[x86 setup] Fix assembly constraints

Fix incorrect assembly constraints.  In particular, fix memory
constraints used inside push..pop, which can cause invalid operation
since gcc may generate %esp-relative references.

Additionally:

outl() should have "dN" not "dn".

query_mca() shouldn't listen 16/32-bit registers in an 8-bit only
context.

has_eflag(): the "mask" is only used well after both the stack pointer
and the output registers have been touched; this requires the output
registers to be earlyclobbers (=&) and the input to exclude memory (so
"ri", not "g").

Thanks to Etienne Lorrain and Chuck Ebbert for prompting this review.

Cc: Etienne Lorrain <etienne_lorrain@yahoo.fr>
Cc: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/i386/boot/cpucheck.c b/arch/i386/boot/cpucheck.c
index 8b0f4473b083..991e8ceae1de 100644
--- a/arch/i386/boot/cpucheck.c
+++ b/arch/i386/boot/cpucheck.c
@@ -115,8 +115,8 @@ static int has_eflag(u32 mask)
             "pushfl ; "
             "popl %1 ; "
             "popfl"
-            : "=r" (f0), "=r" (f1)
-            : "g" (mask));
+            : "=&r" (f0), "=&r" (f1)
+            : "ri" (mask));
 
         return !!((f0^f1) & mask);
 }