From 57737c49dd72c96cfbcd4f66559f3ffc399aeb4f Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Fri, 31 Jan 2014 21:33:17 +0100 Subject: [PATCH] parisc: fix cache-flushing This commit: f8dae00684d678afa13041ef170cecfd1297ed40: parisc: Ensure full cache coherency for kmap/kunmap caused negative caching side-effects, e.g. hanging processes with expect and too many inequivalent alias messages from flush_dcache_page() on Debian 5 systems. This patch now partly reverts it and has been in production use on our debian buildd makeservers since a week without any major problems. Signed-off-by: Helge Deller Signed-off-by: John David Anglin Cc: stable@vger.kernel.org # v3.9+ Signed-off-by: Helge Deller --- arch/parisc/include/asm/cacheflush.h | 2 -- arch/parisc/include/asm/page.h | 3 ++- arch/parisc/kernel/cache.c | 14 ++++++++++++++ 3 files changed, 16 insertions(+), 3 deletions(-) diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h index 2f9b751878ba..de65f66ea64e 100644 --- a/arch/parisc/include/asm/cacheflush.h +++ b/arch/parisc/include/asm/cacheflush.h @@ -132,7 +132,6 @@ void mark_rodata_ro(void); static inline void *kmap(struct page *page) { might_sleep(); - flush_dcache_page(page); return page_address(page); } @@ -144,7 +143,6 @@ static inline void kunmap(struct page *page) static inline void *kmap_atomic(struct page *page) { pagefault_disable(); - flush_dcache_page(page); return page_address(page); } diff --git a/arch/parisc/include/asm/page.h b/arch/parisc/include/asm/page.h index c53fc63149e8..637fe031aa84 100644 --- a/arch/parisc/include/asm/page.h +++ b/arch/parisc/include/asm/page.h @@ -29,7 +29,8 @@ struct page; void clear_page_asm(void *page); void copy_page_asm(void *to, void *from); #define clear_user_page(vto, vaddr, page) clear_page_asm(vto) -#define copy_user_page(vto, vfrom, vaddr, page) copy_page_asm(vto, vfrom) +void copy_user_page(void *vto, void *vfrom, unsigned long vaddr, + struct page *pg); /* #define CONFIG_PARISC_TMPALIAS */ diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index a72545554a31..ac87a40502e6 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -388,6 +388,20 @@ void flush_kernel_dcache_page_addr(void *addr) } EXPORT_SYMBOL(flush_kernel_dcache_page_addr); +void copy_user_page(void *vto, void *vfrom, unsigned long vaddr, + struct page *pg) +{ + /* Copy using kernel mapping. No coherency is needed (all in + kunmap) for the `to' page. However, the `from' page needs to + be flushed through a mapping equivalent to the user mapping + before it can be accessed through the kernel mapping. */ + preempt_disable(); + flush_dcache_page_asm(__pa(vfrom), vaddr); + preempt_enable(); + copy_page_asm(vto, vfrom); +} +EXPORT_SYMBOL(copy_user_page); + void purge_tlb_entries(struct mm_struct *mm, unsigned long addr) { unsigned long flags; -- 2.20.1