[PATCH] powerpc/fsl-booke64: Set vmemmap_psize to 4K

Scott Wood scottwood at freescale.com
Tue May 6 10:46:55 EST 2014

The only way Freescale booke chips support mappings larger than 4K
is via TLB1.  The only way we support (direct) TLB1 entries is via
hugetlb, which is not what map_kernel_page() does when given a large
page size.

Without this, a kernel with CONFIG_SPARSEMEM_VMEMMAP enabled crashes on
boot with messages such as:

PID hash table entries: 4096 (order: 3, 32768 bytes)
Sorting __ex_table...
BUG: Bad page state in process swapper  pfn:00a2f
page:8000040000023a48 count:0 mapcount:0 mapping:0000040000ffce48 index:0x40000ffbe50
page flags: 0x40000ffda40(active|arch_1|private|private_2|head|tail|swapcache|mappedtodisk|reclaim|swapbacked|unevictable|mlocked)
page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set
bad because of flags:
page flags: 0x311840(active|private|private_2|swapcache|unevictable|mlocked)
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.15.0-rc1-00003-g7fa250c #299
Call Trace:
[c00000000098ba20] [c000000000008b3c] .show_stack+0x7c/0x1cc (unreliable)
[c00000000098baf0] [c00000000060aa50] .dump_stack+0x88/0xb4
[c00000000098bb70] [c0000000000c0468] .bad_page+0x144/0x1a0
[c00000000098bc10] [c0000000000c0628] .free_pages_prepare+0x164/0x17c
[c00000000098bcc0] [c0000000000c24cc] .free_hot_cold_page+0x48/0x214
[c00000000098bd60] [c00000000086c318] .free_all_bootmem+0x1fc/0x354
[c00000000098be70] [c00000000085da84] .mem_init+0xac/0xdc
[c00000000098bef0] [c0000000008547b0] .start_kernel+0x21c/0x4d4
[c00000000098bf90] [c000000000000448] .start_here_common+0x20/0x58

Signed-off-by: Scott Wood <scottwood at freescale.com>
 arch/powerpc/mm/tlb_nohash.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index ae3d5b7..92cb18d 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -596,8 +596,13 @@ static void __early_init_mmu(int boot_cpu)
 	/* XXX This should be decided at runtime based on supported
 	 * page sizes in the TLB, but for now let's assume 16M is
 	 * always there and a good fit (which it probably is)
+	 *
+	 * Freescale booke only supports 4K pages in TLB0, so use that.
-	mmu_vmemmap_psize = MMU_PAGE_16M;
+	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
+		mmu_vmemmap_psize = MMU_PAGE_4K;
+	else
+		mmu_vmemmap_psize = MMU_PAGE_16M;
 	/* XXX This code only checks for TLB 0 capabilities and doesn't
 	 *     check what page size combos are supported by the HW. It

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