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147 lines
4.0 KiB
147 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Routines for doing kexec-based kdump. |
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* |
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* Copyright (C) 2005, IBM Corp. |
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* |
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* Created by: Michael Ellerman |
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*/ |
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#undef DEBUG |
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#include <linux/crash_dump.h> |
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#include <linux/io.h> |
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#include <linux/memblock.h> |
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#include <asm/code-patching.h> |
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#include <asm/kdump.h> |
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#include <asm/prom.h> |
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#include <asm/firmware.h> |
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#include <linux/uaccess.h> |
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#include <asm/rtas.h> |
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#include <asm/inst.h> |
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#ifdef DEBUG |
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#include <asm/udbg.h> |
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#define DBG(fmt...) udbg_printf(fmt) |
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#else |
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#define DBG(fmt...) |
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#endif |
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#ifndef CONFIG_NONSTATIC_KERNEL |
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void __init reserve_kdump_trampoline(void) |
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{ |
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memblock_reserve(0, KDUMP_RESERVE_LIMIT); |
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} |
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static void __init create_trampoline(unsigned long addr) |
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{ |
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struct ppc_inst *p = (struct ppc_inst *)addr; |
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/* The maximum range of a single instruction branch, is the current |
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* instruction's address + (32 MB - 4) bytes. For the trampoline we |
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* need to branch to current address + 32 MB. So we insert a nop at |
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* the trampoline address, then the next instruction (+ 4 bytes) |
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* does a branch to (32 MB - 4). The net effect is that when we |
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* branch to "addr" we jump to ("addr" + 32 MB). Although it requires |
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* two instructions it doesn't require any registers. |
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*/ |
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patch_instruction(p, ppc_inst(PPC_INST_NOP)); |
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patch_branch((void *)p + 4, addr + PHYSICAL_START, 0); |
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} |
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void __init setup_kdump_trampoline(void) |
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{ |
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unsigned long i; |
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DBG(" -> setup_kdump_trampoline()\n"); |
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for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) { |
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create_trampoline(i); |
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} |
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#ifdef CONFIG_PPC_PSERIES |
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create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START); |
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create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START); |
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#endif /* CONFIG_PPC_PSERIES */ |
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DBG(" <- setup_kdump_trampoline()\n"); |
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} |
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#endif /* CONFIG_NONSTATIC_KERNEL */ |
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static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, |
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unsigned long offset, int userbuf) |
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{ |
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if (userbuf) { |
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if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) |
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return -EFAULT; |
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} else |
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memcpy(buf, (vaddr + offset), csize); |
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return csize; |
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} |
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/** |
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* copy_oldmem_page - copy one page from "oldmem" |
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* @pfn: page frame number to be copied |
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* @buf: target memory address for the copy; this can be in kernel address |
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* space or user address space (see @userbuf) |
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* @csize: number of bytes to copy |
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* @offset: offset in bytes into the page (based on pfn) to begin the copy |
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* @userbuf: if set, @buf is in user address space, use copy_to_user(), |
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* otherwise @buf is in kernel address space, use memcpy(). |
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* |
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* Copy a page from "oldmem". For this page, there is no pte mapped |
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* in the current kernel. We stitch up a pte, similar to kmap_atomic. |
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*/ |
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ssize_t copy_oldmem_page(unsigned long pfn, char *buf, |
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size_t csize, unsigned long offset, int userbuf) |
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{ |
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void *vaddr; |
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phys_addr_t paddr; |
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if (!csize) |
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return 0; |
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csize = min_t(size_t, csize, PAGE_SIZE); |
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paddr = pfn << PAGE_SHIFT; |
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if (memblock_is_region_memory(paddr, csize)) { |
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vaddr = __va(paddr); |
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csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); |
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} else { |
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vaddr = ioremap_cache(paddr, PAGE_SIZE); |
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csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); |
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iounmap(vaddr); |
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} |
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return csize; |
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} |
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#ifdef CONFIG_PPC_RTAS |
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/* |
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* The crashkernel region will almost always overlap the RTAS region, so |
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* we have to be careful when shrinking the crashkernel region. |
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*/ |
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void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) |
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{ |
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unsigned long addr; |
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const __be32 *basep, *sizep; |
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unsigned int rtas_start = 0, rtas_end = 0; |
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basep = of_get_property(rtas.dev, "linux,rtas-base", NULL); |
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sizep = of_get_property(rtas.dev, "rtas-size", NULL); |
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if (basep && sizep) { |
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rtas_start = be32_to_cpup(basep); |
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rtas_end = rtas_start + be32_to_cpup(sizep); |
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} |
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for (addr = begin; addr < end; addr += PAGE_SIZE) { |
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/* Does this page overlap with the RTAS region? */ |
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if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start)) |
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continue; |
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free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT)); |
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} |
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} |
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#endif
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