* [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS
@ 2014-09-26 23:46 Nathan Lynch
2014-09-27 10:30 ` Joachim Eastwood
0 siblings, 1 reply; 4+ messages in thread
From: Nathan Lynch @ 2014-09-26 23:46 UTC (permalink / raw)
To: linux-arm-kernel
Joachim Eastwood reports that commit fbfb872f5f41 "ARM: 8148/1: flush
TLS and thumbee register state during exec" causes a boot-time crash
on a Cortex-M4 nommu system:
Freeing unused kernel memory: 68K (281e5000 - 281f6000)
Unhandled exception: IPSR = 00000005 LR = fffffff1
CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
task: 29834000 ti: 29832000 task.ti: 29832000
PC is at flush_thread+0x2e/0x40
LR is at flush_thread+0x21/0x40
pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b
sp : 29833d60 ip : 00000000 fp : 00000001
r10: 00003cf8 r9 : 29b1f000 r8 : 00000000
r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000
r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0
xPSR: 4100000b
CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
[<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc)
[<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c)
The problem is that set_tls is attempting to clear the TLS location in
the kernel-user helper page, which isn't set up on V7M.
Fix this by guarding the write to the kuser helper page with
a CONFIG_KUSER_HELPERS ifdef.
Reported-by: Joachim Eastwood <manabian@gmail.com>
Fixes: fbfb872f5f41 ARM: 8148/1: flush TLS and thumbee register state during exec
Cc: stable at vger.kernel.org
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
---
arch/arm/include/asm/tls.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/include/asm/tls.h b/arch/arm/include/asm/tls.h
index 36172adda9d0..5f833f7adba1 100644
--- a/arch/arm/include/asm/tls.h
+++ b/arch/arm/include/asm/tls.h
@@ -81,6 +81,7 @@ static inline void set_tls(unsigned long val)
asm("mcr p15, 0, %0, c13, c0, 3"
: : "r" (val));
} else {
+#ifdef CONFIG_KUSER_HELPERS
/*
* User space must never try to access this
* directly. Expect your app to break
@@ -89,6 +90,7 @@ static inline void set_tls(unsigned long val)
* entry-armv.S for details)
*/
*((unsigned int *)0xffff0ff0) = val;
+#endif
}
}
--
1.9.3
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS
2014-09-26 23:46 [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS Nathan Lynch
@ 2014-09-27 10:30 ` Joachim Eastwood
2014-09-29 9:03 ` Will Deacon
0 siblings, 1 reply; 4+ messages in thread
From: Joachim Eastwood @ 2014-09-27 10:30 UTC (permalink / raw)
To: linux-arm-kernel
On 27 September 2014 01:46, Nathan Lynch <nathan_lynch@mentor.com> wrote:
> Joachim Eastwood reports that commit fbfb872f5f41 "ARM: 8148/1: flush
> TLS and thumbee register state during exec" causes a boot-time crash
> on a Cortex-M4 nommu system:
>
> Freeing unused kernel memory: 68K (281e5000 - 281f6000)
> Unhandled exception: IPSR = 00000005 LR = fffffff1
> CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
> task: 29834000 ti: 29832000 task.ti: 29832000
> PC is at flush_thread+0x2e/0x40
> LR is at flush_thread+0x21/0x40
> pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b
> sp : 29833d60 ip : 00000000 fp : 00000001
> r10: 00003cf8 r9 : 29b1f000 r8 : 00000000
> r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000
> r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0
> xPSR: 4100000b
> CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
> [<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc)
> [<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c)
>
> The problem is that set_tls is attempting to clear the TLS location in
> the kernel-user helper page, which isn't set up on V7M.
>
> Fix this by guarding the write to the kuser helper page with
> a CONFIG_KUSER_HELPERS ifdef.
>
> Reported-by: Joachim Eastwood <manabian@gmail.com>
> Fixes: fbfb872f5f41 ARM: 8148/1: flush TLS and thumbee register state during exec
> Cc: stable at vger.kernel.org
> Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
> ---
Works for me.
Tested-by: Joachim Eastwood <manabian@gmail.com>
Thanks!
regards,
Joachim Eastwood
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS
2014-09-27 10:30 ` Joachim Eastwood
@ 2014-09-29 9:03 ` Will Deacon
2014-09-29 10:15 ` Joachim Eastwood
0 siblings, 1 reply; 4+ messages in thread
From: Will Deacon @ 2014-09-29 9:03 UTC (permalink / raw)
To: linux-arm-kernel
On Sat, Sep 27, 2014 at 11:30:26AM +0100, Joachim Eastwood wrote:
> On 27 September 2014 01:46, Nathan Lynch <nathan_lynch@mentor.com> wrote:
> > Joachim Eastwood reports that commit fbfb872f5f41 "ARM: 8148/1: flush
> > TLS and thumbee register state during exec" causes a boot-time crash
> > on a Cortex-M4 nommu system:
> >
> > Freeing unused kernel memory: 68K (281e5000 - 281f6000)
> > Unhandled exception: IPSR = 00000005 LR = fffffff1
> > CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
> > task: 29834000 ti: 29832000 task.ti: 29832000
> > PC is at flush_thread+0x2e/0x40
> > LR is at flush_thread+0x21/0x40
> > pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b
> > sp : 29833d60 ip : 00000000 fp : 00000001
> > r10: 00003cf8 r9 : 29b1f000 r8 : 00000000
> > r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000
> > r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0
> > xPSR: 4100000b
> > CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
> > [<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc)
> > [<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c)
> >
> > The problem is that set_tls is attempting to clear the TLS location in
> > the kernel-user helper page, which isn't set up on V7M.
> >
> > Fix this by guarding the write to the kuser helper page with
> > a CONFIG_KUSER_HELPERS ifdef.
> >
> > Reported-by: Joachim Eastwood <manabian@gmail.com>
> > Fixes: fbfb872f5f41 ARM: 8148/1: flush TLS and thumbee register state during exec
> > Cc: stable at vger.kernel.org
> > Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
> > ---
>
> Works for me.
>
> Tested-by: Joachim Eastwood <manabian@gmail.com>
Out of interest, which M4 board are you using to run Linux? Are they
generally available?
Will
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS
2014-09-29 9:03 ` Will Deacon
@ 2014-09-29 10:15 ` Joachim Eastwood
0 siblings, 0 replies; 4+ messages in thread
From: Joachim Eastwood @ 2014-09-29 10:15 UTC (permalink / raw)
To: linux-arm-kernel
On 29 September 2014 11:03, Will Deacon <will.deacon@arm.com> wrote:
> On Sat, Sep 27, 2014 at 11:30:26AM +0100, Joachim Eastwood wrote:
>> On 27 September 2014 01:46, Nathan Lynch <nathan_lynch@mentor.com> wrote:
>> > Joachim Eastwood reports that commit fbfb872f5f41 "ARM: 8148/1: flush
>> > TLS and thumbee register state during exec" causes a boot-time crash
>> > on a Cortex-M4 nommu system:
>> >
>> > Freeing unused kernel memory: 68K (281e5000 - 281f6000)
>> > Unhandled exception: IPSR = 00000005 LR = fffffff1
>> > CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
>> > task: 29834000 ti: 29832000 task.ti: 29832000
>> > PC is at flush_thread+0x2e/0x40
>> > LR is at flush_thread+0x21/0x40
>> > pc : [<2800954a>] lr : [<2800953d>] psr: 4100000b
>> > sp : 29833d60 ip : 00000000 fp : 00000001
>> > r10: 00003cf8 r9 : 29b1f000 r8 : 00000000
>> > r7 : 29b0bc00 r6 : 29834000 r5 : 29832000 r4 : 29832000
>> > r3 : ffff0ff0 r2 : 29832000 r1 : 00000000 r0 : 282121f0
>> > xPSR: 4100000b
>> > CPU: 0 PID: 1 Comm: swapper Not tainted 3.17.0-rc6-00313-gd2205fa30aa7 #191
>> > [<2800afa5>] (unwind_backtrace) from [<2800a327>] (show_stack+0xb/0xc)
>> > [<2800a327>] (show_stack) from [<2800a963>] (__invalid_entry+0x4b/0x4c)
>> >
>> > The problem is that set_tls is attempting to clear the TLS location in
>> > the kernel-user helper page, which isn't set up on V7M.
>> >
>> > Fix this by guarding the write to the kuser helper page with
>> > a CONFIG_KUSER_HELPERS ifdef.
>> >
>> > Reported-by: Joachim Eastwood <manabian@gmail.com>
>> > Fixes: fbfb872f5f41 ARM: 8148/1: flush TLS and thumbee register state during exec
>> > Cc: stable at vger.kernel.org
>> > Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
>> > ---
>>
>> Works for me.
>>
>> Tested-by: Joachim Eastwood <manabian@gmail.com>
>
> Out of interest, which M4 board are you using to run Linux?
I am using Embedded Artists' LPC4357 Developer's Kit.
http://www.embeddedartists.com/products/kits/lpc4357_kit.php
>Are they generally available?
They have a webshop so you should be able to buy one. Seems to be out
of stock now, though.
I have a github repo with all my code for LPC4357 here:
https://github.com/manabian/linux-lpc
regards
Joachim Eastwood
^ permalink raw reply [flat|nested] 4+ messages in thread
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2014-09-26 23:46 [PATCH] ARM: fix set_tls for !CONFIG_KUSER_HELPERS Nathan Lynch
2014-09-27 10:30 ` Joachim Eastwood
2014-09-29 9:03 ` Will Deacon
2014-09-29 10:15 ` Joachim Eastwood
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