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authorPaul Mackerras <paulus@samba.org>2006-04-18 21:49:11 +1000
committerPaul Mackerras <paulus@samba.org>2006-04-18 21:49:11 +1000
commitf39224a8c1828bdd327539da72a53d8a13595838 (patch)
treecc9e9139e2e7e2e36774e5c52a5311439160633c /arch/powerpc/Kconfig
parent183b73ae7c9e4e19fa95d88e1778481899a65210 (diff)
powerpc: Use correct sequence for putting CPU into nap mode
We weren't using the recommended sequence for putting the CPU into nap mode. When I changed the idle loop, for some reason 7447A cpus started hanging when we put them into nap mode. Changing to the recommended sequence fixes that. The complexity here is that the recommended sequence is a loop that keeps putting the cpu back into nap mode. Clearly we need some way to break out of the loop when an interrupt (external interrupt, decrementer, performance monitor) occurs. Here we use a bit in the thread_info struct to indicate that we need this, and the exception entry code notices this and arranges for the exception to return to the value in the link register, thus breaking out of the loop. We use a new `local_flags' field in the thread_info which we can alter without needing to use an atomic update sequence. The PPC970 has the same recommended sequence, so we do the same thing there too. This also fixes a bug in the kernel stack overflow handling code on 32-bit, since it was causing a value that we needed in a register to get trashed. Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/Kconfig')
-rw-r--r--arch/powerpc/Kconfig6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2cdc35ce8045..65f67f986156 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -366,6 +366,7 @@ config PPC_PMAC64
select U3_DART
select MPIC_BROKEN_U3
select GENERIC_TBSYNC
+ select PPC_970_NAP
default y
config PPC_PREP
@@ -383,6 +384,7 @@ config PPC_MAPLE
select MPIC_BROKEN_U3
select GENERIC_TBSYNC
select PPC_UDBG_16550
+ select PPC_970_NAP
default n
help
This option enables support for the Maple 970FX Evaluation Board.
@@ -457,6 +459,10 @@ config PPC_MPC106
bool
default n
+config PPC_970_NAP
+ bool
+ default n
+
source "drivers/cpufreq/Kconfig"
config CPU_FREQ_PMAC