[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>
diff --git a/arch/i386/boot/mca.c b/arch/i386/boot/mca.c
index 9b68bd1..68222f2 100644
--- a/arch/i386/boot/mca.c
+++ b/arch/i386/boot/mca.c
@@ -26,7 +26,7 @@
"setc %0 ; "
"movw %%es, %1 ; "
"popw %%es"
- : "=acdSDm" (err), "=acdSDm" (es), "=b" (bx)
+ : "=acd" (err), "=acdSD" (es), "=b" (bx)
: "a" (0xc000));
if (err)