[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/cpucheck.c b/arch/i386/boot/cpucheck.c
index 8b0f447..991e8ce 100644
--- a/arch/i386/boot/cpucheck.c
+++ b/arch/i386/boot/cpucheck.c
@@ -115,8 +115,8 @@
"pushfl ; "
"popl %1 ; "
"popfl"
- : "=r" (f0), "=r" (f1)
- : "g" (mask));
+ : "=&r" (f0), "=&r" (f1)
+ : "ri" (mask));
return !!((f0^f1) & mask);
}