* [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
@ 2016-02-22 19:00 Yu-cheng Yu
2016-02-22 20:00 ` Dave Hansen
2016-02-22 22:45 ` Andy Lutomirski
0 siblings, 2 replies; 9+ messages in thread
From: Yu-cheng Yu @ 2016-02-22 19:00 UTC (permalink / raw)
To: x86, H. Peter Anvin, Thomas Gleixner, Ingo Molnar, linux-kernel
Cc: Dave Hansen, Andy Lutomirski, Borislav Petkov,
Sai Praneeth Prakhya, Ravi V. Shankar, Fenghua Yu, Yu-cheng Yu
XSAVES uses compacted format and is a kernel instruction. The kernel
should use standard-format, non-supervisor state data for PTRACE.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
arch/x86/include/asm/fpu/xstate.h | 4 +
arch/x86/kernel/fpu/regset.c | 56 +++++++++----
arch/x86/kernel/fpu/xstate.c | 167 +++++++++++++++++++++++++++++++++++++-
3 files changed, 211 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index b4f5d94..a5cd808 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -50,5 +50,9 @@ extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask);
void fpu__xstate_clear_all_cpu_caps(void);
void *get_xsave_addr(struct xregs_state *xsave, int xstate);
const void *get_xsave_field_ptr(int xstate_field);
+int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
+ void __user *ubuf, const struct xregs_state *xsave);
+int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
+ struct xregs_state *xsave);
#endif
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 0bc3490..61fe8e9 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -4,6 +4,7 @@
#include <asm/fpu/internal.h>
#include <asm/fpu/signal.h>
#include <asm/fpu/regset.h>
+#include <asm/fpu/xstate.h>
/*
* The xstateregs_active() routine is the same as the regset_fpregs_active() routine,
@@ -82,21 +83,30 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_xsave)
return -ENODEV;
+ xsave = &fpu->state.xsave;
+
fpu__activate_fpstate_read(fpu);
- xsave = &fpu->state.xsave;
+ if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+ ret = copyout_from_xsaves(pos, count, kbuf, ubuf, xsave);
+ } else {
+ fpstate_sanitize_xstate(fpu);
+
+ /*
+ * Copy the 48 bytes defined by the software into the xsave
+ * area in the thread struct, so that we can copy the whole
+ * area to user using one user_regset_copyout().
+ */
+ 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, xsave, 0, -1);
+ }
- /*
- * Copy the 48bytes defined by the software first into the xstate
- * memory layout in the thread struct, so that we can copy the entire
- * xstateregs to the user using one user_regset_copyout().
- */
- 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, xsave, 0, -1);
return ret;
}
@@ -111,11 +121,29 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
if (!cpu_has_xsave)
return -ENODEV;
- fpu__activate_fpstate_write(fpu);
+ /*
+ * A whole standard-format XSAVE buffer is needed.
+ */
+ if ((pos != 0) || (count < user_xstate_size))
+ return -EFAULT;
xsave = &fpu->state.xsave;
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
+ fpu__activate_fpstate_write(fpu);
+
+ if (boot_cpu_has(X86_FEATURE_XSAVES))
+ ret = copyin_to_xsaves(kbuf, ubuf, xsave);
+ else
+ ret = user_regset_copyin(&pos,
+ &count, &kbuf, &ubuf, xsave, 0, -1);
+
+ /*
+ * In case of failure, mark all states as init.
+ */
+
+ if (ret)
+ fpstate_init(&fpu->state);
+
/*
* mxcsr reserved bits must be masked to zero for security reasons.
*/
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 4087261..512e71f 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -677,7 +677,13 @@ void __init fpu__init_system_xstate(void)
return;
}
- update_regset_xstate_info(kernel_xstate_size, xfeatures_mask);
+ /*
+ * Update info used for ptrace frames; use standard-format size and no
+ * supervisor xstates.
+ */
+ update_regset_xstate_info(user_xstate_size,
+ xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR);
+
fpu__init_prepare_fx_sw_frame();
setup_init_fpu_buf();
setup_xstate_comp();
@@ -701,6 +707,15 @@ void fpu__resume_cpu(void)
}
/*
+ * Get an xstate component address for either kernel or user mode.
+ */
+static void *get_xsave_addr_no_check(const struct xregs_state *xsave,
+ int feature_nr)
+{
+ return (void *)xsave + xstate_comp_offsets[feature_nr];
+}
+
+/*
* Given the xsave area and a state inside, this function returns the
* address of the state.
*
@@ -748,7 +763,7 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature)
if (!(xsave->header.xfeatures & xstate_feature))
return NULL;
- return (void *)xsave + xstate_comp_offsets[feature_nr];
+ return get_xsave_addr_no_check(xsave, feature_nr);
}
EXPORT_SYMBOL_GPL(get_xsave_addr);
@@ -783,3 +798,151 @@ const void *get_xsave_field_ptr(int xsave_state)
return get_xsave_addr(&fpu->state.xsave, xsave_state);
}
+
+/*
+ * This is similar to user_regset_copyout(), but will not add offset to
+ * the source data pointer or increment pos, count, kbuf, and ubuf.
+ */
+static inline int xstate_copyout(unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf,
+ const void *data, const int start_pos,
+ const int end_pos)
+{
+ if ((count == 0) || (pos < start_pos))
+ return 0;
+
+ if (end_pos < 0 || pos < end_pos) {
+ unsigned int copy =
+ (end_pos < 0 ? count : min(count, end_pos - pos));
+
+ if (kbuf)
+ memcpy(kbuf + pos, data, copy);
+ else if (__copy_to_user(ubuf + pos, data, copy))
+ return -EFAULT;
+ }
+ return 0;
+}
+
+/*
+ * Convert from kernel XSAVES compacted format to standard format and copy
+ * to a ptrace buffer. It supports partial copy but pos always starts from
+ * zero. This is called from xstateregs_get() and there we check the cpu
+ * has XSAVES.
+ */
+int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
+ void __user *ubuf, const struct xregs_state *xsave)
+{
+ unsigned int offset, size;
+ int ret, i;
+ struct xstate_header header;
+
+ /*
+ * Currently copy_regset_to_user() starts from pos 0.
+ */
+ if (unlikely(pos != 0))
+ return -EFAULT;
+
+ /*
+ * The destination is a ptrace buffer; we put in only user xstates.
+ */
+ memset(&header, 0, sizeof(header));
+ header.xfeatures = xsave->header.xfeatures;
+ header.xfeatures &= ~XFEATURE_MASK_SUPERVISOR;
+
+ /*
+ * Copy xregs_state->header.
+ */
+ offset = offsetof(struct xregs_state, header);
+ size = sizeof(header);
+
+ ret = xstate_copyout(offset, size, kbuf, ubuf, &header, 0, count);
+
+ if (ret)
+ return ret;
+
+ for (i = 0; i < XFEATURE_MAX; i++) {
+ /*
+ * Copy only in-use xstates.
+ */
+ if (((header.xfeatures >> i) & 1) && xfeature_enabled(i)) {
+ void *src = get_xsave_addr_no_check(xsave, i);
+
+ offset = xstate_offsets[i];
+ size = xstate_sizes[i];
+
+ ret = xstate_copyout(offset, size, kbuf, ubuf, src, 0,
+ count);
+
+ if (ret)
+ return ret;
+
+ if (offset + size >= count)
+ break;
+ }
+ }
+
+ /*
+ * Fill xsave->i387.sw_reserved value for ptrace frame.
+ */
+ offset = offsetof(struct fxregs_state, sw_reserved);
+ size = sizeof(xstate_fx_sw_bytes);
+
+ ret = xstate_copyout(offset, size, kbuf, ubuf, xstate_fx_sw_bytes, 0,
+ count);
+
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+/*
+ * Convert from a ptrace standard-format buffer to kernel XSAVES format
+ * and copy to the target thread. This is called from xstateregs_set() and
+ * there we check the cpu has XSAVES and a whole standard-sized buffer
+ * exists.
+ */
+int copyin_to_xsaves(const void *kbuf, const void __user *ubuf,
+ struct xregs_state *xsave)
+{
+ unsigned int offset, size;
+ int i;
+ u64 xfeatures;
+
+ offset = offsetof(struct xregs_state, header);
+ size = sizeof(xfeatures);
+
+ if (kbuf)
+ memcpy(&xfeatures, kbuf + offset, size);
+ else if (__copy_from_user(&xfeatures, ubuf + offset, size))
+ return -EFAULT;
+
+ /*
+ * Reject if the user tries to set any supervisor xstates.
+ */
+ if (xfeatures & XFEATURE_MASK_SUPERVISOR)
+ return -EINVAL;
+
+ for (i = 0; i < XFEATURE_MAX; i++) {
+ u64 mask = ((u64)1 << i);
+
+ if ((xfeatures & mask) && xfeature_enabled(i)) {
+ void *dst = get_xsave_addr_no_check(xsave, i);
+
+ offset = xstate_offsets[i];
+ size = xstate_sizes[i];
+
+ if (kbuf)
+ memcpy(dst, kbuf + offset, size);
+ else if (__copy_from_user(dst, ubuf + offset, size))
+ return -EFAULT;
+ }
+ }
+
+ if (xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR)
+ xsave->header.xfeatures = xfeatures | XFEATURE_MASK_SUPERVISOR;
+ else
+ xsave->header.xfeatures = xfeatures;
+
+ return 0;
+}
--
1.9.1
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 19:00 [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES Yu-cheng Yu
@ 2016-02-22 20:00 ` Dave Hansen
2016-02-22 20:48 ` Yu-cheng Yu
2016-02-22 22:45 ` Andy Lutomirski
1 sibling, 1 reply; 9+ messages in thread
From: Dave Hansen @ 2016-02-22 20:00 UTC (permalink / raw)
To: Yu-cheng Yu, x86, H. Peter Anvin, Thomas Gleixner, Ingo Molnar,
linux-kernel
Cc: Andy Lutomirski, Borislav Petkov, Sai Praneeth Prakhya,
Ravi V. Shankar, Fenghua Yu
On 02/22/2016 11:00 AM, Yu-cheng Yu wrote:
> + if (xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR)
> + xsave->header.xfeatures = xfeatures | XFEATURE_MASK_SUPERVISOR;
> + else
> + xsave->header.xfeatures = xfeatures;
This is dangerous. It says, "if any supervisor feature bit is set, then
set *ALL* of the known bits". There's no way that can work.
Don't you just want to or in the new bits that were in the passed-in
'xfeatures':
xsave->header.xfeatures |= xfeatures;
'xfeatures' is known not to contain any supervisor bits.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 20:00 ` Dave Hansen
@ 2016-02-22 20:48 ` Yu-cheng Yu
2016-02-22 22:19 ` Dave Hansen
0 siblings, 1 reply; 9+ messages in thread
From: Yu-cheng Yu @ 2016-02-22 20:48 UTC (permalink / raw)
To: Dave Hansen
Cc: x86, H. Peter Anvin, Thomas Gleixner, Ingo Molnar, linux-kernel,
Andy Lutomirski, Borislav Petkov, Sai Praneeth Prakhya,
Ravi V. Shankar, Fenghua Yu
On Mon, Feb 22, 2016 at 12:00:02PM -0800, Dave Hansen wrote:
> On 02/22/2016 11:00 AM, Yu-cheng Yu wrote:
> > + if (xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR)
> > + xsave->header.xfeatures = xfeatures | XFEATURE_MASK_SUPERVISOR;
> > + else
> > + xsave->header.xfeatures = xfeatures;
>
> This is dangerous. It says, "if any supervisor feature bit is set, then
> set *ALL* of the known bits". There's no way that can work.
>
> Don't you just want to or in the new bits that were in the passed-in
> 'xfeatures':
>
> xsave->header.xfeatures |= xfeatures;
>
> 'xfeatures' is known not to contain any supervisor bits.
>
It should have been:
xsave->header.xfeatures = xfeatures |
(xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR);
I'll fix it.
--Yu-cheng
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 20:48 ` Yu-cheng Yu
@ 2016-02-22 22:19 ` Dave Hansen
2016-02-22 22:29 ` Yu-cheng Yu
0 siblings, 1 reply; 9+ messages in thread
From: Dave Hansen @ 2016-02-22 22:19 UTC (permalink / raw)
To: Yu-cheng Yu
Cc: x86, H. Peter Anvin, Thomas Gleixner, Ingo Molnar, linux-kernel,
Andy Lutomirski, Borislav Petkov, Sai Praneeth Prakhya,
Ravi V. Shankar, Fenghua Yu
On 02/22/2016 12:48 PM, Yu-cheng Yu wrote:
> It should have been:
>
> xsave->header.xfeatures = xfeatures |
> (xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR);
>
> I'll fix it.
Can we break it out to make it more clear?
/*
* The state that came in from userspace was user-state only.
* Mask all the user states out of 'xfeatures'.
*/
xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
/*
* add back in the features that came in from userspace
*/
xsave->header.xfeatures |= xfeatures
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 22:19 ` Dave Hansen
@ 2016-02-22 22:29 ` Yu-cheng Yu
0 siblings, 0 replies; 9+ messages in thread
From: Yu-cheng Yu @ 2016-02-22 22:29 UTC (permalink / raw)
To: Dave Hansen
Cc: x86, H. Peter Anvin, Thomas Gleixner, Ingo Molnar, linux-kernel,
Andy Lutomirski, Borislav Petkov, Sai Praneeth Prakhya,
Ravi V. Shankar, Fenghua Yu
On Mon, Feb 22, 2016 at 02:19:05PM -0800, Dave Hansen wrote:
> On 02/22/2016 12:48 PM, Yu-cheng Yu wrote:
> > It should have been:
> >
> > xsave->header.xfeatures = xfeatures |
> > (xsave->header.xfeatures & XFEATURE_MASK_SUPERVISOR);
> >
> > I'll fix it.
>
> Can we break it out to make it more clear?
>
> /*
> * The state that came in from userspace was user-state only.
> * Mask all the user states out of 'xfeatures'.
> */
> xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
> /*
> * add back in the features that came in from userspace
> */
> xsave->header.xfeatures |= xfeatures
I will update it in the next version. Thanks!
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 19:00 [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES Yu-cheng Yu
2016-02-22 20:00 ` Dave Hansen
@ 2016-02-22 22:45 ` Andy Lutomirski
2016-02-22 22:50 ` Yu-cheng Yu
2016-02-22 22:53 ` Dave Hansen
1 sibling, 2 replies; 9+ messages in thread
From: Andy Lutomirski @ 2016-02-22 22:45 UTC (permalink / raw)
To: Yu-cheng Yu
Cc: X86 ML, H. Peter Anvin, Thomas Gleixner, Ingo Molnar,
linux-kernel, Dave Hansen, Andy Lutomirski, Borislav Petkov,
Sai Praneeth Prakhya, Ravi V. Shankar, Fenghua Yu
On Mon, Feb 22, 2016 at 11:00 AM, Yu-cheng Yu <yu-cheng.yu@intel.com> wrote:
> XSAVES uses compacted format and is a kernel instruction. The kernel
> should use standard-format, non-supervisor state data for PTRACE.
>
> +/*
> + * Convert from kernel XSAVES compacted format to standard format and copy
> + * to a ptrace buffer. It supports partial copy but pos always starts from
> + * zero. This is called from xstateregs_get() and there we check the cpu
> + * has XSAVES.
> + */
> +int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
> + void __user *ubuf, const struct xregs_state *xsave)
Now that you've written this code, can it be shared with the signal
handling code?
--Andy
--Andy
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 22:45 ` Andy Lutomirski
@ 2016-02-22 22:50 ` Yu-cheng Yu
2016-02-22 22:53 ` Dave Hansen
1 sibling, 0 replies; 9+ messages in thread
From: Yu-cheng Yu @ 2016-02-22 22:50 UTC (permalink / raw)
To: Andy Lutomirski
Cc: X86 ML, H. Peter Anvin, Thomas Gleixner, Ingo Molnar,
linux-kernel, Dave Hansen, Andy Lutomirski, Borislav Petkov,
Sai Praneeth Prakhya, Ravi V. Shankar, Fenghua Yu
On Mon, Feb 22, 2016 at 02:45:54PM -0800, Andy Lutomirski wrote:
> > +/*
> > + * Convert from kernel XSAVES compacted format to standard format and copy
> > + * to a ptrace buffer. It supports partial copy but pos always starts from
> > + * zero. This is called from xstateregs_get() and there we check the cpu
> > + * has XSAVES.
> > + */
> > +int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
> > + void __user *ubuf, const struct xregs_state *xsave)
>
> Now that you've written this code, can it be shared with the signal
> handling code?
>
For signal handling, we most likely save registers directly to memory.
But for ptrace, the thread being debugged is not the active thread.
Please let me think about it more.
--Yu-cheng
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 22:45 ` Andy Lutomirski
2016-02-22 22:50 ` Yu-cheng Yu
@ 2016-02-22 22:53 ` Dave Hansen
2016-02-22 22:55 ` Andy Lutomirski
1 sibling, 1 reply; 9+ messages in thread
From: Dave Hansen @ 2016-02-22 22:53 UTC (permalink / raw)
To: Andy Lutomirski, Yu-cheng Yu
Cc: X86 ML, H. Peter Anvin, Thomas Gleixner, Ingo Molnar,
linux-kernel, Andy Lutomirski, Borislav Petkov,
Sai Praneeth Prakhya, Ravi V. Shankar, Fenghua Yu
On 02/22/2016 02:45 PM, Andy Lutomirski wrote:
>> +/*
>> > + * Convert from kernel XSAVES compacted format to standard format and copy
>> > + * to a ptrace buffer. It supports partial copy but pos always starts from
>> > + * zero. This is called from xstateregs_get() and there we check the cpu
>> > + * has XSAVES.
>> > + */
>> > +int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
>> > + void __user *ubuf, const struct xregs_state *xsave)
> Now that you've written this code, can it be shared with the signal
> handling code?
It could be. But the signal handler code has the advantage of already
having the data in the registers since it's running on its *own* FPU
state, so it can just call XSAVE(S) directly.
This ptrace code *could* do a kernel_fpu_begin(), XRSTOR the user buffer
into the registers, XRSTOR the ptracee's system state in to the
registers, then XSAVES the whole thing to the kernel buffer, then
kernel_fpu_end().
Or, we could remove the signal handler's ability to XSAVE directly to
userspace. But it already *had* that and we know it works.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES
2016-02-22 22:53 ` Dave Hansen
@ 2016-02-22 22:55 ` Andy Lutomirski
0 siblings, 0 replies; 9+ messages in thread
From: Andy Lutomirski @ 2016-02-22 22:55 UTC (permalink / raw)
To: Dave Hansen
Cc: Yu-cheng Yu, X86 ML, H. Peter Anvin, Thomas Gleixner,
Ingo Molnar, linux-kernel, Andy Lutomirski, Borislav Petkov,
Sai Praneeth Prakhya, Ravi V. Shankar, Fenghua Yu
On Mon, Feb 22, 2016 at 2:53 PM, Dave Hansen
<dave.hansen@linux.intel.com> wrote:
> On 02/22/2016 02:45 PM, Andy Lutomirski wrote:
>>> +/*
>>> > + * Convert from kernel XSAVES compacted format to standard format and copy
>>> > + * to a ptrace buffer. It supports partial copy but pos always starts from
>>> > + * zero. This is called from xstateregs_get() and there we check the cpu
>>> > + * has XSAVES.
>>> > + */
>>> > +int copyout_from_xsaves(unsigned int pos, unsigned int count, void *kbuf,
>>> > + void __user *ubuf, const struct xregs_state *xsave)
>> Now that you've written this code, can it be shared with the signal
>> handling code?
>
> It could be. But the signal handler code has the advantage of already
> having the data in the registers since it's running on its *own* FPU
> state, so it can just call XSAVE(S) directly.
>
> This ptrace code *could* do a kernel_fpu_begin(), XRSTOR the user buffer
> into the registers, XRSTOR the ptracee's system state in to the
> registers, then XSAVES the whole thing to the kernel buffer, then
> kernel_fpu_end().
>
> Or, we could remove the signal handler's ability to XSAVE directly to
> userspace. But it already *had* that and we know it works.
Some day I kind of want to delete all this xsave/xrstor directly on
user buffers code. I've never been thrilled with the concept, and it
has messy (although AFAICT not presently buggy [1]) interactions with
context switches, and it can't run with preemption disabled because it
can take page faults.
In the mean time, it's fine as far as I know, but maybe it would be
cleaner if it used the software copy code. Or maybe we can change it
later if a good reason shows up.
[1] actually there's a minor bug in the 32-bit compat code that
Borislav has a patch for.
--
Andy Lutomirski
AMA Capital Management, LLC
^ permalink raw reply [flat|nested] 9+ messages in thread
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2016-02-22 19:00 [PATCH 08/10] x86/xsaves: Fix PTRACE frames for XSAVES Yu-cheng Yu
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2016-02-22 22:19 ` Dave Hansen
2016-02-22 22:29 ` Yu-cheng Yu
2016-02-22 22:45 ` Andy Lutomirski
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