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 <[email protected]>

Signed-off-by Helge Deller <[email protected]>

arch/parisc/include/asm/page.h +16 -4

index 4e0e7db..d9812d8 100644
@@ -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..

arch/parisc/kernel/cache.c +21 -28

index b89a85a..703ed48 100644
@@ -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);
 }

arch/parisc/kernel/parisc_ksyms.c +3 -2

index ceec85d..6795dc6 100644
@@ -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);

Need to mention here:

Author of this patch series is:
Author: John David Anglin <[email protected]>

When I sent the mail the "Author" tag vanished in the mail header...

Helge

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.

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Is this series expected to fix the thread related problems I see in the git testsuite?

Quoted 14 lines

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Quoted 2 lines

Is this series expected to fix the thread related problems I see in the git testsuite?

I expect so, if not, please let us know!

Quoted 13 lines

Quoted 13 lines

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Quoted 3 lines

Quoted 2 lines

Is this series expected to fix the thread related problems I see in the git testsuite?

I expect so, if not, please let us know!

Ahem... actually:
MAYBE!!!

The problem is, that you probably will need an updated glibc (and maybe compiler) as well. Dave has done a lot of work to fix stuff. We have copied the most important update-packages to ftp.parisc-linux.org. To update, just make sure the following lines are in your /etc/apt/source.list file:
deb ftp://ftp.de.debian.org/debian-ports unstable main
deb ftp://ftp.parisc-linux.org/debian-ports/unstable unstable main
deb-src ftp://ftp.de.debian.org/debian unstable main

Do *not* just update to the packages of debian-ports.org. If you do that it will render your system unbootable, since the udev-package is broken and it will not find your discs at startup.

It's on my todo-list to upload further packages, update the website on how to update your system, and of course to get a buildd working...

Quoted 36 lines · Helge Deller

Quoted 15 lines

Quoted 15 lines

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Quoted 4 lines

Quoted 2 lines

Is this series expected to fix the thread related problems I see in the git testsuite?

I expect so, if not, please let us know!

Ahem... actually:
MAYBE!!!

The problem is, that you probably will need an updated glibc (and maybe compiler) as well. Dave has done a lot of work to fix stuff. We have copied the most important update-packages to ftp.parisc-linux.org. To update, just make sure the following lines are in your /etc/apt/source.list file: deb ftp://ftp.de.debian.org/debian-ports unstable main
deb ftp://ftp.parisc-linux.org/debian-ports/unstable unstable main deb-src ftp://ftp.de.debian.org/debian unstable main

Do *not* just update to the packages of debian-ports.org. If you do that it will render your system unbootable, since the udev-package is broken and it will not find your discs at startup.

Quoted 2 lines

It's on my todo-list to upload further packages, update the website on how to update your system, and of course to get a buildd working...

Just a note, these packages are for debian systems. I believe that Eike is running gentoo. With respect to glibc, Carlos had a set of changes which I submitted to Debian. The full set was accepted around the -30 unstable release.
I think most of these are in gentoo but the matter needs review.

Quoted 34 lines · John David Anglin

Quoted 33 lines · Helge Deller

Quoted 14 lines

Quoted 14 lines

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Quoted 3 lines

Quoted 2 lines

Is this series expected to fix the thread related problems I see in the git testsuite?

I expect so, if not, please let us know!

Ahem... actually:
MAYBE!!!

The problem is, that you probably will need an updated glibc (and maybe compiler) as well. Dave has done a lot of work to fix stuff. We have copied the most important update-packages to ftp.parisc-linux.org. To update, just make sure the following lines are in your /etc/apt/source.list file: deb ftp://ftp.de.debian.org/debian-ports unstable main
deb ftp://ftp.parisc-linux.org/debian-ports/unstable unstable main deb-src ftp://ftp.de.debian.org/debian unstable main

Do *not* just update to the packages of debian-ports.org. If you do that it will render your system unbootable, since the udev-package is broken and it will not find your discs at startup.

Quoted 7 lines

Quoted 2 lines

It's on my todo-list to upload further packages, update the website on how to update your system, and of course to get a buildd working...

Just a note, these packages are for debian systems. I believe that Eike is running gentoo. With respect to glibc, Carlos had a set of changes which I submitted to Debian. The full set was accepted around the -30 unstable release.
I think most of these are in gentoo but the matter needs review.

Oh Dave, I wanted to write a mail with "apt-get: no such command" or something ;) I have tested your patchset you sent on 2012-12-31 and it fixed my git issues. So it simply boils down to: is everything from that patchset now in Helge's tree?

Quoted 36 lines · Helge Deller

Quoted 15 lines

Quoted 15 lines

Von: Rolf Eike Beer <[email protected]>

Quoted 11 lines · Helge Deller

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.

Quoted 4 lines

Quoted 2 lines

Is this series expected to fix the thread related problems I see in the git testsuite?

I expect so, if not, please let us know!

Ahem... actually:
MAYBE!!!

The problem is, that you probably will need an updated glibc (and maybe compiler) as well. Dave has done a lot of work to fix stuff. We have copied the most important update-packages to ftp.parisc-linux.org. To update, just make sure the following lines are in your /etc/apt/source.list file: deb ftp://ftp.de.debian.org/debian-ports unstable main
deb ftp://ftp.parisc-linux.org/debian-ports/unstable unstable main deb-src ftp://ftp.de.debian.org/debian unstable main

Do *not* just update to the packages of debian-ports.org. If you do that it will render your system unbootable, since the udev-package is broken and it will not find your discs at startup.

Quoted 2 lines

It's on my todo-list to upload further packages, update the website on how to update your system, and of course to get a buildd working...

Just a note, these packages are for debian systems. I believe that Eike is running gentoo. With respect to glibc, Carlos had a set of changes which I submitted to Debian. The full set was accepted around the -30 unstable release.
I think most of these are in gentoo but the matter needs review.