linux-kernel - [PATCH v2] powerpc/8xx: Fix permanently mapped IMMR region.

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Date:   Tue, 26 Nov 2019 13:16:50 +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 v2] 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.

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

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>

---
v2: rebased on today's powerpc/next (this drops the change to mem.c which is already merged)
---
 arch/powerpc/mm/nohash/8xx.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c
index 090af2d2d3e4..2c98078d2ede 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