From 50cce7284c64901e34ad982f6422aae1ebd55ec7 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@csgroup.eu>
Date: Tue, 19 May 2020 05:48:54 +0000
Subject: [PATCH] powerpc/ptdump: Properly handle non standard page size

commit b00ff6d8c1c3898b0f768cbb38ef722d25bd2f39 upstream.

In order to properly display information regardless of the page size,
it is necessary to take into account real page size.

Fixes: cabe8138b23c ("powerpc: dump as a single line areas mapping a single physical page.")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a53b2a0ffd042a8d85464bf90d55bc5b970e00a1.1589866984.git.christophe.leroy@csgroup.eu
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
index 49cee97c0207..485363358395 100644
--- a/arch/powerpc/mm/ptdump/ptdump.c
+++ b/arch/powerpc/mm/ptdump/ptdump.c
@@ -62,6 +62,7 @@ struct pg_state {
 	unsigned long start_address;
 	unsigned long start_pa;
 	unsigned long last_pa;
+	unsigned long page_size;
 	unsigned int level;
 	u64 current_flags;
 	bool check_wx;
@@ -163,9 +164,9 @@ static void dump_addr(struct pg_state *st, unsigned long addr)
 #endif
 
 	pt_dump_seq_printf(st->seq, REG "-" REG " ", st->start_address, addr - 1);
-	if (st->start_pa == st->last_pa && st->start_address + PAGE_SIZE != addr) {
+	if (st->start_pa == st->last_pa && st->start_address + st->page_size != addr) {
 		pt_dump_seq_printf(st->seq, "[" REG "]", st->start_pa);
-		delta = PAGE_SIZE >> 10;
+		delta = st->page_size >> 10;
 	} else {
 		pt_dump_seq_printf(st->seq, " " REG " ", st->start_pa);
 		delta = (addr - st->start_address) >> 10;
@@ -196,7 +197,7 @@ static void note_prot_wx(struct pg_state *st, unsigned long addr)
 }
 
 static void note_page(struct pg_state *st, unsigned long addr,
-	       unsigned int level, u64 val)
+	       unsigned int level, u64 val, unsigned long page_size)
 {
 	u64 flag = val & pg_level[level].mask;
 	u64 pa = val & PTE_RPN_MASK;
@@ -208,6 +209,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
 		st->start_address = addr;
 		st->start_pa = pa;
 		st->last_pa = pa;
+		st->page_size = page_size;
 		pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
 	/*
 	 * Dump the section of virtual memory when:
@@ -219,7 +221,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
 	 */
 	} else if (flag != st->current_flags || level != st->level ||
 		   addr >= st->marker[1].start_address ||
-		   (pa != st->last_pa + PAGE_SIZE &&
+		   (pa != st->last_pa + st->page_size &&
 		    (pa != st->start_pa || st->start_pa != st->last_pa))) {
 
 		/* Check the PTE flags */
@@ -247,6 +249,7 @@ static void note_page(struct pg_state *st, unsigned long addr,
 		st->start_address = addr;
 		st->start_pa = pa;
 		st->last_pa = pa;
+		st->page_size = page_size;
 		st->current_flags = flag;
 		st->level = level;
 	} else {
@@ -262,7 +265,7 @@ 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));
+		note_page(st, addr, 4, pte_val(*pte), PAGE_SIZE);
 
 	}
 }
@@ -279,7 +282,7 @@ static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
 			/* pmd exists */
 			walk_pte(st, pmd, addr);
 		else
-			note_page(st, addr, 3, pmd_val(*pmd));
+			note_page(st, addr, 3, pmd_val(*pmd), PMD_SIZE);
 	}
 }
 
@@ -295,7 +298,7 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
 			/* pud exists */
 			walk_pmd(st, pud, addr);
 		else
-			note_page(st, addr, 2, pud_val(*pud));
+			note_page(st, addr, 2, pud_val(*pud), PUD_SIZE);
 	}
 }
 
@@ -316,7 +319,7 @@ static void walk_pagetables(struct pg_state *st)
 			/* pgd exists */
 			walk_pud(st, pgd, addr);
 		else
-			note_page(st, addr, 1, pgd_val(*pgd));
+			note_page(st, addr, 1, pgd_val(*pgd), PGDIR_SIZE);
 	}
 }
 
@@ -375,7 +378,7 @@ static int ptdump_show(struct seq_file *m, void *v)
 
 	/* Traverse kernel page tables */
 	walk_pagetables(&st);
-	note_page(&st, 0, 0, 0);
+	note_page(&st, 0, 0, 0, 0);
 	return 0;
 }
 
-- 
2.27.0