@@ -210,15 +210,8 @@ extern void kdump_nmi_shootdown_cpus(void);
void arch_crash_handle_hotplug_event(struct kimage *image, void *arg);
#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
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags);
+#define arch_crash_hotplug_support arch_crash_hotplug_support
unsigned int arch_crash_get_elfcorehdr_size(void);
#define crash_get_elfcorehdr_size arch_crash_get_elfcorehdr_size
@@ -402,20 +402,26 @@ int crash_load_segments(struct kimage *image)
#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)
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
{
- return crash_check_update_elfcorehdr();
-}
-#endif
-#ifdef CONFIG_MEMORY_HOTPLUG
-int arch_crash_hotplug_memory_support(void)
-{
- return crash_check_update_elfcorehdr();
-}
+#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)
{
@@ -306,7 +306,7 @@ static ssize_t crash_hotplug_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
- return sysfs_emit(buf, "%d\n", crash_hotplug_cpu_support());
+ return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
}
static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
#endif
@@ -535,7 +535,7 @@ static DEVICE_ATTR_RW(auto_online_blocks);
static ssize_t crash_hotplug_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- return sysfs_emit(buf, "%d\n", crash_hotplug_memory_support());
+ return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
}
static DEVICE_ATTR_RO(crash_hotplug);
#endif
@@ -40,14 +40,13 @@ static inline void arch_kexec_unprotect_crashkres(void) { }
static inline void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) { }
#endif
-int crash_check_update_elfcorehdr(void);
+int crash_check_hotplug_support(void);
-#ifndef crash_hotplug_cpu_support
-static inline int crash_hotplug_cpu_support(void) { return 0; }
-#endif
-
-#ifndef crash_hotplug_memory_support
-static inline int crash_hotplug_memory_support(void) { return 0; }
+#ifndef arch_crash_hotplug_support
+static inline int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
+{
+ return 0;
+}
#endif
#ifndef crash_get_elfcorehdr_size
@@ -319,8 +319,10 @@ struct kimage {
/* If set, we are using file mode kexec syscall */
unsigned int file_mode:1;
#ifdef CONFIG_CRASH_HOTPLUG
- /* If set, allow changes to elfcorehdr of kexec_load'd image */
- unsigned int update_elfcorehdr:1;
+ /* If set, it is safe to update kexec segments that are
+ * excluded from SHA calculation.
+ */
+ unsigned int hotplug_support:1;
#endif
#ifdef ARCH_HAS_KIMAGE_ARCH
@@ -391,9 +393,10 @@ bool kexec_load_permitted(int kexec_image_type);
/* List of defined/legal kexec flags */
#ifndef CONFIG_KEXEC_JUMP
-#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR)
+#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_UPDATE_ELFCOREHDR | KEXEC_CRASH_HOTPLUG_SUPPORT)
#else
-#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_UPDATE_ELFCOREHDR)
+#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_UPDATE_ELFCOREHDR | \
+ KEXEC_CRASH_HOTPLUG_SUPPORT)
#endif
/* List of defined/legal kexec file flags */
@@ -13,6 +13,7 @@
#define KEXEC_ON_CRASH 0x00000001
#define KEXEC_PRESERVE_CONTEXT 0x00000002
#define KEXEC_UPDATE_ELFCOREHDR 0x00000004
+#define KEXEC_CRASH_HOTPLUG_SUPPORT 0x00000008
#define KEXEC_ARCH_MASK 0xffff0000
/*
@@ -493,10 +493,10 @@ static DEFINE_MUTEX(__crash_hotplug_lock);
/*
* This routine utilized when the crash_hotplug sysfs node is read.
- * It reflects the kernel's ability/permission to update the crash
- * elfcorehdr directly.
+ * It reflects the kernel's ability/permission to update the kdump
+ * image directly.
*/
-int crash_check_update_elfcorehdr(void)
+int crash_check_hotplug_support(void)
{
int rc = 0;
@@ -508,10 +508,7 @@ int crash_check_update_elfcorehdr(void)
return 0;
}
if (kexec_crash_image) {
- if (kexec_crash_image->file_mode)
- rc = 1;
- else
- rc = kexec_crash_image->update_elfcorehdr;
+ rc = kexec_crash_image->hotplug_support;
}
/* Release lock now that update complete */
kexec_unlock();
@@ -552,8 +549,8 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu,
image = kexec_crash_image;
- /* Check that updating elfcorehdr is permitted */
- if (!(image->file_mode || image->update_elfcorehdr))
+ /* Check that kexec segments update is permitted */
+ if (!image->hotplug_support)
goto out;
if (hp_action == KEXEC_CRASH_HP_ADD_CPU ||
@@ -135,8 +135,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
image->preserve_context = 1;
#ifdef CONFIG_CRASH_HOTPLUG
- if (flags & KEXEC_UPDATE_ELFCOREHDR)
- image->update_elfcorehdr = 1;
+ if ((flags & KEXEC_ON_CRASH) && arch_crash_hotplug_support(image, flags))
+ image->hotplug_support = 1;
#endif
ret = machine_kexec_prepare(image);
@@ -376,6 +376,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
if (ret)
goto out;
+#ifdef CONFIG_CRASH_HOTPLUG
+ if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags))
+ image->hotplug_support = 1;
+#endif
+
ret = machine_kexec_prepare(image);
if (ret)
goto out;
Commit a72bbec70da2 ("crash: hotplug support for kexec_load()") introduced a new kexec flag, `KEXEC_UPDATE_ELFCOREHDR`. Kexec tool uses this flag to indicate to the kernel that it is safe to modify the elfcorehdr of the kdump image loaded using the kexec_load system call. However, it is possible that architectures may need to update kexec segments other then elfcorehdr. For example, FDT (Flatten Device Tree) on PowerPC. Introducing a new kexec flag for every new kexec segment may not be a good solution. Hence, a generic kexec flag bit, `KEXEC_CRASH_HOTPLUG_SUPPORT`, is introduced to share the CPU/Memory hotplug support intent between the kexec tool and the kernel for the kexec_load system call. Now we have two kexec flags that enables crash hotplug support for kexec_load system call. First is KEXEC_UPDATE_ELFCOREHDR (only used in x86), and second is KEXEC_CRASH_HOTPLUG_SUPPORT (for all architectures). To simplify the process of finding and reporting the crash hotplug support the following changes are introduced. 1. Define arch specific function to process the kexec flags and determine crash hotplug support 2. Rename the @update_elfcorehdr member of struct kimage to @hotplug_support and populate it for both kexec_load and kexec_file_load syscalls, because architecture can update more than one kexec segment 3. Let generic function crash_check_hotplug_support report hotplug support for loaded kdump image based on value of @hotplug_support To bring the x86 crash hotplug support in line with the above points, the following changes have been made: - Introduce the arch_crash_hotplug_support function to process kexec flags and determine crash hotplug support - Remove the arch_crash_hotplug_[cpu|memory]_support functions Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Acked-by: Hari Bathini <hbathini@linux.ibm.com> Cc: Akhil Raj <lf32.dev@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Young <dyoung@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric DeVolder <eric.devolder@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Laurent Dufour <laurent.dufour@fr.ibm.com> Cc: Mahesh Salgaonkar <mahesh@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mimi Zohar <zohar@linux.ibm.com> Cc: Naveen N Rao <naveen@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: kexec@lists.infradead.org Cc: x86@kernel.org --- Changes in v18: * Describe x86 changes in commit message * Update comment of crash_check_hotplug_support() arch/x86/include/asm/kexec.h | 11 ++--------- arch/x86/kernel/crash.c | 28 +++++++++++++++++----------- drivers/base/cpu.c | 2 +- drivers/base/memory.c | 2 +- include/linux/crash_core.h | 13 ++++++------- include/linux/kexec.h | 11 +++++++---- include/uapi/linux/kexec.h | 1 + kernel/crash_core.c | 15 ++++++--------- kernel/kexec.c | 4 ++-- kernel/kexec_file.c | 5 +++++ 10 files changed, 48 insertions(+), 44 deletions(-)