Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc fixes from Ben Herrenschmidt:
 "Here are a handful of small powerpc fixes.

  A couple of section mismatches (always worth fixing), a missing export
  of a new symbol causing build failures of modules, a page fault
  deadlock fix (interestingly that bug has been around for a LONG time,
  though it seems to be more easily triggered by KVM) and fixing pseries
  default idle loop in the absence of the cpuidle drivers (such as
  during boot)"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc: Default arch idle could cede processor on pseries
  fbdev/ps3fb: Fix section mismatch warning for ps3fb_probe
  powerpc: Fix section mismatch warning for prom_rtas_call
  powerpc: Fix possible deadlock on page fault
  powerpc: Export cpu_to_chip_id() to fix build error

4 files changed, 34 insertions, 14 deletions

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 7b6391b68fb8..12e656ffe60e 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1297,7 +1297,8 @@ static void __init prom_query_opal(void)
                 prom_opal_align = 0x10000;
 }
 
-static int prom_rtas_call(int token, int nargs, int nret, int *outputs, ...)
+static int __init prom_rtas_call(int token, int nargs, int nret,
+                                 int *outputs, ...)
 {
         struct rtas_args rtas_args;
         va_list list;
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 442d8e23f8f4..8e59abc237d7 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -611,6 +611,7 @@ int cpu_to_chip_id(int cpu)
         of_node_put(np);
         return of_get_ibm_chip_id(np);
 }
+EXPORT_SYMBOL(cpu_to_chip_id);
 
 /* Helper routines for cpu to core mapping */
 int cpu_core_index_of_thread(int cpu)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 76d8e7cc7805..2dd69bf4af46 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -206,7 +206,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
         int trap = TRAP(regs);
         int is_exec = trap == 0x400;
         int fault;
-        int rc = 0;
+        int rc = 0, store_update_sp = 0;
 
 #if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))
         /*
@@ -280,6 +280,14 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
 
         perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
 
+        /*
+         * We want to do this outside mmap_sem, because reading code around nip
+         * can result in fault, which will cause a deadlock when called with
+         * mmap_sem held
+         */
+        if (user_mode(regs))
+                store_update_sp = store_updates_sp(regs);
+
         /* When running in the kernel we expect faults to occur only to
          * addresses in user space.  All other faults represent errors in the
          * kernel and should generate an OOPS.  Unfortunately, in the case of an
@@ -345,8 +353,7 @@ retry:
                  * between the last mapped region and the stack will
                  * expand the stack rather than segfaulting.
                  */
-                if (address + 2048 < uregs->gpr[1]
-                    && (!user_mode(regs) || !store_updates_sp(regs)))
+                if (address + 2048 < uregs->gpr[1] && !store_update_sp)
                         goto bad_area;
         }
         if (expand_stack(vma, address))
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index d64feb3ea0be..1f97e2b87a62 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -354,7 +354,7 @@ static int alloc_dispatch_log_kmem_cache(void)
 }
 early_initcall(alloc_dispatch_log_kmem_cache);
 
-static void pSeries_idle(void)
+static void pseries_lpar_idle(void)
 {
         /* This would call on the cpuidle framework, and the back-end pseries
          * driver to  go to idle states
@@ -362,10 +362,22 @@ static void pSeries_idle(void)
         if (cpuidle_idle_call()) {
                 /* On error, execute default handler
                  * to go into low thread priority and possibly
-                 * low power mode.
+                 * low power mode by cedeing processor to hypervisor
                  */
-                HMT_low();
-                HMT_very_low();
+
+                /* Indicate to hypervisor that we are idle. */
+                get_lppaca()->idle = 1;
+
+                /*
+                 * Yield the processor to the hypervisor.  We return if
+                 * an external interrupt occurs (which are driven prior
+                 * to returning here) or if a prod occurs from another
+                 * processor. When returning here, external interrupts
+                 * are enabled.
+                 */
+                cede_processor();
+
+                get_lppaca()->idle = 0;
         }
 }
 
@@ -456,15 +468,14 @@ static void __init pSeries_setup_arch(void)
 
         pSeries_nvram_init();
 
-        if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
+        if (firmware_has_feature(FW_FEATURE_LPAR)) {
                 vpa_init(boot_cpuid);
-                ppc_md.power_save = pSeries_idle;
-        }
-
-        if (firmware_has_feature(FW_FEATURE_LPAR))
+                ppc_md.power_save = pseries_lpar_idle;
                 ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
-        else
+        } else {
+                /* No special idle routine */
                 ppc_md.enable_pmcs = power4_enable_pmcs;
+        }
 
         ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;