e7a57273c6
Currently create_branch() creates a branch instruction for you, and patches it into the call site. In some circumstances it would be nice to be able to create the instruction and patch it later, and also some code might want to check for errors in the branch creation before doing the patching. A future commit will change create_branch() to check for errors. For callers that don't care, replace create_branch() with patch_branch(), which just creates the branch and patches it directly. While we're touching all the callers, change to using unsigned int *, as this seems to match usage better. That allows (and requires) us to remove the volatile in the definition of vector in powermac/smp.c and mpc86xx_smp.c, that's correct because now that we're passing vector as an unsigned int * the compiler knows that it's value might change across the patch_branch() call. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Kumar Gala <galak@kernel.crashing.org> Acked-by: Jon Loeliger <jdl@freescale.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
123 lines
3.1 KiB
C
123 lines
3.1 KiB
C
/*
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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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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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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/bootmem.h>
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#include <linux/lmb.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 <asm/uaccess.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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void __init reserve_kdump_trampoline(void)
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{
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lmb_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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unsigned int *p = (unsigned int *)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, 0x60000000); /* nop */
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patch_branch(++p, 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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#ifdef CONFIG_PROC_VMCORE
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static int __init parse_elfcorehdr(char *p)
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{
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if (p)
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elfcorehdr_addr = memparse(p, &p);
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return 1;
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}
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__setup("elfcorehdr=", parse_elfcorehdr);
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#endif
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static int __init parse_savemaxmem(char *p)
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{
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if (p)
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saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
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return 1;
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}
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__setup("savemaxmem=", parse_savemaxmem);
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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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if (!csize)
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return 0;
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vaddr = __ioremap(pfn << PAGE_SHIFT, PAGE_SIZE, 0);
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if (userbuf) {
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if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) {
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iounmap(vaddr);
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return -EFAULT;
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}
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} else
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memcpy(buf, (vaddr + offset), csize);
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iounmap(vaddr);
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return csize;
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}
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