From 18ed1c01a7dd3d7c780b06a49124da237a4c1790 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Sat, 18 Sep 2021 10:44:38 +0200 Subject: ARM: smp: Enable THREAD_INFO_IN_TASK Now that we no longer rely on thread_info living at the base of the task stack to be able to access the 'current' pointer, we can wire up the generic support for moving thread_info into the task struct itself. Note that this requires us to update the cpu field in thread_info explicitly, now that the core code no longer does so. Ideally, we would switch the percpu code to access the cpu field in task_struct instead, but this unleashes #include circular dependency hell. Co-developed-by: Keith Packard Signed-off-by: Keith Packard Signed-off-by: Ard Biesheuvel Reviewed-by: Linus Walleij Tested-by: Amit Daniel Kachhap --- arch/arm/kernel/asm-offsets.c | 2 ++ arch/arm/kernel/entry-armv.S | 2 +- arch/arm/kernel/smp.c | 3 +++ 3 files changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c index 9c864ee76107..645845e4982a 100644 --- a/arch/arm/kernel/asm-offsets.c +++ b/arch/arm/kernel/asm-offsets.c @@ -43,7 +43,9 @@ int main(void) BLANK(); DEFINE(TI_FLAGS, offsetof(struct thread_info, flags)); DEFINE(TI_PREEMPT, offsetof(struct thread_info, preempt_count)); +#ifndef CONFIG_THREAD_INFO_IN_TASK DEFINE(TI_TASK, offsetof(struct thread_info, task)); +#endif DEFINE(TI_CPU, offsetof(struct thread_info, cpu)); DEFINE(TI_CPU_DOMAIN, offsetof(struct thread_info, cpu_domain)); DEFINE(TI_CPU_SAVE, offsetof(struct thread_info, cpu_context)); diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index 7263a45abf3d..a54b5044d406 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -765,7 +765,7 @@ ENTRY(__switch_to) .endif ldr r7, [r7, #TSK_STACK_CANARY & IMM12_MASK] #elif defined(CONFIG_CURRENT_POINTER_IN_TPIDRURO) - ldr r7, [r2, #TI_TASK] + mov r7, r2 @ Preserve 'next' #endif #ifdef CONFIG_CPU_USE_DOMAINS mcr p15, 0, r6, c3, c0, 0 @ Set domain register diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 97ee6b1567e9..cde5b6d8bac5 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -154,6 +154,9 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); #endif secondary_data.task = idle; + if (IS_ENABLED(CONFIG_THREAD_INFO_IN_TASK)) + task_thread_info(idle)->cpu = cpu; + sync_cache_w(&secondary_data); /* -- cgit v1.2.3