linux-kernel - [PATCH] powerpc/8xx: Fix permanently mapped IMMR region.

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Message-Id: <ad9d45119a48a92bf122781d0c79c9407baa12d7.1566554026.git.christophe.leroy@c-s.fr>
Date:   Fri, 23 Aug 2019 09:56:22 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc/8xx: Fix permanently mapped IMMR region.

When not using large TLBs, the IMMR region is still
mapped as a whole block in the FIXMAP area.

Do not remove pages mapped in the FIXMAP region when
initialising paging.

Properly report that the IMMR region is block-mapped even
when not using large TLBs.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/mm/mem.c        |  8 --------
 arch/powerpc/mm/nohash/8xx.c | 13 +++++++------
 2 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 69f99128a8d6..8e221d8744ba 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -216,14 +216,6 @@ void __init paging_init(void)
 	unsigned long long total_ram = memblock_phys_mem_size();
 	phys_addr_t top_of_ram = memblock_end_of_DRAM();
 
-#ifdef CONFIG_PPC32
-	unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
-	unsigned long end = __fix_to_virt(FIX_HOLE);
-
-	for (; v < end; v += PAGE_SIZE)
-		map_kernel_page(v, 0, __pgprot(0)); /* XXX gross */
-#endif
-
 #ifdef CONFIG_HIGHMEM
 	map_kernel_page(PKMAP_BASE, 0, __pgprot(0));	/* XXX gross */
 	pkmap_page_table = virt_to_kpte(PKMAP_BASE);
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index 4a06cb342da2..e6918235fe04 100644
--- a/arch/powerpc/mm/nohash/8xx.c
+++ b/arch/powerpc/mm/nohash/8xx.c
@@ -21,33 +21,34 @@ extern int __map_without_ltlbs;
 static unsigned long block_mapped_ram;
 
 /*
- * Return PA for this VA if it is in an area mapped with LTLBs.
+ * Return PA for this VA if it is in an area mapped with LTLBs or fixmap.
  * Otherwise, returns 0
  */
 phys_addr_t v_block_mapped(unsigned long va)
 {
 	unsigned long p = PHYS_IMMR_BASE;
 
-	if (__map_without_ltlbs)
-		return 0;
 	if (va >= VIRT_IMMR_BASE && va < VIRT_IMMR_BASE + IMMR_SIZE)
 		return p + va - VIRT_IMMR_BASE;
+	if (__map_without_ltlbs)
+		return 0;
 	if (va >= PAGE_OFFSET && va < PAGE_OFFSET + block_mapped_ram)
 		return __pa(va);
 	return 0;
 }
 
 /*
- * Return VA for a given PA mapped with LTLBs or 0 if not mapped
+ * Return VA for a given PA mapped with LTLBs or fixmap
+ * Return 0 if not mapped
  */
 unsigned long p_block_mapped(phys_addr_t pa)
 {
 	unsigned long p = PHYS_IMMR_BASE;
 
-	if (__map_without_ltlbs)
-		return 0;
 	if (pa >= p && pa < p + IMMR_SIZE)
 		return VIRT_IMMR_BASE + pa - p;
+	if (__map_without_ltlbs)
+		return 0;
 	if (pa < block_mapped_ram)
 		return (unsigned long)__va(pa);
 	return 0;
-- 
2.13.3