5.4-stable review patch. If anyone has any objections, please let me know.
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From: Paul Burton paulburton@kernel.org
[ Upstream commit 00a134fc2bb4a5f8fada58cf7ff4259149691d64 ]
The pm-cps code has up until now used per-CPU variables indexed by core, rather than CPU number, in order to share data amongst sibling CPUs (ie. VPs/threads in a core). This works fine for single cluster systems, but with multi-cluster systems a core number is no longer unique in the system, leading to sharing between CPUs that are not actually siblings.
Avoid this issue by using per-CPU variables as they are more generally used - ie. access them using CPU numbers rather than core numbers. Sharing between siblings is then accomplished by: - Assigning the same pointer to entries for each sibling CPU for the nc_asm_enter & ready_count variables, which allow this by virtue of being per-CPU pointers.
- Indexing by the first CPU set in a CPUs cpu_sibling_map in the case of pm_barrier, for which we can't use the previous approach because the per-CPU variable is not a pointer.
Signed-off-by: Paul Burton paulburton@kernel.org Signed-off-by: Dragan Mladjenovic dragan.mladjenovic@syrmia.com Signed-off-by: Aleksandar Rikalo arikalo@gmail.com Tested-by: Serge Semin fancer.lancer@gmail.com Tested-by: Gregory CLEMENT gregory.clement@bootlin.com Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/mips/kernel/pm-cps.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-)
diff --git a/arch/mips/kernel/pm-cps.c b/arch/mips/kernel/pm-cps.c index a26f40db15d00..cb09536fb986b 100644 --- a/arch/mips/kernel/pm-cps.c +++ b/arch/mips/kernel/pm-cps.c @@ -56,10 +56,7 @@ static DEFINE_PER_CPU_ALIGNED(u32*, ready_count); /* Indicates online CPUs coupled with the current CPU */ static DEFINE_PER_CPU_ALIGNED(cpumask_t, online_coupled);
-/* - * Used to synchronize entry to deep idle states. Actually per-core rather - * than per-CPU. - */ +/* Used to synchronize entry to deep idle states */ static DEFINE_PER_CPU_ALIGNED(atomic_t, pm_barrier);
/* Saved CPU state across the CPS_PM_POWER_GATED state */ @@ -118,9 +115,10 @@ int cps_pm_enter_state(enum cps_pm_state state) cps_nc_entry_fn entry; struct core_boot_config *core_cfg; struct vpe_boot_config *vpe_cfg; + atomic_t *barrier;
/* Check that there is an entry function for this state */ - entry = per_cpu(nc_asm_enter, core)[state]; + entry = per_cpu(nc_asm_enter, cpu)[state]; if (!entry) return -EINVAL;
@@ -156,7 +154,7 @@ int cps_pm_enter_state(enum cps_pm_state state) smp_mb__after_atomic();
/* Create a non-coherent mapping of the core ready_count */ - core_ready_count = per_cpu(ready_count, core); + core_ready_count = per_cpu(ready_count, cpu); nc_addr = kmap_noncoherent(virt_to_page(core_ready_count), (unsigned long)core_ready_count); nc_addr += ((unsigned long)core_ready_count & ~PAGE_MASK); @@ -164,7 +162,8 @@ int cps_pm_enter_state(enum cps_pm_state state)
/* Ensure ready_count is zero-initialised before the assembly runs */ WRITE_ONCE(*nc_core_ready_count, 0); - coupled_barrier(&per_cpu(pm_barrier, core), online); + barrier = &per_cpu(pm_barrier, cpumask_first(&cpu_sibling_map[cpu])); + coupled_barrier(barrier, online);
/* Run the generated entry code */ left = entry(online, nc_core_ready_count); @@ -635,12 +634,14 @@ static void *cps_gen_entry_code(unsigned cpu, enum cps_pm_state state)
static int cps_pm_online_cpu(unsigned int cpu) { - enum cps_pm_state state; - unsigned core = cpu_core(&cpu_data[cpu]); + unsigned int sibling, core; void *entry_fn, *core_rc; + enum cps_pm_state state; + + core = cpu_core(&cpu_data[cpu]);
for (state = CPS_PM_NC_WAIT; state < CPS_PM_STATE_COUNT; state++) { - if (per_cpu(nc_asm_enter, core)[state]) + if (per_cpu(nc_asm_enter, cpu)[state]) continue; if (!test_bit(state, state_support)) continue; @@ -652,16 +653,19 @@ static int cps_pm_online_cpu(unsigned int cpu) clear_bit(state, state_support); }
- per_cpu(nc_asm_enter, core)[state] = entry_fn; + for_each_cpu(sibling, &cpu_sibling_map[cpu]) + per_cpu(nc_asm_enter, sibling)[state] = entry_fn; }
- if (!per_cpu(ready_count, core)) { + if (!per_cpu(ready_count, cpu)) { core_rc = kmalloc(sizeof(u32), GFP_KERNEL); if (!core_rc) { pr_err("Failed allocate core %u ready_count\n", core); return -ENOMEM; } - per_cpu(ready_count, core) = core_rc; + + for_each_cpu(sibling, &cpu_sibling_map[cpu]) + per_cpu(ready_count, sibling) = core_rc; }
return 0;