Re: MAX_PAGE_SIZE for m68k (Re: CVS commit: src/sys/arch/arm/include/arm32)

[Jason Thorpe <thorpej%me.com@localhost>]

> On Jan 13, 2020, at 8:15 AM, Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost> wrote:
> 
> christos@ wrote:
> 
>>> Now I get the following erro during local tests of
>>> "build.sh -U -m hp300 release" on NetBSD/i386 9.0_RC1 host:
>>> 
>>> ---
>>> #    create  compat_util/compat_exec.d
> :
>>> In file included from /s/cvs/src/sys/sys/param.h:149:0,
>>>                from /s/cvs/src/sys/compat/common/compat_exec.c:41:
>>> ./m68k/pmap_motorola.h:165:5: error: operator '*' has no left operand
>>> #if PAGE_SIZE == 8192 /* NBPG / (SG4_LEV1SIZE * sizeof(st_entry_t)) */
>>>    ^
>>> nbmkdep: compile failed.
>>> *** [compat_exec.d] Error code 1
>> 
>> try cc -E?
> 
> It turns out the problem is more complicated.
> 
> <uvm/uvm_param.h> has the following definitions:
> 
> https://nxr.netbsd.org/xref/src/sys/uvm/uvm_param.h?r=1.38#135

I would suggest a possible workaround for this could be to define an additional:

#define __HAVE_FIXED_PAGE_SIZE

...at could also be tested here... the kernel truly does have a fixed page size, but userland not necessarily so.

> ---
>    135  * If MIN_PAGE_SIZE and MAX_PAGE_SIZE are not equal, then we must use
>    136  * non-constant PAGE_SIZE, et al for LKMs.
>    137  */
>    138 #if (MIN_PAGE_SIZE != MAX_PAGE_SIZE)
>    139 #define	__uvmexp_pagesize
>    140 #if defined(_LKM) || defined(_MODULE)
>    141 #undef PAGE_SIZE
>    142 #undef PAGE_MASK
>    143 #undef PAGE_SHIFT
>    144 #endif
>    145 #endif
>    146 
>    147 /*
>    148  * Now provide PAGE_SIZE, PAGE_MASK, and PAGE_SHIFT if we do not
>    149  * have ones that are compile-time constants.
>    150  */
>    151 #if !defined(PAGE_SIZE)
>    152 extern const int *const uvmexp_pagesize;
>    153 extern const int *const uvmexp_pagemask;
>    154 extern const int *const uvmexp_pageshift;
>    155 #define	PAGE_SIZE	(*uvmexp_pagesize)	/* size of page */
>    156 #define	PAGE_MASK	(*uvmexp_pagemask)	/* size of page - 1 */
>    157 #define	PAGE_SHIFT	(*uvmexp_pageshift)	/* bits to shift for pages */
>    158 #endif /* PAGE_SIZE */
> ---
> 
> I.e. <uvm/uvm_param> assumes PAGE_SIZE is not compile time constant
> for MODULEs if (MIN_PAGE_SIZE != MAX_PAGE_SIZE).
> 
> Probably this is the same reason of recent arm build failures:
> https://releng.netbsd.org/builds/HEAD/202001130720Z/
> https://releng.netbsd.org/builds/HEAD/202001130720Z/evbarm-earm.build.failed
> ---
> /tmp/genassym.Lq8h9d/assym.c:57:1: error: asm operand 0 probably doesn't match constraints [-Werror]
> __asm("XYZZY VM_MIN_ADDRESS %0" : : "n" (VM_MIN_ADDRESS));
> ^~~~~
> /tmp/genassym.Lq8h9d/assym.c:58:1: error: asm operand 0 probably doesn't match constraints [-Werror]
> __asm("XYZZY VM_MAXUSER_ADDRESS %0" : : "n" (VM_MAXUSER_ADDRESS));
> ^~~~~
> /tmp/genassym.Lq8h9d/assym.c:97:1: error: asm operand 0 probably doesn't match constraints [-Werror]
> __asm("XYZZY PAGE_MASK %0" : : "n" (PAGE_MASK));
> ^~~~~
> /tmp/genassym.Lq8h9d/assym.c:98:1: error: asm operand 0 probably doesn't match constraints [-Werror]
> __asm("XYZZY PAGE_SIZE %0" : : "n" (PAGE_SIZE));
> ^~~~~
> ---
> 
> Should we prepare independent constant for
> "possible pagesize value among different MACHINE with the same MACHINE_ARCH"
> for jemalloc(3)?
> 
> ---
> Izumi Tsutsui

-- thorpej