From: Bill Wendling <morbo@xxxxxxxxxx>
According to GCC's documentation, the only supported use for specifying
registers for local variables is "to specify registers for input and
output operands when calling Extended asm." Using it as a shortcut to
get the value in a register isn't guaranteed to work, and clang
complains that the variable is uninitialized.
Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx>
Message-Id: <20191030210419.213407-7-morbo@xxxxxxxxxx>
Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
---
x86/vmx_tests.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/x86/vmx_tests.c b/x86/vmx_tests.c
index 0909adb..dbf5375 100644
--- a/x86/vmx_tests.c
+++ b/x86/vmx_tests.c
@@ -2135,7 +2135,9 @@ static void into_guest_main(void)
.offset = (uintptr_t)&&into,
.selector = KERNEL_CS32,
};
- register uintptr_t rsp asm("rsp");
+ uintptr_t rsp;
+
+ asm volatile ("mov %%rsp, %0" : "=r"(rsp));
if (fp.offset != (uintptr_t)&&into) {
printf("Code address too high.\n");
@@ -3231,7 +3233,9 @@ static void try_compat_invvpid(void *unused)
.offset = (uintptr_t)&&invvpid,
.selector = KERNEL_CS32,
};
- register uintptr_t rsp asm("rsp");
+ uintptr_t rsp;
+
+ asm volatile ("mov %%rsp, %0" : "=r"(rsp));
TEST_ASSERT_MSG(fp.offset == (uintptr_t)&&invvpid,
"Code address too high.");
--
2.18.1
