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5d8de293c2
Patch series "Convert vmcore to use an iov_iter", v5. For some reason several people have been sending bad patches to fix compiler warnings in vmcore recently. Here's how it should be done. Compile-tested only on x86. As noted in the first patch, s390 should take this conversion a bit further, but I'm not inclined to do that work myself. This patch (of 3): Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter. s390 needs more work to pass the iov_iter down further, or refactor, but I'd be more comfortable if someone who can test on s390 did that work. It's more convenient to convert the whole of read_from_oldmem() to take an iov_iter at the same time, so rename it to read_from_oldmem_iter() and add a temporary read_from_oldmem() wrapper that creates an iov_iter. Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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 <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/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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