1 files changed, 252 insertions, 165 deletions

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index c8b07d8ea5a2..335fd2ee9766 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Architecture specific (i386/x86_64) functions for kexec based crash dumps.
  *
@@ -23,7 +24,9 @@
 #include <linux/export.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/memblock.h>
 
+#include <asm/bootparam.h>
 #include <asm/processor.h>
 #include <asm/hardirq.h>
 #include <asm/nmi.h>
@@ -35,9 +38,10 @@
 #include <linux/kdebug.h>
 #include <asm/cpu.h>
 #include <asm/reboot.h>
-#include <asm/virtext.h>
 #include <asm/intel_pt.h>
 #include <asm/crash.h>
+#include <asm/cmdline.h>
+#include <asm/sev.h>
 
 /* Used while preparing memory map entries for second kernel */
 struct crash_memmap_data {
@@ -46,61 +50,19 @@ struct crash_memmap_data {
 	unsigned int type;
 };
 
-/*
- * This is used to VMCLEAR all VMCSs loaded on the
- * processor. And when loading kvm_intel module, the
- * callback function pointer will be assigned.
- *
- * protected by rcu.
- */
-crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss = NULL;
-EXPORT_SYMBOL_GPL(crash_vmclear_loaded_vmcss);
-unsigned long crash_zero_bytes;
-
-static inline void cpu_crash_vmclear_loaded_vmcss(void)
-{
-	crash_vmclear_fn *do_vmclear_operation = NULL;
-
-	rcu_read_lock();
-	do_vmclear_operation = rcu_dereference(crash_vmclear_loaded_vmcss);
-	if (do_vmclear_operation)
-		do_vmclear_operation();
-	rcu_read_unlock();
-}
-
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 
 static void kdump_nmi_callback(int cpu, struct pt_regs *regs)
 {
-#ifdef CONFIG_X86_32
-	struct pt_regs fixed_regs;
-
-	if (!user_mode(regs)) {
-		crash_fixup_ss_esp(&fixed_regs, regs);
-		regs = &fixed_regs;
-	}
-#endif
 	crash_save_cpu(regs, cpu);
 
 	/*
-	 * VMCLEAR VMCSs loaded on all cpus if needed.
-	 */
-	cpu_crash_vmclear_loaded_vmcss();
-
-	/* Disable VMX or SVM if needed.
-	 *
-	 * We need to disable virtualization on all CPUs.
-	 * Having VMX or SVM enabled on any CPU may break rebooting
-	 * after the kdump kernel has finished its task.
-	 */
-	cpu_emergency_vmxoff();
-	cpu_emergency_svm_disable();
-
-	/*
 	 * Disable Intel PT to stop its logging
 	 */
 	cpu_emergency_stop_pt();
 
+	kdump_sev_callback();
+
 	disable_local_APIC();
 }
 
@@ -149,17 +111,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 
 	crash_smp_send_stop();
 
-	/*
-	 * VMCLEAR VMCSs loaded on this cpu if needed.
-	 */
-	cpu_crash_vmclear_loaded_vmcss();
-
-	/* Booting kdump kernel with VMX or SVM enabled won't work,
-	 * because (among other limitations) we can't disable paging
-	 * with the virt flags.
-	 */
-	cpu_emergency_vmxoff();
-	cpu_emergency_svm_disable();
+	cpu_emergency_disable_virtualization();
 
 	/*
 	 * Disable Intel PT to stop its logging
@@ -176,10 +128,22 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 #ifdef CONFIG_HPET_TIMER
 	hpet_disable();
 #endif
-	crash_save_cpu(regs, safe_smp_processor_id());
+
+	/*
+	 * Non-crash kexec calls enc_kexec_begin() while scheduling is still
+	 * active. This allows the callback to wait until all in-flight
+	 * shared<->private conversions are complete. In a crash scenario,
+	 * enc_kexec_begin() gets called after all but one CPU have been shut
+	 * down and interrupts have been disabled. This allows the callback to
+	 * detect a race with the conversion and report it.
+	 */
+	x86_platform.guest.enc_kexec_begin();
+	x86_platform.guest.enc_kexec_finish();
+
+	crash_save_cpu(regs, smp_processor_id());
 }
 
-#ifdef CONFIG_KEXEC_FILE
+#if defined(CONFIG_KEXEC_FILE) || defined(CONFIG_CRASH_HOTPLUG)
 static int get_nr_ram_ranges_callback(struct resource *res, void *arg)
 {
 	unsigned int *nr_ranges = arg;
@@ -194,23 +158,30 @@ static struct crash_mem *fill_up_crash_elf_data(void)
 	unsigned int nr_ranges = 0;
 	struct crash_mem *cmem;
 
-	walk_system_ram_res(0, -1, &nr_ranges,
-				get_nr_ram_ranges_callback);
+	walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);
 	if (!nr_ranges)
 		return NULL;
 
 	/*
-	 * Exclusion of crash region and/or crashk_low_res may cause
-	 * another range split. So add extra two slots here.
+	 * Exclusion of crash region, crashk_low_res and/or crashk_cma_ranges
+	 * may cause range splits. So add extra slots here.
+	 *
+	 * Exclusion of low 1M may not cause another range split, because the
+	 * range of exclude is [0, 1M] and the condition for splitting a new
+	 * region is that the start, end parameters are both in a certain
+	 * existing region in cmem and cannot be equal to existing region's
+	 * start or end. Obviously, the start of [0, 1M] cannot meet this
+	 * condition.
+	 *
+	 * But in order to lest the low 1M could be changed in the future,
+	 * (e.g. [start, 1M]), add a extra slot.
 	 */
-	nr_ranges += 2;
-	cmem = vzalloc(sizeof(struct crash_mem) +
-			sizeof(struct crash_mem_range) * nr_ranges);
+	nr_ranges += 3 + crashk_cma_cnt;
+	cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
 	if (!cmem)
 		return NULL;
 
 	cmem->max_nr_ranges = nr_ranges;
-	cmem->nr_ranges = 0;
 
 	return cmem;
 }
@@ -222,20 +193,32 @@ static struct crash_mem *fill_up_crash_elf_data(void)
 static int elf_header_exclude_ranges(struct crash_mem *cmem)
 {
 	int ret = 0;
+	int i;
+
+	/* Exclude the low 1M because it is always reserved */
+	ret = crash_exclude_mem_range(cmem, 0, SZ_1M - 1);
+	if (ret)
+		return ret;
 
 	/* Exclude crashkernel region */
 	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
 	if (ret)
 		return ret;
 
-	if (crashk_low_res.end) {
+	if (crashk_low_res.end)
 		ret = crash_exclude_mem_range(cmem, crashk_low_res.start,
-							crashk_low_res.end);
+					      crashk_low_res.end);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < crashk_cma_cnt; ++i) {
+		ret = crash_exclude_mem_range(cmem, crashk_cma_ranges[i].start,
+					      crashk_cma_ranges[i].end);
 		if (ret)
 			return ret;
 	}
 
-	return ret;
+	return 0;
 }
 
 static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
@@ -250,20 +233,17 @@ static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)
 }
 
 /* Prepare elf headers. Return addr and size */
-static int prepare_elf_headers(struct kimage *image, void **addr,
-					unsigned long *sz)
+static int prepare_elf_headers(void **addr, unsigned long *sz,
+			       unsigned long *nr_mem_ranges)
 {
 	struct crash_mem *cmem;
-	Elf64_Ehdr *ehdr;
-	Elf64_Phdr *phdr;
-	int ret, i;
+	int ret;
 
 	cmem = fill_up_crash_elf_data();
 	if (!cmem)
 		return -ENOMEM;
 
-	ret = walk_system_ram_res(0, -1, cmem,
-				prepare_elf64_ram_headers_callback);
+	ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);
 	if (ret)
 		goto out;
 
@@ -272,30 +252,19 @@ static int prepare_elf_headers(struct kimage *image, void **addr,
 	if (ret)
 		goto out;
 
+	/* Return the computed number of memory ranges, for hotplug usage */
+	*nr_mem_ranges = cmem->nr_ranges;
+
 	/* By default prepare 64bit headers */
-	ret =  crash_prepare_elf64_headers(cmem,
-				IS_ENABLED(CONFIG_X86_64), addr, sz);
-	if (ret)
-		goto out;
+	ret = crash_prepare_elf64_headers(cmem, IS_ENABLED(CONFIG_X86_64), addr, sz);
 
-	/*
-	 * If a range matches backup region, adjust offset to backup
-	 * segment.
-	 */
-	ehdr = (Elf64_Ehdr *)*addr;
-	phdr = (Elf64_Phdr *)(ehdr + 1);
-	for (i = 0; i < ehdr->e_phnum; phdr++, i++)
-		if (phdr->p_type == PT_LOAD &&
-				phdr->p_paddr == image->arch.backup_src_start &&
-				phdr->p_memsz == image->arch.backup_src_sz) {
-			phdr->p_offset = image->arch.backup_load_addr;
-			break;
-		}
 out:
 	vfree(cmem);
 	return ret;
 }
+#endif
 
+#ifdef CONFIG_KEXEC_FILE
 static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
 {
 	unsigned int nr_e820_entries;
@@ -304,8 +273,7 @@ static int add_e820_entry(struct boot_params *params, struct e820_entry *entry)
 	if (nr_e820_entries >= E820_MAX_ENTRIES_ZEROPAGE)
 		return 1;
 
-	memcpy(&params->e820_table[nr_e820_entries], entry,
-			sizeof(struct e820_entry));
+	memcpy(&params->e820_table[nr_e820_entries], entry, sizeof(struct e820_entry));
 	params->e820_entries++;
 	return 0;
 }
@@ -329,69 +297,92 @@ static int memmap_exclude_ranges(struct kimage *image, struct crash_mem *cmem,
 				 unsigned long long mend)
 {
 	unsigned long start, end;
-	int ret = 0;
+	int ret;
 
 	cmem->ranges[0].start = mstart;
 	cmem->ranges[0].end = mend;
 	cmem->nr_ranges = 1;
 
-	/* Exclude Backup region */
-	start = image->arch.backup_load_addr;
-	end = start + image->arch.backup_src_sz - 1;
+	/* Exclude elf header region */
+	start = image->elf_load_addr;
+	end = start + image->elf_headers_sz - 1;
 	ret = crash_exclude_mem_range(cmem, start, end);
+
 	if (ret)
 		return ret;
 
-	/* Exclude elf header region */
-	start = image->arch.elf_load_addr;
-	end = start + image->arch.elf_headers_sz - 1;
-	return crash_exclude_mem_range(cmem, start, end);
+	/* Exclude dm crypt keys region */
+	if (image->dm_crypt_keys_addr) {
+		start = image->dm_crypt_keys_addr;
+		end = start + image->dm_crypt_keys_sz - 1;
+		return crash_exclude_mem_range(cmem, start, end);
+	}
+
+	return ret;
 }
 
 /* Prepare memory map for crash dump kernel */
 int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 {
+	unsigned int nr_ranges = 0;
 	int i, ret = 0;
 	unsigned long flags;
 	struct e820_entry ei;
 	struct crash_memmap_data cmd;
 	struct crash_mem *cmem;
 
-	cmem = vzalloc(sizeof(struct crash_mem));
+	/*
+	 * In the current x86 architecture code, the elfheader is always
+	 * allocated at crashk_res.start. But it depends on the allocation
+	 * position of elfheader in crashk_res. To avoid potential out of
+	 * bounds in future, add an extra slot.
+	 *
+	 * And using random kexec_buf for passing dm crypt keys may cause a
+	 * range split too, add another extra slot here.
+	 */
+	nr_ranges = 3;
+	cmem = vzalloc(struct_size(cmem, ranges, nr_ranges));
 	if (!cmem)
 		return -ENOMEM;
 
+	cmem->max_nr_ranges = nr_ranges;
+
 	memset(&cmd, 0, sizeof(struct crash_memmap_data));
 	cmd.params = params;
 
-	/* Add first 640K segment */
-	ei.addr = image->arch.backup_src_start;
-	ei.size = image->arch.backup_src_sz;
-	ei.type = E820_TYPE_RAM;
-	add_e820_entry(params, &ei);
+	/* Add the low 1M */
+	cmd.type = E820_TYPE_RAM;
+	flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+	walk_iomem_res_desc(IORES_DESC_NONE, flags, 0, (1<<20)-1, &cmd,
+			    memmap_entry_callback);
 
 	/* Add ACPI tables */
 	cmd.type = E820_TYPE_ACPI;
 	flags = IORESOURCE_MEM | IORESOURCE_BUSY;
 	walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1, &cmd,
-		       memmap_entry_callback);
+			    memmap_entry_callback);
 
 	/* Add ACPI Non-volatile Storage */
 	cmd.type = E820_TYPE_NVS;
 	walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
-			memmap_entry_callback);
+			    memmap_entry_callback);
+
+	/* Add e820 reserved ranges */
+	cmd.type = E820_TYPE_RESERVED;
+	flags = IORESOURCE_MEM;
+	walk_iomem_res_desc(IORES_DESC_RESERVED, flags, 0, -1, &cmd,
+			    memmap_entry_callback);
 
 	/* Add crashk_low_res region */
 	if (crashk_low_res.end) {
 		ei.addr = crashk_low_res.start;
-		ei.size = crashk_low_res.end - crashk_low_res.start + 1;
+		ei.size = resource_size(&crashk_low_res);
 		ei.type = E820_TYPE_RAM;
 		add_e820_entry(params, &ei);
 	}
 
 	/* Exclude some ranges from crashk_res and add rest to memmap */
-	ret = memmap_exclude_ranges(image, cmem, crashk_res.start,
-						crashk_res.end);
+	ret = memmap_exclude_ranges(image, cmem, crashk_res.start, crashk_res.end);
 	if (ret)
 		goto out;
 
@@ -406,79 +397,175 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 		add_e820_entry(params, &ei);
 	}
 
+	for (i = 0; i < crashk_cma_cnt; ++i) {
+		ei.addr = crashk_cma_ranges[i].start;
+		ei.size = crashk_cma_ranges[i].end -
+			  crashk_cma_ranges[i].start + 1;
+		ei.type = E820_TYPE_RAM;
+		add_e820_entry(params, &ei);
+	}
+
 out:
 	vfree(cmem);
 	return ret;
 }
 
-static int determine_backup_region(struct resource *res, void *arg)
-{
-	struct kimage *image = arg;
-
-	image->arch.backup_src_start = res->start;
-	image->arch.backup_src_sz = resource_size(res);
-
-	/* Expecting only one range for backup region */
-	return 1;
-}
-
 int crash_load_segments(struct kimage *image)
 {
 	int ret;
+	unsigned long pnum = 0;
 	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
 				  .buf_max = ULONG_MAX, .top_down = false };
 
+	/* Prepare elf headers and add a segment */
+	ret = prepare_elf_headers(&kbuf.buffer, &kbuf.bufsz, &pnum);
+	if (ret)
+		return ret;
+
+	image->elf_headers	= kbuf.buffer;
+	image->elf_headers_sz	= kbuf.bufsz;
+	kbuf.memsz		= kbuf.bufsz;
+
+#ifdef CONFIG_CRASH_HOTPLUG
 	/*
-	 * Determine and load a segment for backup area. First 640K RAM
-	 * region is backup source
+	 * The elfcorehdr segment size accounts for VMCOREINFO, kernel_map,
+	 * maximum CPUs and maximum memory ranges.
 	 */
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+		pnum = 2 + CONFIG_NR_CPUS_DEFAULT + CONFIG_CRASH_MAX_MEMORY_RANGES;
+	else
+		pnum += 2 + CONFIG_NR_CPUS_DEFAULT;
 
-	ret = walk_system_ram_res(KEXEC_BACKUP_SRC_START, KEXEC_BACKUP_SRC_END,
-				image, determine_backup_region);
+	if (pnum < (unsigned long)PN_XNUM) {
+		kbuf.memsz = pnum * sizeof(Elf64_Phdr);
+		kbuf.memsz += sizeof(Elf64_Ehdr);
 
-	/* Zero or postive return values are ok */
-	if (ret < 0)
-		return ret;
+		image->elfcorehdr_index = image->nr_segments;
 
-	/* Add backup segment. */
-	if (image->arch.backup_src_sz) {
-		kbuf.buffer = &crash_zero_bytes;
-		kbuf.bufsz = sizeof(crash_zero_bytes);
-		kbuf.memsz = image->arch.backup_src_sz;
-		kbuf.buf_align = PAGE_SIZE;
-		/*
-		 * Ideally there is no source for backup segment. This is
-		 * copied in purgatory after crash. Just add a zero filled
-		 * segment for now to make sure checksum logic works fine.
-		 */
-		ret = kexec_add_buffer(&kbuf);
-		if (ret)
-			return ret;
-		image->arch.backup_load_addr = kbuf.mem;
-		pr_debug("Loaded backup region at 0x%lx backup_start=0x%lx memsz=0x%lx\n",
-			 image->arch.backup_load_addr,
-			 image->arch.backup_src_start, kbuf.memsz);
+		/* Mark as usable to crash kernel, else crash kernel fails on boot */
+		image->elf_headers_sz = kbuf.memsz;
+	} else {
+		pr_err("number of Phdrs %lu exceeds max\n", pnum);
 	}
+#endif
 
-	/* Prepare elf headers and add a segment */
-	ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz);
-	if (ret)
-		return ret;
-
-	image->arch.elf_headers = kbuf.buffer;
-	image->arch.elf_headers_sz = kbuf.bufsz;
-
-	kbuf.memsz = kbuf.bufsz;
 	kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 	ret = kexec_add_buffer(&kbuf);
-	if (ret) {
-		vfree((void *)image->arch.elf_headers);
+	if (ret)
 		return ret;
-	}
-	image->arch.elf_load_addr = kbuf.mem;
-	pr_debug("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
-		 image->arch.elf_load_addr, kbuf.bufsz, kbuf.bufsz);
+	image->elf_load_addr = kbuf.mem;
+	kexec_dprintk("Loaded ELF headers at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+		      image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
 
 	return ret;
 }
 #endif /* CONFIG_KEXEC_FILE */
+
+#ifdef CONFIG_CRASH_HOTPLUG
+
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
+{
+
+#ifdef CONFIG_KEXEC_FILE
+	if (image->file_mode)
+		return 1;
+#endif
+	/*
+	 * Initially, crash hotplug support for kexec_load was added
+	 * with the KEXEC_UPDATE_ELFCOREHDR flag. Later, this
+	 * functionality was expanded to accommodate multiple kexec
+	 * segment updates, leading to the introduction of the
+	 * KEXEC_CRASH_HOTPLUG_SUPPORT kexec flag bit. Consequently,
+	 * when the kexec tool sends either of these flags, it indicates
+	 * that the required kexec segment (elfcorehdr) is excluded from
+	 * the SHA calculation.
+	 */
+	return (kexec_flags & KEXEC_UPDATE_ELFCOREHDR ||
+		kexec_flags & KEXEC_CRASH_HOTPLUG_SUPPORT);
+}
+
+unsigned int arch_crash_get_elfcorehdr_size(void)
+{
+	unsigned int sz;
+
+	/* kernel_map, VMCOREINFO and maximum CPUs */
+	sz = 2 + CONFIG_NR_CPUS_DEFAULT;
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+		sz += CONFIG_CRASH_MAX_MEMORY_RANGES;
+	sz *= sizeof(Elf64_Phdr);
+	return sz;
+}
+
+/**
+ * arch_crash_handle_hotplug_event() - Handle hotplug elfcorehdr changes
+ * @image: a pointer to kexec_crash_image
+ * @arg: struct memory_notify handler for memory hotplug case and
+ *       NULL for CPU hotplug case.
+ *
+ * Prepare the new elfcorehdr and replace the existing elfcorehdr.
+ */
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
+{
+	void *elfbuf = NULL, *old_elfcorehdr;
+	unsigned long nr_mem_ranges;
+	unsigned long mem, memsz;
+	unsigned long elfsz = 0;
+
+	/*
+	 * As crash_prepare_elf64_headers() has already described all
+	 * possible CPUs, there is no need to update the elfcorehdr
+	 * for additional CPU changes.
+	 */
+	if ((image->file_mode || image->elfcorehdr_updated) &&
+		((image->hp_action == KEXEC_CRASH_HP_ADD_CPU) ||
+		(image->hp_action == KEXEC_CRASH_HP_REMOVE_CPU)))
+		return;
+
+	/*
+	 * Create the new elfcorehdr reflecting the changes to CPU and/or
+	 * memory resources.
+	 */
+	if (prepare_elf_headers(&elfbuf, &elfsz, &nr_mem_ranges)) {
+		pr_err("unable to create new elfcorehdr");
+		goto out;
+	}
+
+	/*
+	 * Obtain address and size of the elfcorehdr segment, and
+	 * check it against the new elfcorehdr buffer.
+	 */
+	mem = image->segment[image->elfcorehdr_index].mem;
+	memsz = image->segment[image->elfcorehdr_index].memsz;
+	if (elfsz > memsz) {
+		pr_err("update elfcorehdr elfsz %lu > memsz %lu",
+			elfsz, memsz);
+		goto out;
+	}
+
+	/*
+	 * Copy new elfcorehdr over the old elfcorehdr at destination.
+	 */
+	old_elfcorehdr = kmap_local_page(pfn_to_page(mem >> PAGE_SHIFT));
+	if (!old_elfcorehdr) {
+		pr_err("mapping elfcorehdr segment failed\n");
+		goto out;
+	}
+
+	/*
+	 * Temporarily invalidate the crash image while the
+	 * elfcorehdr is updated.
+	 */
+	xchg(&kexec_crash_image, NULL);
+	memcpy_flushcache(old_elfcorehdr, elfbuf, elfsz);
+	xchg(&kexec_crash_image, image);
+	kunmap_local(old_elfcorehdr);
+	pr_debug("updated elfcorehdr\n");
+
+out:
+	vfree(elfbuf);
+}
+#endif