b2bb65f680
It is possible to configure a kernel which has xmon enabled, but has no udbg backend to provide IO. This can make xmon rather confusing, as it produces no output, blocks for two seconds, and then returns. As a last resort we can instead try to printk(), which may deadlock or otherwise crash, but tries quite hard not to. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
132 lines
2.2 KiB
C
132 lines
2.2 KiB
C
/*
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* Copyright (C) 1996-2005 Paul Mackerras.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/string.h>
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#include <asm/udbg.h>
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#include <asm/time.h>
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#include "nonstdio.h"
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static int xmon_write(const void *ptr, int nb)
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{
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return udbg_write(ptr, nb);
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}
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static int xmon_readchar(void)
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{
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if (udbg_getc)
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return udbg_getc();
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return -1;
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}
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int xmon_putchar(int c)
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{
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char ch = c;
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if (c == '\n')
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xmon_putchar('\r');
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return xmon_write(&ch, 1) == 1? c: -1;
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}
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static char line[256];
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static char *lineptr;
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static int lineleft;
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static int xmon_getchar(void)
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{
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int c;
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if (lineleft == 0) {
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lineptr = line;
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for (;;) {
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c = xmon_readchar();
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if (c == -1 || c == 4)
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break;
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if (c == '\r' || c == '\n') {
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*lineptr++ = '\n';
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xmon_putchar('\n');
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break;
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}
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switch (c) {
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case 0177:
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case '\b':
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if (lineptr > line) {
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xmon_putchar('\b');
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xmon_putchar(' ');
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xmon_putchar('\b');
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--lineptr;
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}
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break;
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case 'U' & 0x1F:
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while (lineptr > line) {
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xmon_putchar('\b');
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xmon_putchar(' ');
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xmon_putchar('\b');
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--lineptr;
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}
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break;
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default:
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if (lineptr >= &line[sizeof(line) - 1])
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xmon_putchar('\a');
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else {
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xmon_putchar(c);
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*lineptr++ = c;
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}
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}
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}
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lineleft = lineptr - line;
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lineptr = line;
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}
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if (lineleft == 0)
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return -1;
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--lineleft;
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return *lineptr++;
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}
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char *xmon_gets(char *str, int nb)
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{
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char *p;
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int c;
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for (p = str; p < str + nb - 1; ) {
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c = xmon_getchar();
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if (c == -1) {
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if (p == str)
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return NULL;
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break;
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}
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*p++ = c;
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if (c == '\n')
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break;
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}
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*p = 0;
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return str;
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}
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void xmon_printf(const char *format, ...)
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{
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va_list args;
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static char xmon_outbuf[1024];
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int rc, n;
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va_start(args, format);
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n = vsnprintf(xmon_outbuf, sizeof(xmon_outbuf), format, args);
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va_end(args);
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rc = xmon_write(xmon_outbuf, n);
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if (n && rc == 0) {
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/* No udbg hooks, fallback to printk() - dangerous */
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printk(xmon_outbuf);
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}
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}
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void xmon_puts(const char *str)
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{
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xmon_write(str, strlen(str));
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}
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