arch/s390/kernel/machine_kexec.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright IBM Corp. 2005, 2011
  *
  * Author(s): Rolf Adelsberger,
  *	      Heiko Carstens <heiko.carstens@de.ibm.com>
  *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
  */

 #include <linux/device.h>
 #include <linux/mm.h>
 #include <linux/kexec.h>
 #include <linux/delay.h>
 #include <linux/reboot.h>
 #include <linux/ftrace.h>
 #include <linux/debug_locks.h>
 #include <asm/cio.h>
 #include <asm/setup.h>
 #include <asm/smp.h>
 #include <asm/ipl.h>
 #include <asm/diag.h>
 #include <asm/elf.h>
 #include <asm/asm-offsets.h>
 #include <asm/cacheflush.h>
 #include <asm/os_info.h>
 #include <asm/set_memory.h>
 #include <asm/stacktrace.h>
 #include <asm/switch_to.h>
 #include <asm/nmi.h>

 typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);

 extern const unsigned char relocate_kernel[];
 extern const unsigned long long relocate_kernel_len;

 #ifdef CONFIG_CRASH_DUMP

 /*
  * Reset the system, copy boot CPU registers to absolute zero,
  * and jump to the kdump image
  */
 static void __do_machine_kdump(void *image)
 {
 	int (*start_kdump)(int);
 	unsigned long prefix;

 	/* store_status() saved the prefix register to lowcore */
 	prefix = (unsigned long) S390_lowcore.prefixreg_save_area;

 	/* Now do the reset  */
 	s390_reset_system();

 	/*
 	 * Copy dump CPU store status info to absolute zero.
 	 * This need to be done *after* s390_reset_system set the
 	 * prefix register of this CPU to zero
 	 */
 	memcpy((void *) __LC_FPREGS_SAVE_AREA,
 	       (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);

 	__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
 	start_kdump = (void *)((struct kimage *) image)->start;
 	start_kdump(1);

 	/* Die if start_kdump returns */
 	disabled_wait();
 }

 /*
  * Start kdump: create a LGR log entry, store status of all CPUs and
  * branch to __do_machine_kdump.
  */
 static noinline void __machine_kdump(void *image)
 {
 	struct mcesa *mcesa;
 	union ctlreg2 cr2_old, cr2_new;
 	int this_cpu, cpu;

 	lgr_info_log();
 	/* Get status of the other CPUs */
 	this_cpu = smp_find_processor_id(stap());
 	for_each_online_cpu(cpu) {
 		if (cpu == this_cpu)
 			continue;
 		if (smp_store_status(cpu))
 			continue;
 	}
 	/* Store status of the boot CPU */
 	mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
 	if (MACHINE_HAS_VX)
 		save_vx_regs((__vector128 *) mcesa->vector_save_area);
 	if (MACHINE_HAS_GS) {
 		__ctl_store(cr2_old.val, 2, 2);
 		cr2_new = cr2_old;
 		cr2_new.gse = 1;
 		__ctl_load(cr2_new.val, 2, 2);
 		save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
 		__ctl_load(cr2_old.val, 2, 2);
 	}
 	/*
 	 * To create a good backchain for this CPU in the dump store_status
 	 * is passed the address of a function. The address is saved into
 	 * the PSW save area of the boot CPU and the function is invoked as
 	 * a tail call of store_status. The backchain in the dump will look
 	 * like this:
 	 *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
 	 * The call to store_status() will not return.
 	 */
 	store_status(__do_machine_kdump, image);
 }

 static unsigned long do_start_kdump(unsigned long addr)
 {
 	struct kimage *image = (struct kimage *) addr;
 	int (*start_kdump)(int) = (void *)image->start;
 	int rc;

 	__arch_local_irq_stnsm(0xfb); /* disable DAT */
 	rc = start_kdump(0);
 	__arch_local_irq_stosm(0x04); /* enable DAT */
 	return rc;
 }

 #endif /* CONFIG_CRASH_DUMP */

 /*
  * Check if kdump checksums are valid: We call purgatory with parameter "0"
  */
 static bool kdump_csum_valid(struct kimage *image)
 {
 #ifdef CONFIG_CRASH_DUMP
 	int rc;

 	preempt_disable();
 	rc = call_on_stack(1, S390_lowcore.nodat_stack, unsigned long, do_start_kdump,
 			   unsigned long, (unsigned long)image);
 	preempt_enable();
 	return rc == 0;
 #else
 	return false;
 #endif
 }

 #ifdef CONFIG_CRASH_DUMP

 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
 {
 	unsigned long addr, size;

 	for (addr = begin; addr < end; addr += PAGE_SIZE)
 		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
 	size = begin - crashk_res.start;
 	if (size)
 		os_info_crashkernel_add(crashk_res.start, size);
 	else
 		os_info_crashkernel_add(0, 0);
 }

 static void crash_protect_pages(int protect)
 {
 	unsigned long size;

 	if (!crashk_res.end)
 		return;
 	size = resource_size(&crashk_res);
 	if (protect)
 		set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
 	else
 		set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
 }

 void arch_kexec_protect_crashkres(void)
 {
 	crash_protect_pages(1);
 }

 void arch_kexec_unprotect_crashkres(void)
 {
 	crash_protect_pages(0);
 }

 #endif

 /*
  * Give back memory to hypervisor before new kdump is loaded
  */
 static int machine_kexec_prepare_kdump(void)
 {
 #ifdef CONFIG_CRASH_DUMP
 	if (MACHINE_IS_VM)
 		diag10_range(PFN_DOWN(crashk_res.start),
 			     PFN_DOWN(crashk_res.end - crashk_res.start + 1));
 	return 0;
 #else
 	return -EINVAL;
 #endif
 }

 int machine_kexec_prepare(struct kimage *image)
 {
 	void *reboot_code_buffer;

 	if (image->type == KEXEC_TYPE_CRASH)
 		return machine_kexec_prepare_kdump();

 	/* We don't support anything but the default image type for now. */
 	if (image->type != KEXEC_TYPE_DEFAULT)
 		return -EINVAL;

 	/* Get the destination where the assembler code should be copied to.*/
 	reboot_code_buffer = (void *) page_to_phys(image->control_code_page);

 	/* Then copy it */
 	memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
 	return 0;
 }

 void machine_kexec_cleanup(struct kimage *image)
 {
 }

 void arch_crash_save_vmcoreinfo(void)
 {
 	VMCOREINFO_SYMBOL(lowcore_ptr);
 	VMCOREINFO_SYMBOL(high_memory);
 	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
 	vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31);
 	vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31);
 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
 	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
 }

 void machine_shutdown(void)
 {
 }

 void machine_crash_shutdown(struct pt_regs *regs)
 {
 	set_os_info_reipl_block();
 }

 /*
  * Do normal kexec
  */
 static void __do_machine_kexec(void *data)
 {
 	relocate_kernel_t data_mover;
 	struct kimage *image = data;

 	s390_reset_system();
 	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);

 	__arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
 	/* Call the moving routine */
 	(*data_mover)(&image->head, image->start);

 	/* Die if kexec returns */
 	disabled_wait();
 }

 /*
  * Reset system and call either kdump or normal kexec
  */
 static void __machine_kexec(void *data)
 {
 	pfault_fini();
 	tracing_off();
 	debug_locks_off();
 #ifdef CONFIG_CRASH_DUMP
 	if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
 		__machine_kdump(data);
 #endif
 	__do_machine_kexec(data);
 }

 /*
  * Do either kdump or normal kexec. In case of kdump we first ask
  * purgatory, if kdump checksums are valid.
  */
 void machine_kexec(struct kimage *image)
 {
 	if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
 		return;
 	tracer_disable();
 	smp_send_stop();
 	smp_call_ipl_cpu(__machine_kexec, image);
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* Copyright IBM Corp. 2005, 2011
	*
	* Author(s): Rolf Adelsberger,
	* Heiko Carstens <heiko.carstens@de.ibm.com>
	* Michael Holzheu <holzheu@linux.vnet.ibm.com>
	*/

	#include <linux/device.h>
	#include <linux/mm.h>
	#include <linux/kexec.h>
	#include <linux/delay.h>
	#include <linux/reboot.h>
	#include <linux/ftrace.h>
	#include <linux/debug_locks.h>
	#include <asm/cio.h>
	#include <asm/setup.h>
	#include <asm/smp.h>
	#include <asm/ipl.h>
	#include <asm/diag.h>
	#include <asm/elf.h>
	#include <asm/asm-offsets.h>
	#include <asm/cacheflush.h>
	#include <asm/os_info.h>
	#include <asm/set_memory.h>
	#include <asm/stacktrace.h>
	#include <asm/switch_to.h>
	#include <asm/nmi.h>

	typedef void (relocate_kernel_t)(kimage_entry_t , unsigned long);

	extern const unsigned char relocate_kernel[];
	extern const unsigned long long relocate_kernel_len;

	#ifdef CONFIG_CRASH_DUMP

	/*
	* Reset the system, copy boot CPU registers to absolute zero,
	* and jump to the kdump image
	*/
	static void __do_machine_kdump(void *image)
	{
	int (*start_kdump)(int);
	unsigned long prefix;

	/* store_status() saved the prefix register to lowcore */
	prefix = (unsigned long) S390_lowcore.prefixreg_save_area;

	/* Now do the reset */
	s390_reset_system();

	/*
	* Copy dump CPU store status info to absolute zero.
	* This need to be done after s390_reset_system set the
	* prefix register of this CPU to zero
	*/
	memcpy((void *) __LC_FPREGS_SAVE_AREA,
	(void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);

	__load_psw_mask(PSW_MASK_BASE \| PSW_DEFAULT_KEY \| PSW_MASK_EA \| PSW_MASK_BA);
	start_kdump = (void )((struct kimage ) image)->start;
	start_kdump(1);

	/* Die if start_kdump returns */
	disabled_wait();
	}

	/*
	* Start kdump: create a LGR log entry, store status of all CPUs and
	* branch to __do_machine_kdump.
	*/
	static noinline void __machine_kdump(void *image)
	{
	struct mcesa *mcesa;
	union ctlreg2 cr2_old, cr2_new;
	int this_cpu, cpu;

	lgr_info_log();
	/* Get status of the other CPUs */
	this_cpu = smp_find_processor_id(stap());
	for_each_online_cpu(cpu) {
	if (cpu == this_cpu)
	continue;
	if (smp_store_status(cpu))
	continue;
	}
	/* Store status of the boot CPU */
	mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
	if (MACHINE_HAS_VX)
	save_vx_regs((__vector128 *) mcesa->vector_save_area);
	if (MACHINE_HAS_GS) {
	__ctl_store(cr2_old.val, 2, 2);
	cr2_new = cr2_old;
	cr2_new.gse = 1;
	__ctl_load(cr2_new.val, 2, 2);
	save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
	__ctl_load(cr2_old.val, 2, 2);
	}
	/*
	* To create a good backchain for this CPU in the dump store_status
	* is passed the address of a function. The address is saved into
	* the PSW save area of the boot CPU and the function is invoked as
	* a tail call of store_status. The backchain in the dump will look
	* like this:
	* restart_int_handler -> __machine_kexec -> __do_machine_kdump
	* The call to store_status() will not return.
	*/
	store_status(__do_machine_kdump, image);
	}

	static unsigned long do_start_kdump(unsigned long addr)
	{
	struct kimage image = (struct kimage ) addr;
	int (start_kdump)(int) = (void )image->start;
	int rc;

	__arch_local_irq_stnsm(0xfb); /* disable DAT */
	rc = start_kdump(0);
	__arch_local_irq_stosm(0x04); /* enable DAT */
	return rc;
	}

	#endif /* CONFIG_CRASH_DUMP */

	/*
	* Check if kdump checksums are valid: We call purgatory with parameter "0"
	*/
	static bool kdump_csum_valid(struct kimage *image)
	{
	#ifdef CONFIG_CRASH_DUMP
	int rc;

	preempt_disable();
	rc = call_on_stack(1, S390_lowcore.nodat_stack, unsigned long, do_start_kdump,
	unsigned long, (unsigned long)image);
	preempt_enable();
	return rc == 0;
	#else
	return false;
	#endif
	}

	#ifdef CONFIG_CRASH_DUMP

	void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
	{
	unsigned long addr, size;

	for (addr = begin; addr < end; addr += PAGE_SIZE)
	free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
	size = begin - crashk_res.start;
	if (size)
	os_info_crashkernel_add(crashk_res.start, size);
	else
	os_info_crashkernel_add(0, 0);
	}

	static void crash_protect_pages(int protect)
	{
	unsigned long size;

	if (!crashk_res.end)
	return;
	size = resource_size(&crashk_res);
	if (protect)
	set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
	else
	set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
	}

	void arch_kexec_protect_crashkres(void)
	{
	crash_protect_pages(1);
	}

	void arch_kexec_unprotect_crashkres(void)
	{
	crash_protect_pages(0);
	}

	#endif

	/*
	* Give back memory to hypervisor before new kdump is loaded
	*/
	static int machine_kexec_prepare_kdump(void)
	{
	#ifdef CONFIG_CRASH_DUMP
	if (MACHINE_IS_VM)
	diag10_range(PFN_DOWN(crashk_res.start),
	PFN_DOWN(crashk_res.end - crashk_res.start + 1));
	return 0;
	#else
	return -EINVAL;
	#endif
	}

	int machine_kexec_prepare(struct kimage *image)
	{
	void *reboot_code_buffer;

	if (image->type == KEXEC_TYPE_CRASH)
	return machine_kexec_prepare_kdump();

	/* We don't support anything but the default image type for now. */
	if (image->type != KEXEC_TYPE_DEFAULT)
	return -EINVAL;

	/* Get the destination where the assembler code should be copied to.*/
	reboot_code_buffer = (void *) page_to_phys(image->control_code_page);

	/* Then copy it */
	memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
	return 0;
	}

	void machine_kexec_cleanup(struct kimage *image)
	{
	}

	void arch_crash_save_vmcoreinfo(void)
	{
	VMCOREINFO_SYMBOL(lowcore_ptr);
	VMCOREINFO_SYMBOL(high_memory);
	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
	vmcoreinfo_append_str("SAMODE31=%lx\n", __samode31);
	vmcoreinfo_append_str("EAMODE31=%lx\n", __eamode31);
	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
	}

	void machine_shutdown(void)
	{
	}

	void machine_crash_shutdown(struct pt_regs *regs)
	{
	set_os_info_reipl_block();
	}

	/*
	* Do normal kexec
	*/
	static void __do_machine_kexec(void *data)
	{
	relocate_kernel_t data_mover;
	struct kimage *image = data;

	s390_reset_system();
	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);

	__arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
	/* Call the moving routine */
	(*data_mover)(&image->head, image->start);

	/* Die if kexec returns */
	disabled_wait();
	}

	/*
	* Reset system and call either kdump or normal kexec
	*/
	static void __machine_kexec(void *data)
	{
	pfault_fini();
	tracing_off();
	debug_locks_off();
	#ifdef CONFIG_CRASH_DUMP
	if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
	__machine_kdump(data);
	#endif
	__do_machine_kexec(data);
	}

	/*
	* Do either kdump or normal kexec. In case of kdump we first ask
	* purgatory, if kdump checksums are valid.
	*/
	void machine_kexec(struct kimage *image)
	{
	if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
	return;
	tracer_disable();
	smp_send_stop();
	smp_call_ipl_cpu(__machine_kexec, image);
	}