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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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55a5542a54
The resume code checks if the resume cpu is the same as the suspend cpu. If not, and if it is also not possible to switch to the suspend cpu, an error message should be printed and the resume process should be stopped by loading a disabled wait psw. The current logic is broken in multiple ways, the message is never printed, and the disabled wait psw never loaded because the kernel panics before that: - sam31 and SIGP_SET_ARCHITECTURE to ESA mode is wrong, this will break on the first 64bit instruction in sclp_early_printk(). - The init stack should be used, but the stack pointer is not set up correctly (missing aghi %r15,-STACK_FRAME_OVERHEAD). - __sclp_early_printk() checks the sclp_init_state. If it is not sclp_init_state_uninitialized, it simply returns w/o printing anything. In the resumed kernel however, sclp_init_state will never be uninitialized. This patch fixes those issues by removing the sam31/ESA logic, adding a correct init stack pointer, and also introducing sclp_early_printk_force() to allow using sclp_early_printk() even when sclp_init_state is not uninitialized. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
37 lines
824 B
C
37 lines
824 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/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, 0);
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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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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 && strncmp(buf, "sclp", 4))
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return 0;
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if (!sclp.has_linemode && !sclp.has_vt220)
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return 0;
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early_console = &sclp_early_console;
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register_console(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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