Re: a synonym problem

[Hideo S. <sa...@de...>]

On Tue, 20 Feb 2007 10:48:12 +0900, Paul Mundt <le...@li...> wrote:
> Please also provide the n_aliases printk() from the boot log.

Feb 17 08:31:05 shlinux kernel: [42949372.970000] I-cache : n_ways=4 n_sets=256 way_incr=8192
Feb 17 08:31:05 shlinux kernel: [42949372.970000] I-cache : entry_mask=0x00001fe0 alias_mask=0x00001000 n_aliases=2
Feb 17 08:31:05 shlinux kernel: [42949372.970000] D-cache : n_ways=4 n_sets=256 way_incr=8192
Feb 17 08:31:06 shlinux kernel: [42949372.970000] D-cache : entry_mask=0x00001fe0 alias_mask=0x00001000 n_aliases=2
Feb 17 08:31:06 shlinux kernel: [42949373.190000] Mount-cache hash table entries: 512
Feb 17 08:31:06 shlinux kernel: [42949373.190000] CPU: SH7780

> Can you move your __flush_wback_region() in to the else path in
> flush_dcache_page() in arch/sh/mm/cache-sh4.c and see if the problem
> persists?

I backed out the change for install_arg_page() at fs/exec.c and applied following patch and tested it using appended test program. I can not see this problem by my test.

--- arch/sh/mm/cache-sh4.c.org	Mon Feb  5 03:44:54 2007
+++ arch/sh/mm/cache-sh4.c	Tue Feb 20 12:59:46 2007
@@ -243,16 +243,21 @@ void flush_dcache_page(struct page *page
 		unsigned long phys = PHYSADDR(page_address(page));
 		unsigned long addr = CACHE_OC_ADDRESS_ARRAY;
 		int i, n;
 
 		/* Loop all the D-cache */
 		n = cpu_data->dcache.n_aliases;
 		for (i = 0; i < n; i++, addr += 4096)
 			flush_cache_4096(addr, phys);
+	} else {
+		unsigned long phys = PHYSADDR(page_address(page));
+		int size = cpu_data->dcache.n_aliases << PAGE_SHIFT;
+
+		__flush_wback_region((void *)P1SEGADDR(phys), size);
 	}
 
 	wmb();
 }
 
 /* TODO: Selective icache invalidation through IC address array.. */
 static inline void flush_icache_all(void)
 {

-error log if original code---------------------------
% ./vfork_test 
******29 != 30
*stat = 0x100

-test programs----------------------------------------
% gcc -o args args.c
% gcc -o vfork_test vfork_test.c
-args.c-----------------------------------------------
#include <stdio.h>
#include <stdlib.h>

int main(int ac, char **av)
{
	int n = 1;
	int nn = 0;
	int err = 0;

	ac--, av++;
	while (ac > 0) {
		nn = atoi(*av);
		if (nn != n) {
			fprintf(stderr, "%d != %d\n", nn , n);
			err++;
			break;
		}
		n++;
		ac--, av++;
	}
	fprintf(stderr, "*");
	exit(err);
}

-vfork_test.c-------------------------------------------------
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/wait.h>

#define ARGS	1000

char* argv[ARGS];

exec_test(int ac, char** av)
{
	int id, stat;

	id = vfork();
	if (id == 0) {
		execve("./args", argv, NULL);
		fprintf(stderr, "can not exec args command\n");
		exit(0);
	}
	wait(&stat);
	return stat;
}

int main(int ac, char** av)
{
	int i, stat;
	char* str;

	str = calloc(ARGS, 12);
	for (i = 0; i < ARGS; i++) {
		sprintf(str, "%010d", i);
		argv[i] = str;
		str += strlen(str) + 1;
	}
	for (;;) {
		stat = exec_test(ARGS, argv);
		if (WEXITSTATUS(stat) != 0) {
			printf("stat = 0x%x\n", stat);
			exit(1);
		}
	}
}