cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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crash_dump.c (3099B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Routines for doing kexec-based kdump.
      4 *
      5 * Copyright (C) 2005, IBM Corp.
      6 *
      7 * Created by: Michael Ellerman
      8 */
      9
     10#undef DEBUG
     11
     12#include <linux/crash_dump.h>
     13#include <linux/io.h>
     14#include <linux/memblock.h>
     15#include <linux/of.h>
     16#include <asm/code-patching.h>
     17#include <asm/kdump.h>
     18#include <asm/firmware.h>
     19#include <linux/uio.h>
     20#include <asm/rtas.h>
     21#include <asm/inst.h>
     22
     23#ifdef DEBUG
     24#include <asm/udbg.h>
     25#define DBG(fmt...) udbg_printf(fmt)
     26#else
     27#define DBG(fmt...)
     28#endif
     29
     30#ifndef CONFIG_NONSTATIC_KERNEL
     31void __init reserve_kdump_trampoline(void)
     32{
     33	memblock_reserve(0, KDUMP_RESERVE_LIMIT);
     34}
     35
     36static void __init create_trampoline(unsigned long addr)
     37{
     38	u32 *p = (u32 *)addr;
     39
     40	/* The maximum range of a single instruction branch, is the current
     41	 * instruction's address + (32 MB - 4) bytes. For the trampoline we
     42	 * need to branch to current address + 32 MB. So we insert a nop at
     43	 * the trampoline address, then the next instruction (+ 4 bytes)
     44	 * does a branch to (32 MB - 4). The net effect is that when we
     45	 * branch to "addr" we jump to ("addr" + 32 MB). Although it requires
     46	 * two instructions it doesn't require any registers.
     47	 */
     48	patch_instruction(p, ppc_inst(PPC_RAW_NOP()));
     49	patch_branch(p + 1, addr + PHYSICAL_START, 0);
     50}
     51
     52void __init setup_kdump_trampoline(void)
     53{
     54	unsigned long i;
     55
     56	DBG(" -> setup_kdump_trampoline()\n");
     57
     58	for (i = KDUMP_TRAMPOLINE_START; i < KDUMP_TRAMPOLINE_END; i += 8) {
     59		create_trampoline(i);
     60	}
     61
     62#ifdef CONFIG_PPC_PSERIES
     63	create_trampoline(__pa(system_reset_fwnmi) - PHYSICAL_START);
     64	create_trampoline(__pa(machine_check_fwnmi) - PHYSICAL_START);
     65#endif /* CONFIG_PPC_PSERIES */
     66
     67	DBG(" <- setup_kdump_trampoline()\n");
     68}
     69#endif /* CONFIG_NONSTATIC_KERNEL */
     70
     71ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
     72			size_t csize, unsigned long offset)
     73{
     74	void  *vaddr;
     75	phys_addr_t paddr;
     76
     77	if (!csize)
     78		return 0;
     79
     80	csize = min_t(size_t, csize, PAGE_SIZE);
     81	paddr = pfn << PAGE_SHIFT;
     82
     83	if (memblock_is_region_memory(paddr, csize)) {
     84		vaddr = __va(paddr);
     85		csize = copy_to_iter(vaddr + offset, csize, iter);
     86	} else {
     87		vaddr = ioremap_cache(paddr, PAGE_SIZE);
     88		csize = copy_to_iter(vaddr + offset, csize, iter);
     89		iounmap(vaddr);
     90	}
     91
     92	return csize;
     93}
     94
     95#ifdef CONFIG_PPC_RTAS
     96/*
     97 * The crashkernel region will almost always overlap the RTAS region, so
     98 * we have to be careful when shrinking the crashkernel region.
     99 */
    100void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
    101{
    102	unsigned long addr;
    103	const __be32 *basep, *sizep;
    104	unsigned int rtas_start = 0, rtas_end = 0;
    105
    106	basep = of_get_property(rtas.dev, "linux,rtas-base", NULL);
    107	sizep = of_get_property(rtas.dev, "rtas-size", NULL);
    108
    109	if (basep && sizep) {
    110		rtas_start = be32_to_cpup(basep);
    111		rtas_end = rtas_start + be32_to_cpup(sizep);
    112	}
    113
    114	for (addr = begin; addr < end; addr += PAGE_SIZE) {
    115		/* Does this page overlap with the RTAS region? */
    116		if (addr <= rtas_end && ((addr + PAGE_SIZE) > rtas_start))
    117			continue;
    118
    119		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
    120	}
    121}
    122#endif