From: Will Deacon Date: Fri, 9 Oct 2020 10:24:17 +0000 (+0100) Subject: Revert "arm64: initialize per-cpu offsets earlier" X-Git-Tag: v5.10.7~1343^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=d13027bb35e089bc1bb9f19c4976decf32a09b97;p=platform%2Fkernel%2Flinux-rpi.git Revert "arm64: initialize per-cpu offsets earlier" This reverts commit 353e228eb355be5a65a3c0996c774a0f46737fda. Qian Cai reports that TX2 no longer boots with his .config as it appears that task_cpu() gets instrumented and used before KASAN has been initialised. Although Mark has a proposed fix, let's take the safe option of reverting this for now and sorting it out properly later. Link: https://lore.kernel.org/r/711bc57a314d8d646b41307008db2845b7537b3d.camel@redhat.com Reported-by: Qian Cai Tested-by: Mark Rutland Signed-off-by: Will Deacon --- diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h index d9d60b1..7faae6f 100644 --- a/arch/arm64/include/asm/cpu.h +++ b/arch/arm64/include/asm/cpu.h @@ -68,6 +68,4 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info); void update_cpu_features(int cpu, struct cpuinfo_arm64 *info, struct cpuinfo_arm64 *boot); -void init_this_cpu_offset(void); - #endif /* __ASM_CPU_H */ diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index e28c9d4..d8d9caf 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -448,8 +448,6 @@ SYM_FUNC_START_LOCAL(__primary_switched) bl __pi_memset dsb ishst // Make zero page visible to PTW - bl init_this_cpu_offset - #ifdef CONFIG_KASAN bl kasan_early_init #endif @@ -756,7 +754,6 @@ SYM_FUNC_START_LOCAL(__secondary_switched) ptrauth_keys_init_cpu x2, x3, x4, x5 #endif - bl init_this_cpu_offset b secondary_start_kernel SYM_FUNC_END(__secondary_switched) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 0051719..77c4c9b 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -87,6 +87,12 @@ void __init smp_setup_processor_id(void) u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; set_cpu_logical_map(0, mpidr); + /* + * clear __my_cpu_offset on boot CPU to avoid hang caused by + * using percpu variable early, for example, lockdep will + * access percpu variable inside lock_release + */ + set_my_cpu_offset(0); pr_info("Booting Linux on physical CPU 0x%010lx [0x%08x]\n", (unsigned long)mpidr, read_cpuid_id()); } @@ -276,12 +282,6 @@ u64 cpu_logical_map(int cpu) } EXPORT_SYMBOL_GPL(cpu_logical_map); -void noinstr init_this_cpu_offset(void) -{ - unsigned int cpu = task_cpu(current); - set_my_cpu_offset(per_cpu_offset(cpu)); -} - void __init __no_sanitize_address setup_arch(char **cmdline_p) { init_mm.start_code = (unsigned long) _text; diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 7714310..355ee9e 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -192,7 +192,10 @@ asmlinkage notrace void secondary_start_kernel(void) u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK; struct mm_struct *mm = &init_mm; const struct cpu_operations *ops; - unsigned int cpu = smp_processor_id(); + unsigned int cpu; + + cpu = task_cpu(current); + set_my_cpu_offset(per_cpu_offset(cpu)); /* * All kernel threads share the same mm context; grab a @@ -432,13 +435,7 @@ void __init smp_cpus_done(unsigned int max_cpus) void __init smp_prepare_boot_cpu(void) { - /* - * Now that setup_per_cpu_areas() has allocated the runtime per-cpu - * areas it is only safe to read the CPU0 boot-time area, and we must - * reinitialize the offset to point to the runtime area. - */ - init_this_cpu_offset(); - + set_my_cpu_offset(per_cpu_offset(smp_processor_id())); cpuinfo_store_boot_cpu(); /*