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x86, ptrace: regset extensions to support xstate

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Add the xstate regset support which helps extend the kernel ptrace and the
core-dump interfaces to support AVX state etc.

This regset interface is designed to support all the future state that gets
supported using xsave/xrstor infrastructure.

Looking at the memory layout saved by "xsave", one can't say which state
is represented in the memory layout. This is because if a particular state is
in init state, in the xsave hdr it can be represented by bit '0'. And hence
we can't really say by the xsave header wether a state is in init state or
the state is not saved in the memory layout.

And hence the xsave memory layout available through this regset
interface uses SW usable bytes [464..511] to convey what state is represented
in the memory layout.

First 8 bytes of the sw_usable_bytes[464..467] will be set to OS enabled xstate
mask(which is same as the 64bit mask returned by the xgetbv's xCR0).

The note NT_X86_XSTATE represents the extended state information in the
core file, using the above mentioned memory layout.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100211195614.802495327@sbs-t61.sc.intel.com>
Signed-off-by: Hongjiu Lu <hjl.tools@gmail.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Suresh Siddha
2010-02-11 11:50:59 -08:00
committed by H. Peter Anvin
parent 676ad58553
commit 5b3efd5008
7 changed files with 187 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

83
arch/x86/kernel/i387.c
View File

@@ -164,6 +164,11 @@ int init_fpu(struct task_struct *tsk)
return 0;
}
/*
* The xstateregs_active() routine is the same as the fpregs_active() routine,
* as the "regset->n" for the xstate regset will be updated based on the feature
* capabilites supported by the xsave.
*/
int fpregs_active(struct task_struct *target, const struct user_regset *regset)
{
return tsk_used_math(target) ? regset->n : 0;
@@ -224,6 +229,84 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
return ret;
}
int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
int ret;
if (!cpu_has_xsave)
return -ENODEV;
ret = init_fpu(target);
if (ret)
return ret;
/*
* First copy the fxsave bytes 0..463.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->xsave, 0,
offsetof(struct user_xstateregs,
i387.xstate_fx_sw));
if (ret)
return ret;
/*
* Copy the 48bytes defined by software.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
xstate_fx_sw_bytes,
offsetof(struct user_xstateregs,
i387.xstate_fx_sw),
offsetof(struct user_xstateregs,
xsave_hdr));
if (ret)
return ret;
/*
* Copy the rest of xstate memory layout.
*/
ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->xsave.xsave_hdr,
offsetof(struct user_xstateregs,
xsave_hdr), -1);
return ret;
}
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)
{
int ret;
struct xsave_hdr_struct *xsave_hdr;
if (!cpu_has_xsave)
return -ENODEV;
ret = init_fpu(target);
if (ret)
return ret;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
&target->thread.xstate->xsave, 0, -1);
/*
* mxcsr reserved bits must be masked to zero for security reasons.
*/
target->thread.xstate->fxsave.mxcsr &= mxcsr_feature_mask;
xsave_hdr = &target->thread.xstate->xsave.xsave_hdr;
xsave_hdr->xstate_bv &= pcntxt_mask;
/*
* These bits must be zero.
*/
xsave_hdr->reserved1[0] = xsave_hdr->reserved1[1] = 0;
return ret;
}
#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
/*