linux-kernel - [PATCH] flush icache before set_pte take6. [4/4] optimization for cpus other than montecito

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Message-Id: <20070731114155.5785123c.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Tue, 31 Jul 2007 11:41:55 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	"linux-ia64@...r.kernel.org" <linux-ia64@...r.kernel.org>,
	"tony.luck@...el.com" <tony.luck@...el.com>,
	"Zoltan.Menyhart@...l.net" <Zoltan.Menyhart@...l.net>,
	Christoph Lameter <clameter@....com>
Subject: [PATCH] flush icache before set_pte take6. [4/4] optimization for
 cpus other than montecito


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@...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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