cregit-Linux how code gets into the kernel

Release 4.14 arch/powerpc/kernel/crash_dump.c

/*
 * Routines for doing kexec-based kdump.
 *
 * Copyright (C) 2005, IBM Corp.
 *
 * Created by: Michael Ellerman
 *
 * This source code is licensed under the GNU General Public License,
 * Version 2.  See the file COPYING for more details.
 */


#undef DEBUG

#include <linux/crash_dump.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <asm/code-patching.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/firmware.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>

#ifdef DEBUG
#include <asm/udbg.h>

#define DBG(fmt...) udbg_printf(fmt)
#else

#define DBG(fmt...)
#endif

#ifndef CONFIG_NONSTATIC_KERNEL

void __init reserve_kdump_trampoline(void) { memblock_reserve(0, KDUMP_RESERVE_LIMIT); }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman1386.67%133.33%
Stephen Rothwell16.67%133.33%
Yinghai Lu16.67%133.33%
Total15100.00%3100.00%


static void __init create_trampoline(unsigned long addr) { unsigned int *p = (unsigned int *)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_NOP); patch_branch(++p, addr + PHYSICAL_START, 0); }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman4297.67%266.67%
Kumar Gala12.33%133.33%
Total43100.00%3100.00%


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"); }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman6391.30%266.67%
Stephen Rothwell68.70%133.33%
Total69100.00%3100.00%

#endif /* CONFIG_NONSTATIC_KERNEL */
static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, unsigned long offset, int userbuf) { if (userbuf) { if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) return -EFAULT; } else memcpy(buf, (vaddr + offset), csize); return csize; }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman71100.00%1100.00%
Total71100.00%1100.00%

/** * copy_oldmem_page - copy one page from "oldmem" * @pfn: page frame number to be copied * @buf: target memory address for the copy; this can be in kernel address * space or user address space (see @userbuf) * @csize: number of bytes to copy * @offset: offset in bytes into the page (based on pfn) to begin the copy * @userbuf: if set, @buf is in user address space, use copy_to_user(), * otherwise @buf is in kernel address space, use memcpy(). * * Copy a page from "oldmem". For this page, there is no pte mapped * in the current kernel. We stitch up a pte, similar to kmap_atomic. */
ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { 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_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); } else { vaddr = __ioremap(paddr, PAGE_SIZE, 0); csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); iounmap(vaddr); } return csize; }

Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman10584.00%250.00%
Laurent Dufour1713.60%125.00%
Matthew McClintock32.40%125.00%
Total125100.00%4100.00%

#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)); } }

Contributors

PersonTokensPropCommitsCommitProp
Anton Blanchard12899.22%266.67%
Jiang Liu10.78%133.33%
Total129100.00%3100.00%

#endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Michael Ellerman34365.83%940.91%
Anton Blanchard13726.30%29.09%
Laurent Dufour173.26%14.55%
Stephen Rothwell71.34%29.09%
M. Mohan Kumar40.77%14.55%
Matthew McClintock30.58%14.55%
David S. Miller30.58%14.55%
Suzuki K. Poulose20.38%14.55%
Yinghai Lu20.38%14.55%
Kumar Gala10.19%14.55%
Jiang Liu10.19%14.55%
Linus Torvalds10.19%14.55%
Total521100.00%22100.00%
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