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-rw-r--r--arch/x86/lib/insn-eval.c66
1 files changed, 52 insertions, 14 deletions
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 4229950a5d78..bb0b3fe1e0a0 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -1415,6 +1415,25 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
}
}
+static unsigned long insn_get_effective_ip(struct pt_regs *regs)
+{
+ unsigned long seg_base = 0;
+
+ /*
+ * If not in user-space long mode, a custom code segment could be in
+ * use. This is true in protected mode (if the process defined a local
+ * descriptor table), or virtual-8086 mode. In most of the cases
+ * seg_base will be zero as in USER_CS.
+ */
+ if (!user_64bit_mode(regs)) {
+ seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS);
+ if (seg_base == -1L)
+ return 0;
+ }
+
+ return seg_base + regs->ip;
+}
+
/**
* insn_fetch_from_user() - Copy instruction bytes from user-space memory
* @regs: Structure with register values as seen when entering kernel mode
@@ -1431,24 +1450,43 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs)
*/
int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE])
{
- unsigned long seg_base = 0;
+ unsigned long ip;
int not_copied;
- /*
- * If not in user-space long mode, a custom code segment could be in
- * use. This is true in protected mode (if the process defined a local
- * descriptor table), or virtual-8086 mode. In most of the cases
- * seg_base will be zero as in USER_CS.
- */
- if (!user_64bit_mode(regs)) {
- seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS);
- if (seg_base == -1L)
- return 0;
- }
+ ip = insn_get_effective_ip(regs);
+ if (!ip)
+ return 0;
+
+ not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE);
+ return MAX_INSN_SIZE - not_copied;
+}
+
+/**
+ * insn_fetch_from_user_inatomic() - Copy instruction bytes from user-space memory
+ * while in atomic code
+ * @regs: Structure with register values as seen when entering kernel mode
+ * @buf: Array to store the fetched instruction
+ *
+ * Gets the linear address of the instruction and copies the instruction bytes
+ * to the buf. This function must be used in atomic context.
+ *
+ * Returns:
+ *
+ * Number of instruction bytes copied.
+ *
+ * 0 if nothing was copied.
+ */
+int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE])
+{
+ unsigned long ip;
+ int not_copied;
+
+ ip = insn_get_effective_ip(regs);
+ if (!ip)
+ return 0;
- not_copied = copy_from_user(buf, (void __user *)(seg_base + regs->ip),
- MAX_INSN_SIZE);
+ not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE);
return MAX_INSN_SIZE - not_copied;
}