linux/arch/powerpc
Benjamin Herrenschmidt f4ac7b5eb7 [POWERPC] Fix device-tree locking vs. interrupts
Lockdep found out that we can occasionally take the device-tree
lock for reading from softirq time (from rtas_token called
by the rtas real time clock code called by the NTP code),
while we take it occasionally for writing without masking
interrupts. The combination of those two can thus deadlock.

While some of those cases of interrupt read lock could be fixed
(such as caching the RTAS tokens) I figured that taking the
lock for writing is so rare (device-tree modification) that we
may as well penalize that case and allow reading from interrupts.

Thus, this turns all the writers to take the lock with irqs
masked to avoid the situation.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-04-18 15:37:16 +10:00
..
boot [POWERPC] 85xx: Fix the size of qe muram for MPC8568E 2008-04-17 09:52:18 -05:00
configs [POWERPC] 83xx: Enable FCM NAND and OF partitions in defconfig 2008-04-17 01:01:41 -05:00
kernel [POWERPC] Fix device-tree locking vs. interrupts 2008-04-18 15:37:16 +10:00
lib [POWERPC] Make rheap safe for spinlocks 2008-04-17 09:50:38 -05:00
math-emu [POWERPC] Replace remaining __FUNCTION__ occurrences 2008-04-01 20:43:09 +11:00
mm [POWERPC] Remove unused __max_memory variable 2008-04-18 15:37:11 +10:00
oprofile Merge branch 'linux-2.6' 2008-04-14 21:11:02 +10:00
platforms [POWERPC] Simplify xics direct/lpar irq_host setup 2008-04-18 15:36:11 +10:00
sysdev [POWERPC] fsl_soc: Factor fsl_get_sys_freq() out of the wdt and spi inits. 2008-04-17 01:01:40 -05:00
xmon [POWERPC] iSeries: Make iseries_reg_save private to iSeries 2008-04-15 21:21:25 +10:00
.gitignore [POWERPC] Add files build to .gitignore 2006-12-04 20:41:29 +11:00
Kconfig [POWERPC] fsl_lbc: implement few UPM routines 2008-04-17 01:01:38 -05:00
Kconfig.debug [POWERPC] cpm-serial: Relocate CPM buffer descriptors and SMC parameter ram. 2008-04-17 01:01:37 -05:00
Makefile [POWERPC] Provide access to arch/powerpc include path on ppc64 2008-04-17 07:46:12 +10:00