x86/fpu: Add a pkru argument to copy_uabi_from_kernel_to_xstate().

commit 1c813ce upstream

ptrace (through PTRACE_SETREGSET with NT_X86_XSTATE) ultimately calls
copy_uabi_from_kernel_to_xstate(). In preparation for eventually handling
PKRU in copy_uabi_to_xstate, pass in a pointer to the PKRU location.

Signed-off-by: Kyle Huey <me@kylehuey.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20221115230932.7126-3-khuey%40kylehuey.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: khuey

arch/x86/include/asm/fpu/xstate.h

@@ -136,7 +136,7 @@ extern void __init update_regset_xstate_info(unsigned int size,
 
 void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);
 int xfeature_size(int xfeature_nr);
-int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf);
+int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf, u32 *pkru);
 int copy_sigframe_from_user_to_xstate(struct task_struct *tsk, const void __user *ubuf);
 
 void xsaves(struct xregs_state *xsave, u64 mask);

arch/x86/kernel/fpu/regset.c

@@ -163,7 +163,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 	}
 
 	fpu_force_restore(fpu);
-	ret = copy_uabi_from_kernel_to_xstate(&fpu->state.xsave, kbuf ?: tmpbuf);
+	ret = copy_uabi_from_kernel_to_xstate(&fpu->state.xsave, kbuf ?: tmpbuf, &target->thread.pkru);
 
 out:
 	vfree(tmpbuf);

arch/x86/kernel/fpu/xstate.c

@@ -1159,7 +1159,7 @@ static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf,
  * format and copy to the target thread. This is called from
  * xstateregs_set().
  */
-int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf)
+int copy_uabi_from_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf, u32 *pkru)
 {
 	return copy_uabi_to_xstate(xsave, kbuf, NULL);
 }