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>
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index f2f8540..7a8a193 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -164,6 +164,11 @@
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 @@
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
/*