123 lines
3.0 KiB
C
123 lines
3.0 KiB
C
// 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 <linux/of.h>
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#include <asm/code-patching.h>
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#include <asm/kdump.h>
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#include <asm/firmware.h>
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#include <linux/uio.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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u32 *p = (u32 *)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_RAW_NOP()));
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patch_branch(p + 1, 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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ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
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size_t csize, unsigned long offset)
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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_to_iter(vaddr + offset, csize, iter);
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} else {
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vaddr = ioremap_cache(paddr, PAGE_SIZE);
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csize = copy_to_iter(vaddr + offset, csize, iter);
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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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