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916cda1aa1
This adds a new system call to enable the use of guarded storage for
user space processes. The system call takes two arguments, a command
and pointer to a guarded storage control block:
s390_guarded_storage(int command, struct gs_cb *gs_cb);
The second argument is relevant only for the GS_SET_BC_CB command.
The commands in detail:
0 - GS_ENABLE
Enable the guarded storage facility for the current task. The
initial content of the guarded storage control block will be
all zeros. After the enablement the user space code can use
load-guarded-storage-controls instruction (LGSC) to load an
arbitrary control block. While a task is enabled the kernel
will save and restore the current content of the guarded
storage registers on context switch.
1 - GS_DISABLE
Disables the use of the guarded storage facility for the current
task. The kernel will cease to save and restore the content of
the guarded storage registers, the task specific content of
these registers is lost.
2 - GS_SET_BC_CB
Set a broadcast guarded storage control block. This is called
per thread and stores a specific guarded storage control block
in the task struct of the current task. This control block will
be used for the broadcast event GS_BROADCAST.
3 - GS_CLEAR_BC_CB
Clears the broadcast guarded storage control block. The guarded-
storage control block is removed from the task struct that was
established by GS_SET_BC_CB.
4 - GS_BROADCAST
Sends a broadcast to all thread siblings of the current task.
Every sibling that has established a broadcast guarded storage
control block will load this control block and will be enabled
for guarded storage. The broadcast guarded storage control block
is used up, a second broadcast without a refresh of the stored
control block with GS_SET_BC_CB will not have any effect.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
391 lines
10 KiB
C
391 lines
10 KiB
C
/*
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* Machine check handler
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*
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* Copyright IBM Corp. 2000, 2009
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* Author(s): Ingo Adlung <adlung@de.ibm.com>,
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* Martin Schwidefsky <schwidefsky@de.ibm.com>,
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* Cornelia Huck <cornelia.huck@de.ibm.com>,
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* Heiko Carstens <heiko.carstens@de.ibm.com>,
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*/
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#include <linux/kernel_stat.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/hardirq.h>
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#include <linux/time.h>
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#include <linux/module.h>
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#include <linux/sched/signal.h>
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#include <linux/export.h>
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#include <asm/lowcore.h>
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#include <asm/smp.h>
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#include <asm/stp.h>
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#include <asm/cputime.h>
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#include <asm/nmi.h>
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#include <asm/crw.h>
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#include <asm/switch_to.h>
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#include <asm/ctl_reg.h>
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struct mcck_struct {
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unsigned int kill_task : 1;
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unsigned int channel_report : 1;
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unsigned int warning : 1;
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unsigned int stp_queue : 1;
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unsigned long mcck_code;
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};
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static DEFINE_PER_CPU(struct mcck_struct, cpu_mcck);
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static void s390_handle_damage(void)
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{
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smp_send_stop();
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disabled_wait((unsigned long) __builtin_return_address(0));
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while (1);
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}
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/*
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* Main machine check handler function. Will be called with interrupts enabled
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* or disabled and machine checks enabled or disabled.
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*/
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void s390_handle_mcck(void)
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{
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unsigned long flags;
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struct mcck_struct mcck;
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/*
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* Disable machine checks and get the current state of accumulated
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* machine checks. Afterwards delete the old state and enable machine
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* checks again.
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*/
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local_irq_save(flags);
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local_mcck_disable();
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mcck = *this_cpu_ptr(&cpu_mcck);
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memset(this_cpu_ptr(&cpu_mcck), 0, sizeof(mcck));
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clear_cpu_flag(CIF_MCCK_PENDING);
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local_mcck_enable();
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local_irq_restore(flags);
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if (mcck.channel_report)
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crw_handle_channel_report();
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/*
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* A warning may remain for a prolonged period on the bare iron.
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* (actually until the machine is powered off, or the problem is gone)
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* So we just stop listening for the WARNING MCH and avoid continuously
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* being interrupted. One caveat is however, that we must do this per
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* processor and cannot use the smp version of ctl_clear_bit().
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* On VM we only get one interrupt per virtally presented machinecheck.
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* Though one suffices, we may get one interrupt per (virtual) cpu.
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*/
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if (mcck.warning) { /* WARNING pending ? */
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static int mchchk_wng_posted = 0;
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/* Use single cpu clear, as we cannot handle smp here. */
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__ctl_clear_bit(14, 24); /* Disable WARNING MCH */
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if (xchg(&mchchk_wng_posted, 1) == 0)
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kill_cad_pid(SIGPWR, 1);
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}
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if (mcck.stp_queue)
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stp_queue_work();
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if (mcck.kill_task) {
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local_irq_enable();
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printk(KERN_EMERG "mcck: Terminating task because of machine "
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"malfunction (code 0x%016lx).\n", mcck.mcck_code);
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printk(KERN_EMERG "mcck: task: %s, pid: %d.\n",
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current->comm, current->pid);
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do_exit(SIGSEGV);
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}
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}
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EXPORT_SYMBOL_GPL(s390_handle_mcck);
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/*
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* returns 0 if all registers could be validated
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* returns 1 otherwise
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*/
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static int notrace s390_validate_registers(union mci mci, int umode)
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{
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int kill_task;
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u64 zero;
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void *fpt_save_area;
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struct mcesa *mcesa;
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kill_task = 0;
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zero = 0;
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if (!mci.gr) {
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/*
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* General purpose registers couldn't be restored and have
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* unknown contents. Stop system or terminate process.
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*/
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if (!umode)
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s390_handle_damage();
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kill_task = 1;
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}
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/* Validate control registers */
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if (!mci.cr) {
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/*
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* Control registers have unknown contents.
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* Can't recover and therefore stopping machine.
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*/
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s390_handle_damage();
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} else {
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asm volatile(
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" lctlg 0,15,0(%0)\n"
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" ptlb\n"
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: : "a" (&S390_lowcore.cregs_save_area) : "memory");
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}
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if (!mci.fp) {
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/*
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* Floating point registers can't be restored. If the
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* kernel currently uses floating point registers the
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* system is stopped. If the process has its floating
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* pointer registers loaded it is terminated.
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* Otherwise just revalidate the registers.
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*/
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if (S390_lowcore.fpu_flags & KERNEL_VXR_V0V7)
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s390_handle_damage();
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if (!test_cpu_flag(CIF_FPU))
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kill_task = 1;
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}
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fpt_save_area = &S390_lowcore.floating_pt_save_area;
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if (!mci.fc) {
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/*
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* Floating point control register can't be restored.
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* If the kernel currently uses the floating pointer
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* registers and needs the FPC register the system is
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* stopped. If the process has its floating pointer
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* registers loaded it is terminated. Otherwiese the
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* FPC is just revalidated.
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*/
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if (S390_lowcore.fpu_flags & KERNEL_FPC)
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s390_handle_damage();
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asm volatile("lfpc %0" : : "Q" (zero));
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if (!test_cpu_flag(CIF_FPU))
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kill_task = 1;
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} else {
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asm volatile("lfpc %0"
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: : "Q" (S390_lowcore.fpt_creg_save_area));
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}
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mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
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if (!MACHINE_HAS_VX) {
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/* Validate floating point registers */
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asm volatile(
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" ld 0,0(%0)\n"
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" ld 1,8(%0)\n"
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" ld 2,16(%0)\n"
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" ld 3,24(%0)\n"
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" ld 4,32(%0)\n"
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" ld 5,40(%0)\n"
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" ld 6,48(%0)\n"
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" ld 7,56(%0)\n"
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" ld 8,64(%0)\n"
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" ld 9,72(%0)\n"
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" ld 10,80(%0)\n"
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" ld 11,88(%0)\n"
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" ld 12,96(%0)\n"
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" ld 13,104(%0)\n"
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" ld 14,112(%0)\n"
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" ld 15,120(%0)\n"
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: : "a" (fpt_save_area) : "memory");
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} else {
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/* Validate vector registers */
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union ctlreg0 cr0;
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if (!mci.vr) {
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/*
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* Vector registers can't be restored. If the kernel
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* currently uses vector registers the system is
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* stopped. If the process has its vector registers
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* loaded it is terminated. Otherwise just revalidate
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* the registers.
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*/
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if (S390_lowcore.fpu_flags & KERNEL_VXR)
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s390_handle_damage();
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if (!test_cpu_flag(CIF_FPU))
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kill_task = 1;
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}
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cr0.val = S390_lowcore.cregs_save_area[0];
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cr0.afp = cr0.vx = 1;
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__ctl_load(cr0.val, 0, 0);
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asm volatile(
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" la 1,%0\n"
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" .word 0xe70f,0x1000,0x0036\n" /* vlm 0,15,0(1) */
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" .word 0xe70f,0x1100,0x0c36\n" /* vlm 16,31,256(1) */
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: : "Q" (*(struct vx_array *) mcesa->vector_save_area)
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: "1");
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__ctl_load(S390_lowcore.cregs_save_area[0], 0, 0);
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}
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/* Validate access registers */
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asm volatile(
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" lam 0,15,0(%0)"
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: : "a" (&S390_lowcore.access_regs_save_area));
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if (!mci.ar) {
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/*
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* Access registers have unknown contents.
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* Terminating task.
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*/
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kill_task = 1;
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}
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/* Validate guarded storage registers */
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if (MACHINE_HAS_GS && (S390_lowcore.cregs_save_area[2] & (1UL << 4))) {
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if (!mci.gs)
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/*
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* Guarded storage register can't be restored and
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* the current processes uses guarded storage.
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* It has to be terminated.
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*/
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kill_task = 1;
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else
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load_gs_cb((struct gs_cb *)
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mcesa->guarded_storage_save_area);
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}
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/*
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* We don't even try to validate the TOD register, since we simply
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* can't write something sensible into that register.
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*/
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/*
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* See if we can validate the TOD programmable register with its
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* old contents (should be zero) otherwise set it to zero.
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*/
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if (!mci.pr)
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asm volatile(
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" sr 0,0\n"
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" sckpf"
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: : : "0", "cc");
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else
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asm volatile(
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" l 0,%0\n"
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" sckpf"
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: : "Q" (S390_lowcore.tod_progreg_save_area)
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: "0", "cc");
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/* Validate clock comparator register */
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set_clock_comparator(S390_lowcore.clock_comparator);
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/* Check if old PSW is valid */
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if (!mci.wp)
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/*
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* Can't tell if we come from user or kernel mode
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* -> stopping machine.
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*/
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s390_handle_damage();
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if (!mci.ms || !mci.pm || !mci.ia)
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kill_task = 1;
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return kill_task;
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}
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#define MAX_IPD_COUNT 29
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#define MAX_IPD_TIME (5 * 60 * USEC_PER_SEC) /* 5 minutes */
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#define ED_STP_ISLAND 6 /* External damage STP island check */
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#define ED_STP_SYNC 7 /* External damage STP sync check */
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/*
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* machine check handler.
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*/
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void notrace s390_do_machine_check(struct pt_regs *regs)
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{
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static int ipd_count;
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static DEFINE_SPINLOCK(ipd_lock);
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static unsigned long long last_ipd;
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struct mcck_struct *mcck;
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unsigned long long tmp;
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union mci mci;
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nmi_enter();
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inc_irq_stat(NMI_NMI);
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mci.val = S390_lowcore.mcck_interruption_code;
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mcck = this_cpu_ptr(&cpu_mcck);
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if (mci.sd) {
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/* System damage -> stopping machine */
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s390_handle_damage();
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}
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if (mci.pd) {
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if (mci.b) {
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/* Processing backup -> verify if we can survive this */
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u64 z_mcic, o_mcic, t_mcic;
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z_mcic = (1ULL<<63 | 1ULL<<59 | 1ULL<<29);
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o_mcic = (1ULL<<43 | 1ULL<<42 | 1ULL<<41 | 1ULL<<40 |
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1ULL<<36 | 1ULL<<35 | 1ULL<<34 | 1ULL<<32 |
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1ULL<<30 | 1ULL<<21 | 1ULL<<20 | 1ULL<<17 |
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1ULL<<16);
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t_mcic = mci.val;
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if (((t_mcic & z_mcic) != 0) ||
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((t_mcic & o_mcic) != o_mcic)) {
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s390_handle_damage();
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}
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/*
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* Nullifying exigent condition, therefore we might
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* retry this instruction.
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*/
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spin_lock(&ipd_lock);
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tmp = get_tod_clock();
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if (((tmp - last_ipd) >> 12) < MAX_IPD_TIME)
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ipd_count++;
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else
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ipd_count = 1;
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last_ipd = tmp;
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if (ipd_count == MAX_IPD_COUNT)
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s390_handle_damage();
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spin_unlock(&ipd_lock);
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} else {
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/* Processing damage -> stopping machine */
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s390_handle_damage();
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}
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}
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if (s390_validate_registers(mci, user_mode(regs))) {
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/*
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* Couldn't restore all register contents for the
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* user space process -> mark task for termination.
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*/
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mcck->kill_task = 1;
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mcck->mcck_code = mci.val;
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set_cpu_flag(CIF_MCCK_PENDING);
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}
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if (mci.cd) {
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/* Timing facility damage */
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s390_handle_damage();
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}
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if (mci.ed && mci.ec) {
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/* External damage */
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if (S390_lowcore.external_damage_code & (1U << ED_STP_SYNC))
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mcck->stp_queue |= stp_sync_check();
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if (S390_lowcore.external_damage_code & (1U << ED_STP_ISLAND))
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mcck->stp_queue |= stp_island_check();
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if (mcck->stp_queue)
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set_cpu_flag(CIF_MCCK_PENDING);
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}
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if (mci.se)
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/* Storage error uncorrected */
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s390_handle_damage();
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if (mci.ke)
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/* Storage key-error uncorrected */
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s390_handle_damage();
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if (mci.ds && mci.fa)
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/* Storage degradation */
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s390_handle_damage();
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if (mci.cp) {
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/* Channel report word pending */
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mcck->channel_report = 1;
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set_cpu_flag(CIF_MCCK_PENDING);
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}
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if (mci.w) {
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/* Warning pending */
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mcck->warning = 1;
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set_cpu_flag(CIF_MCCK_PENDING);
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}
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nmi_exit();
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}
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static int __init machine_check_init(void)
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{
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ctl_set_bit(14, 25); /* enable external damage MCH */
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ctl_set_bit(14, 27); /* enable system recovery MCH */
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ctl_set_bit(14, 24); /* enable warning MCH */
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return 0;
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}
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early_initcall(machine_check_init);
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