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Commit 5593eaa8 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

[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: default avatarH. Peter Anvin <hpa@zytor.com>
parent 9aa3909c

arch/i386/boot/boot.h

+1 −1
Original line number Diff line number Diff line
@@ -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)

{

arch/i386/boot/cpucheck.c

+2 −2
Original line number Diff line number Diff line
@@ -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);

}

arch/i386/boot/mca.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

arch/i386/boot/pm.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

arch/i386/boot/video.c

+1 −1
Original line number Diff line number Diff line
@@ -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));

	}