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
15static unsigned int __aligned(16) toc_lock = 1;
16DEFINE_PER_CPU_PAGE_ALIGNED(char [16384], toc_stack) __visible;
17
18static 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
41static 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
64void 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
108static __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}
126early_initcall(setup_toc);
127