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// SPDX-License-Identifier: GPL-2.0-only
/*
* Routines for doing kexec-based kdump.
*
* Copyright (C) 2005, IBM Corp.
*
* Created by: Michael Ellerman
*/
#undef DEBUG
#include <linux/crash_dump.h>
#include <linux/io.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <asm/code-patching.h>
#include <asm/kdump.h>
#include <asm/firmware.h>
#include <linux/uio.h>
#include <asm/rtas.h>
#include <asm/inst.h>
#include <asm/fadump.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);
}
static void __init create_trampoline(unsigned long addr)
{
u32 *p = (u32 *)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(PPC_RAW_NOP()));
patch_branch(p + 1, addr + PHYSICAL_START, 0);
}
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");
}
#endif /* CONFIG_NONSTATIC_KERNEL */
ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
size_t csize, unsigned long offset)
{
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_to_iter(vaddr + offset, csize, iter);
} else {
vaddr = ioremap_cache(paddr, PAGE_SIZE);
csize = copy_to_iter(vaddr + offset, csize, iter);
iounmap(vaddr);
}
return csize;
}
/*
* Return true only when kexec based kernel dump capturing method is used.
* This ensures all restritions applied for kdump case are not automatically
* applied for fadump case.
*/
bool is_kdump_kernel(void)
{
return !is_fadump_active() && elfcorehdr_addr != ELFCORE_ADDR_MAX;
}
EXPORT_SYMBOL_GPL(is_kdump_kernel);
#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));
}
}
#endif
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