The following commit has been merged into the x86/seves branch of tip:
Commit-ID: 5901781a11175a5e5ee91746ec8627f18d47eebd
Gitweb: https://git.kernel.org/tip/5901781a11175a5e5ee91746ec8627f18d47eebd
Author: Joerg Roedel <jroedel@xxxxxxx>
AuthorDate: Mon, 07 Sep 2020 15:15:12 +02:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Mon, 07 Sep 2020 19:45:25 +02:00
x86/insn: Add insn_has_rep_prefix() helper
Add a function to check whether an instruction has a REP prefix.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20200907131613.12703-12-joro@xxxxxxxxxx
---
arch/x86/include/asm/insn-eval.h | 1 +
arch/x86/lib/insn-eval.c | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h
index f748f57..a0f839a 100644
--- a/arch/x86/include/asm/insn-eval.h
+++ b/arch/x86/include/asm/insn-eval.h
@@ -15,6 +15,7 @@
#define INSN_CODE_SEG_OPND_SZ(params) (params & 0xf)
#define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4))
+bool insn_has_rep_prefix(struct insn *insn);
void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs);
int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs);
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index f20942c..58f7fb9 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -54,6 +54,30 @@ static bool is_string_insn(struct insn *insn)
}
/**
+ * insn_has_rep_prefix() - Determine if instruction has a REP prefix
+ * @insn: Instruction containing the prefix to inspect
+ *
+ * Returns:
+ *
+ * true if the instruction has a REP prefix, false if not.
+ */
+bool insn_has_rep_prefix(struct insn *insn)
+{
+ int i;
+
+ insn_get_prefixes(insn);
+
+ for (i = 0; i < insn->prefixes.nbytes; i++) {
+ insn_byte_t p = insn->prefixes.bytes[i];
+
+ if (p == 0xf2 || p == 0xf3)
+ return true;
+ }
+
+ return false;
+}
+
+/**
* get_seg_reg_override_idx() - obtain segment register override index
* @insn: Valid instruction with segment override prefixes
*
|