This is the first patch in a series of 4, with which the page cache flushing of parisc will gets fixed and enhanced. This even fixes the nasty "minifail" bug (http://wiki.parisc-linux.org/TestCases?highlight=%28minifail%29) which prevented parisc to stay an official debian port. Basically the flush in copy_user_page together with the TLB patch from commit 7139bc1579901b53db7e898789e916ee2fb52d78 is what fixes the minifail bug. This patch still uses the TMPALIAS approach. The new copy_user_page implementation calls flush_dcache_page_asm to flush the user dcache page (crucial for minifail fix) via a kernel TMPALIAS mapping. After that, it just copies the page using the kernel mapping. It does a final flush if needed. Generally it is hard to avoid doing some cache flushes using the kernel mapping (e.g., copy_to_user_page and copy_from_user_page). This patch depends on a subsequent change to pacache.S implementing clear_page_asm and copy_page_asm. These are optimized routines to clear and copy a page. The calls in clear_user_page and copy_user_page could be replaced by calls to memset and memcpy, respectively. I tested prefetch optimizations in clear_page_asm and copy_page_asm but didn't see any significant performance improvement on rp3440. I'm not sure if these are routines are significantly faster than memset and/or memcpy, but they are there for further performance evaluation. Signed-off-by: John David Anglin <dave.anglin@xxxxxxxx> Signed-off-by: Helge Deller <deller@xxxxxx> diff --git a/arch/parisc/include/asm/page.h b/arch/parisc/include/asm/page.h index 4e0e7db..d9812d8 100644 --- a/arch/parisc/include/asm/page.h +++ b/arch/parisc/include/asm/page.h @@ -21,15 +21,27 @@ #include <asm/types.h> #include <asm/cache.h> -#define clear_page(page) memset((void *)(page), 0, PAGE_SIZE) -#define copy_page(to,from) copy_user_page_asm((void *)(to), (void *)(from)) +#define clear_page(page) clear_page_asm((void *)(page)) +#define copy_page(to, from) copy_page_asm((void *)(to), (void *)(from)) struct page; -void copy_user_page_asm(void *to, void *from); +void clear_page_asm(void *page); +void copy_page_asm(void *to, void *from); +void clear_user_page(void *vto, unsigned long vaddr, struct page *pg); void copy_user_page(void *vto, void *vfrom, unsigned long vaddr, struct page *pg); -void clear_user_page(void *page, unsigned long vaddr, struct page *pg); + +/* #define CONFIG_PARISC_TMPALIAS */ + +#ifdef CONFIG_PARISC_TMPALIAS +void clear_user_highpage(struct page *page, unsigned long vaddr); +#define clear_user_highpage clear_user_highpage +struct vm_area_struct; +void copy_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma); +#define __HAVE_ARCH_COPY_USER_HIGHPAGE +#endif /* * These are used to make use of C type-checking.. diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index b89a85a..703ed48 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -329,17 +331,6 @@ EXPORT_SYMBOL(flush_kernel_dcache_page_asm); EXPORT_SYMBOL(flush_data_cache_local); EXPORT_SYMBOL(flush_kernel_icache_range_asm); -void clear_user_page_asm(void *page, unsigned long vaddr) -{ - unsigned long flags; - /* This function is implemented in assembly in pacache.S */ - extern void __clear_user_page_asm(void *page, unsigned long vaddr); - - purge_tlb_start(flags); - __clear_user_page_asm(page, vaddr); - purge_tlb_end(flags); -} - #define FLUSH_THRESHOLD 0x80000 /* 0.5MB */ int parisc_cache_flush_threshold __read_mostly = FLUSH_THRESHOLD; @@ -373,20 +364,9 @@ void __init parisc_setup_cache_timing(void) printk(KERN_INFO "Setting cache flush threshold to %x (%d CPUs online)\n", parisc_cache_flush_threshold, num_online_cpus()); } -extern void purge_kernel_dcache_page(unsigned long); -extern void clear_user_page_asm(void *page, unsigned long vaddr); - -void clear_user_page(void *page, unsigned long vaddr, struct page *pg) -{ - unsigned long flags; - - purge_kernel_dcache_page((unsigned long)page); - purge_tlb_start(flags); - pdtlb_kernel(page); - purge_tlb_end(flags); - clear_user_page_asm(page, vaddr); -} -EXPORT_SYMBOL(clear_user_page); +extern void purge_kernel_dcache_page_asm(unsigned long); +extern void clear_user_page_asm(void *, unsigned long); +extern void copy_user_page_asm(void *, void *, unsigned long); void flush_kernel_dcache_page_addr(void *addr) { @@ -399,11 +379,26 @@ void flush_kernel_dcache_page_addr(void *addr) } EXPORT_SYMBOL(flush_kernel_dcache_page_addr); +void clear_user_page(void *vto, unsigned long vaddr, struct page *page) +{ + clear_page_asm(vto); + if (!parisc_requires_coherency()) + flush_kernel_dcache_page_asm(vto); +} +EXPORT_SYMBOL(clear_user_page); + void copy_user_page(void *vto, void *vfrom, unsigned long vaddr, - struct page *pg) + struct page *pg) { - /* no coherency needed (all in kmap/kunmap) */ - copy_user_page_asm(vto, vfrom); + /* Copy using kernel mapping. No coherency is needed + (all in kmap/kunmap) on machines that don't support + non-equivalent aliasing. However, the `from' page + needs to be flushed 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); if (!parisc_requires_coherency()) flush_kernel_dcache_page_asm(vto); } diff --git a/arch/parisc/kernel/parisc_ksyms.c b/arch/parisc/kernel/parisc_ksyms.c index ceec85d..6795dc6 100644 --- a/arch/parisc/kernel/parisc_ksyms.c +++ b/arch/parisc/kernel/parisc_ksyms.c @@ -157,5 +157,6 @@ extern void _mcount(void); EXPORT_SYMBOL(_mcount); #endif -/* from pacache.S -- needed for copy_page */ -EXPORT_SYMBOL(copy_user_page_asm); +/* from pacache.S -- needed for clear/copy_page */ +EXPORT_SYMBOL(clear_page_asm); +EXPORT_SYMBOL(copy_page_asm); -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
