mm: pgtable: add shortcuts for accessing kernel PMD and PTE

The powerpc 32-bit implementation of pgtable has nice shortcuts for
accessing kernel PMD and PTE for a given virtual address.  Make these
helpers available for all architectures.

[rppt@linux.ibm.com: microblaze: fix page table traversal in setup_rt_frame()]
  Link: http://lkml.kernel.org/r/20200518191511.GD1118872@kernel.org
[akpm@linux-foundation.org: s/pmd_ptr_k/pmd_off_k/ in various powerpc places]

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
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/20200514170327.31389-9-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 3 insertions, 18 deletions

diff --git a/arch/nds32/include/asm/pgtable.h b/arch/nds32/include/asm/pgtable.h
index 51fe1c567702..95c75282cb47 100644
--- a/arch/nds32/include/asm/pgtable.h
+++ b/arch/nds32/include/asm/pgtable.h
@@ -195,8 +195,6 @@ extern void paging_init(void);
 #define pte_unmap(pte)		do { } while (0)
 #define pte_unmap_nested(pte)	do { } while (0)
 
-#define pmd_off_k(address)	pmd_offset(pud_offset(p4d_offset(pgd_offset_k(address), (address)), (address)), (address))
-
 #define set_pte_at(mm,addr,ptep,pteval) set_pte(ptep,pteval)
 /*
  * Set a level 1 translation table entry, and clean it out of
diff --git a/arch/nds32/mm/init.c b/arch/nds32/mm/init.c
index 91147cca4b64..fa86f7b2f416 100644
--- a/arch/nds32/mm/init.c
+++ b/arch/nds32/mm/init.c
@@ -98,9 +98,6 @@ static pmd_t *fixmap_pmd_p;
 static void __init fixedrange_init(void)
 {
 	unsigned long vaddr;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
 	pmd_t *pmd;
 #ifdef CONFIG_HIGHMEM
 	pte_t *pte;
@@ -110,10 +107,7 @@ static void __init fixedrange_init(void)
 	 * Fixed mappings:
 	 */
 	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1);
-	pgd = swapper_pg_dir + pgd_index(vaddr);
-	p4d = p4d_offset(pgd, vaddr);
-	pud = pud_offset(p4d, vaddr);
-	pmd = pmd_offset(pud, vaddr);
+	pmd = pmd_off_k(vaddr);
 	fixmap_pmd_p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	if (!fixmap_pmd_p)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
@@ -126,10 +120,7 @@ static void __init fixedrange_init(void)
 	 */
 	vaddr = PKMAP_BASE;
 
-	pgd = swapper_pg_dir + pgd_index(vaddr);
-	p4d = p4d_offset(pgd, vaddr);
-	pud = pud_offset(p4d, vaddr);
-	pmd = pmd_offset(pud, vaddr);
+	pmd = pmd_off_k(vaddr);
 	pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 	if (!pte)
 		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
diff --git a/arch/nds32/mm/proc.c b/arch/nds32/mm/proc.c
index a2b9aacc5f89..848c845f5f33 100644
--- a/arch/nds32/mm/proc.c
+++ b/arch/nds32/mm/proc.c
@@ -15,14 +15,10 @@ extern struct cache_info L1_cache_info[2];
 
 int va_kernel_present(unsigned long addr)
 {
-	p4d_t *p4d;
-	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *ptep, pte;
 
-	p4d = p4d_offset(pgd_offset_k(addr), addr);
-	pud = pud_offset(p4d, addr);
-	pmd = pmd_offset(pud, addr);
+	pmd = pmd_off_k(addr);
 	if (!pmd_none(*pmd)) {
 		ptep = pte_offset_map(pmd, addr);
 		pte = *ptep;