// SPDX-License-Identifier: GPL-2.0-only/* * Routines for doing kexec-based kdump. * * Copyright (C) 2005, IBM Corp. * * Created by: Michael Ellerman */ #undef DEBUG #include <linux/crash_dump.h>#include <linux/io.h>#include <linux/memblock.h>#include <linux/of.h>#include <asm/text-patching.h>#include <asm/kdump.h>#include <asm/firmware.h>#include <linux/uio.h>#include <asm/rtas.h>#include <asm/inst.h>#include <asm/fadump.h> #ifdef DEBUG#include <asm/udbg.h>#define DBG(fmt...) udbg_printf(fmt)#else#define DBG(fmt...)#endif #ifndef CONFIG_NONSTATIC_KERNELvoid __init reserve_kdump_trampoline(void){	memblock_reserve(0, KDUMP_RESERVE_LIMIT);} static void __init create_trampoline(unsigned long addr){	u32 *p = (u32 *)addr; 	/* The maximum range of a single instruction branch, is the current	 * instruction's address + (32 MB - 4) bytes. For the trampoline we	 * need to branch to current address + 32 MB. So we insert a nop at	 * the trampoline address, then the next instruction (+ 4 bytes)	 * does a branch to (32 MB - 4). The net effect is that when we	 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires	 * two instructions it doesn't require any registers.	 */	patch_instruction(p, ppc_inst(PPC_RAW_NOP()));	patch_branch(p + 1, addr + PHYSICAL_START, 0);} void __init setup_kdump_trampoline(void){	unsigned long i; 	DBG(" -> setup_kdump_trampoline()\n"); 	for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {		create_trampoline(i);	} #ifdef CONFIG_PPC_PSERIES	create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);	create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);#endif /* CONFIG_PPC_PSERIES */ 	DBG(" <- setup_kdump_trampoline()\n");}#endif /* CONFIG_NONSTATIC_KERNEL */ ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,			size_t csize, unsigned long offset){	void  *vaddr;	phys_addr_t paddr; 	if (!csize)		return 0; 	csize = min_t(size_t, csize, PAGE_SIZE);	paddr = pfn << PAGE_SHIFT; 	if (memblock_is_region_memory(paddr, csize)) {		vaddr = __va(paddr);		csize = copy_to_iter(vaddr + offset, csize, iter);	} else {		vaddr = ioremap_cache(paddr, PAGE_SIZE);		csize = copy_to_iter(vaddr + offset, csize, iter);		iounmap(vaddr);	} 	return csize;} /* * Return true only when kexec based kernel dump capturing method is used. * This ensures all restritions applied for kdump case are not automatically * applied for fadump case. */bool is_kdump_kernel(void){	return !is_fadump_active() && elfcorehdr_addr != ELFCORE_ADDR_MAX;}EXPORT_SYMBOL_GPL(is_kdump_kernel); #ifdef CONFIG_PPC_RTAS/* * The crashkernel region will almost always overlap the RTAS region, so * we have to be careful when shrinking the crashkernel region. */void crash_free_reserved_phys_range(unsigned long begin, unsigned long end){	unsigned long addr;	const __be32 *basep, *sizep;	unsigned int rtas_start = 0, rtas_end = 0; 	basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);	sizep = of_get_property(rtas.dev, "rtas-size", NULL); 	if (basep && sizep) {		rtas_start = be32_to_cpup(basep);		rtas_end = rtas_start + be32_to_cpup(sizep);	} 	for (addr = begin; addr < end; addr += PAGE_SIZE) {		/* Does this page overlap with the RTAS region? */		if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))			continue; 		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));	}}#endif