linux/arch/arm64/kernel/machine_kexec.c
Mike Rapoport 6d47c23b16 set_memory: allow querying whether set_direct_map_*() is actually enabled
On arm64, set_direct_map_*() functions may return 0 without actually
changing the linear map.  This behaviour can be controlled using kernel
parameters, so we need a way to determine at runtime whether calls to
set_direct_map_invalid_noflush() and set_direct_map_default_noflush() have
any effect.

Extend set_memory API with can_set_direct_map() function that allows
checking if calling set_direct_map_*() will actually change the page
table, replace several occurrences of open coded checks in arm64 with the
new function and provide a generic stub for architectures that always
modify page tables upon calls to set_direct_map APIs.

[arnd@arndb.de: arm64: kfence: fix header inclusion ]

Link: https://lkml.kernel.org/r/20210518072034.31572-4-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tycho Andersen <tycho@tycho.ws>
Cc: Will Deacon <will@kernel.org>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08 11:48:20 -07:00

350 lines
8.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* kexec for arm64
*
* Copyright (C) Linaro.
* Copyright (C) Huawei Futurewei Technologies.
*/
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/page-flags.h>
#include <linux/set_memory.h>
#include <linux/smp.h>
#include <asm/cacheflush.h>
#include <asm/cpu_ops.h>
#include <asm/daifflags.h>
#include <asm/memory.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/page.h>
#include "cpu-reset.h"
/* Global variables for the arm64_relocate_new_kernel routine. */
extern const unsigned char arm64_relocate_new_kernel[];
extern const unsigned long arm64_relocate_new_kernel_size;
/**
* kexec_image_info - For debugging output.
*/
#define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
static void _kexec_image_info(const char *func, int line,
const struct kimage *kimage)
{
unsigned long i;
pr_debug("%s:%d:\n", func, line);
pr_debug(" kexec kimage info:\n");
pr_debug(" type: %d\n", kimage->type);
pr_debug(" start: %lx\n", kimage->start);
pr_debug(" head: %lx\n", kimage->head);
pr_debug(" nr_segments: %lu\n", kimage->nr_segments);
pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);
for (i = 0; i < kimage->nr_segments; i++) {
pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
i,
kimage->segment[i].mem,
kimage->segment[i].mem + kimage->segment[i].memsz,
kimage->segment[i].memsz,
kimage->segment[i].memsz / PAGE_SIZE);
}
}
void machine_kexec_cleanup(struct kimage *kimage)
{
/* Empty routine needed to avoid build errors. */
}
int machine_kexec_post_load(struct kimage *kimage)
{
void *reloc_code = page_to_virt(kimage->control_code_page);
memcpy(reloc_code, arm64_relocate_new_kernel,
arm64_relocate_new_kernel_size);
kimage->arch.kern_reloc = __pa(reloc_code);
kexec_image_info(kimage);
/*
* For execution with the MMU off, reloc_code needs to be cleaned to the
* PoC and invalidated from the I-cache.
*/
dcache_clean_inval_poc((unsigned long)reloc_code,
(unsigned long)reloc_code +
arm64_relocate_new_kernel_size);
icache_inval_pou((uintptr_t)reloc_code,
(uintptr_t)reloc_code +
arm64_relocate_new_kernel_size);
return 0;
}
/**
* machine_kexec_prepare - Prepare for a kexec reboot.
*
* Called from the core kexec code when a kernel image is loaded.
* Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus
* are stuck in the kernel. This avoids a panic once we hit machine_kexec().
*/
int machine_kexec_prepare(struct kimage *kimage)
{
if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
return -EBUSY;
}
return 0;
}
/**
* kexec_list_flush - Helper to flush the kimage list and source pages to PoC.
*/
static void kexec_list_flush(struct kimage *kimage)
{
kimage_entry_t *entry;
for (entry = &kimage->head; ; entry++) {
unsigned int flag;
unsigned long addr;
/* flush the list entries. */
dcache_clean_inval_poc((unsigned long)entry,
(unsigned long)entry +
sizeof(kimage_entry_t));
flag = *entry & IND_FLAGS;
if (flag == IND_DONE)
break;
addr = (unsigned long)phys_to_virt(*entry & PAGE_MASK);
switch (flag) {
case IND_INDIRECTION:
/* Set entry point just before the new list page. */
entry = (kimage_entry_t *)addr - 1;
break;
case IND_SOURCE:
/* flush the source pages. */
dcache_clean_inval_poc(addr, addr + PAGE_SIZE);
break;
case IND_DESTINATION:
break;
default:
BUG();
}
}
}
/**
* kexec_segment_flush - Helper to flush the kimage segments to PoC.
*/
static void kexec_segment_flush(const struct kimage *kimage)
{
unsigned long i;
pr_debug("%s:\n", __func__);
for (i = 0; i < kimage->nr_segments; i++) {
pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
i,
kimage->segment[i].mem,
kimage->segment[i].mem + kimage->segment[i].memsz,
kimage->segment[i].memsz,
kimage->segment[i].memsz / PAGE_SIZE);
dcache_clean_inval_poc(
(unsigned long)phys_to_virt(kimage->segment[i].mem),
(unsigned long)phys_to_virt(kimage->segment[i].mem) +
kimage->segment[i].memsz);
}
}
/**
* machine_kexec - Do the kexec reboot.
*
* Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
*/
void machine_kexec(struct kimage *kimage)
{
bool in_kexec_crash = (kimage == kexec_crash_image);
bool stuck_cpus = cpus_are_stuck_in_kernel();
/*
* New cpus may have become stuck_in_kernel after we loaded the image.
*/
BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
"Some CPUs may be stale, kdump will be unreliable.\n");
/* Flush the kimage list and its buffers. */
kexec_list_flush(kimage);
/* Flush the new image if already in place. */
if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE))
kexec_segment_flush(kimage);
pr_info("Bye!\n");
local_daif_mask();
/*
* cpu_soft_restart will shutdown the MMU, disable data caches, then
* transfer control to the kern_reloc which contains a copy of
* the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel
* uses physical addressing to relocate the new image to its final
* position and transfers control to the image entry point when the
* relocation is complete.
* In kexec case, kimage->start points to purgatory assuming that
* kernel entry and dtb address are embedded in purgatory by
* userspace (kexec-tools).
* In kexec_file case, the kernel starts directly without purgatory.
*/
cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start,
kimage->arch.dtb_mem);
BUG(); /* Should never get here. */
}
static void machine_kexec_mask_interrupts(void)
{
unsigned int i;
struct irq_desc *desc;
for_each_irq_desc(i, desc) {
struct irq_chip *chip;
int ret;
chip = irq_desc_get_chip(desc);
if (!chip)
continue;
/*
* First try to remove the active state. If this
* fails, try to EOI the interrupt.
*/
ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
if (ret && irqd_irq_inprogress(&desc->irq_data) &&
chip->irq_eoi)
chip->irq_eoi(&desc->irq_data);
if (chip->irq_mask)
chip->irq_mask(&desc->irq_data);
if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
chip->irq_disable(&desc->irq_data);
}
}
/**
* machine_crash_shutdown - shutdown non-crashing cpus and save registers
*/
void machine_crash_shutdown(struct pt_regs *regs)
{
local_irq_disable();
/* shutdown non-crashing cpus */
crash_smp_send_stop();
/* for crashing cpu */
crash_save_cpu(regs, smp_processor_id());
machine_kexec_mask_interrupts();
pr_info("Starting crashdump kernel...\n");
}
void arch_kexec_protect_crashkres(void)
{
int i;
kexec_segment_flush(kexec_crash_image);
for (i = 0; i < kexec_crash_image->nr_segments; i++)
set_memory_valid(
__phys_to_virt(kexec_crash_image->segment[i].mem),
kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0);
}
void arch_kexec_unprotect_crashkres(void)
{
int i;
for (i = 0; i < kexec_crash_image->nr_segments; i++)
set_memory_valid(
__phys_to_virt(kexec_crash_image->segment[i].mem),
kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1);
}
#ifdef CONFIG_HIBERNATION
/*
* To preserve the crash dump kernel image, the relevant memory segments
* should be mapped again around the hibernation.
*/
void crash_prepare_suspend(void)
{
if (kexec_crash_image)
arch_kexec_unprotect_crashkres();
}
void crash_post_resume(void)
{
if (kexec_crash_image)
arch_kexec_protect_crashkres();
}
/*
* crash_is_nosave
*
* Return true only if a page is part of reserved memory for crash dump kernel,
* but does not hold any data of loaded kernel image.
*
* Note that all the pages in crash dump kernel memory have been initially
* marked as Reserved as memory was allocated via memblock_reserve().
*
* In hibernation, the pages which are Reserved and yet "nosave" are excluded
* from the hibernation iamge. crash_is_nosave() does thich check for crash
* dump kernel and will reduce the total size of hibernation image.
*/
bool crash_is_nosave(unsigned long pfn)
{
int i;
phys_addr_t addr;
if (!crashk_res.end)
return false;
/* in reserved memory? */
addr = __pfn_to_phys(pfn);
if ((addr < crashk_res.start) || (crashk_res.end < addr))
return false;
if (!kexec_crash_image)
return true;
/* not part of loaded kernel image? */
for (i = 0; i < kexec_crash_image->nr_segments; i++)
if (addr >= kexec_crash_image->segment[i].mem &&
addr < (kexec_crash_image->segment[i].mem +
kexec_crash_image->segment[i].memsz))
return false;
return true;
}
void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
{
unsigned long addr;
struct page *page;
for (addr = begin; addr < end; addr += PAGE_SIZE) {
page = phys_to_page(addr);
free_reserved_page(page);
}
}
#endif /* CONFIG_HIBERNATION */