Re: Possibly icahe/dcache synchronization problem on sh7785lcr

[Paul Mundt <lethal@linux-sh.org>]

On Fri, Oct 09, 2009 at 04:55:30PM +0400, Valentin R Sitsikov wrote:
> During execution of user space application form time to time
> invalid instruction or bus error occured or even init dies during sturtup.
> The situation became more stable if i use the following code:
> static void sh4_flush_icache_page(void *arg)
> {
>         flush_dcache_all();
>         flush_icache_all();
> }
> ...
> local_flush_icache_page         = sh4_flush_icache_page;
> This is done because previous experience  with 2.6.20 on sdk7785.
> There was the similar problems (at least it looks like).
> 
flush_icache_page() is a legacy interface, all of which can be handled in
flush_dcache_page()/update_mmu_cache() (well, __update_cache() now) these
days. I think you've hit a case where we need to throw in an I-cache
invalidation in. Can you give the following patch a try and see how that
behaves (while leaving local_flush_icache_page unset)?

---

diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c
index a98c7d8..74b44ab 100644
--- a/arch/sh/mm/cache-sh4.c
+++ b/arch/sh/mm/cache-sh4.c
@@ -115,9 +115,9 @@ static inline void flush_cache_4096(unsigned long start,
 static void sh4_flush_dcache_page(void *arg)
 {
 	struct page *page = arg;
-#ifndef CONFIG_SMP
 	struct address_space *mapping = page_mapping(page);
 
+#ifndef CONFIG_SMP
 	if (mapping && !mapping_mapped(mapping))
 		set_bit(PG_dcache_dirty, &page->flags);
 	else
@@ -131,6 +131,8 @@ static void sh4_flush_dcache_page(void *arg)
 		n = boot_cpu_data.dcache.n_aliases;
 		for (i = 0; i < n; i++, addr += 4096)
 			flush_cache_4096(addr, phys);
+
+		flush_icache_all();
 	}
 
 	wmb();