[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>

6 files changed, 7 insertions, 7 deletions

diff --git a/arch/i386/boot/boot.h b/arch/i386/boot/boot.h
index 0329c4fe4f88..dec70c9b6050 100644
--- a/arch/i386/boot/boot.h
+++ b/arch/i386/boot/boot.h
@@ -56,7 +56,7 @@ static inline u16 inw(u16 port)
 
 static inline void outl(u32 v, u16 port)
 {
-        asm volatile("outl %0,%1" : : "a" (v), "dn" (port));
+        asm volatile("outl %0,%1" : : "a" (v), "dN" (port));
 }
 static inline u32 inl(u32 port)
 {
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);
 }
diff --git a/arch/i386/boot/mca.c b/arch/i386/boot/mca.c
index 9b68bd1aef19..68222f2d4b67 100644
--- a/arch/i386/boot/mca.c
+++ b/arch/i386/boot/mca.c
@@ -26,7 +26,7 @@ int query_mca(void)
             "setc %0 ; "
             "movw %%es, %1 ; "
             "popw %%es"
-            : "=acdSDm" (err), "=acdSDm" (es), "=b" (bx)
+            : "=acd" (err), "=acdSD" (es), "=b" (bx)
             : "a" (0xc000));
 
         if (err)
diff --git a/arch/i386/boot/pm.c b/arch/i386/boot/pm.c
index 3fa53e15ed77..1df025c73261 100644
--- a/arch/i386/boot/pm.c
+++ b/arch/i386/boot/pm.c
@@ -65,7 +65,7 @@ static void move_kernel_around(void)
                              "popw %%ds ; "
                              "popw %%es"
                              : "+c" (dwords)
-                             : "rm" (dst_seg), "rm" (src_seg)
+                             : "r" (dst_seg), "r" (src_seg)
                              : "esi", "edi");
 
                 syssize -= paras;
diff --git a/arch/i386/boot/video.c b/arch/i386/boot/video.c
index 3bb3573cd6a1..027a2c90300b 100644
--- a/arch/i386/boot/video.c
+++ b/arch/i386/boot/video.c
@@ -411,7 +411,7 @@ static void restore_screen(void)
                              "1: rep;stosl ; "
                              "popw %%es"
                              : "+D" (dst), "+c" (npad)
-                             : "bdSm" (video_segment),
+                             : "bdS" (video_segment),
                                "a" (0x07200720));
         }
 
diff --git a/arch/i386/boot/voyager.c b/arch/i386/boot/voyager.c
index 9221614d0db8..61c8fe0453be 100644
--- a/arch/i386/boot/voyager.c
+++ b/arch/i386/boot/voyager.c
@@ -32,7 +32,7 @@ int query_voyager(void)
             "setc %0 ; "
             "movw %%es, %1 ; "
             "popw %%es"
-            : "=qm" (err), "=rm" (es), "=D" (di)
+            : "=q" (err), "=r" (es), "=D" (di)
             : "a" (0xffc0));
 
         if (err)