powerpc: add support for folded p4d page tables

Implement primitives necessary for the 4th level folding, add walks of p4d
level where appropriate and replace 5level-fixup.h with pgtable-nop4d.h.

[rppt@linux.ibm.com: powerpc/xmon: drop unused pgdir varialble in show_pte() function]
  Link: http://lkml.kernel.org/r/20200519181454.GI1059226@linux.ibm.com
[rppt@linux.ibm.com; build fix]
  Link: http://lkml.kernel.org/r/20200423141845.GI13521@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> # 8xx and 83xx
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: 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/20200414153455.21744-9-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 12 deletions

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 4d5ed1093615..f122d0f2c295 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -119,6 +119,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 {
 	pgd_t *pg;
+	p4d_t *p4;
 	pud_t *pu;
 	pmd_t *pm;
 	hugepd_t *hpdp = NULL;
@@ -128,20 +129,21 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
 
 	addr &= ~(sz-1);
 	pg = pgd_offset(mm, addr);
+	p4 = p4d_offset(pg, addr);
 
 #ifdef CONFIG_PPC_BOOK3S_64
 	if (pshift == PGDIR_SHIFT)
 		/* 16GB huge page */
-		return (pte_t *) pg;
+		return (pte_t *) p4;
 	else if (pshift > PUD_SHIFT) {
 		/*
 		 * We need to use hugepd table
 		 */
 		ptl = &mm->page_table_lock;
-		hpdp = (hugepd_t *)pg;
+		hpdp = (hugepd_t *)p4;
 	} else {
 		pdshift = PUD_SHIFT;
-		pu = pud_alloc(mm, pg, addr);
+		pu = pud_alloc(mm, p4, addr);
 		if (!pu)
 			return NULL;
 		if (pshift == PUD_SHIFT)
@@ -166,10 +168,10 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
 #else
 	if (pshift >= PGDIR_SHIFT) {
 		ptl = &mm->page_table_lock;
-		hpdp = (hugepd_t *)pg;
+		hpdp = (hugepd_t *)p4;
 	} else {
 		pdshift = PUD_SHIFT;
-		pu = pud_alloc(mm, pg, addr);
+		pu = pud_alloc(mm, p4, addr);
 		if (!pu)
 			return NULL;
 		if (pshift >= PUD_SHIFT) {
@@ -390,7 +392,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 	mm_dec_nr_pmds(tlb->mm);
 }
 
-static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
+static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
 				   unsigned long addr, unsigned long end,
 				   unsigned long floor, unsigned long ceiling)
 {
@@ -400,7 +402,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 
 	start = addr;
 	do {
-		pud = pud_offset(pgd, addr);
+		pud = pud_offset(p4d, addr);
 		next = pud_addr_end(addr, end);
 		if (!is_hugepd(__hugepd(pud_val(*pud)))) {
 			if (pud_none_or_clear_bad(pud))
@@ -435,8 +437,8 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 	if (end - 1 > ceiling - 1)
 		return;
 
-	pud = pud_offset(pgd, start);
-	pgd_clear(pgd);
+	pud = pud_offset(p4d, start);
+	p4d_clear(p4d);
 	pud_free_tlb(tlb, pud, start);
 	mm_dec_nr_puds(tlb->mm);
 }
@@ -449,6 +451,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 			    unsigned long floor, unsigned long ceiling)
 {
 	pgd_t *pgd;
+	p4d_t *p4d;
 	unsigned long next;
 
 	/*
@@ -471,10 +474,11 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 	do {
 		next = pgd_addr_end(addr, end);
 		pgd = pgd_offset(tlb->mm, addr);
+		p4d = p4d_offset(pgd, addr);
 		if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
-			if (pgd_none_or_clear_bad(pgd))
+			if (p4d_none_or_clear_bad(p4d))
 				continue;
-			hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
+			hugetlb_free_pud_range(tlb, p4d, addr, next, floor, ceiling);
 		} else {
 			unsigned long more;
 			/*
@@ -487,7 +491,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 			if (more > next)
 				next = more;
 
-			free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
+			free_hugepd_range(tlb, (hugepd_t *)p4d, PGDIR_SHIFT,
 					  addr, next, floor, ceiling);
 		}
 	} while (addr = next, addr != end);