| Message ID | 20191024093716.49420-13-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Generic page walk and ptdump | expand |
On 27/10/2019 07:59, kbuild test robot wrote: > Hi Steven, > > Thank you for the patch! Yet something to improve: > > [auto build test ERROR on linus/master] > [also build test ERROR on v5.4-rc4 next-20191025] > [if your patch is applied to the wrong git tree, please drop us a note to help > improve the system. BTW, we also suggest to use '--base' option to specify the > base tree in git format-patch, please see https://stackoverflow.com/a/37406982] > > url: https://github.com/0day-ci/linux/commits/Steven-Price/Generic-page-walk-and-ptdump/20191027-140322 > base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 5a1e843c66fa6438f389045981c37e4073917641 > config: arc-defconfig (attached as .config) > compiler: arc-elf-gcc (GCC) 7.4.0 > 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=7.4.0 make.cross ARCH=arc First off, these instructions don't work! make.cross attempts to download a sparc toolchain. However, the issue is actually quite easy to see if you look more closely at patch 2: > +#define pmd_leaf(x) (pmd_val(pmd) & _PAGE_HW_SZ) That 'pmd' variable should really have been 'x'! Below diff should fix this up - I'll repost with this squashed in shortly: ----8<---- diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h index 5ec798e50836..b4a0cf27ac1c 100644 --- a/arch/arc/include/asm/pgtable.h +++ b/arch/arc/include/asm/pgtable.h @@ -274,7 +274,7 @@ static inline void pmd_set(pmd_t *pmdp, pte_t *ptep) #define pmd_none(x) (!pmd_val(x)) #define pmd_bad(x) ((pmd_val(x) & ~PAGE_MASK)) #define pmd_present(x) (pmd_val(x)) -#define pmd_leaf(x) (pmd_val(pmd) & _PAGE_HW_SZ) +#define pmd_leaf(x) (pmd_val(x) & _PAGE_HW_SZ) #define pmd_clear(xp) do { pmd_val(*(xp)) = 0; } while (0) #define pte_page(pte) pfn_to_page(pte_pfn(pte))
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index fc4d98a3a5a0..4139e9163aee 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -38,7 +38,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, do { again: next = pmd_addr_end(addr, end); - if (pmd_none(*pmd) || !walk->vma) { + if (pmd_none(*pmd)) { if (ops->pte_hole) err = ops->pte_hole(addr, next, walk); if (err) @@ -61,9 +61,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, if (!ops->pte_entry) continue; - split_huge_pmd(walk->vma, pmd, addr); - if (pmd_trans_unstable(pmd)) - goto again; + if (walk->vma) { + split_huge_pmd(walk->vma, pmd, addr); + if (pmd_trans_unstable(pmd)) + goto again; + } else if (pmd_leaf(*pmd)) { + continue; + } + err = walk_pte_range(pmd, addr, next, walk); if (err) break; @@ -84,7 +89,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, do { again: next = pud_addr_end(addr, end); - if (pud_none(*pud) || !walk->vma) { + if (pud_none(*pud)) { if (ops->pte_hole) err = ops->pte_hole(addr, next, walk); if (err) @@ -98,9 +103,13 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, break; } - split_huge_pud(walk->vma, pud, addr); - if (pud_none(*pud)) - goto again; + if (walk->vma) { + split_huge_pud(walk->vma, pud, addr); + if (pud_none(*pud)) + goto again; + } else if (pud_leaf(*pud)) { + continue; + } if (ops->pmd_entry || ops->pte_entry) err = walk_pmd_range(pud, addr, next, walk);
Since 48684a65b4e3: "mm: pagewalk: fix misbehavior of walk_page_range for vma(VM_PFNMAP)", page_table_walk() will report any kernel area as a hole, because it lacks a vma. This means each arch has re-implemented page table walking when needed, for example in the per-arch ptdump walker. Remove the requirement to have a vma except when trying to split huge pages. Signed-off-by: Steven Price <steven.price@arm.com> --- mm/pagewalk.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)