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