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If the early program check handler cannot resolve a program check dump register contents and a call trace to the console before loading a disabled wait psw. This makes debugging much easier. Emit an extra message with early_printk() for cases where regular printk() via the early console is not yet working so that at least some information is available. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
45 lines
950 B
C
45 lines
950 B
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright IBM Corp. 2017
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*/
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#include <linux/console.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <asm/setup.h>
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#include <asm/sclp.h>
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static void sclp_early_write(struct console *con, const char *s, unsigned int len)
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{
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__sclp_early_printk(s, len);
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}
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static struct console sclp_early_console = {
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.name = "earlysclp",
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.write = sclp_early_write,
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.flags = CON_PRINTBUFFER | CON_BOOT,
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.index = -1,
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};
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void __init register_early_console(void)
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{
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if (early_console)
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return;
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if (!sclp.has_linemode && !sclp.has_vt220)
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return;
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early_console = &sclp_early_console;
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register_console(early_console);
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}
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static int __init setup_early_printk(char *buf)
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{
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if (early_console)
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return 0;
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/* Accept only "earlyprintk" and "earlyprintk=sclp" */
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if (buf && !str_has_prefix(buf, "sclp"))
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return 0;
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register_early_console();
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return 0;
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}
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early_param("earlyprintk", setup_early_printk);
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