From 3570ee046c46b5dc3d077e3e60616b141a221027 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Mon, 31 Jul 2023 17:07:11 +0200 Subject: [PATCH] s390/smp: keep the original lowcore for CPU 0 Now that CPU 0 is not hotpluggable, it is not necessary to support freeing its stacks. Delete all the code that migrates it to new stacks and a new lowcore. Suggested-by: Heiko Carstens Signed-off-by: Ilya Leoshkevich Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik --- arch/s390/include/asm/smp.h | 1 - arch/s390/kernel/setup.c | 6 ---- arch/s390/kernel/smp.c | 57 ------------------------------------- 3 files changed, 64 deletions(-) diff --git a/arch/s390/include/asm/smp.h b/arch/s390/include/asm/smp.h index 73ed2781073b..6e5b1b4b19a9 100644 --- a/arch/s390/include/asm/smp.h +++ b/arch/s390/include/asm/smp.h @@ -59,7 +59,6 @@ static inline void smp_cpus_done(unsigned int max_cpus) { } -extern int smp_reinit_ipl_cpu(void); extern int smp_rescan_cpus(void); extern void __noreturn cpu_die(void); extern void __cpu_die(unsigned int cpu); diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index de6ad0fb2328..deb97723c890 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -381,12 +381,6 @@ void stack_free(unsigned long stack) #endif } -void __init __noreturn arch_call_rest_init(void) -{ - smp_reinit_ipl_cpu(); - rest_init(); -} - static unsigned long __init stack_alloc_early(void) { unsigned long stack; diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index e8284cec36e7..9c5e107da4b4 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -1256,60 +1256,3 @@ out: return rc; } subsys_initcall(s390_smp_init); - -static __always_inline void set_new_lowcore(struct lowcore *lc) -{ - union register_pair dst, src; - u32 pfx; - - src.even = (unsigned long) &S390_lowcore; - src.odd = sizeof(S390_lowcore); - dst.even = (unsigned long) lc; - dst.odd = sizeof(*lc); - pfx = __pa(lc); - - asm volatile( - " mvcl %[dst],%[src]\n" - " spx %[pfx]\n" - : [dst] "+&d" (dst.pair), [src] "+&d" (src.pair) - : [pfx] "Q" (pfx) - : "memory", "cc"); -} - -int __init smp_reinit_ipl_cpu(void) -{ - unsigned long async_stack, nodat_stack, mcck_stack; - struct lowcore *lc, *lc_ipl; - unsigned long flags, cr0; - u64 mcesad; - - lc_ipl = lowcore_ptr[0]; - lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER); - nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); - async_stack = stack_alloc(); - mcck_stack = stack_alloc(); - if (!lc || !nodat_stack || !async_stack || !mcck_stack || nmi_alloc_mcesa(&mcesad)) - panic("Couldn't allocate memory"); - - local_irq_save(flags); - local_mcck_disable(); - set_new_lowcore(lc); - S390_lowcore.nodat_stack = nodat_stack + STACK_INIT_OFFSET; - S390_lowcore.async_stack = async_stack + STACK_INIT_OFFSET; - S390_lowcore.mcck_stack = mcck_stack + STACK_INIT_OFFSET; - __ctl_store(cr0, 0, 0); - __ctl_clear_bit(0, 28); /* disable lowcore protection */ - S390_lowcore.mcesad = mcesad; - __ctl_load(cr0, 0, 0); - if (abs_lowcore_map(0, lc, false)) - panic("Couldn't remap absolute lowcore"); - lowcore_ptr[0] = lc; - local_mcck_enable(); - local_irq_restore(flags); - - memblock_free_late(__pa(lc_ipl->mcck_stack - STACK_INIT_OFFSET), THREAD_SIZE); - memblock_free_late(__pa(lc_ipl->async_stack - STACK_INIT_OFFSET), THREAD_SIZE); - memblock_free_late(__pa(lc_ipl->nodat_stack - STACK_INIT_OFFSET), THREAD_SIZE); - memblock_free_late(__pa(lc_ipl), sizeof(*lc_ipl)); - return 0; -} -- 2.49.0