arm: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate, and remove __ARCH_USE_5LEVEL_HACK.

[rppt@linux.ibm.com: fix kexec]
  Link: http://lkml.kernel.org/r/20200508174232.GA759899@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: James Morse <james.morse@arm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200414153455.21744-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 6 deletions

diff --git a/arch/arm/mm/dump.c b/arch/arm/mm/dump.c
index 7d6291f23251..677549d6854c 100644
--- a/arch/arm/mm/dump.c
+++ b/arch/arm/mm/dump.c
@@ -207,6 +207,7 @@ struct pg_level {
 static struct pg_level pg_level[] = {
 	{
 	}, { /* pgd */
+	}, { /* p4d */
 	}, { /* pud */
 	}, { /* pmd */
 		.bits	= section_bits,
@@ -308,7 +309,7 @@ static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
 
 	for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
 		addr = start + i * PAGE_SIZE;
-		note_page(st, addr, 4, pte_val(*pte), domain);
+		note_page(st, addr, 5, pte_val(*pte), domain);
 	}
 }
 
@@ -350,14 +351,14 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 			addr += SECTION_SIZE;
 			pmd++;
 			domain = get_domain_name(pmd);
-			note_page(st, addr, 3, pmd_val(*pmd), domain);
+			note_page(st, addr, 4, pmd_val(*pmd), domain);
 		}
 	}
 }
 
-static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
+static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
 {
-	pud_t *pud = pud_offset(pgd, 0);
+	pud_t *pud = pud_offset(p4d, 0);
 	unsigned long addr;
 	unsigned i;
 
@@ -366,7 +367,23 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 		if (!pud_none(*pud)) {
 			walk_pmd(st, pud, addr);
 		} else {
-			note_page(st, addr, 2, pud_val(*pud), NULL);
+			note_page(st, addr, 3, pud_val(*pud), NULL);
+		}
+	}
+}
+
+static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
+{
+	p4d_t *p4d = p4d_offset(pgd, 0);
+	unsigned long addr;
+	unsigned i;
+
+	for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
+		addr = start + i * P4D_SIZE;
+		if (!p4d_none(*p4d)) {
+			walk_pud(st, p4d, addr);
+		} else {
+			note_page(st, addr, 2, p4d_val(*p4d), NULL);
 		}
 	}
 }
@@ -381,7 +398,7 @@ static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
 	for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
 		addr = start + i * PGDIR_SIZE;
 		if (!pgd_none(*pgd)) {
-			walk_pud(st, pgd, addr);
+			walk_p4d(st, pgd, addr);
 		} else {
 			note_page(st, addr, 1, pgd_val(*pgd), NULL);
 		}