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author | John David Anglin <dave.anglin@bell.net> | 2013-02-03 22:59:09 +0000 |
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committer | Helge Deller <deller@gmx.de> | 2013-02-20 22:49:19 +0100 |
commit | 7633453978c54874849c5f40487ac9e14d43fc12 (patch) | |
tree | 552bc9a01785d2bcdca5cb283b6b2b3af5e3e5b8 /arch/parisc | |
parent | 93c3e913e104c9277e32a0d7e03f268d146c57ee (diff) | |
download | linux-3.10-7633453978c54874849c5f40487ac9e14d43fc12.tar.gz linux-3.10-7633453978c54874849c5f40487ac9e14d43fc12.tar.bz2 linux-3.10-7633453978c54874849c5f40487ac9e14d43fc12.zip |
parisc: fixes and cleanups in page cache flushing (1/4)
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@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc')
-rw-r--r-- | arch/parisc/include/asm/page.h | 20 | ||||
-rw-r--r-- | arch/parisc/kernel/cache.c | 49 | ||||
-rw-r--r-- | arch/parisc/kernel/parisc_ksyms.c | 5 |
3 files changed, 40 insertions, 34 deletions
diff --git a/arch/parisc/include/asm/page.h b/arch/parisc/include/asm/page.h index 4e0e7dbf0f3..b7adb2ac049 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 b89a85ab945..d9cbb4b22c9 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -329,17 +329,6 @@ 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 +362,9 @@ 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 +377,26 @@ 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 ceec85de629..6795dc6c995 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); |