Commit 57737c49 authored by Helge Deller's avatar Helge Deller
Browse files

parisc: fix cache-flushing 



This commit:
f8dae006: 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: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # v3.9+
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 8a10bc9d

arch/parisc/include/asm/cacheflush.h

+0 −2
Original line number Diff line number Diff line
@@ -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);

}

arch/parisc/include/asm/page.h

+2 −1
Original line number Diff line number Diff line
@@ -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 */

arch/parisc/kernel/cache.c

+14 −0
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE