Merge tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull non-MM updates from Andrew Morton:

 - An extensive rework of kexec and crash Kconfig from Eric DeVolder
   ("refactor Kconfig to consolidate KEXEC and CRASH options")

 - kernel.h slimming work from Andy Shevchenko ("kernel.h: Split out a
   couple of macros to args.h")

 - gdb feature work from Kuan-Ying Lee ("Add GDB memory helper
   commands")

 - vsprintf inclusion rationalization from Andy Shevchenko
   ("lib/vsprintf: Rework header inclusions")

 - Switch the handling of kdump from a udev scheme to in-kernel
   handling, by Eric DeVolder ("crash: Kernel handling of CPU and memory
   hot un/plug")

 - Many singleton patches to various parts of the tree

* tag 'mm-nonmm-stable-2023-08-28-22-48' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (81 commits)
  document while_each_thread(), change first_tid() to use for_each_thread()
  drivers/char/mem.c: shrink character device's devlist[] array
  x86/crash: optimize CPU changes
  crash: change crash_prepare_elf64_headers() to for_each_possible_cpu()
  crash: hotplug support for kexec_load()
  x86/crash: add x86 crash hotplug support
  crash: memory and CPU hotplug sysfs attributes
  kexec: exclude elfcorehdr from the segment digest
  crash: add generic infrastructure for crash hotplug support
  crash: move a few code bits to setup support of crash hotplug
  kstrtox: consistently use _tolower()
  kill do_each_thread()
  nilfs2: fix WARNING in mark_buffer_dirty due to discarded buffer reuse
  scripts/bloat-o-meter: count weak symbol sizes
  treewide: drop CONFIG_EMBEDDED
  lockdep: fix static memory detection even more
  lib/vsprintf: declare no_hash_pointers in sprintf.h
  lib/vsprintf: split out sprintf() and friends
  kernel/fork: stop playing lockless games for exe_file replacement
  adfs: delete unused "union adfs_dirtail" definition
  ...

10 files changed, 194 insertions, 115 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ad3a53e28aac..bd9a1804cf72 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2006,88 +2006,37 @@ config EFI_RUNTIME_MAP
 
 source "kernel/Kconfig.hz"
 
-config KEXEC
-	bool "kexec system call"
-	select KEXEC_CORE
-	help
-	  kexec is a system call that implements the ability to shutdown your
-	  current kernel, and to start another kernel.  It is like a reboot
-	  but it is independent of the system firmware.   And like a reboot
-	  you can start any kernel with it, not just Linux.
-
-	  The name comes from the similarity to the exec system call.
-
-	  It is an ongoing process to be certain the hardware in a machine
-	  is properly shutdown, so do not be surprised if this code does not
-	  initially work for you.  As of this writing the exact hardware
-	  interface is strongly in flux, so no good recommendation can be
-	  made.
-
-config KEXEC_FILE
-	bool "kexec file based system call"
-	select KEXEC_CORE
-	select HAVE_IMA_KEXEC if IMA
-	depends on X86_64
-	depends on CRYPTO=y
-	depends on CRYPTO_SHA256=y
-	help
-	  This is new version of kexec system call. This system call is
-	  file based and takes file descriptors as system call argument
-	  for kernel and initramfs as opposed to list of segments as
-	  accepted by previous system call.
+config ARCH_SUPPORTS_KEXEC
+	def_bool y
 
-config ARCH_HAS_KEXEC_PURGATORY
-	def_bool KEXEC_FILE
+config ARCH_SUPPORTS_KEXEC_FILE
+	def_bool X86_64 && CRYPTO && CRYPTO_SHA256
 
-config KEXEC_SIG
-	bool "Verify kernel signature during kexec_file_load() syscall"
+config ARCH_SELECTS_KEXEC_FILE
+	def_bool y
 	depends on KEXEC_FILE
-	help
+	select HAVE_IMA_KEXEC if IMA
 
-	  This option makes the kexec_file_load() syscall check for a valid
-	  signature of the kernel image.  The image can still be loaded without
-	  a valid signature unless you also enable KEXEC_SIG_FORCE, though if
-	  there's a signature that we can check, then it must be valid.
+config ARCH_SUPPORTS_KEXEC_PURGATORY
+	def_bool KEXEC_FILE
 
-	  In addition to this option, you need to enable signature
-	  verification for the corresponding kernel image type being
-	  loaded in order for this to work.
+config ARCH_SUPPORTS_KEXEC_SIG
+	def_bool y
 
-config KEXEC_SIG_FORCE
-	bool "Require a valid signature in kexec_file_load() syscall"
-	depends on KEXEC_SIG
-	help
-	  This option makes kernel signature verification mandatory for
-	  the kexec_file_load() syscall.
+config ARCH_SUPPORTS_KEXEC_SIG_FORCE
+	def_bool y
 
-config KEXEC_BZIMAGE_VERIFY_SIG
-	bool "Enable bzImage signature verification support"
-	depends on KEXEC_SIG
-	depends on SIGNED_PE_FILE_VERIFICATION
-	select SYSTEM_TRUSTED_KEYRING
-	help
-	  Enable bzImage signature verification support.
+config ARCH_SUPPORTS_KEXEC_BZIMAGE_VERIFY_SIG
+	def_bool y
 
-config CRASH_DUMP
-	bool "kernel crash dumps"
-	depends on X86_64 || (X86_32 && HIGHMEM)
-	help
-	  Generate crash dump after being started by kexec.
-	  This should be normally only set in special crash dump kernels
-	  which are loaded in the main kernel with kexec-tools into
-	  a specially reserved region and then later executed after
-	  a crash by kdump/kexec. The crash dump kernel must be compiled
-	  to a memory address not used by the main kernel or BIOS using
-	  PHYSICAL_START, or it must be built as a relocatable image
-	  (CONFIG_RELOCATABLE=y).
-	  For more details see Documentation/admin-guide/kdump/kdump.rst
+config ARCH_SUPPORTS_KEXEC_JUMP
+	def_bool y
 
-config KEXEC_JUMP
-	bool "kexec jump"
-	depends on KEXEC && HIBERNATION
-	help
-	  Jump between original kernel and kexeced kernel and invoke
-	  code in physical address mode via KEXEC
+config ARCH_SUPPORTS_CRASH_DUMP
+	def_bool X86_64 || (X86_32 && HIGHMEM)
+
+config ARCH_SUPPORTS_CRASH_HOTPLUG
+	def_bool y
 
 config PHYSICAL_START
 	hex "Physical address where the kernel is loaded" if (EXPERT || CRASH_DUMP)
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 29e083b92813..836c170d3087 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -42,7 +42,7 @@ extern void init_ISA_irqs(void);
 
 #ifdef CONFIG_X86_LOCAL_APIC
 void arch_trigger_cpumask_backtrace(const struct cpumask *mask,
-				    bool exclude_self);
+				    int exclude_cpu);
 
 #define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
 #endif
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 5b77bbc28f96..3be6a98751f0 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -209,6 +209,24 @@ typedef void crash_vmclear_fn(void);
 extern crash_vmclear_fn __rcu *crash_vmclear_loaded_vmcss;
 extern void kdump_nmi_shootdown_cpus(void);
 
+#ifdef CONFIG_CRASH_HOTPLUG
+void arch_crash_handle_hotplug_event(struct kimage *image);
+#define arch_crash_handle_hotplug_event arch_crash_handle_hotplug_event
+
+#ifdef CONFIG_HOTPLUG_CPU
+int arch_crash_hotplug_cpu_support(void);
+#define crash_hotplug_cpu_support arch_crash_hotplug_cpu_support
+#endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_crash_hotplug_memory_support(void);
+#define crash_hotplug_memory_support arch_crash_hotplug_memory_support
+#endif
+
+unsigned int arch_crash_get_elfcorehdr_size(void);
+#define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_KEXEC_H */
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 7fa611216417..4b081e0d3306 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -2,12 +2,7 @@
 #ifndef _ASM_X86_RMWcc
 #define _ASM_X86_RMWcc
 
-/* This counts to 12. Any more, it will return 13th argument. */
-#define __RMWcc_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
-#define RMWcc_ARGS(X...) __RMWcc_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
-
-#define __RMWcc_CONCAT(a, b) a ## b
-#define RMWcc_CONCAT(a, b) __RMWcc_CONCAT(a, b)
+#include <linux/args.h>
 
 #define __CLOBBERS_MEM(clb...)	"memory", ## clb
 
@@ -48,7 +43,7 @@ cc_label:	c = true;						\
 #define GEN_UNARY_RMWcc_3(op, var, cc)					\
 	GEN_UNARY_RMWcc_4(op, var, cc, "%[var]")
 
-#define GEN_UNARY_RMWcc(X...) RMWcc_CONCAT(GEN_UNARY_RMWcc_, RMWcc_ARGS(X))(X)
+#define GEN_UNARY_RMWcc(X...)	CONCATENATE(GEN_UNARY_RMWcc_, COUNT_ARGS(X))(X)
 
 #define GEN_BINARY_RMWcc_6(op, var, cc, vcon, _val, arg0)		\
 	__GEN_RMWcc(op " %[val], " arg0, var, cc,			\
@@ -57,7 +52,7 @@ cc_label:	c = true;						\
 #define GEN_BINARY_RMWcc_5(op, var, cc, vcon, val)			\
 	GEN_BINARY_RMWcc_6(op, var, cc, vcon, val, "%[var]")
 
-#define GEN_BINARY_RMWcc(X...) RMWcc_CONCAT(GEN_BINARY_RMWcc_, RMWcc_ARGS(X))(X)
+#define GEN_BINARY_RMWcc(X...)	CONCATENATE(GEN_BINARY_RMWcc_, COUNT_ARGS(X))(X)
 
 #define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, cc, clobbers...)	\
 	__GEN_RMWcc(op " %[var]\n\t" suffix, var, cc,			\
diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h
index a6e8373a5170..3fa87e5e11ab 100644
--- a/arch/x86/include/asm/sections.h
+++ b/arch/x86/include/asm/sections.h
@@ -2,8 +2,6 @@
 #ifndef _ASM_X86_SECTIONS_H
 #define _ASM_X86_SECTIONS_H
 
-#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
-
 #include <asm-generic/sections.h>
 #include <asm/extable.h>
 
@@ -18,20 +16,4 @@ extern char __end_of_kernel_reserve[];
 
 extern unsigned long _brk_start, _brk_end;
 
-static inline bool arch_is_kernel_initmem_freed(unsigned long addr)
-{
-	/*
-	 * If _brk_start has not been cleared, brk allocation is incomplete,
-	 * and we can not make assumptions about its use.
-	 */
-	if (_brk_start)
-		return 0;
-
-	/*
-	 * After brk allocation is complete, space between _brk_end and _end
-	 * is available for allocation.
-	 */
-	return addr >= _brk_end && addr < (unsigned long)&_end;
-}
-
 #endif	/* _ASM_X86_SECTIONS_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 4070a01c11b7..00df34c263cc 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -33,11 +33,10 @@ KCSAN_SANITIZE := n
 KMSAN_SANITIZE_head$(BITS).o				:= n
 KMSAN_SANITIZE_nmi.o					:= n
 
-# If instrumentation of this dir is enabled, boot hangs during first second.
-# Probably could be more selective here, but note that files related to irqs,
-# boot, dumpstack/stacktrace, etc are either non-interesting or can lead to
-# non-deterministic coverage.
-KCOV_INSTRUMENT		:= n
+# If instrumentation of the following files is enabled, boot hangs during
+# first second.
+KCOV_INSTRUMENT_head$(BITS).o				:= n
+KCOV_INSTRUMENT_sev.o					:= n
 
 CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
 
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 34a992e275ef..d6e01f924299 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -34,9 +34,9 @@ static void nmi_raise_cpu_backtrace(cpumask_t *mask)
 	apic->send_IPI_mask(mask, NMI_VECTOR);
 }
 
-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
+void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
 {
-	nmi_trigger_cpumask_backtrace(mask, exclude_self,
+	nmi_trigger_cpumask_backtrace(mask, exclude_cpu,
 				      nmi_raise_cpu_backtrace);
 }
 
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index cdd92ab43cda..587c7743fd21 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -158,8 +158,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs)
 	crash_save_cpu(regs, safe_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;
@@ -231,7 +230,7 @@ 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)
+					unsigned long *sz, unsigned long *nr_mem_ranges)
 {
 	struct crash_mem *cmem;
 	int ret;
@@ -249,6 +248,9 @@ 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);
 
@@ -256,7 +258,9 @@ 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;
@@ -371,18 +375,42 @@ out:
 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(image, &kbuf.buffer, &kbuf.bufsz);
+	ret = prepare_elf_headers(image, &kbuf.buffer, &kbuf.bufsz, &pnum);
 	if (ret)
 		return ret;
 
-	image->elf_headers = kbuf.buffer;
-	image->elf_headers_sz = kbuf.bufsz;
+	image->elf_headers	= kbuf.buffer;
+	image->elf_headers_sz	= kbuf.bufsz;
+	kbuf.memsz		= kbuf.bufsz;
+
+#ifdef CONFIG_CRASH_HOTPLUG
+	/*
+	 * 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;
+
+	if (pnum < (unsigned long)PN_XNUM) {
+		kbuf.memsz = pnum * sizeof(Elf64_Phdr);
+		kbuf.memsz += sizeof(Elf64_Ehdr);
+
+		image->elfcorehdr_index = image->nr_segments;
+
+		/* 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
 
-	kbuf.memsz = kbuf.bufsz;
 	kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
 	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 	ret = kexec_add_buffer(&kbuf);
@@ -395,3 +423,103 @@ int crash_load_segments(struct kimage *image)
 	return ret;
 }
 #endif /* CONFIG_KEXEC_FILE */
+
+#ifdef CONFIG_CRASH_HOTPLUG
+
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+/* These functions provide the value for the sysfs crash_hotplug nodes */
+#ifdef CONFIG_HOTPLUG_CPU
+int arch_crash_hotplug_cpu_support(void)
+{
+	return crash_check_update_elfcorehdr();
+}
+#endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_crash_hotplug_memory_support(void)
+{
+	return crash_check_update_elfcorehdr();
+}
+#endif
+
+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
+ *
+ * Prepare the new elfcorehdr and replace the existing elfcorehdr.
+ */
+void arch_crash_handle_hotplug_event(struct kimage *image)
+{
+	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(image, &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
diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
index dd40d3fea74e..631512f7ec85 100644
--- a/arch/x86/pci/amd_bus.c
+++ b/arch/x86/pci/amd_bus.c
@@ -51,6 +51,14 @@ static struct pci_root_info __init *find_pci_root_info(int node, int link)
 	return NULL;
 }
 
+static inline resource_size_t cap_resource(u64 val)
+{
+	if (val > RESOURCE_SIZE_MAX)
+		return RESOURCE_SIZE_MAX;
+
+	return val;
+}
+
 /**
  * early_root_info_init()
  * called before pcibios_scan_root and pci_scan_bus
diff --git a/arch/x86/pci/bus_numa.c b/arch/x86/pci/bus_numa.c
index 2752c02e3f0e..e4a525e59eaf 100644
--- a/arch/x86/pci/bus_numa.c
+++ b/arch/x86/pci/bus_numa.c
@@ -101,7 +101,7 @@ void update_res(struct pci_root_info *info, resource_size_t start,
 	if (start > end)
 		return;
 
-	if (start == MAX_RESOURCE)
+	if (start == RESOURCE_SIZE_MAX)
 		return;
 
 	if (!merge)