[PATCH v3 07/10] x86/umip: Avoid crossing the page boundary

[Alexey Gladkov]

From: "Alexey Gladkov (Intel)" <legion@xxxxxxxxxx>

Try to avoid crossing the page boundary to avoid side effects if the
next page belongs to another VMA.

Signed-off-by: Alexey Gladkov (Intel) <legion@xxxxxxxxxx>
---
 arch/x86/kernel/umip.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c
index 5a4b21389b1d..e85c3cafc258 100644
--- a/arch/x86/kernel/umip.c
+++ b/arch/x86/kernel/umip.c
@@ -338,7 +338,6 @@ bool fixup_umip_exception(struct pt_regs *regs)
 	int nr_copied, reg_offset, dummy_data_size, umip_inst;
 	/* 10 bytes is the maximum size of the result of UMIP instructions */
 	unsigned char dummy_data[10] = { 0 };
-	unsigned char buf[MAX_INSN_SIZE];
 	unsigned long *reg_addr;
 	void __user *uaddr;
 	struct insn insn;
@@ -350,11 +349,7 @@ bool fixup_umip_exception(struct pt_regs *regs)
 	 * Give up on emulation if fetching the instruction failed. Should a
 	 * page fault or a #GP be issued?
 	 */
-	nr_copied = insn_fetch_from_user(regs, buf);
-	if (nr_copied <= 0)
-		return false;
-
-	if (!insn_decode_from_regs(&insn, regs, buf, nr_copied))
+	if (insn_fetch_decode_from_user(&insn, regs))
 		return false;
 
 	umip_inst = identify_insn(&insn);
-- 
2.45.2