kernel/linux.git/arch/mips/include/asm/smp.h, branch linux-4.4.y

MIPS: SMP: Update cpu_foreign_map on CPU disable

2020-05-10T08:25:45+00:00

commit 826e99be6ab5189dbfb096389016ffb8d20a683e upstream. When a CPU is disabled via CPU hotplug, cpu_foreign_map is not updated. This could result in cache management SMP calls being sent to offline CPUs instead of online siblings in the same core. Add a call to calculate_cpu_foreign_map() in the various MIPS cpu disable callbacks after set_cpu_online(). All cases are updated for consistency and to keep cpu_foreign_map strictly up to date, not just those which may support hardware multithreading. Fixes: cccf34e9411c ("MIPS: c-r4k: Fix cache flushing for MT cores") Signed-off-by: James Hogan Cc: Paul Burton Cc: David Daney Cc: Kevin Cernekee Cc: Florian Fainelli Cc: Huacai Chen Cc: Hongliang Tao Cc: Hua Yan Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13799/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman

MIPS: VDSO: Prevent use of smp_processor_id()

2019-09-21T05:12:44+00:00

commit 351fdddd366245c0fb4636f32edfb4198c8d6b8c upstream. VDSO code should not be using smp_processor_id(), since it is executed in user mode. Introduce a VDSO-specific path which will cause a compile-time or link-time error (depending upon support for __compiletime_error) if the VDSO ever incorrectly attempts to use smp_processor_id(). [Matt Redfearn : Move before change to smp_processor_id in series] Signed-off-by: Paul Burton Signed-off-by: Matt Redfearn Patchwork: https://patchwork.linux-mips.org/patch/17932/ Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

MIPS: SMP: Don't increment irq_count multiple times for call function IPIs

2015-08-03T07:25:12+00:00

The majority of SMP platforms handle their IPIs through do_IRQ() which calls irq_{enter/exit}(). When a call function IPI is received, smp_call_function_interrupt() is called which also calls irq_{enter,exit}(), meaning irq_count is raised twice. When tick broadcasting is used (which is implemented via a call function IPI), this incorrectly causes all CPU idle time on the core receiving broadcast ticks to be accounted as time spent servicing IRQs, as account_process_tick() will account as such if irq_count is greater than 1. This results in 100% CPU usage being reported on a core which receives its ticks via broadcast. This patch removes the SMP smp_call_function_interrupt() wrapper which calls irq_{enter,exit}(). Platforms which handle their IPIs through do_IRQ() now call generic_smp_call_function_interrupt() directly to avoid incrementing irq_count a second time. Platforms which don't (loongson, sgi-ip27, sibyte) call generic_smp_call_function_interrupt() wrapped in irq_{enter,exit}(). Signed-off-by: Alex Smith Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10770/ Signed-off-by: Ralf Baechle

MIPS: c-r4k: Fix cache flushing for MT cores

2015-07-10T08:59:16+00:00

MT_SMP is not the only SMP option for MT cores. The MT_SMP option allows more than one VPE per core to appear as a secondary CPU in the system. Because of how CM works, it propagates the address-based cache ops to the secondary cores but not the index-based ones. Because of that, the code does not use IPIs to flush the L1 caches on secondary cores because the CM would have done that already. However, the CM functionality is independent of the type of SMP kernel so even in non-MT kernels, IPIs are not necessary. As a result of which, we change the conditional to depend on the CM presence. Moreover, since VPEs on the same core share the same L1 caches, there is no need to send an IPI on all of them so we calculate a suitable cpumask with only one VPE per core. Signed-off-by: Markos Chandras Cc: # 3.15+ Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/10654/ Signed-off-by: Ralf Baechle

MIPS: SMP: Fix build error.

2015-05-12T07:13:30+00:00

CC arch/mips/kernel/smp.o arch/mips/kernel/smp.c: In function ‘start_secondary’: arch/mips/kernel/smp.c:149:2: error: passing argument 2 of ‘cpumask_set_cpu’ discards ‘volatile’ qualifier from pointer target type [-Werror] cpumask_set_cpu(cpu, &cpu_callin_map); ^ In file included from ./arch/mips/include/asm/processor.h:14:0, from ./arch/mips/include/asm/thread_info.h:15, from include/linux/thread_info.h:54, from include/asm-generic/preempt.h:4, from arch/mips/include/generated/asm/preempt.h:1, from include/linux/preempt.h:18, from include/linux/interrupt.h:8, from arch/mips/kernel/smp.c:24: include/linux/cpumask.h:272:91: note: expected ‘struct cpumask *’ but argument is of type ‘volatile struct cpumask_t *’ static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) ^ arch/mips/kernel/smp.c: In function ‘smp_prepare_boot_cpu’: arch/mips/kernel/smp.c:211:2: error: passing argument 2 of ‘cpumask_set_cpu’ discards ‘volatile’ qualifier from pointer target type [-Werror] cpumask_set_cpu(0, &cpu_callin_map); ^ In file included from ./arch/mips/include/asm/processor.h:14:0, from ./arch/mips/include/asm/thread_info.h:15, from include/linux/thread_info.h:54, from include/asm-generic/preempt.h:4, from arch/mips/include/generated/asm/preempt.h:1, from include/linux/preempt.h:18, from include/linux/interrupt.h:8, from arch/mips/kernel/smp.c:24: include/linux/cpumask.h:272:91: note: expected ‘struct cpumask *’ but argument is of type ‘volatile struct cpumask_t *’ static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp) ^ arch/mips/kernel/smp.c: In function ‘__cpu_up’: arch/mips/kernel/smp.c:221:10: error: passing argument 2 of ‘cpumask_test_cpu’ discards ‘volatile’ qualifier from pointer target type [-Werror] while (!cpumask_test_cpu(cpu, &cpu_callin_map)) ^ In file included from ./arch/mips/include/asm/processor.h:14:0, from ./arch/mips/include/asm/thread_info.h:15, from include/linux/thread_info.h:54, from include/asm-generic/preempt.h:4, from arch/mips/include/generated/asm/preempt.h:1, from include/linux/preempt.h:18, from include/linux/interrupt.h:8, from arch/mips/kernel/smp.c:24: include/linux/cpumask.h:294:90: note: expected ‘const struct cpumask *’ but argument is of type ‘volatile struct cpumask_t *’ static inline int cpumask_test_cpu(int cpu, const struct cpumask *cpumask) ^ cc1: all warnings being treated as errors make[2]: *** [arch/mips/kernel/smp.o] Error 1 make[1]: *** [arch/mips/kernel] Error 2 make: *** [arch/mips] Error 2 Signed-off-by: Ralf Baechle

mips: fix obsolete cpumask_of_cpu usage.

2015-03-10T03:24:40+00:00

Plus, it's weird. Signed-off-by: Rusty Russell

MIPS: Move CPU topology macros to topology.h

2014-08-27T11:44:44+00:00

The correct position is topology.h, and this fix macros redefinition problems for Netlogic. [ralf@linux-mips.org: Fix build - the original patch broke most configurations.] Signed-off-by: Huacai Chen Cc: Jayachandran C. Cc: John Crispin Cc: Steven J. Hill Cc: Aurelien Jarno Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang Cc: Zhangjin Wu Patchwork: https://patchwork.linux-mips.org/patch/7575/ Signed-off-by: Ralf Baechle

MIPS: Support CPU topology files in sysfs

2014-07-30T19:45:39+00:00

This patch is prepared for Loongson's NUMA support, it offer meaningful sysfs files such as physical_package_id, core_id, core_siblings and thread_siblings in /sys/devices/system/cpu/cpu?/topology. Signed-off-by: Huacai Chen Reviewed-by: Andreas Herrmann Cc: John Crispin Cc: Steven J. Hill Cc: Aurelien Jarno Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang Cc: Zhangjin Wu Patchwork: https://patchwork.linux-mips.org/patch/7184/ Signed-off-by: Ralf Baechle

MIPS: introduce cpu_coherent_mask

2014-05-02T15:39:13+00:00

Add a mask of CPUs which are currently known to be operating coherently. This is setup initially to be all present CPUs, but in a subsequent patch CPUs in a MIPS Coherent Processing System will be cleared in this mask as they enter non-coherent idle states. This will be used in order to determine when a CPU within a CPS system may need to be powered back up, but may also be used in future to optimise away wakeups for cache operations or TLB invalidations. Signed-off-by: Paul Burton

MIPS: Loongson 3: Add CPU hotplug support

2014-03-31T16:17:12+00:00

Tips of Loongson's CPU hotplug: 1, To fully shutdown a core in Loongson 3, the target core should go to CKSEG1 and flush all L1 cache entries at first. Then, another core (usually Core 0) can safely disable the clock of the target core. So play_dead() call loongson3_play_dead() via CKSEG1 (both uncached and unmmaped). 2, The default clocksource of Loongson is MIPS. Since clock source is a global device, timekeeping need the CP0' Count registers of each core be synchronous. Thus, when a core is up, we use a SMP_ASK_C0COUNT IPI to ask Core-0's Count. Signed-off-by: Huacai Chen Signed-off-by: Hongliang Tao Signed-off-by: Hua Yan Tested-by: Alex Smith Reviewed-by: Alex Smith Cc: John Crispin Cc: Steven J. Hill Cc: Aurelien Jarno Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang Cc: Zhangjin Wu Patchwork: https://patchwork.linux-mips.org/patch/6639 Signed-off-by: Ralf Baechle