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authorSuresh Siddha <suresh.b.siddha@intel.com>2010-02-11 11:50:59 -0800
committerH. Peter Anvin <hpa@zytor.com>2010-02-11 15:08:17 -0800
commit5b3efd500854d45d305b53c54c97db5970959980 (patch)
tree731629e22791d14b9661cada9c0c69eb38776c3b /arch/x86/kernel/i387.c
parent676ad585531e965416fd958747894541dabcec96 (diff)
x86, ptrace: regset extensions to support xstate
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>
Diffstat (limited to 'arch/x86/kernel/i387.c')
-rw-r--r--arch/x86/kernel/i387.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index f2f8540a7f3d..7a8a193b5144 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -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
/*