Hi Geert,
On 01/03/16 12:01, Geert Uytterhoeven wrote:
Hi Robin,
On Tue, Jan 26, 2016 at 6:13 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote:
Add a nearly-complete ARMv7 short descriptor implementation, omitting
only a few legacy and CPU-centric aspects which shouldn't be necessary
for IOMMU API use anyway.
Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
---
drivers/iommu/Kconfig | 19 +
drivers/iommu/Makefile | 1 +
drivers/iommu/io-pgtable-arm-v7s.c | 849 +++++++++++++++++++++++++++++++++++++
drivers/iommu/io-pgtable.c | 3 +
drivers/iommu/io-pgtable.h | 14 +-
5 files changed, 885 insertions(+), 1 deletion(-)
create mode 100644 drivers/iommu/io-pgtable-arm-v7s.c
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index a1e75cb..dc1aaa5 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -39,6 +39,25 @@ config IOMMU_IO_PGTABLE_LPAE_SELFTEST
If unsure, say N here.
+config IOMMU_IO_PGTABLE_ARMV7S
+ bool "ARMv7/v8 Short Descriptor Format"
+ select IOMMU_IO_PGTABLE
+ depends on HAS_DMA && (ARM || ARM64 || COMPILE_TEST)
+ help
+ Enable support for the ARM Short-descriptor pagetable format.
+ This supports 32-bit virtual and physical addresses mapped using
+ 2-level tables with 4KB pages/1MB sections, and contiguous entries
+ for 64KB pages/16MB supersections if indicated by the IOMMU driver.
+
+config IOMMU_IO_PGTABLE_ARMV7S_SELFTEST
+ bool "ARMv7s selftests"
+ depends on IOMMU_IO_PGTABLE_ARMV7S
+ help
+ Enable self-tests for ARMv7s page table allocator. This performs
+ a series of page-table consistency checks during boot.
+
+ If unsure, say N here.
+
When enabling IOMMU_IO_PGTABLE_ARMV7S_SELFTEST on r8a7791 (dual Cortex A15),
the kernel crashes with:
kernel BUG at mm/slab.c:2536!
Internal error: Oops - BUG: 0 [#1] SMP ARM
Modules linked in:[ 1.299311] Modules linked in:
CPU: 1 PID: 1 Comm: swapper/0 Not tainted
4.5.0-rc6-koelsch-05892-ge7e45ad53ab6795e #2270
Hardware name: Generic R8A7791 (Flattened Device Tree)
task: ef422040 ti: ef442000 task.ti: ef442000
PC is at cache_alloc_refill+0x2a0/0x530
LR is at _raw_spin_unlock+0x8/0xc
pc : [<c02c6928>] lr : [<c067f97c>] psr: 00000093
sp : ef443d88 ip : d0a7b1f0 fp : 02000020
r10: 00000010 r9 : 00000000 r8 : 02088020
r7 : 00000000 r6 : ef5172c0 r5 : 00000000 r4 : ef5d7f40
r3 : 00004001 r2 : 00000001 r1 : 00020001 r0 : ef5172c0
Flags: nzcv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 30c5387d Table: 40003000 DAC: 55555555
Process swapper/0 (pid: 1, stack limit = 0xef442210)
Stack: (0xef443d88 to 0xef444000)
3d80: ef48b4c0 00000000 ef5172d0 c0e38280 00000000 00001000
3da0: 02088020 60000013 ef5d7f40 c0445010 00000000 ef517340 00001000 c02c6630
3dc0: 00000008 00001000 00000000 00000400 00000002 c04444bc 00000000 00000000
3de0: 024000c0 ef517340 00000000 00004000 00000001 00000001 c0e3b000 ef517340
3e00: 00000000 00001000 00000000 ef5f8000 ef517340 c0445010 00000000 0000000f
3e20: 00001000 c0444e1c 00000000 00000000 ef517350 00000000 ef520f15 ef517340
3e40: ef443ea0 ef517390 00000000 00000000 00001000 c0445010 00000000 ef517390
3e60: 00001000 c0445044 00001000 0000000f ef5f8000 ef443ea0 c0e92a00 c0e92a00
3e80: 00000000 00000000 0000000c c0c18ee4 00001000 0000000f 00000001 00000014
3ea0: 00000001 01111000 00000020 00000020 c0e25bc8 00000000 6f5f806a 00000000
3ec0: 00000020 40004000 800b8204 00000000 00000000 00000000 00000000 00000000
3ee0: c0c3ce94 ef520f00 c0c18da4 00000000 c0e05550 c0e05550 c0e3b000 c0c2d848
3f00: 00000000 c0201760 ef5036c0 c0804b44 c0e5fdd0 00000000 c0e0be00 c0e0be7c
3f20: 00000000 60000013 00000000 efffec51 efffec59 c023893c c09dc204 00000004
3f40: 00000004 c09dce98 000000a0 c09dce98 c0e09e78 00000004 c0c2d834 00000004
3f60: c0c2d838 000000a1 c0c3ce94 c0e3b000 c0e3b000 c0c00d4c 00000004 00000004
3f80: 00000000 c0c0058c 00000000 c067a35c 00000000 00000000 00000000 00000000
3fa0: 00000000 c067a364 00000000 c0206b68 00000000 00000000 00000000 00000000
3fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
3fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ef443ff4 00000000
[<c02c6928>] (cache_alloc_refill) from [<c02c6630>] (kmem_cache_alloc+0x7c/0xd4)
[<c02c6630>] (kmem_cache_alloc) from [<c04444bc>]
(__arm_v7s_alloc_table+0x5c/0x278)
[<c04444bc>] (__arm_v7s_alloc_table) from [<c0444e1c>]
(__arm_v7s_map.constprop.6+0x68/0x25c)
[<c0444e1c>] (__arm_v7s_map.constprop.6) from [<c0445044>]
(arm_v7s_map+0x34/0xa4)
[<c0445044>] (arm_v7s_map) from [<c0c18ee4>] (arm_v7s_do_selftests+0x140/0x418)
[<c0c18ee4>] (arm_v7s_do_selftests) from [<c0201760>]
(do_one_initcall+0x100/0x1b4)
[<c0201760>] (do_one_initcall) from [<c0c00d4c>]
(kernel_init_freeable+0x120/0x1e8)
[<c0c00d4c>] (kernel_init_freeable) from [<c067a364>] (kernel_init+0x8/0xec)
[<c067a364>] (kernel_init) from [<c0206b68>] (ret_from_fork+0x14/0x2c)
Code: 1a000003 e7f001f2 e3130001 0a000000 (e7f001f2)
---[ end trace 190f6f6b84352efd ]---
Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
I don't know if r8a7791 supports v7s. Still, I don't expect a crash.
The LPAE selftest runs fine.
On r8a7795 (arm64), both the LPAE and V7S selftests run fine.
The hardware itself shouldn't matter, as the selftests run without
reference to any device at all. At a glance this looks like a difference
in behaviour between SLAB and SLUB - I see shmobile_defconfig sets
CONFIG_SLAB=y. I'll reproduce it locally to make sure.
Thanks for the report,
Robin.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
