linux.git/arch/arm/mm/alignment.c, branch v4.3 Linux kernel source tree ARM: alignment: fix alignment handling for uaccess changes 2015-09-24T10:07:00+00:00 Russell King rmk+kernel@arm.linux.org.uk 2015-09-23T10:06:30+00:00 274e91b81ed22957b510ad2988359584eea95dae Jonathan Liu reports that the recent addition of CPU_SW_DOMAIN_PAN causes wpa_supplicant to die due to the following kernel oops: Unhandled fault: page domain fault (0x81b) at 0x001017a2 pgd = ee1b8000 [001017a2] *pgd=6ebee831, *pte=6c35475f, *ppte=6c354c7f Internal error: : 81b [#1] SMP ARM Modules linked in: rt2800usb rt2x00usb rt2800librt2x00lib crc_ccitt mac80211 CPU: 1 PID: 202 Comm: wpa_supplicant Not tainted 4.3.0-rc2 #1 Hardware name: Allwinner sun7i (A20) Family task: ec872f80 ti: ee364000 task.ti: ee364000 PC is at do_alignment_ldmstm+0x1d4/0x238 LR is at 0x0 pc : [<c001d1d8>] lr : [<00000000>] psr: 600c0113 sp : ee365e18 ip : 00000000 fp : 00000002 r10: 001017a2 r9 : 00000002 r8 : 001017aa r7 : ee365fb0 r6 : e8820018 r5 : 001017a2 r4 : 00000003 r3 : d49e30e0 r2 : 00000000 r1 : ee365fbc r0 : 00000000 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none[ 34.393106] Control: 10c5387d Table: 6e1b806a DAC: 00000051 Process wpa_supplicant (pid: 202, stack limit = 0xee364210) Stack: (0xee365e18 to 0xee366000) ... [<c001d1d8>] (do_alignment_ldmstm) from [<c001d510>] (do_alignment+0x1f0/0x904) [<c001d510>] (do_alignment) from [<c00092a0>] (do_DataAbort+0x38/0xb4) [<c00092a0>] (do_DataAbort) from [<c0013d7c>] (__dabt_usr+0x3c/0x40) Exception stack(0xee365fb0 to 0xee365ff8) 5fa0: 00000000 56c728c0 001017a2 d49e30e0 5fc0: 775448d2 597d4e74 00200800 7a9e1625 00802001 00000021 b6deec84 00000100 5fe0: 08020200 be9f4f20 0c0b0d0a b6d9b3e0 600c0010 ffffffff Code: e1a0a005 e1a0000c 1affffe8 e5913000 (e4ea3001) ---[ end trace 0acd3882fcfdf9dd ]--- This is caused by the alignment handler not being fixed up for the uaccess changes, and userspace issuing an unaligned LDM instruction. So, fix the problem by adding the necessary fixups. Reported-by: Jonathan Liu <net147@gmail.com> Tested-by: Jonathan Liu <net147@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Jonathan Liu reports that the recent addition of CPU_SW_DOMAIN_PAN
causes wpa_supplicant to die due to the following kernel oops:

Unhandled fault: page domain fault (0x81b) at 0x001017a2
pgd = ee1b8000
[001017a2] *pgd=6ebee831, *pte=6c35475f, *ppte=6c354c7f
Internal error: : 81b [#1] SMP ARM
Modules linked in: rt2800usb rt2x00usb rt2800librt2x00lib crc_ccitt mac80211
CPU: 1 PID: 202 Comm: wpa_supplicant Not tainted 4.3.0-rc2 #1
Hardware name: Allwinner sun7i (A20) Family
task: ec872f80 ti: ee364000 task.ti: ee364000
PC is at do_alignment_ldmstm+0x1d4/0x238
LR is at 0x0
pc : [<c001d1d8>]    lr : [<00000000>]    psr: 600c0113
sp : ee365e18  ip : 00000000  fp : 00000002
r10: 001017a2  r9 : 00000002  r8 : 001017aa
r7 : ee365fb0  r6 : e8820018  r5 : 001017a2  r4 : 00000003
r3 : d49e30e0  r2 : 00000000  r1 : ee365fbc  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none[   34.393106] Control: 10c5387d  Table: 6e1b806a  DAC: 00000051
Process wpa_supplicant (pid: 202, stack limit = 0xee364210)
Stack: (0xee365e18 to 0xee366000)
...
[<c001d1d8>] (do_alignment_ldmstm) from [<c001d510>] (do_alignment+0x1f0/0x904)
[<c001d510>] (do_alignment) from [<c00092a0>] (do_DataAbort+0x38/0xb4)
[<c00092a0>] (do_DataAbort) from [<c0013d7c>] (__dabt_usr+0x3c/0x40)
Exception stack(0xee365fb0 to 0xee365ff8)
5fa0:                                     00000000 56c728c0 001017a2 d49e30e0
5fc0: 775448d2 597d4e74 00200800 7a9e1625 00802001 00000021 b6deec84 00000100
5fe0: 08020200 be9f4f20 0c0b0d0a b6d9b3e0 600c0010 ffffffff
Code: e1a0a005 e1a0000c 1affffe8 e5913000 (e4ea3001)
---[ end trace 0acd3882fcfdf9dd ]---

This is caused by the alignment handler not being fixed up for the
uaccess changes, and userspace issuing an unaligned LDM instruction.
So, fix the problem by adding the necessary fixups.

Reported-by: Jonathan Liu <net147@gmail.com>
Tested-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 8322/1: keep .text and .fixup regions closer together 2015-03-29T22:11:56+00:00 Ard Biesheuvel ard.biesheuvel@linaro.org 2015-03-24T09:41:09+00:00 c4a84ae39b4a5bdf609c0001e14207aa731aab30 This moves all fixup snippets to the .text.fixup section, which is a special section that gets emitted along with the .text section for each input object file, i.e., the snippets are kept much closer to the code they refer to, which helps prevent linker failure on large kernels. Acked-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
This moves all fixup snippets to the .text.fixup section, which is
a special section that gets emitted along with the .text section
for each input object file, i.e., the snippets are kept much closer
to the code they refer to, which helps prevent linker failure on
large kernels.

Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: convert printk(KERN_* to pr_* 2014-11-21T15:24:50+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-10-28T11:26:42+00:00 4ed89f2228061422ce5f62545fd0b6f6648bd2cc Convert many (but not all) printk(KERN_* to pr_* to simplify the code. We take the opportunity to join some printk lines together so we don't split the message across several lines, and we also add a few levels to some messages which were previously missing them. Tested-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Convert many (but not all) printk(KERN_* to pr_* to simplify the code.
We take the opportunity to join some printk lines together so we don't
split the message across several lines, and we also add a few levels
to some messages which were previously missing them.

Tested-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: 8165/1: alignment: don't break misaligned NEON load/store 2014-09-25T14:32:57+00:00 Robin Murphy robin.murphy@arm.com 2014-09-25T10:56:19+00:00 5ca918e5e3f9df4634077c06585c42bc6a8d699a The alignment fixup incorrectly decodes faulting ARM VLDn/VSTn instructions (where the optional alignment hint is given but incorrect) as LDR/STR, leading to register corruption. Detect these and correctly treat them as unhandled, so that userspace gets the fault it expects. Reported-by: Simon Hosie <simon.hosie@arm.com> Signed-off-by: Robin Murphy <robin.murphy@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
The alignment fixup incorrectly decodes faulting ARM VLDn/VSTn
instructions (where the optional alignment hint is given but incorrect)
as LDR/STR, leading to register corruption. Detect these and correctly
treat them as unhandled, so that userspace gets the fault it expects.

Reported-by: Simon Hosie <simon.hosie@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: alignment: save last kernel aligned fault location 2014-07-18T11:29:06+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-07-04T13:32:43+00:00 1e7e3211854507d6c2695126d6d30a7762cf4006 Save and report (via the procfs file) the last kernel unaligned fault location. This allows us to trivially inspect where the last fault happened for cases which we don't expect to occur. Since we expect the kernel to generate misalignment faults (due to the networking layer), even when warnings are enabled, we don't log them for the kernel. Tested-by: Tony Lindgren <tony@atomide.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Save and report (via the procfs file) the last kernel unaligned fault
location.  This allows us to trivially inspect where the last fault
happened for cases which we don't expect to occur.

Since we expect the kernel to generate misalignment faults (due to
the networking layer), even when warnings are enabled, we don't log
them for the kernel.

Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: remove global cr_no_alignment 2014-06-02T08:20:18+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-04-13T18:43:26+00:00 0aeb3408ca9773283b0ae63771c4b17f39e204df cr_no_alignment is really only used by the alignment code. Since we no longer change the setting of cr_alignment after boot, we can localise this to alignment.c Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
cr_no_alignment is really only used by the alignment code.  Since we no
longer change the setting of cr_alignment after boot, we can localise
this to alignment.c

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: remove CPU_CP15 conditional from alignment.c 2014-06-02T08:20:16+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-04-13T18:40:12+00:00 3cb099f0894c06359dd6495dec81359591d06207 alignment.c will not be built unless CPU_CP15 is set: config CPU_CP15 bool config CPU_CP15_MMU bool select CPU_CP15 config ALIGNMENT_TRAP bool depends on CPU_CP15_MMU So there's no point having conditionals on CPU_CP15 within this code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
alignment.c will not be built unless CPU_CP15 is set:

config CPU_CP15
        bool

config CPU_CP15_MMU
        bool
        select CPU_CP15

config ALIGNMENT_TRAP
        bool
        depends on CPU_CP15_MMU

So there's no point having conditionals on CPU_CP15 within this code.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: move "noalign" command line option to alignment.c 2014-06-02T08:20:13+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-04-13T18:00:17+00:00 175352a51cfc275b8590d27be6fdd4b14f416c32 Keep all bits of alignment handling together. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Keep all bits of alignment handling together.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: provide common method to clear bits in CPU control register 2014-06-02T08:20:11+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-04-13T17:57:29+00:00 b4b20ad881f5a5c19ae9199547ddbb00fa4825eb Several places open-code this manipulation, let's consolidate this. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Several places open-code this manipulation, let's consolidate this.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM: use get_cr() rather than cr_alignment 2014-05-22T15:27:27+00:00 Russell King rmk+kernel@arm.linux.org.uk 2014-04-13T17:47:34+00:00 4585eaff634b1bbb09686895221b3645f53f7a60 Rather than reading the cr_alignment variable, use get_cr() to read directly from the hardware instead. We have two places where this occurs, neither of them are performance critical. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> 
Rather than reading the cr_alignment variable, use get_cr() to read
directly from the hardware instead.  We have two places where this
occurs, neither of them are performance critical.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>