| Message ID | 20181205041146.8481-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [V3,updated] arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade | expand |
Hi Aneesh,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on v4.20-rc5 next-20181207]
[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/Aneesh-Kumar-K-V/arch-powerpc-mm-hugetlb-NestMMU-workaround-for-hugetlb-mprotect-RW-upgrade/20181207-025514
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allmodconfig (attached as .config)
compiler: powerpc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=powerpc
All errors (new ones prefixed by >>):
arch/powerpc/mm/hugetlbpage-radix.c: In function 'radix__huge_ptep_modify_prot_commit':
>> arch/powerpc/mm/hugetlbpage-radix.c:104:6: error: implicit declaration of function 'is_pte_rw_upgrade' [-Werror=implicit-function-declaration]
if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&
^~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +/is_pte_rw_upgrade +104 arch/powerpc/mm/hugetlbpage-radix.c
93
94 void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
95 unsigned long addr, pte_t *ptep,
96 pte_t old_pte, pte_t pte)
97 {
98 struct mm_struct *mm = vma->vm_mm;
99
100 /*
101 * To avoid NMMU hang while relaxing access we need to flush the tlb before
102 * we set the new value.
103 */
> 104 if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h index 5b0177733994..66c1e4f88d65 100644 --- a/arch/powerpc/include/asm/book3s/64/hugetlb.h +++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h @@ -13,6 +13,10 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); +extern void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t pte); + static inline int hstate_get_psize(struct hstate *hstate) { unsigned long shift; @@ -42,4 +46,12 @@ static inline bool gigantic_page_supported(void) /* hugepd entry valid bit */ #define HUGEPD_VAL_BITS (0x8000000000000000UL) +#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start +extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); + +#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit +extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t new_pte); #endif diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c index 2e6a8f9345d3..48fe74bfeab1 100644 --- a/arch/powerpc/mm/hugetlbpage-hash64.c +++ b/arch/powerpc/mm/hugetlbpage-hash64.c @@ -121,3 +121,30 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, *ptep = __pte(new_pte & ~H_PAGE_BUSY); return 0; } + +pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep) +{ + unsigned long pte_val; + /* + * Clear the _PAGE_PRESENT so that no hardware parallel update is + * possible. Also keep the pte_present true so that we don't take + * wrong fault. + */ + pte_val = pte_update(vma->vm_mm, addr, ptep, + _PAGE_PRESENT, _PAGE_INVALID, 1); + + return __pte(pte_val); +} +EXPORT_SYMBOL(huge_ptep_modify_prot_start); + +void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, + pte_t *ptep, pte_t old_pte, pte_t pte) +{ + + if (radix_enabled()) + return radix__huge_ptep_modify_prot_commit(vma, addr, ptep, + old_pte, pte); + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); +} +EXPORT_SYMBOL(huge_ptep_modify_prot_commit); diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c index 2486bee0f93e..11d9ea28a816 100644 --- a/arch/powerpc/mm/hugetlbpage-radix.c +++ b/arch/powerpc/mm/hugetlbpage-radix.c @@ -90,3 +90,20 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, return vm_unmapped_area(&info); } + +void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t pte) +{ + struct mm_struct *mm = vma->vm_mm; + + /* + * To avoid NMMU hang while relaxing access we need to flush the tlb before + * we set the new value. + */ + if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) && + (atomic_read(&mm->context.copros) > 0)) + radix__flush_hugetlb_page(vma, addr); + + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); +}
NestMMU requires us to mark the pte invalid and flush the tlb when we do a RW upgrade of pte. We fixed a variant of this in the fault path in commit Fixes: bd5050e38aec ("powerpc/mm/radix: Change pte relax sequence to handle nest MMU hang") Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- arch/powerpc/include/asm/book3s/64/hugetlb.h | 12 +++++++++ arch/powerpc/mm/hugetlbpage-hash64.c | 27 ++++++++++++++++++++ arch/powerpc/mm/hugetlbpage-radix.c | 17 ++++++++++++ 3 files changed, 56 insertions(+)