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authorSteven Price <steven.price@arm.com>2019-11-19 11:47:24 +1100
committerStephen Rothwell <sfr@canb.auug.org.au>2019-11-25 17:09:55 +1100
commitf32a941a5363715428273eeacd96a56cb3578e86 (patch)
tree996ebe0fe0917ace3d62d3ae07c6a18289a49f7c
parent3907ac5b27c8437d3c2680b23b295513fe953f13 (diff)
download96b-common-f32a941a5363715428273eeacd96a56cb3578e86.tar.gz
mm: pagewalk: add test_p?d callbacks
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. Link: http://lkml.kernel.org/r/20191028135910.33253-14-steven.price@arm.com Signed-off-by: Steven Price <steven.price@arm.com> Tested-by: Zong Li <zong.li@sifive.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Potapenko <glider@google.com> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: James Hogan <jhogan@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: "Liang, Kan" <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Shiraz Hashim <shashim@codeaurora.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
-rw-r--r--include/linux/pagewalk.h11
-rw-r--r--mm/pagewalk.c24
2 files changed, 35 insertions, 0 deletions
diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index ed2bb399fac2..fe61448c5900 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 f43c0b96f594..c9c3f8ddabf5 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);