From f1a0a376ca0c4ef1fc3d24e3e502acbb5b795674 Mon Sep 17 00:00:00 2001 From: Valentin Schneider Date: Wed, 12 May 2021 10:46:36 +0100 Subject: sched/core: Initialize the idle task with preemption disabled 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 --- arch/s390/include/asm/preempt.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/preempt.h b/arch/s390/include/asm/preempt.h index b49e0492842c..23ff51be7e29 100644 --- a/arch/s390/include/asm/preempt.h +++ b/arch/s390/include/asm/preempt.h @@ -32,7 +32,7 @@ static inline void preempt_count_set(int pc) #define init_task_preempt_count(p) do { } while (0) #define init_idle_preempt_count(p, cpu) do { \ - S390_lowcore.preempt_count = PREEMPT_ENABLED; \ + S390_lowcore.preempt_count = PREEMPT_DISABLED; \ } while (0) static inline void set_preempt_need_resched(void) @@ -91,7 +91,7 @@ static inline void preempt_count_set(int pc) #define init_task_preempt_count(p) do { } while (0) #define init_idle_preempt_count(p, cpu) do { \ - S390_lowcore.preempt_count = PREEMPT_ENABLED; \ + S390_lowcore.preempt_count = PREEMPT_DISABLED; \ } while (0) static inline void set_preempt_need_resched(void) -- cgit From 9be85de97786a75f62080de1c0c13656f65cba84 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Tue, 25 May 2021 15:02:00 +0100 Subject: locking/atomic: make ARCH_ATOMIC a Kconfig symbol Subsequent patches will move architectures over to the ARCH_ATOMIC API, after preparing the asm-generic atomic implementations to function with or without ARCH_ATOMIC. As some architectures use the asm-generic implementations exclusively (and don't have a local atomic.h), and to avoid the risk that ARCH_ATOMIC isn't defined in some cases we expect, let's make the ARCH_ATOMIC macro a Kconfig symbol instead, so that we can guarantee it is consistently available where needed. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Cc: Boqun Feng Cc: Peter Zijlstra Cc: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210525140232.53872-2-mark.rutland@arm.com --- arch/s390/include/asm/atomic.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h index 7c93c6573524..7138d189cc42 100644 --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -147,6 +147,4 @@ ATOMIC64_OPS(xor) #define arch_atomic64_fetch_sub(_i, _v) arch_atomic64_fetch_add(-(s64)(_i), _v) #define arch_atomic64_sub(_i, _v) arch_atomic64_add(-(s64)(_i), _v) -#define ARCH_ATOMIC - #endif /* __ARCH_S390_ATOMIC__ */ -- cgit From 92638b4e1b47f97d7269e74465dedf73096f777d Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Wed, 2 Jun 2021 16:52:27 -0700 Subject: mm: arch: remove indirection level in alloc_zeroed_user_highpage_movable() In an upcoming change we would like to add a flag to GFP_HIGHUSER_MOVABLE so that it would no longer be an OR of GFP_HIGHUSER and __GFP_MOVABLE. This poses a problem for alloc_zeroed_user_highpage_movable() which passes __GFP_MOVABLE into an arch-specific __alloc_zeroed_user_highpage() hook which ORs in GFP_HIGHUSER. Since __alloc_zeroed_user_highpage() is only ever called from alloc_zeroed_user_highpage_movable(), we can remove one level of indirection here. Remove __alloc_zeroed_user_highpage(), make alloc_zeroed_user_highpage_movable() the hook, and use GFP_HIGHUSER_MOVABLE in the hook implementations so that they will pick up the new flag that we are going to add. Signed-off-by: Peter Collingbourne Link: https://linux-review.googlesource.com/id/Ic6361c657b2cdcd896adbe0cf7cb5a7fbb1ed7bf Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20210602235230.3928842-2-pcc@google.com Signed-off-by: Will Deacon --- arch/s390/include/asm/page.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h index cc98f9b78fd4..479dc76e0eca 100644 --- a/arch/s390/include/asm/page.h +++ b/arch/s390/include/asm/page.h @@ -68,9 +68,9 @@ static inline void copy_page(void *to, void *from) #define clear_user_page(page, vaddr, pg) clear_page(page) #define copy_user_page(to, from, vaddr, pg) copy_page(to, from) -#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \ - alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr) -#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE +#define alloc_zeroed_user_highpage_movable(vma, vaddr) \ + alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, vma, vaddr) +#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE /* * These are used to make use of C type-checking.. -- cgit From 67147e96a332b56c7206238162771d82467f86c0 Mon Sep 17 00:00:00 2001 From: Heiko Carstens Date: Fri, 18 Jun 2021 16:58:47 +0200 Subject: s390/stack: fix possible register corruption with stack switch helper The CALL_ON_STACK macro is used to call a C function from inline assembly, and therefore must consider the C ABI, which says that only registers 6-13, and 15 are non-volatile (restored by the called function). The inline assembly incorrectly marks all registers used to pass parameters to the called function as read-only input operands, instead of operands that are read and written to. This might result in register corruption depending on usage, compiler, and compile options. Fix this by marking all operands used to pass parameters as read/write operands. To keep the code simple even register 6, if used, is marked as read-write operand. Fixes: ff340d2472ec ("s390: add stack switch helper") Cc: # 4.20 Reviewed-by: Vasily Gorbik Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/stacktrace.h | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index 2b543163d90a..76c6034428be 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -91,12 +91,16 @@ struct stack_frame { CALL_ARGS_4(arg1, arg2, arg3, arg4); \ register unsigned long r4 asm("6") = (unsigned long)(arg5) -#define CALL_FMT_0 "=&d" (r2) : -#define CALL_FMT_1 "+&d" (r2) : -#define CALL_FMT_2 CALL_FMT_1 "d" (r3), -#define CALL_FMT_3 CALL_FMT_2 "d" (r4), -#define CALL_FMT_4 CALL_FMT_3 "d" (r5), -#define CALL_FMT_5 CALL_FMT_4 "d" (r6), +/* + * To keep this simple mark register 2-6 as being changed (volatile) + * by the called function, even though register 6 is saved/nonvolatile. + */ +#define CALL_FMT_0 "=&d" (r2) +#define CALL_FMT_1 "+&d" (r2) +#define CALL_FMT_2 CALL_FMT_1, "+&d" (r3) +#define CALL_FMT_3 CALL_FMT_2, "+&d" (r4) +#define CALL_FMT_4 CALL_FMT_3, "+&d" (r5) +#define CALL_FMT_5 CALL_FMT_4, "+&d" (r6) #define CALL_CLOBBER_5 "0", "1", "14", "cc", "memory" #define CALL_CLOBBER_4 CALL_CLOBBER_5 @@ -118,7 +122,7 @@ struct stack_frame { " brasl 14,%[_fn]\n" \ " la 15,0(%[_prev])\n" \ : [_prev] "=&a" (prev), CALL_FMT_##nr \ - [_stack] "R" (stack), \ + : [_stack] "R" (stack), \ [_bc] "i" (offsetof(struct stack_frame, back_chain)), \ [_frame] "d" (frame), \ [_fn] "X" (fn) : CALL_CLOBBER_##nr); \ -- cgit From 0193cc908b5ae8aff2e2d2997ca5d4ae26ed24d4 Mon Sep 17 00:00:00 2001 From: Jing Zhang Date: Fri, 18 Jun 2021 22:27:03 +0000 Subject: KVM: stats: Separate generic stats from architecture specific ones Generic KVM stats are those collected in architecture independent code or those supported by all architectures; put all generic statistics in a separate structure. This ensures that they are defined the same way in the statistics API which is being added, removing duplication among different architectures in the declaration of the descriptors. No functional change intended. Reviewed-by: David Matlack Reviewed-by: Ricardo Koller Reviewed-by: Krish Sadhukhan Signed-off-by: Jing Zhang Message-Id: <20210618222709.1858088-2-jingzhangos@google.com> Signed-off-by: Paolo Bonzini --- arch/s390/include/asm/kvm_host.h | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h index 8925f3969478..9b4473f76e56 100644 --- a/arch/s390/include/asm/kvm_host.h +++ b/arch/s390/include/asm/kvm_host.h @@ -361,6 +361,7 @@ struct sie_page { }; struct kvm_vcpu_stat { + struct kvm_vcpu_stat_generic generic; u64 exit_userspace; u64 exit_null; u64 exit_external_request; @@ -370,13 +371,7 @@ struct kvm_vcpu_stat { u64 exit_validity; u64 exit_instruction; u64 exit_pei; - u64 halt_successful_poll; - u64 halt_attempted_poll; - u64 halt_poll_invalid; u64 halt_no_poll_steal; - u64 halt_wakeup; - u64 halt_poll_success_ns; - u64 halt_poll_fail_ns; u64 instruction_lctl; u64 instruction_lctlg; u64 instruction_stctl; @@ -755,12 +750,12 @@ struct kvm_vcpu_arch { }; struct kvm_vm_stat { + struct kvm_vm_stat_generic generic; u64 inject_io; u64 inject_float_mchk; u64 inject_pfault_done; u64 inject_service_signal; u64 inject_virtio; - u64 remote_tlb_flush; }; struct kvm_arch_memory_slot { -- cgit From c0f8aa4fa815daacb6eca52cae04820d6aecb7c2 Mon Sep 17 00:00:00 2001 From: Daniel Axtens Date: Mon, 28 Jun 2021 19:40:46 -0700 Subject: mm: define default MAX_PTRS_PER_* in include/pgtable.h Commit c65e774fb3f6 ("x86/mm: Make PGDIR_SHIFT and PTRS_PER_P4D variable") made PTRS_PER_P4D variable on x86 and introduced MAX_PTRS_PER_P4D as a constant for cases which need a compile-time constant (e.g. fixed-size arrays). powerpc likewise has boot-time selectable MMU features which can cause other mm "constants" to vary. For KASAN, we have some static PTE/PMD/PUD/P4D arrays so we need compile-time maximums for all these constants. Extend the MAX_PTRS_PER_ idiom, and place default definitions in include/pgtable.h. These define MAX_PTRS_PER_x to be PTRS_PER_x unless an architecture has defined MAX_PTRS_PER_x in its arch headers. Clean up pgtable-nop4d.h and s390's MAX_PTRS_PER_P4D definitions while we're at it: both can just pick up the default now. Link: https://lkml.kernel.org/r/20210624034050.511391-4-dja@axtens.net Signed-off-by: Daniel Axtens Acked-by: Andrey Konovalov Reviewed-by: Christophe Leroy Reviewed-by: Marco Elver Cc: Aneesh Kumar K.V Cc: Balbir Singh Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/s390/include/asm/pgtable.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/s390/include') diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 29c7ecd5ad1d..b38f7b781564 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -344,8 +344,6 @@ static inline int is_module_addr(void *addr) #define PTRS_PER_P4D _CRST_ENTRIES #define PTRS_PER_PGD _CRST_ENTRIES -#define MAX_PTRS_PER_P4D PTRS_PER_P4D - /* * Segment table and region3 table entry encoding * (R = read-only, I = invalid, y = young bit): -- cgit