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commit 09c2fe608a2608f9c7de7928f96f0ebc6197e195
parent 333478a7eb21245880c89aad166ad08478cc577d
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 24 Jan 2019 08:58:01 +1300

Merge tag 's390-5.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Martin Schwidefsky:

 - Do not claim to run under z/VM if the hypervisor can not be
   identified

 - Fix crashes due to outdated ASCEs in CR1

 - Avoid a deadlock in regard to CPU hotplug

 - Really fix the vdso mapping issue for compat tasks

 - Avoid crash on restart due to an incorrect stack address

* tag 's390-5.0-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/smp: Fix calling smp_call_ipl_cpu() from ipl CPU
  s390/vdso: correct vdso mapping for compat tasks
  s390/smp: fix CPU hotplug deadlock with CPU rescan
  s390/mm: always force a load of the primary ASCE on context switch
  s390/early: improve machine detection

Diffstat:
March/s390/include/asm/mmu_context.h | 7+++----
March/s390/kernel/early.c | 4++--
March/s390/kernel/setup.c | 2++
March/s390/kernel/smp.c | 11++++++++++-
March/s390/kernel/vdso.c | 5++---
Mdrivers/s390/char/sclp_config.c | 2++
6 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h @@ -25,7 +25,7 @@ static inline int init_new_context(struct task_struct *tsk, atomic_set(&mm->context.flush_count, 0); mm->context.gmap_asce = 0; mm->context.flush_mm = 0; - mm->context.compat_mm = 0; + mm->context.compat_mm = test_thread_flag(TIF_31BIT); #ifdef CONFIG_PGSTE mm->context.alloc_pgste = page_table_allocate_pgste || test_thread_flag(TIF_PGSTE) || @@ -90,8 +90,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, { int cpu = smp_processor_id(); - if (prev == next) - return; S390_lowcore.user_asce = next->context.asce; cpumask_set_cpu(cpu, &next->context.cpu_attach_mask); /* Clear previous user-ASCE from CR1 and CR7 */ @@ -103,7 +101,8 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, __ctl_load(S390_lowcore.vdso_asce, 7, 7); clear_cpu_flag(CIF_ASCE_SECONDARY); } - cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask); + if (prev != next) + cpumask_clear_cpu(cpu, &prev->context.cpu_attach_mask); } #define finish_arch_post_lock_switch finish_arch_post_lock_switch diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c @@ -63,10 +63,10 @@ static noinline __init void detect_machine_type(void) if (stsi(vmms, 3, 2, 2) || !vmms->count) return; - /* Running under KVM? If not we assume z/VM */ + /* Detect known hypervisors */ if (!memcmp(vmms->vm[0].cpi, "\xd2\xe5\xd4", 3)) S390_lowcore.machine_flags |= MACHINE_FLAG_KVM; - else + else if (!memcmp(vmms->vm[0].cpi, "\xa9\x61\xe5\xd4", 4)) S390_lowcore.machine_flags |= MACHINE_FLAG_VM; } diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c @@ -1006,6 +1006,8 @@ void __init setup_arch(char **cmdline_p) pr_info("Linux is running under KVM in 64-bit mode\n"); else if (MACHINE_IS_LPAR) pr_info("Linux is running natively in 64-bit mode\n"); + else + pr_info("Linux is running as a guest in 64-bit mode\n"); /* Have one command line that is parsed and saved in /proc/cmdline */ /* boot_command_line has been already set up in early.c */ diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c @@ -381,8 +381,13 @@ void smp_call_online_cpu(void (*func)(void *), void *data) */ void smp_call_ipl_cpu(void (*func)(void *), void *data) { + struct lowcore *lc = pcpu_devices->lowcore; + + if (pcpu_devices[0].address == stap()) + lc = &S390_lowcore; + pcpu_delegate(&pcpu_devices[0], func, data, - pcpu_devices->lowcore->nodat_stack); + lc->nodat_stack); } int smp_find_processor_id(u16 address) @@ -1166,7 +1171,11 @@ static ssize_t __ref rescan_store(struct device *dev, { int rc; + rc = lock_device_hotplug_sysfs(); + if (rc) + return rc; rc = smp_rescan_cpus(); + unlock_device_hotplug(); return rc ? rc : count; } static DEVICE_ATTR_WO(rescan); diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c @@ -224,10 +224,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) vdso_pages = vdso64_pages; #ifdef CONFIG_COMPAT - if (is_compat_task()) { + mm->context.compat_mm = is_compat_task(); + if (mm->context.compat_mm) vdso_pages = vdso32_pages; - mm->context.compat_mm = 1; - } #endif /* * vDSO has a problem and was disabled, just don't "enable" it for diff --git a/drivers/s390/char/sclp_config.c b/drivers/s390/char/sclp_config.c @@ -60,7 +60,9 @@ static void sclp_cpu_capability_notify(struct work_struct *work) static void __ref sclp_cpu_change_notify(struct work_struct *work) { + lock_device_hotplug(); smp_rescan_cpus(); + unlock_device_hotplug(); } static void sclp_conf_receiver_fn(struct evbuf_header *evbuf)