arch/parisc/kernel/toc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/kernel.h>
   4 #include <linux/kgdb.h>
   5 #include <linux/printk.h>
   6 #include <linux/sched/debug.h>
   7 #include <linux/delay.h>
   8 #include <linux/reboot.h>
   9
  10 #include <asm/pdc.h>
  11 #include <asm/pdc_chassis.h>
  12 #include <asm/ldcw.h>
  13 #include <asm/processor.h>
  14
  15 static unsigned int __aligned(16) toc_lock = 1;
  16 DEFINE_PER_CPU_PAGE_ALIGNED(char [16384], toc_stack) __visible;
  17
  18 static void toc20_to_pt_regs(struct pt_regs *regs, struct pdc_toc_pim_20 *toc)
  19 {
  20         int i;
  21
  22         regs->gr[0] = (unsigned long)toc->cr[22];
  23
  24         for (i = 1; i < 32; i++)
  25                 regs->gr[i] = (unsigned long)toc->gr[i];
  26
  27         for (i = 0; i < 8; i++)
  28                 regs->sr[i] = (unsigned long)toc->sr[i];
  29
  30         regs->iasq[0] = (unsigned long)toc->cr[17];
  31         regs->iasq[1] = (unsigned long)toc->iasq_back;
  32         regs->iaoq[0] = (unsigned long)toc->cr[18];
  33         regs->iaoq[1] = (unsigned long)toc->iaoq_back;
  34
  35         regs->sar = (unsigned long)toc->cr[11];
  36         regs->iir = (unsigned long)toc->cr[19];
  37         regs->isr = (unsigned long)toc->cr[20];
  38         regs->ior = (unsigned long)toc->cr[21];
  39 }
  40
  41 static void toc11_to_pt_regs(struct pt_regs *regs, struct pdc_toc_pim_11 *toc)
  42 {
  43         int i;
  44
  45         regs->gr[0] = toc->cr[22];
  46
  47         for (i = 1; i < 32; i++)
  48                 regs->gr[i] = toc->gr[i];
  49
  50         for (i = 0; i < 8; i++)
  51                 regs->sr[i] = toc->sr[i];
  52
  53         regs->iasq[0] = toc->cr[17];
  54         regs->iasq[1] = toc->iasq_back;
  55         regs->iaoq[0] = toc->cr[18];
  56         regs->iaoq[1] = toc->iaoq_back;
  57
  58         regs->sar  = toc->cr[11];
  59         regs->iir  = toc->cr[19];
  60         regs->isr  = toc->cr[20];
  61         regs->ior  = toc->cr[21];
  62 }
  63
  64 void notrace __noreturn __cold toc_intr(struct pt_regs *regs)
  65 {
  66         struct pdc_toc_pim_20 pim_data20;
  67         struct pdc_toc_pim_11 pim_data11;
  68
  69         /* verify we wrote regs to the correct stack */
  70         BUG_ON(regs != (struct pt_regs *)&per_cpu(toc_stack, raw_smp_processor_id()));
  71
  72         if (boot_cpu_data.cpu_type >= pcxu) {
  73                 if (pdc_pim_toc20(&pim_data20))
  74                         panic("Failed to get PIM data");
  75                 toc20_to_pt_regs(regs, &pim_data20);
  76         } else {
  77                 if (pdc_pim_toc11(&pim_data11))
  78                         panic("Failed to get PIM data");
  79                 toc11_to_pt_regs(regs, &pim_data11);
  80         }
  81
  82 #ifdef CONFIG_KGDB
  83         nmi_enter();
  84
  85         if (atomic_read(&kgdb_active) != -1)
  86                 kgdb_nmicallback(raw_smp_processor_id(), regs);
  87         kgdb_handle_exception(9, SIGTRAP, 0, regs);
  88 #endif
  89
  90         /* serialize output, otherwise all CPUs write backtrace at once */
  91         while (__ldcw(&toc_lock) == 0)
  92                 ; /* wait */
  93         show_regs(regs);
  94         toc_lock = 1;    /* release lock for next CPU */
  95
  96         if (raw_smp_processor_id() != 0)
  97                 while (1) ; /* all but monarch CPU will wait endless. */
  98
  99         /* give other CPUs time to show their backtrace */
 100         mdelay(2000);
 101
 102         machine_restart("TOC");
 103
 104         /* should never reach this */
 105         panic("TOC");
 106 }
 107
 108 static __init int setup_toc(void)
 109 {
 110         unsigned int csum = 0;
 111         unsigned long toc_code = (unsigned long)dereference_function_descriptor(toc_handler);
 112         int i;
 113
 114         PAGE0->vec_toc = __pa(toc_code) & 0xffffffff;
 115 #ifdef CONFIG_64BIT
 116         PAGE0->vec_toc_hi = __pa(toc_code) >> 32;
 117 #endif
 118         PAGE0->vec_toclen = toc_handler_size;
 119
 120         for (i = 0; i < toc_handler_size/4; i++)
 121                 csum += ((u32 *)toc_code)[i];
 122         toc_handler_csum = -csum;
 123         pr_info("TOC handler registered\n");
 124         return 0;
 125 }
 126 early_initcall(setup_toc);