kernel/arch/s390/boot/pgm_check_info.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/stdarg.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <asm/stacktrace.h>
#include <asm/boot_data.h>
#include <asm/lowcore.h>
#include <asm/setup.h>
#include <asm/sclp.h>
#include <asm/uv.h>
#include "boot.h"

const char hex_asc[] = "0123456789abcdef";

static char *as_hex(char *dst, unsigned long val, int pad)
{
	char *p, *end = p = dst + max(pad, (int)__fls(val | 1) / 4 + 1);

	for (*p-- = 0; p >= dst; val >>= 4)
		*p-- = hex_asc[val & 0x0f];
	return end;
}

static char *symstart(char *p)
{
	while (*p)
		p--;
	return p + 1;
}

static noinline char *findsym(unsigned long ip, unsigned short *off, unsigned short *len)
{
	/* symbol entries are in a form "10000 c4 startup\0" */
	char *a = _decompressor_syms_start;
	char *b = _decompressor_syms_end;
	unsigned long start;
	unsigned long size;
	char *pivot;
	char *endp;

	while (a < b) {
		pivot = symstart(a + (b - a) / 2);
		start = simple_strtoull(pivot, &endp, 16);
		size = simple_strtoull(endp + 1, &endp, 16);
		if (ip < start) {
			b = pivot;
			continue;
		}
		if (ip > start + size) {
			a = pivot + strlen(pivot) + 1;
			continue;
		}
		*off = ip - start;
		*len = size;
		return endp + 1;
	}
	return NULL;
}

static noinline char *strsym(void *ip)
{
	static char buf[64];
	unsigned short off;
	unsigned short len;
	char *p;

	p = findsym((unsigned long)ip, &off, &len);
	if (p) {
		strncpy(buf, p, sizeof(buf));
		/* reserve 15 bytes for offset/len in symbol+0x1234/0x1234 */
		p = buf + strnlen(buf, sizeof(buf) - 15);
		strcpy(p, "+0x");
		p = as_hex(p + 3, off, 0);
		strcpy(p, "/0x");
		as_hex(p + 3, len, 0);
	} else {
		as_hex(buf, (unsigned long)ip, 16);
	}
	return buf;
}

void decompressor_printk(const char *fmt, ...)
{
	char buf[1024] = { 0 };
	char *end = buf + sizeof(buf) - 1; /* make sure buf is 0 terminated */
	unsigned long pad;
	char *p = buf;
	va_list args;

	va_start(args, fmt);
	for (; p < end && *fmt; fmt++) {
		if (*fmt != '%') {
			*p++ = *fmt;
			continue;
		}
		pad = isdigit(*++fmt) ? simple_strtol(fmt, (char **)&fmt, 10) : 0;
		switch (*fmt) {
		case 's':
			p = buf + strlcat(buf, va_arg(args, char *), sizeof(buf));
			break;
		case 'p':
			if (*++fmt != 'S')
				goto out;
			p = buf + strlcat(buf, strsym(va_arg(args, void *)), sizeof(buf));
			break;
		case 'l':
			if (*++fmt != 'x' || end - p <= max(sizeof(long) * 2, pad))
				goto out;
			p = as_hex(p, va_arg(args, unsigned long), pad);
			break;
		case 'x':
			if (end - p <= max(sizeof(int) * 2, pad))
				goto out;
			p = as_hex(p, va_arg(args, unsigned int), pad);
			break;
		default:
			goto out;
		}
	}
out:
	va_end(args);
	sclp_early_printk(buf);
}

static noinline void print_stacktrace(void)
{
	struct stack_info boot_stack = { STACK_TYPE_TASK, (unsigned long)_stack_start,
					 (unsigned long)_stack_end };
	unsigned long sp = S390_lowcore.gpregs_save_area[15];
	bool first = true;

	decompressor_printk("Call Trace:\n");
	while (!(sp & 0x7) && on_stack(&boot_stack, sp, sizeof(struct stack_frame))) {
		struct stack_frame *sf = (struct stack_frame *)sp;

		decompressor_printk(first ? "(sp:%016lx [<%016lx>] %pS)\n" :
					    " sp:%016lx [<%016lx>] %pS\n",
				    sp, sf->gprs[8], (void *)sf->gprs[8]);
		if (sf->back_chain <= sp)
			break;
		sp = sf->back_chain;
		first = false;
	}
}

void print_pgm_check_info(void)
{
	unsigned long *gpregs = (unsigned long *)S390_lowcore.gpregs_save_area;
	struct psw_bits *psw = &psw_bits(S390_lowcore.psw_save_area);

	decompressor_printk("Linux version %s\n", kernel_version);
	if (!is_prot_virt_guest() && early_command_line[0])
		decompressor_printk("Kernel command line: %s\n", early_command_line);
	decompressor_printk("Kernel fault: interruption code %04x ilc:%x\n",
			    S390_lowcore.pgm_code, S390_lowcore.pgm_ilc >> 1);
	if (kaslr_enabled)
		decompressor_printk("Kernel random base: %lx\n", __kaslr_offset);
	decompressor_printk("PSW : %016lx %016lx (%pS)\n",
			    S390_lowcore.psw_save_area.mask,
			    S390_lowcore.psw_save_area.addr,
			    (void *)S390_lowcore.psw_save_area.addr);
	decompressor_printk(
		"      R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x P:%x AS:%x CC:%x PM:%x RI:%x EA:%x\n",
		psw->per, psw->dat, psw->io, psw->ext, psw->key, psw->mcheck,
		psw->wait, psw->pstate, psw->as, psw->cc, psw->pm, psw->ri,
		psw->eaba);
	decompressor_printk("GPRS: %016lx %016lx %016lx %016lx\n",
			    gpregs[0], gpregs[1], gpregs[2], gpregs[3]);
	decompressor_printk("      %016lx %016lx %016lx %016lx\n",
			    gpregs[4], gpregs[5], gpregs[6], gpregs[7]);
	decompressor_printk("      %016lx %016lx %016lx %016lx\n",
			    gpregs[8], gpregs[9], gpregs[10], gpregs[11]);
	decompressor_printk("      %016lx %016lx %016lx %016lx\n",
			    gpregs[12], gpregs[13], gpregs[14], gpregs[15]);
	print_stacktrace();
	decompressor_printk("Last Breaking-Event-Address:\n");
	decompressor_printk(" [<%016lx>] %pS\n", (unsigned long)S390_lowcore.breaking_event_addr,
			    (void *)S390_lowcore.breaking_event_addr);
}