[tip: x86/fpu] x86/fpu: Add a pkru argument to copy_uabi_to_xstate()

[tip-bot2 for Kyle Huey]

The following commit has been merged into the x86/fpu branch of tip:

Commit-ID:     2c87767c35ee9744f666ccec869d5fe742c3de0a
Gitweb:        https://git.kernel.org/tip/2c87767c35ee9744f666ccec869d5fe742c3de0a
Author:        Kyle Huey <me@xxxxxxxxxxxx>
AuthorDate:    Tue, 15 Nov 2022 15:09:29 -08:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Wed, 16 Nov 2022 15:03:30 -08:00

x86/fpu: Add a pkru argument to copy_uabi_to_xstate()

In preparation for moving PKRU handling code out of
fpu_copy_uabi_to_guest_fpstate() and into copy_uabi_to_xstate(), add an
argument that copy_uabi_from_kernel_to_xstate() can use to pass the
canonical location of the PKRU value. For
copy_sigframe_from_user_to_xstate() the kernel will actually restore the
PKRU value from the fpstate, but pass in the thread_struct's pkru location
anyways for consistency.

Signed-off-by: Kyle Huey <me@xxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20221115230932.7126-4-khuey%40kylehuey.com
---
 arch/x86/kernel/fpu/xstate.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index d6f414a..d657c8b 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1200,8 +1200,18 @@ static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size,
 }
 
 
+/**
+ * copy_uabi_to_xstate - Copy a UABI format buffer to the kernel xstate
+ * @fpstate:	The fpstate buffer to copy to
+ * @kbuf:	The UABI format buffer, if it comes from the kernel
+ * @ubuf:	The UABI format buffer, if it comes from userspace
+ * @pkru:	unused
+ *
+ * Converts from the UABI format into the kernel internal hardware
+ * dependent format.
+ */
 static int copy_uabi_to_xstate(struct fpstate *fpstate, const void *kbuf,
-			       const void __user *ubuf)
+			       const void __user *ubuf, u32 *pkru)
 {
 	struct xregs_state *xsave = &fpstate->regs.xsave;
 	unsigned int offset, size;
@@ -1270,7 +1280,7 @@ static int copy_uabi_to_xstate(struct fpstate *fpstate, const void *kbuf,
  */
 int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u32 *pkru)
 {
-	return copy_uabi_to_xstate(fpstate, kbuf, NULL);
+	return copy_uabi_to_xstate(fpstate, kbuf, NULL, pkru);
 }
 
 /*
@@ -1281,7 +1291,7 @@ int copy_uabi_from_kernel_to_xstate(struct fpstate *fpstate, const void *kbuf, u
 int copy_sigframe_from_user_to_xstate(struct task_struct *tsk,
 				      const void __user *ubuf)
 {
-	return copy_uabi_to_xstate(tsk->thread.fpu.fpstate, NULL, ubuf);
+	return copy_uabi_to_xstate(tsk->thread.fpu.fpstate, NULL, ubuf, &tsk->thread.pkru);
 }
 
 static bool validate_independent_components(u64 mask)