Need to mention here: Author of this patch series is: Author: John David Anglin <dave.anglin@xxxxxxxx> When I sent the mail the "Author" tag vanished in the mail header... Helge On 02/03/2013 11:59 PM, Helge Deller wrote: > 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
