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authorVladimir Isaev <isaev@synopsys.com>2021-04-27 15:13:54 +0300
committerVineet Gupta <vgupta@synopsys.com>2021-05-10 12:38:59 -0700
commit1d5e4640e5df15252398c1b621f6bd432f2d7f17 (patch)
tree99a3140352787edca09a8eeb8f3e82a0f6ceb0aa /arch/arc
parentc5f756d8c6265ebb1736a7787231f010a3b782e5 (diff)
ARC: mm: Use max_high_pfn as a HIGHMEM zone border
Commit 4af22ded0ecf ("arc: fix memory initialization for systems with two memory banks") fixed highmem, but for the PAE case it causes bug messages: | BUG: Bad page state in process swapper pfn:80000 | page:(ptrval) refcount:0 mapcount:1 mapping:00000000 index:0x0 pfn:0x80000 flags: 0x0() | raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000 | raw: 00000000 | page dumped because: nonzero mapcount | Modules linked in: | CPU: 0 PID: 0 Comm: swapper Not tainted 5.12.0-rc5-00003-g1e43c377a79f #1 This is because the fix expects highmem to be always less than lowmem and uses min_low_pfn as an upper zone border for highmem. max_high_pfn should be ok for both highmem and highmem+PAE cases. Fixes: 4af22ded0ecf ("arc: fix memory initialization for systems with two memory banks") Signed-off-by: Vladimir Isaev <isaev@synopsys.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: stable@vger.kernel.org #5.8 onwards Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc')
-rw-r--r--arch/arc/mm/init.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 33832e36bdb7..e2ed355438c9 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -157,7 +157,16 @@ void __init setup_arch_memory(void)
min_high_pfn = PFN_DOWN(high_mem_start);
max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
- max_zone_pfn[ZONE_HIGHMEM] = min_low_pfn;
+ /*
+ * max_high_pfn should be ok here for both HIGHMEM and HIGHMEM+PAE.
+ * For HIGHMEM without PAE max_high_pfn should be less than
+ * min_low_pfn to guarantee that these two regions don't overlap.
+ * For PAE case highmem is greater than lowmem, so it is natural
+ * to use max_high_pfn.
+ *
+ * In both cases, holes should be handled by pfn_valid().
+ */
+ max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
high_memory = (void *)(min_high_pfn << PAGE_SHIFT);