frv compile error in set_pte()

frv compile error in set_pte()

[Adrian Bunk]

I'm getting the follosing compile error in 2.6.18-rc5-mm1 (it might not 
be specific to -mm):

<--  snip  -->

...
  CC      arch/frv/mm/dma-alloc.o
/home/bunk/linux/kernel-2.6/linux-2.6.18-rc5-mm1/arch/frv/mm/dma-alloc.c: In function 'consistent_alloc':
/home/bunk/linux/kernel-2.6/linux-2.6.18-rc5-mm1/arch/frv/mm/dma-alloc.c:66: error: impossible constraint in 'asm'
make[2]: *** [arch/frv/mm/dma-alloc.o] Error 1

<--  snip  -->

The problem is the following code in include/asm-frv/pgtable.h:

<--  snip  -->

#define set_pte(pteptr, pteval) \
do {                                                    \
        *(pteptr) = (pteval);                           \
        asm volatile("dcf %M0" :: "U"(*pteptr));        \
} while(0)

<--  snip  -->

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed


-- 
VGER BF report: H 1.45283e-06

Re: frv compile error in set_pte()

[David Howells]

Adrian Bunk <bunk@stusta.de> wrote:

> I'm getting the follosing compile error in 2.6.18-rc5-mm1 (it might not 
> be specific to -mm):

Does your compiler support the 'M' and 'U' constraint modifiers on FRV?

David

-- 
VGER BF report: H 0

Re: frv compile error in set_pte()

[Adrian Bunk]

On Mon, Sep 04, 2006 at 10:26:25AM +0100, David Howells wrote:
> Adrian Bunk <bunk@stusta.de> wrote:
> 
> > I'm getting the follosing compile error in 2.6.18-rc5-mm1 (it might not 
> > be specific to -mm):
> 
> Does your compiler support the 'M' and 'U' constraint modifiers on FRV?

It's a gcc 4.1.1 from ftp.gnu.org.

> David

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed


-- 
VGER BF report: H 3.93628e-13

Re: frv compile error in set_pte()

[David Howells]

Adrian Bunk <bunk@stusta.de> wrote:

> > Does your compiler support the 'M' and 'U' constraint modifiers on FRV?
> 
> It's a gcc 4.1.1 from ftp.gnu.org.

I presume this:

	#define set_pte(pteptr, pteval) \
	do {                                                    \
		*(pteptr) = (pteval);                           \
		asm volatile("dcf %M0" :: "U"(*pteptr));        \
	} while(0)

	void jump(unsigned long *ppte, unsigned long pte)
	{
		set_pte(ppte, pte);
	}

Shows the problem.


I was in the process of checking that all the FRV constraint stuff got
upstream, but was stalled by an ICE whilst building the gcc-4.2.  This logged
as gcc bug #28583 and not as yet fixed.

However, I've run the above test program with the xgcc intermediate compiler
built during the compilation of gcc, and that shows the problem you're
reporting.  I'll chase it up.


Meanwhile, if you want to use a working, though older gcc, you can find one in:

	ftp://ftp.ges.redhat.com/private/releng/frv-060512-Fc6734/tools.tar.bz2

David

-- 
VGER BF report: H 0.0672117

Re: frv compile error in set_pte()

[David Howells]

Adrian Bunk <bunk@stusta.de> wrote:

> It's a gcc 4.1.1 from ftp.gnu.org.

If you patch it with the attached patch, does it then work?

David

---
Index: gcc/config/frv/frv.h
===================================================================
--- gcc/config/frv/frv.h	(revision 116693)
+++ gcc/config/frv/frv.h	(working copy)
@@ -1376,6 +1376,9 @@ extern enum reg_class reg_class_from_let
    : (C) == 'U' ? EXTRA_CONSTRAINT_FOR_U (VALUE)			\
    : 0)
 
+#define EXTRA_MEMORY_CONSTRAINT(C,STR) \
+  ((C) == 'U' || (C) == 'R' || (C) == 'T')
+
 #define CONSTRAINT_LEN(C, STR) \
   ((C) == 'D' ? 3 : DEFAULT_CONSTRAINT_LEN ((C), (STR)))
 

Re: frv compile error in set_pte()

[Adrian Bunk]

On Tue, Sep 05, 2006 at 01:31:32PM +0100, David Howells wrote:
> Adrian Bunk <bunk@stusta.de> wrote:
> 
> > It's a gcc 4.1.1 from ftp.gnu.org.
> 
> If you patch it with the attached patch, does it then work?

Yes.  :-)

> David
>...

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed