diff options
| author | Thomas Huth <thuth@redhat.com> | 2015-07-17 12:46:58 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-10-01 12:07:30 +0200 |
| commit | 2ba90c0e0638dba68ffe6e78b135729e41a4540a (patch) | |
| tree | a828187b692fea939a18e8dbfe36df41287336bf | |
| parent | 36e5789bc706a67a0281a14b3888b3f5d0f723e0 (diff) | |
powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers
commit 1c2cb594441d02815d304cccec9742ff5c707495 upstream.
The EPOW interrupt handler uses rtas_get_sensor(), which in turn
uses rtas_busy_delay() to wait for RTAS becoming ready in case it
is necessary. But rtas_busy_delay() is annotated with might_sleep()
and thus may not be used by interrupts handlers like the EPOW handler!
This leads to the following BUG when CONFIG_DEBUG_ATOMIC_SLEEP is
enabled:
BUG: sleeping function called from invalid context at arch/powerpc/kernel/rtas.c:496
in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc2-thuth #6
Call Trace:
[c00000007ffe7b90] [c000000000807670] dump_stack+0xa0/0xdc (unreliable)
[c00000007ffe7bc0] [c0000000000e1f14] ___might_sleep+0x134/0x180
[c00000007ffe7c20] [c00000000002aec0] rtas_busy_delay+0x30/0xd0
[c00000007ffe7c50] [c00000000002bde4] rtas_get_sensor+0x74/0xe0
[c00000007ffe7ce0] [c000000000083264] ras_epow_interrupt+0x44/0x450
[c00000007ffe7d90] [c000000000120260] handle_irq_event_percpu+0xa0/0x300
[c00000007ffe7e70] [c000000000120524] handle_irq_event+0x64/0xc0
[c00000007ffe7eb0] [c000000000124dbc] handle_fasteoi_irq+0xec/0x260
[c00000007ffe7ef0] [c00000000011f4f0] generic_handle_irq+0x50/0x80
[c00000007ffe7f20] [c000000000010f3c] __do_irq+0x8c/0x200
[c00000007ffe7f90] [c0000000000236cc] call_do_irq+0x14/0x24
[c00000007e6f39e0] [c000000000011144] do_IRQ+0x94/0x110
[c00000007e6f3a30] [c000000000002594] hardware_interrupt_common+0x114/0x180
Fix this issue by introducing a new rtas_get_sensor_fast() function
that does not use rtas_busy_delay() - and thus can only be used for
sensors that do not cause a BUSY condition - known as "fast" sensors.
The EPOW sensor is defined to be "fast" in sPAPR - mpe.
Fixes: 587f83e8dd50 ("powerpc/pseries: Use rtas_get_sensor in RAS code")
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/powerpc/include/asm/rtas.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 17 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/ras.c | 3 |
3 files changed, 20 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h index 34fd70488d83..c5d5cb36f6c6 100644 --- a/arch/powerpc/include/asm/rtas.h +++ b/arch/powerpc/include/asm/rtas.h @@ -255,6 +255,7 @@ extern void rtas_power_off(void); extern void rtas_halt(void); extern void rtas_os_term(char *str); extern int rtas_get_sensor(int sensor, int index, int *state); +extern int rtas_get_sensor_fast(int sensor, int index, int *state); extern int rtas_get_power_level(int powerdomain, int *level); extern int rtas_set_power_level(int powerdomain, int level, int *setlevel); extern bool rtas_indicator_present(int token, int *maxindex); diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 52add6f3e201..f956a2f84a15 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -584,6 +584,23 @@ int rtas_get_sensor(int sensor, int index, int *state) } EXPORT_SYMBOL(rtas_get_sensor); +int rtas_get_sensor_fast(int sensor, int index, int *state) +{ + int token = rtas_token("get-sensor-state"); + int rc; + + if (token == RTAS_UNKNOWN_SERVICE) + return -ENOENT; + + rc = rtas_call(token, 2, 2, state, sensor, index); + WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN && + rc <= RTAS_EXTENDED_DELAY_MAX)); + + if (rc < 0) + return rtas_error_rc(rc); + return rc; +} + bool rtas_indicator_present(int token, int *maxindex) { int proplen, count, i; diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c index c4dfccd3a3d9..2338e6e98483 100644 --- a/arch/powerpc/platforms/pseries/ras.c +++ b/arch/powerpc/platforms/pseries/ras.c @@ -187,7 +187,8 @@ static irqreturn_t ras_epow_interrupt(int irq, void *dev_id) int state; int critical; - status = rtas_get_sensor(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX, &state); + status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX, + &state); if (state > 3) critical = 1; /* Time Critical */ |