[patch V2 27/52] x86/fpu: Deduplicate copy_uabi_from_user/kernel_to_xstate()

Thomas Gleixner
2021-06-14T16:39:20Z

copy_uabi_from_user_to_xstate() and copy_uabi_from_kernel_to_xstate() are
almost identical except for the copy function.

Unify them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/fpu/xstate.c | 84 +++++++++++++++----------------------------
1 file changed, 30 insertions(+), 54 deletions(-)

--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1076,20 +1076,30 @@ void copy_uabi_xstate_to_membuf(struct m
membuf_zero(&to, to.left);
}

-/*
- * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S] 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)
+static int copy_from_buffer(void *dst, unsigned int offset, unsigned int size,
+ const void *kbuf, const void __user *ubuf)
+{
+ if (kbuf) {
+ memcpy(dst, kbuf + offset, size);
+ } else {
+ if (copy_from_user(dst, ubuf + offset, size))
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static int copy_uabi_to_xstate(struct xregs_state *xsave, const void *kbuf,
+ const void __user *ubuf)
{
unsigned int offset, size;
- int i;
struct xstate_header hdr;
+ int i;

offset = offsetof(struct xregs_state, header);
size = sizeof(hdr);

- memcpy(&hdr, kbuf + offset, size);
+ if (copy_from_buffer(&hdr, offset, size, kbuf, ubuf))
+ return -EFAULT;

if (validate_user_xstate_header(&hdr))
return -EINVAL;
@@ -1111,7 +1121,8 @@ int copy_uabi_from_kernel_to_xstate(stru
offset = xstate_offsets[i];
size = xstate_sizes[i];

- memcpy(dst, kbuf + offset, size);
+ if (copy_from_buffer(dst, offset, size, kbuf, ubuf))
+ return -EFAULT;
}
}

@@ -1136,6 +1147,16 @@ int copy_uabi_from_kernel_to_xstate(stru
}

/*
+ * Convert from a ptrace standard-format kernel buffer to kernel XSAVE[S]
+ * 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)
+{
+ return copy_uabi_to_xstate(xsave, kbuf, NULL);
+}
+
+/*
* Convert from a sigreturn standard-format user-space buffer to kernel
* XSAVE[S] format and copy to the target thread. This is called from the
* sigreturn() and rt_sigreturn() system calls.
@@ -1143,52 +1164,7 @@ int copy_uabi_from_kernel_to_xstate(stru
int copy_sigframe_from_user_to_xstate(struct xregs_state *xsave,
const void __user *ubuf)
{
- unsigned int offset, size;
- int i;
- struct xstate_header hdr;
-
- offset = offsetof(struct xregs_state, header);
- size = sizeof(hdr);
-
- if (copy_from_user(&hdr, ubuf + offset, size))
- return -EFAULT;
-
- if (validate_user_xstate_header(&hdr))
- return -EINVAL;
-
- for (i = 0; i < XFEATURE_MAX; i++) {
- u64 mask = ((u64)1 << i);
-
- if (hdr.xfeatures & mask) {
- void *dst = __raw_xsave_addr(xsave, i);
-
- offset = xstate_offsets[i];
- size = xstate_sizes[i];
-
- if (copy_from_user(dst, ubuf + offset, size))
- return -EFAULT;
- }
- }
-
- if (xfeatures_mxcsr_quirk(hdr.xfeatures)) {
- offset = offsetof(struct fxregs_state, mxcsr);
- size = MXCSR_AND_FLAGS_SIZE;
- if (copy_from_user(&xsave->i387.mxcsr, ubuf + offset, size))
- return -EFAULT;
- }
-
- /*
- * The state that came in from userspace was user-state only.
- * Mask all the user states out of 'xfeatures':
- */
- xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR_ALL;
-
- /*
- * Add back in the features that came in from userspace:
- */
- xsave->header.xfeatures |= hdr.xfeatures;
-
- return 0;
+ return copy_uabi_to_xstate(xsave, NULL, ubuf);
}

/**