On kexec, the target kernel has to know what memory has been accepted.
Information in EFI map is out of date and cannot be used.
boot_params.unaccepted_memory can be used to pass the bitmap between two
kernels on kexec, but the use-case is not yet implemented.
Disable kexec on machines with unaccepted memory for now.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kexec.h | 5 +++++
arch/x86/mm/unaccepted_memory.c | 16 ++++++++++++++++
include/linux/kexec.h | 7 +++++++
kernel/kexec.c | 4 ++++
kernel/kexec_file.c | 4 ++++
5 files changed, 36 insertions(+)
diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index a3760ca796aa..87abab578154 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -189,6 +189,11 @@ extern void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages);
void arch_kexec_protect_crashkres(void);
#define arch_kexec_protect_crashkres arch_kexec_protect_crashkres
+#ifdef CONFIG_UNACCEPTED_MEMORY
+int arch_kexec_load(void);
+#define arch_kexec_load arch_kexec_load
+#endif
+
void arch_kexec_unprotect_crashkres(void);
#define arch_kexec_unprotect_crashkres arch_kexec_unprotect_crashkres
diff --git a/arch/x86/mm/unaccepted_memory.c b/arch/x86/mm/unaccepted_memory.c
index a0a58486eb74..1745e6a65024 100644
--- a/arch/x86/mm/unaccepted_memory.c
+++ b/arch/x86/mm/unaccepted_memory.c
@@ -1,4 +1,5 @@
// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kexec.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/pfn.h>
@@ -98,3 +99,18 @@ bool range_contains_unaccepted_memory(phys_addr_t start, phys_addr_t end)
return ret;
}
+
+#ifdef CONFIG_KEXEC_CORE
+int arch_kexec_load(void)
+{
+ if (!boot_params.unaccepted_memory)
+ return 0;
+
+ /*
+ * TODO: Information on memory acceptance status has to be communicated
+ * between kernel.
+ */
+ pr_warn_once("Disable kexec: not yet supported on systems with unaccepted memory\n");
+ return -EOPNOTSUPP;
+}
+#endif
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 41a686996aaa..6b75051d5271 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -444,6 +444,13 @@ static inline void arch_kexec_protect_crashkres(void) { }
static inline void arch_kexec_unprotect_crashkres(void) { }
#endif
+#ifndef arch_kexec_load
+static inline int arch_kexec_load(void)
+{
+ return 0;
+}
+#endif
+
#ifndef page_to_boot_pfn
static inline unsigned long page_to_boot_pfn(struct page *page)
{
diff --git a/kernel/kexec.c b/kernel/kexec.c
index cb8e6e6f983c..65dff44b487f 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -192,6 +192,10 @@ static inline int kexec_load_check(unsigned long nr_segments,
{
int result;
+ result = arch_kexec_load();
+ if (result)
+ return result;
+
/* We only trust the superuser with rebooting the system. */
if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
return -EPERM;
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 45637511e0de..8f1454c3776a 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -329,6 +329,10 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
int ret = 0, i;
struct kimage **dest_image, *image;
+ ret = arch_kexec_load();
+ if (ret)
+ return ret;
+
/* We only trust the superuser with rebooting the system. */
if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
return -EPERM;
--
2.38.0
