Failure to add the mapping created in debug_ll_io_init() can lead to the BUG_ON() triggering in lib/ioremap.c:27 if the static virtual address decided for the debug_ll mapping overlaps with another mapping that is created later. This happens because the generic ioremap code has no idea there is a mapping there and it tries to place a mapping in the same location and blows up when it sees that there is a pte already present. kernel BUG at lib/ioremap.c:27! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-rc2-00042-g2af0c67-dirty #316 task: ef088000 ti: ef082000 task.ti: ef082000 PC is at ioremap_page_range+0x16c/0x198 LR is at ioremap_page_range+0xf0/0x198 pc : [<c04cb874>] lr : [<c04cb7f8>] psr: 20000113 sp : ef083e78 ip : af140000 fp : ef083ebc r10: ef7fc100 r9 : ef7fc104 r8 : 000af174 r7 : 00000647 r6 : beffffff r5 : f004c000 r4 : f0040000 r3 : af173417 r2 : 16440653 r1 : af173e07 r0 : ef7fc8fc Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c5787d Table: 8020406a DAC: 00000015 Process swapper/0 (pid: 1, stack limit = 0xef082238) Stack: (0xef083e78 to 0xef084000) 3e60: 00040000 ef083eec 3e80: bf134000 f004bfff c0207c00 f004c000 c02fc120 f000c000 c15e7800 00040000 3ea0: ef083eec 00000647 c098ba9c c0953544 ef083edc ef083ec0 c021b82c c04cb714 3ec0: c09cdc50 00000040 ef0f1e00 ef1003c0 ef083f14 ef083ee0 c09535bc c021b7bc 3ee0: c0953544 c04d0c6c c094e2cc c1600be4 c07440c4 c09a6888 00000002 c0a15f00 3f00: ef082000 00000000 ef083f54 ef083f18 c0208728 c0953550 00000002 c1600bfc 3f20: c08e3fac c0839918 ef083f54 c1600b80 c09a6888 c0a15f00 0000008b c094e2cc 3f40: c098ba9c c098bab8 ef083f94 ef083f58 c094ea0c c020865c 00000002 00000002 3f60: c094e2cc 00000000 c025b674 00000000 c06ff860 00000000 00000000 00000000 3f80: 00000000 00000000 ef083fac ef083f98 c06ff878 c094e910 00000000 00000000 3fa0: 00000000 ef083fb0 c020efe8 c06ff86c 00000000 00000000 00000000 00000000 3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 00000000 c0595108 [<c04cb874>] (ioremap_page_range+0x16c/0x198) from [<c021b82c>] (__alloc_remap_buffer.isra.18+0x7c/0xc4) [<c021b82c>] (__alloc_remap_buffer.isra.18+0x7c/0xc4) from [<c09535bc>] (atomic_pool_init+0x78/0x128) [<c09535bc>] (atomic_pool_init+0x78/0x128) from [<c0208728>] (do_one_initcall+0xd8/0x198) [<c0208728>] (do_one_initcall+0xd8/0x198) from [<c094ea0c>] (kernel_init_freeable+0x108/0x1d0) [<c094ea0c>] (kernel_init_freeable+0x108/0x1d0) from [<c06ff878>] (kernel_init+0x18/0xf4) [<c06ff878>] (kernel_init+0x18/0xf4) from [<c020efe8>] (ret_from_fork+0x14/0x20) Code: e50b0040 ebf54b2f e51b0040 eaffffee (e7f001f2) Fix it by telling generic layers about the static mapping via iotable_init(). This also has the nice side effect of letting you see the mapping in procfs' vmallocinfo file. Cc: Rob Herring <rob.herring@xxxxxxxxxxx> Cc: Stephen Warren <swarren@xxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> --- Changes since v1: * Use iotable_init() instead of open coding it arch/arm/mm/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index e0d8565..18b8aeb 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -947,7 +947,7 @@ void __init debug_ll_io_init(void) map.virtual &= PAGE_MASK; map.length = PAGE_SIZE; map.type = MT_DEVICE; - create_mapping(&map); + iotable_init(&map, 1); } #endif -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
