| Message ID | 20191018101248.33727-14-steven.price@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Generic page walk and ptdump | expand |
Steven Price <steven.price@arm.com> 於 2019年10月19日 週六 下午4:12寫道： > > It is useful to be able to skip parts of the page table tree even when > walking without VMAs. Add test_p?d callbacks similar to test_walk but > which are called just before a table at that level is walked. If the > callback returns non-zero then the entire table is skipped. > > Signed-off-by: Steven Price <steven.price@arm.com> > --- > include/linux/pagewalk.h | 11 +++++++++++ > mm/pagewalk.c | 24 ++++++++++++++++++++++++ > 2 files changed, 35 insertions(+) > > diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h > index 12004b097eae..df424197a25a 100644 > --- a/include/linux/pagewalk.h > +++ b/include/linux/pagewalk.h > @@ -24,6 +24,11 @@ struct mm_walk; > * "do page table walk over the current vma", returning > * a negative value means "abort current page table walk > * right now" and returning 1 means "skip the current vma" > + * @test_pmd: similar to test_walk(), but called for every pmd. > + * @test_pud: similar to test_walk(), but called for every pud. > + * @test_p4d: similar to test_walk(), but called for every p4d. > + * Returning 0 means walk this part of the page tables, > + * returning 1 means to skip this range. > * > * p?d_entry callbacks are called even if those levels are folded on a > * particular architecture/configuration. > @@ -46,6 +51,12 @@ struct mm_walk_ops { > struct mm_walk *walk); > int (*test_walk)(unsigned long addr, unsigned long next, > struct mm_walk *walk); > + int (*test_pmd)(unsigned long addr, unsigned long next, > + pmd_t *pmd_start, struct mm_walk *walk); > + int (*test_pud)(unsigned long addr, unsigned long next, > + pud_t *pud_start, struct mm_walk *walk); > + int (*test_p4d)(unsigned long addr, unsigned long next, > + p4d_t *p4d_start, struct mm_walk *walk); > }; > > /** > diff --git a/mm/pagewalk.c b/mm/pagewalk.c > index 4139e9163aee..43acffefd43f 100644 > --- a/mm/pagewalk.c > +++ b/mm/pagewalk.c > @@ -34,6 +34,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, > const struct mm_walk_ops *ops = walk->ops; > int err = 0; > > + if (ops->test_pmd) { > + err = ops->test_pmd(addr, end, pmd_offset(pud, 0UL), walk); > + if (err < 0) > + return err; > + if (err > 0) > + return 0; > + } > + > pmd = pmd_offset(pud, addr); > do { > again: > @@ -85,6 +93,14 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, > const struct mm_walk_ops *ops = walk->ops; > int err = 0; > > + if (ops->test_pud) { > + err = ops->test_pud(addr, end, pud_offset(p4d, 0UL), walk); > + if (err < 0) > + return err; > + if (err > 0) > + return 0; > + } > + > pud = pud_offset(p4d, addr); > do { > again: > @@ -128,6 +144,14 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, > const struct mm_walk_ops *ops = walk->ops; > int err = 0; > > + if (ops->test_p4d) { > + err = ops->test_p4d(addr, end, p4d_offset(pgd, 0UL), walk); > + if (err < 0) > + return err; > + if (err > 0) > + return 0; > + } > + > p4d = p4d_offset(pgd, addr); > do { > next = p4d_addr_end(addr, end); > -- > 2.20.1 > It's good to me. Tested-by: Zong Li <zong.li@sifive.com>
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h index 12004b097eae..df424197a25a 100644 --- a/include/linux/pagewalk.h +++ b/include/linux/pagewalk.h @@ -24,6 +24,11 @@ struct mm_walk; * "do page table walk over the current vma", returning * a negative value means "abort current page table walk * right now" and returning 1 means "skip the current vma" + * @test_pmd: similar to test_walk(), but called for every pmd. + * @test_pud: similar to test_walk(), but called for every pud. + * @test_p4d: similar to test_walk(), but called for every p4d. + * Returning 0 means walk this part of the page tables, + * returning 1 means to skip this range. * * p?d_entry callbacks are called even if those levels are folded on a * particular architecture/configuration. @@ -46,6 +51,12 @@ struct mm_walk_ops { struct mm_walk *walk); int (*test_walk)(unsigned long addr, unsigned long next, struct mm_walk *walk); + int (*test_pmd)(unsigned long addr, unsigned long next, + pmd_t *pmd_start, struct mm_walk *walk); + int (*test_pud)(unsigned long addr, unsigned long next, + pud_t *pud_start, struct mm_walk *walk); + int (*test_p4d)(unsigned long addr, unsigned long next, + p4d_t *p4d_start, struct mm_walk *walk); }; /** diff --git a/mm/pagewalk.c b/mm/pagewalk.c index 4139e9163aee..43acffefd43f 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -34,6 +34,14 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, const struct mm_walk_ops *ops = walk->ops; int err = 0; + if (ops->test_pmd) { + err = ops->test_pmd(addr, end, pmd_offset(pud, 0UL), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + pmd = pmd_offset(pud, addr); do { again: @@ -85,6 +93,14 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, const struct mm_walk_ops *ops = walk->ops; int err = 0; + if (ops->test_pud) { + err = ops->test_pud(addr, end, pud_offset(p4d, 0UL), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + pud = pud_offset(p4d, addr); do { again: @@ -128,6 +144,14 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, const struct mm_walk_ops *ops = walk->ops; int err = 0; + if (ops->test_p4d) { + err = ops->test_p4d(addr, end, p4d_offset(pgd, 0UL), walk); + if (err < 0) + return err; + if (err > 0) + return 0; + } + p4d = p4d_offset(pgd, addr); do { next = p4d_addr_end(addr, end);
It is useful to be able to skip parts of the page table tree even when walking without VMAs. Add test_p?d callbacks similar to test_walk but which are called just before a table at that level is walked. If the callback returns non-zero then the entire table is skipped. Signed-off-by: Steven Price <steven.price@arm.com> --- include/linux/pagewalk.h | 11 +++++++++++ mm/pagewalk.c | 24 ++++++++++++++++++++++++ 2 files changed, 35 insertions(+)