Re: [PATCH v3 4/6] powerpc/mm: Add devmap support for ppc64

[Oliver]

On Tue, Jun 27, 2017 at 12:33 PM, Michael Ellerman  wrote:
> kbuild test robot  writes:
>
>> Hi Oliver,
>>
>> [auto build test ERROR on powerpc/next]
>> [also build test ERROR on v4.12-rc6 next-20170623]
>> [if your patch is applied to the wrong git tree, please drop us a note to 
>> help improve the system]
>>
>> url:
>> https://github.com/0day-ci/linux/commits/Oliver-O-Halloran/mm-x86-Add-ARCH_HAS_ZONE_DEVICE-to-Kconfig/20170625-102522
>> base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git 
>> next
>> config: powerpc-defconfig (attached as .config)
>> compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
>> reproduce:
>> wget 
>> https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O 
>> ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # save the attached .config to linux build tree
>> make.cross ARCH=powerpc
>>
>> All errors (new ones prefixed by >>):
>>
>>mm/gup.c: In function '__gup_device_huge_pud':
 mm/gup.c:1329:14: error: implicit declaration of function 'pud_pfn' 
 [-Werror=implicit-function-declaration]
>>  fault_pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
>>  ^~~
>>cc1: some warnings being treated as errors
>
> The key here is that CONFIG_TRANSPARENT_HUGEPAGE=n.
>
> So this needs to be fixed before I can merge this.
>
> I think the problem is just that pud_pfn() is inside #ifdef
> CONFIG_TRANSPARENT_HUGEPAGE but shouldn't be.

I'm not 100% sold on making pud_pfn() independent of THP. pmd_pfn() is
used a few times in generic code, but the usages are always gated by a
#ifdef CONFIG_TRANSPARENT_HUGEPAGE so I think we should be doing the
same here. I sent a patch[1] yesterday to fix the usage in gup.c, but
I'll do a respin if you want.

Thanks,
Oliver

[1] http://marc.info/?l=linux-mm=149845912612363=4

Re: [PATCH v3 4/6] powerpc/mm: Add devmap support for ppc64

[Michael Ellerman]

kbuild test robot  writes:

> Hi Oliver,
>
> [auto build test ERROR on powerpc/next]
> [also build test ERROR on v4.12-rc6 next-20170623]
> [if your patch is applied to the wrong git tree, please drop us a note to 
> help improve the system]
>
> url:
> https://github.com/0day-ci/linux/commits/Oliver-O-Halloran/mm-x86-Add-ARCH_HAS_ZONE_DEVICE-to-Kconfig/20170625-102522
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
> config: powerpc-defconfig (attached as .config)
> compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
> wget 
> https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O 
> ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=powerpc 
>
> All errors (new ones prefixed by >>):
>
>mm/gup.c: In function '__gup_device_huge_pud':
>>> mm/gup.c:1329:14: error: implicit declaration of function 'pud_pfn' 
>>> [-Werror=implicit-function-declaration]
>  fault_pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
>  ^~~
>cc1: some warnings being treated as errors

The key here is that CONFIG_TRANSPARENT_HUGEPAGE=n.

So this needs to be fixed before I can merge this.

I think the problem is just that pud_pfn() is inside #ifdef
CONFIG_TRANSPARENT_HUGEPAGE but shouldn't be.

cheers

Re: [PATCH v3 4/6] powerpc/mm: Add devmap support for ppc64

[kbuild test robot]

Hi Oliver,

[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.12-rc6 next-20170623]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Oliver-O-Halloran/mm-x86-Add-ARCH_HAS_ZONE_DEVICE-to-Kconfig/20170625-102522
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-defconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
wget 
https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=powerpc 

All errors (new ones prefixed by >>):

   mm/gup.c: In function '__gup_device_huge_pud':
>> mm/gup.c:1329:14: error: implicit declaration of function 'pud_pfn' 
>> [-Werror=implicit-function-declaration]
 fault_pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
 ^~~
   cc1: some warnings being treated as errors

vim +/pud_pfn +1329 mm/gup.c

b59f65fa Kirill A. Shutemov 2017-03-16  1323  
b59f65fa Kirill A. Shutemov 2017-03-16  1324  static int 
__gup_device_huge_pud(pud_t pud, unsigned long addr,
b59f65fa Kirill A. Shutemov 2017-03-16  1325unsigned long end, 
struct page **pages, int *nr)
b59f65fa Kirill A. Shutemov 2017-03-16  1326  {
b59f65fa Kirill A. Shutemov 2017-03-16  1327unsigned long fault_pfn;
b59f65fa Kirill A. Shutemov 2017-03-16  1328  
b59f65fa Kirill A. Shutemov 2017-03-16 @1329fault_pfn = pud_pfn(pud) + 
((addr & ~PUD_MASK) >> PAGE_SHIFT);
b59f65fa Kirill A. Shutemov 2017-03-16  1330return 
__gup_device_huge(fault_pfn, addr, end, pages, nr);
b59f65fa Kirill A. Shutemov 2017-03-16  1331  }
b59f65fa Kirill A. Shutemov 2017-03-16  1332  #else

:: The code at line 1329 was first introduced by commit
:: b59f65fa076a8eac2ff3a8ab7f8e1705b9fa86cb mm/gup: Implement the 
dev_pagemap() logic in the generic get_user_pages_fast() function

:: TO: Kirill A. Shutemov 
:: CC: Ingo Molnar 

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

[PATCH v3 4/6] powerpc/mm: Add devmap support for ppc64

[Oliver O'Halloran]

Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S.  This
is used to differentiate device backed memory from transparent huge
pages since they are handled in more or less the same manner by the core
mm code.

Cc: Aneesh Kumar K.V 
Signed-off-by: Oliver O'Halloran 
---
v1 -> v2: Properly differentiate THP and PMD Devmap entries. The
mm core assumes that pmd_trans_huge() and pmd_devmap() are mutually
exclusive and v1 had pmd_trans_huge() being true on a devmap pmd.

v2 -> v3:
Remove setting of _PAGE_SPECIAL in pmd_mkdevmap()
Make pud_pfn() a BUILD_BUG()
Remove unnecessary _PAGE_DEVMAP check in hash__pmd_trans_huge()
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 46 +++-
 arch/powerpc/include/asm/book3s/64/radix.h   |  2 +-
 arch/powerpc/include/asm/string.h|  1 +
 arch/powerpc/mm/hugetlbpage.c|  2 +-
 arch/powerpc/mm/pgtable-book3s64.c   |  4 +--
 arch/powerpc/mm/pgtable-hash64.c |  4 ++-
 arch/powerpc/mm/pgtable-radix.c  |  3 +-
 arch/powerpc/mm/pgtable_64.c |  2 +-
 8 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 85bc9875c3be..54b51e0fbe85 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -5,6 +5,7 @@
 
 #ifndef __ASSEMBLY__
 #include 
+#include 
 #endif
 
 /*
@@ -79,6 +80,9 @@
 
 #define _PAGE_SOFT_DIRTY   _RPAGE_SW3 /* software: software dirty tracking 
*/
 #define _PAGE_SPECIAL  _RPAGE_SW2 /* software: special page */
+#define _PAGE_DEVMAP   _RPAGE_SW1
+#define __HAVE_ARCH_PTE_DEVMAP
+
 /*
  * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
  * Instead of fixing all of them, add an alternate define which
@@ -599,6 +603,16 @@ static inline pte_t pte_mkhuge(pte_t pte)
return pte;
 }
 
+static inline pte_t pte_mkdevmap(pte_t pte)
+{
+   return __pte(pte_val(pte) | _PAGE_SPECIAL|_PAGE_DEVMAP);
+}
+
+static inline int pte_devmap(pte_t pte)
+{
+   return !!(pte_raw(pte) & cpu_to_be64(_PAGE_DEVMAP));
+}
+
 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
/* FIXME!! check whether this need to be a conditional */
@@ -1137,7 +1151,6 @@ static inline int pmd_move_must_withdraw(struct spinlock 
*new_pmd_ptl,
return true;
 }
 
-
 #define arch_needs_pgtable_deposit arch_needs_pgtable_deposit
 static inline bool arch_needs_pgtable_deposit(void)
 {
@@ -1146,6 +1159,37 @@ static inline bool arch_needs_pgtable_deposit(void)
return true;
 }
 
+static inline pmd_t pmd_mkdevmap(pmd_t pmd)
+{
+   return __pmd(pmd_val(pmd) | (_PAGE_PTE | _PAGE_DEVMAP));
+}
+
+static inline int pmd_devmap(pmd_t pmd)
+{
+   return pte_devmap(pmd_pte(pmd));
+}
+
+static inline int pud_devmap(pud_t pud)
+{
+   return 0;
+}
+
+static inline const int pud_pfn(pud_t pud)
+{
+   /*
+* Calls to pud_pfn() are gated around a pud_devmap() check
+* so this should never be used. If it grows another user we
+* want to know about it.
+*/
+   BUILD_BUG();
+   return 0;
+}
+
+static inline int pgd_devmap(pgd_t pgd)
+{
+   return 0;
+}
+
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h 
b/arch/powerpc/include/asm/book3s/64/radix.h
index ac16d1943022..ba43754e96d2 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -252,7 +252,7 @@ static inline int radix__pgd_bad(pgd_t pgd)
 
 static inline int radix__pmd_trans_huge(pmd_t pmd)
 {
-   return !!(pmd_val(pmd) & _PAGE_PTE);
+   return (pmd_val(pmd) & (_PAGE_PTE | _PAGE_DEVMAP)) == _PAGE_PTE;
 }
 
 static inline pmd_t radix__pmd_mkhuge(pmd_t pmd)
diff --git a/arch/powerpc/include/asm/string.h 
b/arch/powerpc/include/asm/string.h
index da3cdffca440..ef7c73cf7288 100644
--- a/arch/powerpc/include/asm/string.h
+++ b/arch/powerpc/include/asm/string.h
@@ -10,6 +10,7 @@
 #define __HAVE_ARCH_MEMMOVE
 #define __HAVE_ARCH_MEMCMP
 #define __HAVE_ARCH_MEMCHR
+#define __HAVE_ARCH_MEMCPY_FLUSHCACHE
 
 extern char * strcpy(char *,const char *);
 extern char * strncpy(char *,const char *, __kernel_size_t);
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index a4f33de4008e..d9958af5c98e 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -963,7 +963,7 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned 
long ea,
if (pmd_none(pmd))
return NULL;
 
-   if (pmd_trans_huge(pmd)) {
+   if (pmd_trans_huge(pmd) || pmd_devmap(pmd)) {
if (is_thp)