From: H. Peter Anvin <hpa@zytor.com>
Date: Sat, 14 Jul 2007 23:47:13 +0000 (-0700)
Subject: [x86 setup] Fix assembly constraints
X-Git-Tag: v2.6.23-rc1~490^2~3
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5593eaa854d0b23c3b270933a93b9b82946df729;p=linux-2.6

[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/boot.h b/arch/i386/boot/boot.h
index 0329c4fe4f..dec70c9b60 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 8b0f4473b0..991e8ceae1 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 9b68bd1aef..68222f2d4b 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 3fa53e15ed..1df025c732 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 3bb3573cd6..027a2c9030 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 9221614d0d..61c8fe0453 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)