As pointed out by commit
de9b8f5dcb ("sched: Fix crash trying to dequeue/enqueue the idle thread")
init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.
As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().
Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().
Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().
Secondary startups were patched via coccinelle:
@begone@
@@
-preempt_disable();
...
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU
vendors' errata solution at runtime. The main purpose of this patch is
to provide a framework. Therefore, the implementation is quite basic for
now so that some scenarios could not use this schemei, such as patching
code to a module, relocating the patching code and heterogeneous CPU
topology.
Users could use the macro ALTERNATIVE to apply an errata to the existing
code flow. In the macro ALTERNATIVE, users need to specify the manufacturer
information(vendorid, archid, and impid) for this errata. Therefore, kernel
will know this errata is suitable for which CPU core. During the booting
procedure, kernel will select the errata required by the CPU core and then
patch it. It means that the kernel only applies the errata to the specified
CPU core. In this case, the vendor's errata does not affect each other at
runtime. The above patching procedure only occurs during the booting phase,
so we only take the overhead of the "alternative" mechanism once.
This "alternative" mechanism is enabled by default to ensure that all
required errata will be applied. However, users can disable this feature by
the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE".
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Use the generic numa implementation to add NUMA support for RISC-V.
This is based on Greentime's patch[1] but modified to use generic NUMA
implementation and few more fixes.
[1] https://lkml.org/lkml/2020/1/10/233
Co-developed-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Right now the RISC-V timer driver is convoluted to support:
1. Linux RISC-V S-mode (with MMU) where it will use TIME CSR for
clocksource and SBI timer calls for clockevent device.
2. Linux RISC-V M-mode (without MMU) where it will use CLINT MMIO
counter register for clocksource and CLINT MMIO compare register
for clockevent device.
We now have a separate CLINT timer driver which also provide CLINT
based IPI operations so let's remove CLINT MMIO related code from
arch/riscv directory and RISC-V timer driver.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
We add mechanism to set custom IPI operations so that CLINT driver
from drivers directory can provide custom IPI operations.
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Tested-by: Emil Renner Berhing <kernel@esmil.dk>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
The following warnings are reported by kbuild with W=1.
>> arch/riscv/kernel/smpboot.c:109:5: warning: no previous prototype for
'start_secondary_cpu' [-Wmissing-prototypes]
109 | int start_secondary_cpu(int cpu, struct task_struct *tidle)
| ^~~~~~~~~~~~~~~~~~~
arch/riscv/kernel/smpboot.c:146:34: warning: no previous prototype for
'smp_callin' [-Wmissing-prototypes]
146 | asmlinkage __visible void __init smp_callin(void)
| ^~~~~~~~~~
Fix the warnings by marking the local functions static and adding the prototype
for the global function.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
The trap vector is set only in trap_init which may be too late in some
cases. Early ioremap/efi spits many warning messages which may be useful.
Setup the trap vector early so that any warning/bug can be handled before
generic code invokes trap_init.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
The cpu_running is not a lock-class, it lacks the dep_map member in
completion. It causes the error as follow:
arch/riscv/kernel/smpboot.c: In function '__cpu_up':
./include/linux/lockdep.h:364:52: error: 'struct completion' has no member named 'dep_map'
364 | #define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
| ^~
./include/asm-generic/bug.h:113:25: note: in definition of macro 'WARN_ON'
113 | int __ret_warn_on = !!(condition); \
| ^~~~~~~~~
./include/linux/lockdep.h:390:27: note: in expansion of macro 'lockdep_is_held'
390 | WARN_ON(debug_locks && !lockdep_is_held(l)); \
| ^~~~~~~~~~~~~~~
arch/riscv/kernel/smpboot.c:118:2: note: in expansion of macro 'lockdep_assert_held'
118 | lockdep_assert_held(&cpu_running);
There are a lot of archs which use cpu_running in smpboot.c (arm,
arm64, openrisc, xtensa, s390, x86, mips), but none of them try
lockdep_assert_held(&cpu_running.wait.lock). So Just remove it.
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Store the smp_processor_id() in a local variable to save some
pointer chasing.
Signed-off-by: Greentime Hu <greentime.hu@sifive.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Currently, all harts have to jump Linux in RISC-V. This complicates the
multi-stage boot process as every transient stage also has to ensure all
harts enter to that stage and jump to Linux afterwards. It also obstructs
a clean Kexec implementation.
SBI HSM extension provides alternate solutions where only a single hart
need to boot and enter Linux. The booting hart can bring up secondary
harts one by one afterwards.
Add SBI HSM based cpu_ops that implements an ordered booting method in
RISC-V. This change is also backward compatible with older firmware not
implementing HSM extension. If a latest kernel is used with older
firmware, it will continue to use the default spinning booting method.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Currently, all non-booting harts start booting after the booting hart
updates the per-hart stack pointer. This is done in a way that, it's
difficult to implement any other booting method without breaking the
backward compatibility.
Define a cpu_ops method that allows to introduce other booting methods
in future. Modify the current booting method to be compatible with
cpu_ops.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
RISC-V has the concept of a cpu level interrupt controller. The
interface for it is split between a standardized part that is exposed
as bits in the mstatus/sstatus register and the mie/mip/sie/sip
CRS. But the bit to actually trigger IPIs is not standardized and
just mentioned as implementable using MMIO.
Add support for IPIs using MMIO using the SiFive clint layout (which
is also shared by Ariane, Kendryte and the Qemu virt platform).
Additionally the MMIO block also supports the time value and timer
compare registers, so they are also set up using the same OF node.
Support for other layouts should also be relatively easy to add in the
future.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: update include guard format; fix checkpatch
issues; minor commit message cleanup]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Rather than adding prototypes for C functions called only by assembly
code, mark them as __visible. This avoids adding prototypes that will
never be used by the callers. Resolves the following sparse warnings:
arch/riscv/kernel/irq.c:27:29: warning: symbol 'do_IRQ' was not declared. Should it be static?
arch/riscv/kernel/ptrace.c:151:6: warning: symbol 'do_syscall_trace_enter' was not declared. Should it be static?
arch/riscv/kernel/ptrace.c:165:6: warning: symbol 'do_syscall_trace_exit' was not declared. Should it be static?
arch/riscv/kernel/signal.c:295:17: warning: symbol 'do_notify_resume' was not declared. Should it be static?
arch/riscv/kernel/traps.c:92:1: warning: symbol 'do_trap_unknown' was not declared. Should it be static?
arch/riscv/kernel/traps.c:94:1: warning: symbol 'do_trap_insn_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:96:1: warning: symbol 'do_trap_insn_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:98:1: warning: symbol 'do_trap_insn_illegal' was not declared. Should it be static?
arch/riscv/kernel/traps.c💯1: warning: symbol 'do_trap_load_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:102:1: warning: symbol 'do_trap_load_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:104:1: warning: symbol 'do_trap_store_misaligned' was not declared. Should it be static?
arch/riscv/kernel/traps.c:106:1: warning: symbol 'do_trap_store_fault' was not declared. Should it be static?
arch/riscv/kernel/traps.c:108:1: warning: symbol 'do_trap_ecall_u' was not declared. Should it be static?
arch/riscv/kernel/traps.c:110:1: warning: symbol 'do_trap_ecall_s' was not declared. Should it be static?
arch/riscv/kernel/traps.c:112:1: warning: symbol 'do_trap_ecall_m' was not declared. Should it be static?
arch/riscv/kernel/traps.c:124:17: warning: symbol 'do_trap_break' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:136:24: warning: symbol 'smp_callin' was not declared. Should it be static?
Based on a suggestion from Luc Van Oostenryck.
This version includes changes based on feedback from Christoph Hellwig
<hch@lst.de>.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de> # for do_syscall_trace_*
sparse identifies several missing prototypes caused by missing
preprocessor include directives:
arch/riscv/kernel/cpufeature.c:16:6: warning: symbol 'has_fpu' was not declared. Should it be static?
arch/riscv/kernel/process.c:26:6: warning: symbol 'arch_cpu_idle' was not declared. Should it be static?
arch/riscv/kernel/reset.c:15:6: warning: symbol 'pm_power_off' was not declared. Should it be static?
arch/riscv/kernel/syscall_table.c:15:6: warning: symbol 'sys_call_table' was not declared. Should it be static?
arch/riscv/kernel/traps.c:149:13: warning: symbol 'trap_init' was not declared. Should it be static?
arch/riscv/kernel/vdso.c:54:5: warning: symbol 'arch_setup_additional_pages' was not declared. Should it be static?
arch/riscv/kernel/smp.c:64:6: warning: symbol 'arch_match_cpu_phys_id' was not declared. Should it be static?
arch/riscv/kernel/module-sections.c:89:5: warning: symbol 'module_frob_arch_sections' was not declared. Should it be static?
arch/riscv/mm/context.c:42:6: warning: symbol 'switch_mm' was not declared. Should it be static?
Fix by including the appropriate header files in the appropriate
source files.
This patch should have no functional impact.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Add prototypes for assembly language functions defined in head.S,
and include these prototypes into C source files that call those
functions.
This patch resolves the following warnings from sparse:
arch/riscv/kernel/setup.c:39:10: warning: symbol 'hart_lottery' was not declared. Should it be static?
arch/riscv/kernel/setup.c:42:13: warning: symbol 'parse_dtb' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:33:6: warning: symbol '__cpu_up_stack_pointer' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:34:6: warning: symbol '__cpu_up_task_pointer' was not declared. Should it be static?
arch/riscv/mm/fault.c:25:17: warning: symbol 'do_page_fault' was not declared. Should it be static?
This change should have no functional impact.
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Currently, there are no topology defined for RISC-V.
Parse the cpu-map node from device tree and setup the
cpu topology.
CPU topology after applying the patch.
$cat /sys/devices/system/cpu/cpu2/topology/core_siblings_list
0-3
$cat /sys/devices/system/cpu/cpu3/topology/core_siblings_list
0-3
$cat /sys/devices/system/cpu/cpu3/topology/physical_package_id
0
$cat /sys/devices/system/cpu/cpu3/topology/core_id
3
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 655 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070034.575739538@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If nr_cpus command line option is set, maximum possible cpu should be
set to that value.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
nosmp command line option sets max_cpus to zero. No secondary harts
will boot if this is enabled. But present cpu mask will still point to
all possible masks.
Fix present cpu mask for nosmp usecase.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
We should never have a cpuid greater that NR_CPUS. Compare with NR_CPUS
before creating the mapping between logical and physical CPU ids. This
is also mandatory as NR_CPUS check is removed from
riscv_of_processor_hartid.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
In SMP path, __cpu_up waits for other CPU to come online indefinitely.
This is wrong as other CPU might be disabled in machine mode and
possible CPU is set to the cpus present in DT.
Introduce a completion variable and waits only for a second.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Use the new for_each_of_cpu_node() helper to iterate over cpu nodes
instead of open coding. Note that this will allow matching also on the
node name instead of the (for FDT) deprecated device_type property.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Fix of_node* refcount at various places by using of_node_put.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Setup the cpu_logical_map during boot. Moreover, every SBI call
and PLIC context are based on the physical hartid. Use the logical
CPU to hartid mapping to pass correct hartid to respective functions.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
The secondary harts spin on couple of per cpu variables until both of
these are non-zero so it's not necessary to have any ordering here.
However, WRITE_ONCE should be used to avoid tearing.
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
commit f1f1007644 ("mm: add new mmgrab() helper") added a
helper that we missed out on.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
The old name was a bit odd.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
It's a bit confusing exactly what this function does: it actually
returns the hartid of an OF processor node, failing with -1 on invalid
nodes. I've changed the name to _hartid() in order to make that a bit
more clear, as well as adding a comment.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
[Atish: code comment formatting update]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Currently, irq is enabled before preemption disabling happens.
If the scheduler fired right here and cpu is scheduled then it
may blow up.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
[Atish: Commit text and code comment formatting update]
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
The RISC-V ISA defines a per-hart real-time clock and timer, which is
present on all systems. The clock is accessed via the 'rdtime'
pseudo-instruction (which reads a CSR), and the timer is set via an SBI
call.
Contains various improvements from Atish Patra <atish.patra@wdc.com>.
Signed-off-by: Dmitriy Cherkasov <dmitriy@oss-tech.org>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
[hch: remove dead code, add SPDX tags, used riscv_of_processor_hart(),
minor cleanups, merged hotplug cpu support and other improvements
from Atish]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This contains the various __init C functions, the initial assembly
kernel entry point, and the code to reset the system. When a file was
init-related this patch contains the entire file.
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
