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SubjectRe: [PATCH] flush icache before set_pte take6. [4/4] optimization for cpus other than montecito
This seems crazy to me.  Flushing should occur according to the
*architecture*, not model-by-model. Even if we happen to get "lucky"
on pre-Montecito CPUs, that doesn't justify such ugly hacks. Or you
really want to debug this *again* come next CPU?

--david

On 7/30/07, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
> Add "L2 cache is separated? check flag" as read_mostly global variable.
>
> This add one memory reference to global variable to page faults of "executable"
> map in do_wp_page(page copy case), file-mapped page fault and some system calls
> which does memory map changes. But not so bad as calling sync_icache_dcache in
> architectures which doesn't need it.
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
>
>
> ---
> arch/ia64/kernel/setup.c | 7 +++++++
> include/asm-ia64/pgtable.h | 3 ++-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> Index: linux-2.6.23-rc1.test/arch/ia64/kernel/setup.c
> ===================================================================
> --- linux-2.6.23-rc1.test.orig/arch/ia64/kernel/setup.c
> +++ linux-2.6.23-rc1.test/arch/ia64/kernel/setup.c
> @@ -106,6 +106,8 @@ struct io_space io_space[MAX_IO_SPACES];
> EXPORT_SYMBOL(io_space);
> unsigned int num_io_spaces;
>
> +int separated_l2_icache_dcache __read_mostly;
> +
> /*
> * "flush_icache_range()" needs to know what processor dependent stride size to use
> * when it makes i-cache(s) coherent with d-caches.
> @@ -718,6 +720,11 @@ get_model_name(__u8 family, __u8 model)
> printk(KERN_ERR
> "%s: Table overflow. Some processor model information will be missing\n",
> __FUNCTION__);
> + /* Montecito has separated L2 Icache and Dcache. This requires
> + synchronize Icache and Dcache before set_pte() */
> + if (family == 0x20)
> + separated_l2_icache_dcache = 1;
> +
> return "Unknown";
> }
>
> Index: linux-2.6.23-rc1.test/include/asm-ia64/pgtable.h
> ===================================================================
> --- linux-2.6.23-rc1.test.orig/include/asm-ia64/pgtable.h
> +++ linux-2.6.23-rc1.test/include/asm-ia64/pgtable.h
> @@ -489,9 +489,10 @@ extern struct page *zero_page_memmap_ptr
> * as an executable pte.
> */
> extern void __sync_icache_dcache(pte_t pte);
> +extern int separated_l2_icache_dcache;
> static inline void sync_icache_dcache(pte_t pte)
> {
> - if (pte_exec(pte))
> + if (pte_exec(pte) && separated_l2_icache_dcache)
> __sync_icache_dcache(pte);
> }
> #define __HAVE_ARCH_SYNC_ICACHE_DCACHE
>
> -
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>


--
Mosberger Consulting LLC, http://www.mosberger-consulting.com/
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