kernel.git/arch/csky/kernel, branch linux-5.12.y

sched/core: Initialize the idle task with preemption disabled

2021-07-14T14:59:16Z

[ Upstream commit f1a0a376ca0c4ef1fc3d24e3e502acbb5b795674 ] As pointed out by commit de9b8f5dcbd9 ("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 Signed-off-by: Ingo Molnar Acked-by: Peter Zijlstra Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com Signed-off-by: Sasha Levin

ftrace: Fix spelling mistake "disabed" -> "disabled"

2021-03-17T04:19:40Z

There is a spelling mistake in a comment, fix it. Signed-off-by: Colin Ian King Signed-off-by: Palmer Dabbelt

Merge tag 'csky-for-linus-5.12-rc1' of git://github.com/c-sky/csky-linux

2021-02-28T20:06:45Z

Pull arch/csky updates from Guo Ren: "Features: - add new memory layout 2.5G(user):1.5G(kernel) - add kmemleak support - reconstruct VDSO framework: add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO - add faulthandler_disabled() check - support (fix) swapon - add (fix) _PAGE_ACCESSED for default pgprot - abort uaccess retries upon fatal signal (from arm) Fixes and optimizations: - fix perf probe failure - fix show_regs doesn't contain regs->usp - remove custom asm/atomic.h implementation - fix barrier design - fix futex SMP implementation - fix asm/cmpxchg.h with correct ordering barrier - cleanup asm/spinlock.h - fix PTE global for 2.5:1.5 virtual memory - remove prologue of page fault handler in entry.S - fix TLB maintenance synchronization problem - add show_tlb for CPU_CK860 debug - fix FAULT_FLAG_XXX param for handle_mm_fault - fix update_mmu_cache called with user io mapping - fix do_page_fault parent irq status - fix a size determination in gpr_get() - pgtable.h: Coding convention - kprobe: Fix code in simulate without 'long' - fix pfn_valid error with wrong max_mapnr - use free_initmem_default() in free_initmem() - fix compile error" * tag 'csky-for-linus-5.12-rc1' of git://github.com/c-sky/csky-linux: (30 commits) csky: Fixup compile error csky: use free_initmem_default() in free_initmem() csky: Fixup pfn_valid error with wrong max_mapnr csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO csky: kprobe: Fixup code in simulate without 'long' csky: Fixup swapon csky: pgtable.h: Coding convention csky: Fixup _PAGE_ACCESSED for default pgprot csky: remove unused including csky: Fix a size determination in gpr_get() csky: Reconstruct VDSO framework csky: mm: abort uaccess retries upon fatal signal csky: Sync riscv mm/fault.c for easy maintenance csky: Fixup do_page_fault parent irq status csky: Add faulthandler_disabled() check csky: Fixup update_mmu_cache called with user io mapping csky: Fixup FAULT_FLAG_XXX param for handle_mm_fault csky: Add show_tlb for CPU_CK860 debug csky: Fix TLB maintenance synchronization problem csky: Add kmemleak support ...

csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO

2021-02-27T08:35:09Z

It could help to reduce the latency of the time-related functions in user space. We have referenced arm's and riscv's implementation for the patch. Signed-off-by: Guo Ren Cc: Vincent Chen Cc: Arnd Bergmann

csky: kprobe: Fixup code in simulate without 'long'

2021-02-27T08:34:50Z

The type of 'val' is 'unsigned long' in simulate_blz32, so 'val < 0' can't be true. Cast 'val' to 'long' here to determine branch token or not, Fixup instructions: bnezad32, bhsz32, bhz32, blsz32, blz32 Link: https://lore.kernel.org/linux-csky/CAJF2gTQjKXR9gpo06WAWG1aquiT87mATiMGorXs6ChxOxoe90Q@mail.gmail.com/T/#t Signed-off-by: Guo Ren Co-developed-by: Menglong Dong Signed-off-by: Menglong Dong

arch: setup PF_IO_WORKER threads like PF_KTHREAD

2021-02-22T00:25:22Z

PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the sense that we don't assign ->set_child_tid with our own structure. Just ensure that every arch sets up the PF_IO_WORKER threads like kthreads in the arch implementation of copy_thread(). Signed-off-by: Jens Axboe

csky: Fix a size determination in gpr_get()

2021-01-12T01:52:41Z

"*" is missed in size determination as we are passing register set rather than a pointer. Fixes: dcad7854fcce ("sky: switch to ->regset_get()") Signed-off-by: Zhenzhong Duan Signed-off-by: Guo Ren

csky: Reconstruct VDSO framework

2021-01-12T01:52:41Z

Reconstruct vdso framework to support future vsyscall, vgettimeofday features. These are very important features to reduce system calls into the kernel for performance improvement. The patch is reference RISC-V's Signed-off-by: Guo Ren Cc: Palmer Dabbelt

csky: Fixup do_page_fault parent irq status

2021-01-12T01:52:41Z

We must succeed parent's context irq status in page fault handler. Signed-off-by: Guo Ren

csky: Add show_tlb for CPU_CK860 debug

2021-01-12T01:52:41Z

Print all 1024 jtlb entries and 16 iutlb entries and 16 dutlb entries in show_regs. Signed-off-by: Guo Ren