[x86 setup] Fix assembly constraints

From: H. Peter Anvin
Date: Fri Jul 13 2007 - 18:09:33 EST


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 Chuck Ebbert for prompting this review.

Cc: Chuck Ebbert <cebbert@xxxxxxxxxx>
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx>

diff --git a/arch/i386/boot/boot.h b/arch/i386/boot/boot.h
index 0329c4f..dec70c9 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 8b0f447..991e8ce 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 9b68bd1..68222f2 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 3fa53e1..1df025c 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 3bb3573..027a2c9 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 9221614..61c8fe0 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)
-
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