diff mbox series

[kvm-unit-tests,3/7] x86: realmode: syscall: add explicit size suffix to ambiguous instructions

Message ID 20200226074427.169684-4-morbo@google.com (mailing list archive)
State New, archived
Headers show
Series Fixes for clang builds | expand

Commit Message

Bill Wendling Feb. 26, 2020, 7:44 a.m. UTC 
From: Bill Wendling <morbo@google.com>

Clang requires explicit size suffixes for potentially ambiguous
instructions:

x86/realmode.c:1647:2: error: ambiguous instructions require an explicit suffix (could be 'cmpb', 'cmpw', or 'cmpl')
        MK_INSN_PERF(perf_memory_load, "cmp $0, (%edi)");
        ^
x86/realmode.c:1591:10: note: expanded from macro 'MK_INSN_PERF'
                      "1:" insn "\n"                            \
                       ^
<inline asm>:8:3: note: instantiated into assembly here
1:cmp $0, (%edi)
  ^

The 'w' and 'l' suffixes generate code that's identical to the gcc
version without them.

Signed-off-by: Bill Wendling <morbo@google.com>
---
 x86/realmode.c | 6 +++---
 x86/syscall.c  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)
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Patch

diff --git a/x86/realmode.c b/x86/realmode.c
index f5967ef..31f84d0 100644
--- a/x86/realmode.c
+++ b/x86/realmode.c
@@ -1644,7 +1644,7 @@  static void test_perf_memory_load(void)
 {
 	u32 cyc, tmp;
 
-	MK_INSN_PERF(perf_memory_load, "cmp $0, (%edi)");
+	MK_INSN_PERF(perf_memory_load, "cmpw $0, (%edi)");
 
 	init_inregs(&(struct regs){ .edi = (u32)&tmp });
 
@@ -1657,7 +1657,7 @@  static void test_perf_memory_store(void)
 {
 	u32 cyc, tmp;
 
-	MK_INSN_PERF(perf_memory_store, "mov %ax, (%edi)");
+	MK_INSN_PERF(perf_memory_store, "movw %ax, (%edi)");
 
 	init_inregs(&(struct regs){ .edi = (u32)&tmp });
 
@@ -1670,7 +1670,7 @@  static void test_perf_memory_rmw(void)
 {
 	u32 cyc, tmp;
 
-	MK_INSN_PERF(perf_memory_rmw, "add $1, (%edi)");
+	MK_INSN_PERF(perf_memory_rmw, "addw $1, (%edi)");
 
 	init_inregs(&(struct regs){ .edi = (u32)&tmp });
 
diff --git a/x86/syscall.c b/x86/syscall.c
index b4f5ac0..b7e29d6 100644
--- a/x86/syscall.c
+++ b/x86/syscall.c
@@ -38,7 +38,7 @@  static void handle_db(struct ex_regs *regs)
 
 /* expects desired ring 3 flags in rax */
 asm("syscall32_target:\n"
-    "   cmp $0, code_segment_upon_db(%rip)\n"
+    "   cmpl $0, code_segment_upon_db(%rip)\n"
     "   jne back_to_test\n"
     "   mov %eax,%r11d\n"
     "   sysretl\n");