* [x86 setup] Fix assembly constraints
@ 2007-07-13 22:09 H. Peter Anvin
2007-07-13 22:20 ` Chuck Ebbert
0 siblings, 1 reply; 2+ messages in thread
From: H. Peter Anvin @ 2007-07-13 22:09 UTC (permalink / raw)
To: torvalds; +Cc: linux-kernel, H. Peter Anvin, Chuck Ebbert
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@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 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)
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [x86 setup] Fix assembly constraints
2007-07-13 22:09 [x86 setup] Fix assembly constraints H. Peter Anvin
@ 2007-07-13 22:20 ` Chuck Ebbert
0 siblings, 0 replies; 2+ messages in thread
From: Chuck Ebbert @ 2007-07-13 22:20 UTC (permalink / raw)
To: H. Peter Anvin; +Cc: torvalds, linux-kernel, Etienne Lorrain
On 07/13/2007 06:09 PM, H. Peter Anvin wrote:
> 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.
>
That was Etienne Lorrain (cc'd), not me. All I did was reply
to Etienne's post and add cc:'s because the original only went
to linux-kernel.
> 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 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)
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2007-07-13 22:20 ` Chuck Ebbert
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