size_checks();
+
+	/*
+	 * User space is always in standard format.
+	 */
+	user_xstate_size = xsave_size;
 	return 0;
 }
 
-- 
1.9.1

[toc] | [next] | [standalone]

#1397990 — Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

On Mon, May 09, 2016 at 01:45:58PM -0700, Yu-cheng Yu wrote:
> If "xsaves" is enabled, kernel always uses compacted format of xsave area.
> But user space still uses standard format of xsave area. Thus, xstate size
> in kernel's xsave area is smaller than xstate size in user's xsave area.
> The xstate in signal frame should be in standard format for user's signal
> handler to access.
> 
> In no "xsaves" case, xsave area in both user space and kernel space are in
> standard format. Therefore, user's and kernel's xstate sizes are equal.
> 
> In "xsaves" case, xsave area in user space is in standard format while
> xsave area in kernel space is in compacted format. Therefore, kernel's
> xstate size is smaller than user's xstate size.

So this repeats what the first paragraph said.

> So here is the problem: currently kernel assumes its own xstate size is
> signal frame's xstate size. This is not a problem in no "xsaves" case.

							 ^
							the

This whole text is missing a bunch of "the"s...

> It is an issue in "xsaves" case because kernel's xstate size is smaller
		   ^			 ^
		 the			the

and so on...


> than user's xstate size. In fpu__alloc_mathframe(), a smaller fpstate
> buffer is allocated for the standard format xstate in signal frame.
> Then kernel saves only part of xstate registers into this smaller
> user's fpstate buffer and user will see part of the xstate registers in
> signal context. Similar issue happens after returning from signal handler:
> kernel will only restore part of xstate registers from user's fpstate
> buffer in signal frame.
> 
> This patch defines and uses user_xstate_size for xstate size in signal
> frame. It's read from returned value in ebx from CPUID leaf 0x0D subleaf
> 0x0. This is maximum size required by enabled states in XCR0 and may be
> different from ecx when states at the end of the xsave area are not
> enabled. This value indicates the size required for XSAVE to save all
> supported user states in legacy/standard format.
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>

That SOB chain needs clarification: if Fenghua is the author, the patch
should contain his From: at the top. If it is based on an earlier patch
from him, commit message should say:

Based on an earlier patch from Fenghua... without the SOB.

> Reviewed-by: Dave Hansen <dave.hansen@intel.com>
> ---
>  arch/x86/include/asm/fpu/xstate.h |  1 -
>  arch/x86/include/asm/processor.h  |  1 +
>  arch/x86/kernel/fpu/init.c        |  5 ++-
>  arch/x86/kernel/fpu/signal.c      | 26 ++++++++++----
>  arch/x86/kernel/fpu/xstate.c      | 71 ++++++++++++++++++++++++---------------
>  5 files changed, 67 insertions(+), 37 deletions(-)
> 
> diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
> index 38951b0..16df2c4 100644
> --- a/arch/x86/include/asm/fpu/xstate.h
> +++ b/arch/x86/include/asm/fpu/xstate.h
> @@ -39,7 +39,6 @@
>  #define REX_PREFIX
>  #endif
>  
> -extern unsigned int xstate_size;
>  extern u64 xfeatures_mask;
>  extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
>  
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 9264476..132b4ca 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -368,6 +368,7 @@ DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
>  #endif	/* X86_64 */
>  
>  extern unsigned int xstate_size;
> +extern unsigned int user_xstate_size;

If this is going to be exported, let's prefix it pls:

fpu_user_xstate_size

or

xstate_user_state_size

or somesuch.

And let's add a comment over its definition what exactly it represents.
I.e., the aspect about the signal frame...

...

> @@ -591,7 +593,15 @@ static bool is_supported_xstate_size(unsigned int test_xstate_size)
>  static int init_xstate_size(void)
>  {
>  	/* Recompute the context size for enabled features: */
> -	unsigned int possible_xstate_size = calculate_xstate_size();
> +	unsigned int possible_xstate_size;
> +	unsigned int xsave_size;
> +
> +	xsave_size = get_xsave_size();
> +
> +	if (cpu_has_xsaves)

	if (boot_cpu_has(X86_FEATURE_XSAVES))

> +		possible_xstate_size = get_xsaves_size();
> +	else
> +		possible_xstate_size = xsave_size;
>  
>  	/* Ensure we have the space to store all enabled: */
>  	if (!is_supported_xstate_size(possible_xstate_size))

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

[toc] | [prev] | [next] | [standalone]

#1398281 — Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

On Tue, May 10, 2016 at 01:04:41PM +0200, Borislav Petkov wrote:
> On Mon, May 09, 2016 at 01:45:58PM -0700, Yu-cheng Yu wrote:
> > If "xsaves" is enabled, kernel always uses compacted format of xsave area.
> > But user space still uses standard format of xsave area. Thus, xstate size
> > in kernel's xsave area is smaller than xstate size in user's xsave area.
> > The xstate in signal frame should be in standard format for user's signal
> > handler to access.
> > 
> > In no "xsaves" case, xsave area in both user space and kernel space are in
> > standard format. Therefore, user's and kernel's xstate sizes are equal.
> > 
> > In "xsaves" case, xsave area in user space is in standard format while
> > xsave area in kernel space is in compacted format. Therefore, kernel's
> > xstate size is smaller than user's xstate size.
> 
> So this repeats what the first paragraph said.
> 
> > So here is the problem: currently kernel assumes its own xstate size is
> > signal frame's xstate size. This is not a problem in no "xsaves" case.
> 
> 							 ^
> 							the
> 
> This whole text is missing a bunch of "the"s...
> 
> > It is an issue in "xsaves" case because kernel's xstate size is smaller
> 		   ^			 ^
> 		 the			the
> 
> and so on...
> 
> 
> > than user's xstate size. In fpu__alloc_mathframe(), a smaller fpstate
> > buffer is allocated for the standard format xstate in signal frame.
> > Then kernel saves only part of xstate registers into this smaller
> > user's fpstate buffer and user will see part of the xstate registers in
> > signal context. Similar issue happens after returning from signal handler:
> > kernel will only restore part of xstate registers from user's fpstate
> > buffer in signal frame.
> > 
> > This patch defines and uses user_xstate_size for xstate size in signal
> > frame. It's read from returned value in ebx from CPUID leaf 0x0D subleaf
> > 0x0. This is maximum size required by enabled states in XCR0 and may be
> > different from ecx when states at the end of the xsave area are not
> > enabled. This value indicates the size required for XSAVE to save all
> > supported user states in legacy/standard format.
> > 
> > Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
> 
> That SOB chain needs clarification: if Fenghua is the author, the patch
> should contain his From: at the top. If it is based on an earlier patch
> from him, commit message should say:
> 
> Based on an earlier patch from Fenghua... without the SOB.
> 
> > Reviewed-by: Dave Hansen <dave.hansen@intel.com>
> > ---
> >  arch/x86/include/asm/fpu/xstate.h |  1 -
> >  arch/x86/include/asm/processor.h  |  1 +
> >  arch/x86/kernel/fpu/init.c        |  5 ++-
> >  arch/x86/kernel/fpu/signal.c      | 26 ++++++++++----
> >  arch/x86/kernel/fpu/xstate.c      | 71 ++++++++++++++++++++++++---------------
> >  5 files changed, 67 insertions(+), 37 deletions(-)
> > 
> > diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
> > index 38951b0..16df2c4 100644
> > --- a/arch/x86/include/asm/fpu/xstate.h
> > +++ b/arch/x86/include/asm/fpu/xstate.h
> > @@ -39,7 +39,6 @@
> >  #define REX_PREFIX
> >  #endif
> >  
> > -extern unsigned int xstate_size;
> >  extern u64 xfeatures_mask;
> >  extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS];
> >  
> > diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> > index 9264476..132b4ca 100644
> > --- a/arch/x86/include/asm/processor.h
> > +++ b/arch/x86/include/asm/processor.h
> > @@ -368,6 +368,7 @@ DECLARE_PER_CPU(struct irq_stack *, softirq_stack);
> >  #endif	/* X86_64 */
> >  
> >  extern unsigned int xstate_size;
> > +extern unsigned int user_xstate_size;
> 
> If this is going to be exported, let's prefix it pls:
> 
> fpu_user_xstate_size
> 
> or
> 
> xstate_user_state_size
> 
> or somesuch.
> 
> And let's add a comment over its definition what exactly it represents.
> I.e., the aspect about the signal frame...
> 
> ...
> 
> > @@ -591,7 +593,15 @@ static bool is_supported_xstate_size(unsigned int test_xstate_size)
> >  static int init_xstate_size(void)
> >  {
> >  	/* Recompute the context size for enabled features: */
> > -	unsigned int possible_xstate_size = calculate_xstate_size();
> > +	unsigned int possible_xstate_size;
> > +	unsigned int xsave_size;
> > +
> > +	xsave_size = get_xsave_size();
> > +
> > +	if (cpu_has_xsaves)
> 
> 	if (boot_cpu_has(X86_FEATURE_XSAVES))
> 
> > +		possible_xstate_size = get_xsaves_size();
> > +	else
> > +		possible_xstate_size = xsave_size;
> >  
> >  	/* Ensure we have the space to store all enabled: */
> >  	if (!is_supported_xstate_size(possible_xstate_size))
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
> -- 

This is actually a patch of Fenghua's, but I re-based it.
I will fix it.

Yu-cheng

[toc] | [prev] | [next] | [standalone]

#1398300 — Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

On Tue, May 10, 2016 at 08:59:43AM -0700, Yu-cheng Yu wrote:
> This is actually a patch of Fenghua's, but I re-based it.
> I will fix it.

Then please take a look at Documentation/SubmittingPatches too.

Also, please snip the mail text you're quoting if you're not going to
refer to it. Like I just did.

Thanks.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

[toc] | [prev] | [next] | [standalone]

#1398301 — Re: [PATCH v5 01/13] x86/xsaves: Define and use user_xstate_size for xstate size in signal context

On Tue, May 10, 2016 at 06:29:00PM +0200, Borislav Petkov wrote:
> Also, please snip the mail text you're quoting if you're not going to
> refer to it. Like I just did.

Ok :-)

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web