linux/arch/powerpc, branch v3.0.41

powerpc: Fix wrong divisor in usecs_to_cputime

2012-08-09T15:27:34Z

commit 9f5072d4f63f28d30d343573830ac6c85fc0deff upstream. Commit d57af9b (taskstats: use real microsecond granularity for CPU times) renamed msecs_to_cputime to usecs_to_cputime, but failed to update all numbers on the way. This causes nonsensical cpu idle/iowait values to be displayed in /proc/stat (the only user of usecs_to_cputime so far). This also renames __cputime_msec_factor to __cputime_usec_factor, adapting its value and using it directly in cputime_to_usecs instead of doing two multiplications. Signed-off-by: Andreas Schwab Acked-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt Cc: Michal Hocko Signed-off-by: Greg Kroah-Hartman

powerpc: Add "memory" attribute for mfmsr()

2012-08-09T15:27:33Z

commit b416c9a10baae6a177b4f9ee858b8d309542fbef upstream. Add "memory" attribute in inline assembly language as a compiler barrier to make sure 4.6.x GCC don't reorder mfmsr(). Signed-off-by: Tiejun Chen Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc/ftrace: Fix assembly trampoline register usage

2012-08-09T15:27:33Z

commit fd5a42980e1cf327b7240adf5e7b51ea41c23437 upstream. Just like the module loader, ftrace needs to be updated to use r12 instead of r11 with newer gcc's. Signed-off-by: Roger Blofeld Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Gortmaker Signed-off-by: Greg Kroah-Hartman

powerpc/xmon: Use cpumask iterator to avoid warning

2012-07-16T15:47:35Z

commit bc1d7702910c7c7e88eb60b58429dbfe293683ce upstream. We have a bug report where the kernel hits a warning in the cpumask code: WARNING: at include/linux/cpumask.h:107 Which is: WARN_ON_ONCE(cpu >= nr_cpumask_bits); The backtrace is: cpu_cmd cmds xmon_core xmon die xmon is iterating through 0 to NR_CPUS. I'm not sure why we are still open coding this but iterating above nr_cpu_ids is definitely a bug. This patch iterates through all possible cpus, in case we issue a system reset and CPUs in an offline state call in. Perhaps the old code was trying to handle CPUs that were in the partition but were never started (eg kexec into a kernel with an nr_cpus= boot option). They are going to die way before we get into xmon since we haven't set any kernel state up for them. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc: Fix kernel panic during kernel module load

2012-06-17T18:23:10Z

commit 3c75296562f43e6fbc6cddd3de948a7b3e4e9bcf upstream. This fixes a problem which can causes kernel oopses while loading a kernel module. According to the PowerPC EABI specification, GPR r11 is assigned the dedicated function to point to the previous stack frame. In the powerpc-specific kernel module loader, do_plt_call() (in arch/powerpc/kernel/module_32.c), GPR r11 is also used to generate trampoline code. This combination crashes the kernel, in the case where the compiler chooses to use a helper function for saving GPRs on entry, and the module loader has placed the .init.text section far away from the .text section, meaning that it has to generate a trampoline for functions in the .init.text section to call the GPR save helper. Because the trampoline trashes r11, references to the stack frame using r11 can cause an oops. The fix just uses GPR r12 instead of GPR r11 for generating the trampoline code. According to the statements from Freescale, this is safe from an EABI perspective. I've tested the fix for kernel 2.6.33 on MPC8541. Signed-off-by: Steffen Rumler [paulus@samba.org: reworded the description] Signed-off-by: Paul Mackerras Signed-off-by: Greg Kroah-Hartman

powerpc/pmac: Fix SMP kernels on pre-core99 UP machines

2012-03-23T18:20:52Z

commit 78c5c68a4cf4329d17abfa469345ddf323d4fd62 upstream. The code for "powersurge" SMP would kick in and cause a crash at boot due to the lack of a NULL test. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Jeremy Kerr Reported-by: Adam Conrad Tested-by: Adam Conrad Signed-off-by: Greg Kroah-Hartman

powerpc/perf: power_pmu_start restores incorrect values, breaking frequency events

2012-03-01T00:33:39Z

commit 9a45a9407c69d068500923480884661e2b9cc421 upstream. perf on POWER stopped working after commit e050e3f0a71b (perf: Fix broken interrupt rate throttling). That patch exposed a bug in the POWER perf_events code. Since the PMCs count upwards and take an exception when the top bit is set, we want to write 0x80000000 - left in power_pmu_start. We were instead programming in left which effectively disables the counter until we eventually hit 0x80000000. This could take seconds or longer. With the patch applied I get the expected number of samples: SAMPLE events: 9948 Signed-off-by: Anton Blanchard Acked-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit

2012-01-12T19:35:03Z

commit e4f387d8db3ba3c2dae4d8bdfe7bb5f4fe1bcb0d upstream. Unpaired calling of probe_hcall_entry and probe_hcall_exit might happen as following, which could cause incorrect preempt count. __trace_hcall_entry => trace_hcall_entry -> probe_hcall_entry => get_cpu_var => preempt_disable __trace_hcall_exit => trace_hcall_exit -> probe_hcall_exit => put_cpu_var => preempt_enable where: A => B and A -> B means A calls B, but => means A will call B through function name, and B will definitely be called. -> means A will call B through function pointer, so B might not be called if the function pointer is not set. So error happens when only one of probe_hcall_entry and probe_hcall_exit get called during a hcall. This patch tries to move the preempt count operations from probe_hcall_entry and probe_hcall_exit to its callers. Reported-by: Paul E. McKenney Signed-off-by: Li Zhong Tested-by: Paul E. McKenney Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc/time: Handle wrapping of decrementer

2012-01-12T19:35:02Z

commit 37fb9a0231ee43d42d069863bdfd567fca2b61af upstream. When re-enabling interrupts we have code to handle edge sensitive decrementers by resetting the decrementer to 1 whenever it is negative. If interrupts were disabled long enough that the decrementer wrapped to positive we do nothing. This means interrupts can be delayed for a long time until it finally goes negative again. While we hope interrupts are never be disabled long enough for the decrementer to go positive, we have a very good test team that can drive any kernel into the ground. The softlockup data we get back from these fails could be seconds in the future, completely missing the cause of the lockup. We already keep track of the timebase of the next event so use that to work out if we should trigger a decrementer exception. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman

powerpc: Copy down exception vectors after feature fixups

2011-11-21T22:31:25Z

commit d715e433b7ad19c02fc4becf0d5e9a59f97925de upstream. kdump fails because we try to execute an HV only instruction. Feature fixups are being applied after we copy the exception vectors down to 0 so they miss out on any updates. We have always had this issue but it only became critical in v3.0 when we added CFAR support (breaks POWER5) and v3.1 when we added POWERNV (breaks everyone). Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Greg Kroah-Hartman