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authorMike Rapoport <rppt@linux.ibm.com>2020-06-08 21:33:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-09 09:39:14 -0700
commit974b9b2c68f3d35a65e80af9657fe378d2439b60 (patch)
tree67332a4308b56498008ba8687b99c2ca26215866 /include/linux/pgtable.h
parente05c7b1f2bc4b7b28199b9a7572f73436d97317e (diff)
downloadlinux-sh-974b9b2c68f3d35a65e80af9657fe378d2439b60.tar.gz
mm: consolidate pte_index() and pte_offset_*() definitions
All architectures define pte_index() as (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1) and all architectures define pte_offset_kernel() as an entry in the array of PTEs indexed by the pte_index(). For the most architectures the pte_offset_kernel() implementation relies on the availability of pmd_page_vaddr() that converts a PMD entry value to the virtual address of the page containing PTEs array. Let's move x86 definitions of the PTE accessors to the generic place in <linux/pgtable.h> and then simply drop the respective definitions from the other architectures. The architectures that didn't provide pmd_page_vaddr() are updated to have that defined. The generic implementation of pte_offset_kernel() can be overridden by an architecture and alpha makes use of this because it has special ordering requirements for its version of pte_offset_kernel(). [rppt@linux.ibm.com: v2] Link: http://lkml.kernel.org/r/20200514170327.31389-11-rppt@kernel.org [rppt@linux.ibm.com: update] Link: http://lkml.kernel.org/r/20200514170327.31389-12-rppt@kernel.org [rppt@linux.ibm.com: update] Link: http://lkml.kernel.org/r/20200514170327.31389-13-rppt@kernel.org [akpm@linux-foundation.org: fix x86 warning] [sfr@canb.auug.org.au: fix powerpc build] Link: http://lkml.kernel.org/r/20200607153443.GB738695@linux.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-10-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pgtable.h')
-rw-r--r--include/linux/pgtable.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index ee85b222d098..90a5d0c78fca 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -29,6 +29,97 @@
#endif
/*
+ * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
+ *
+ * The pXx_index() functions return the index of the entry in the page
+ * table page which would control the given virtual address
+ *
+ * As these functions may be used by the same code for different levels of
+ * the page table folding, they are always available, regardless of
+ * CONFIG_PGTABLE_LEVELS value. For the folded levels they simply return 0
+ * because in such cases PTRS_PER_PxD equals 1.
+ */
+
+static inline unsigned long pte_index(unsigned long address)
+{
+ return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
+}
+
+#ifndef pmd_index
+static inline unsigned long pmd_index(unsigned long address)
+{
+ return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
+}
+#define pmd_index pmd_index
+#endif
+
+#ifndef pud_index
+static inline unsigned long pud_index(unsigned long address)
+{
+ return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1);
+}
+#define pud_index pud_index
+#endif
+
+#ifndef pgd_index
+/* Must be a compile-time constant, so implement it as a macro */
+#define pgd_index(a) (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
+#endif
+
+#ifndef pte_offset_kernel
+static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address)
+{
+ return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address);
+}
+#define pte_offset_kernel pte_offset_kernel
+#endif
+
+#if defined(CONFIG_HIGHPTE)
+#define pte_offset_map(dir, address) \
+ ((pte_t *)kmap_atomic(pmd_page(*(dir))) + \
+ pte_index((address)))
+#define pte_unmap(pte) kunmap_atomic((pte))
+#else
+#define pte_offset_map(dir, address) pte_offset_kernel((dir), (address))
+#define pte_unmap(pte) ((void)(pte)) /* NOP */
+#endif
+
+/* Find an entry in the second-level page table.. */
+#ifndef pmd_offset
+static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
+{
+ return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
+}
+#define pmd_offset pmd_offset
+#endif
+
+#ifndef pud_offset
+static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address)
+{
+ return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address);
+}
+#define pud_offset pud_offset
+#endif
+
+static inline pgd_t *pgd_offset_pgd(pgd_t *pgd, unsigned long address)
+{
+ return (pgd + pgd_index(address));
+};
+
+/*
+ * a shortcut to get a pgd_t in a given mm
+ */
+#ifndef pgd_offset
+#define pgd_offset(mm, address) pgd_offset_pgd((mm)->pgd, (address))
+#endif
+
+/*
+ * a shortcut which implies the use of the kernel's pgd, instead
+ * of a process's
+ */
+#define pgd_offset_k(address) pgd_offset(&init_mm, (address))
+
+/*
* In many cases it is known that a virtual address is mapped at PMD or PTE
* level, so instead of traversing all the page table levels, we can get a
* pointer to the PMD entry in user or kernel page table or translate a virtual