[PATCH v2 1/3] kexec_load: Use new kexec flag for hotplug support
Sourabh Jain
sourabhjain at linux.ibm.com
Thu Jun 13 12:07:36 PDT 2024
Kernel commit 79365026f869 (crash: add a new kexec flag for hotplug
support) has introduced a new kexec flag to generalize hotplug support.
The newly introduced kexec flags for hotplug allow architectures to
exclude all the required kexec segments from SHA calculation so that
the kernel can update them on hotplug events. This was not possible
earlier with the KEXEC_UPDATE_ELFCOREHDR kexec flags since it was added
only for the elfcorehdr segment.
To enable architectures to control the list of kexec segments to exclude
when hotplug support is enabled, add a new architecture-specific
function named arch_do_exclude_segment. During the SHA calculation, this
function gets called to let the architecture decide whether a specific
kexec segment should be considered for SHA calculation or not.
Given that the KEXEC_UPDATE_ELFCOREHDR is no longer required and was
colliding with the KEXEC_LIVE_UPDATE update flag, it is removed.
Cc: Aditya Gupta <adityag at linux.ibm.com>
Cc: Baoquan He <bhe at redhat.com>
Cc: Coiby Xu <coxu at redhat.com>
Cc: Mahesh Salgaonkar <mahesh at linux.ibm.com>
Cc: Simon Horman <horms at kernel.org>
Acked-by: Hari Bathini <hbathini at linux.ibm.com>
Signed-off-by: Sourabh Jain <sourabhjain at linux.ibm.com>
---
* No changes in v2.
---
kexec/arch/arm/kexec-arm.c | 5 +++++
kexec/arch/arm64/kexec-arm64.c | 4 ++++
kexec/arch/cris/kexec-cris.c | 4 ++++
kexec/arch/hppa/kexec-hppa.c | 5 +++++
kexec/arch/i386/kexec-x86.c | 8 ++++++++
kexec/arch/ia64/kexec-ia64.c | 4 ++++
kexec/arch/loongarch/kexec-loongarch.c | 5 +++++
kexec/arch/m68k/kexec-m68k.c | 5 +++++
kexec/arch/mips/kexec-mips.c | 4 ++++
kexec/arch/ppc/kexec-ppc.c | 4 ++++
kexec/arch/ppc64/kexec-ppc64.c | 5 +++++
kexec/arch/s390/kexec-s390.c | 5 +++++
kexec/arch/sh/kexec-sh.c | 5 +++++
kexec/arch/x86_64/kexec-x86_64.c | 5 +++++
kexec/kexec-syscall.h | 2 +-
kexec/kexec.c | 14 ++++++++------
kexec/kexec.h | 2 ++
17 files changed, 79 insertions(+), 7 deletions(-)
diff --git a/kexec/arch/arm/kexec-arm.c b/kexec/arch/arm/kexec-arm.c
index 49f35b1..34531f9 100644
--- a/kexec/arch/arm/kexec-arm.c
+++ b/kexec/arch/arm/kexec-arm.c
@@ -148,3 +148,8 @@ int have_sysfs_fdt(void)
{
return !access(SYSFS_FDT, F_OK);
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/arm64/kexec-arm64.c b/kexec/arch/arm64/kexec-arm64.c
index 4a67b0d..9d052b0 100644
--- a/kexec/arch/arm64/kexec-arm64.c
+++ b/kexec/arch/arm64/kexec-arm64.c
@@ -1363,3 +1363,7 @@ void arch_reuse_initrd(void)
void arch_update_purgatory(struct kexec_info *UNUSED(info))
{
}
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/cris/kexec-cris.c b/kexec/arch/cris/kexec-cris.c
index 3b69709..7f09121 100644
--- a/kexec/arch/cris/kexec-cris.c
+++ b/kexec/arch/cris/kexec-cris.c
@@ -109,3 +109,7 @@ unsigned long add_buffer(struct kexec_info *info, const void *buf,
buf_min, buf_max, buf_end, 1);
}
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/hppa/kexec-hppa.c b/kexec/arch/hppa/kexec-hppa.c
index 77c9739..a64dc3d 100644
--- a/kexec/arch/hppa/kexec-hppa.c
+++ b/kexec/arch/hppa/kexec-hppa.c
@@ -146,3 +146,8 @@ unsigned long virt_to_phys(unsigned long addr)
{
return addr - phys_offset;
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/i386/kexec-x86.c b/kexec/arch/i386/kexec-x86.c
index 444cb69..b4947a0 100644
--- a/kexec/arch/i386/kexec-x86.c
+++ b/kexec/arch/i386/kexec-x86.c
@@ -208,3 +208,11 @@ void arch_update_purgatory(struct kexec_info *info)
elf_rel_set_symbol(&info->rhdr, "panic_kernel",
&panic_kernel, sizeof(panic_kernel));
}
+
+int arch_do_exclude_segment(struct kexec_segment *seg_ptr, struct kexec_info *info)
+{
+ if (info->elfcorehdr == (unsigned long) seg_ptr->mem)
+ return 1;
+
+ return 0;
+}
diff --git a/kexec/arch/ia64/kexec-ia64.c b/kexec/arch/ia64/kexec-ia64.c
index 418d997..8d9c1f3 100644
--- a/kexec/arch/ia64/kexec-ia64.c
+++ b/kexec/arch/ia64/kexec-ia64.c
@@ -245,3 +245,7 @@ void arch_update_purgatory(struct kexec_info *UNUSED(info))
{
}
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/loongarch/kexec-loongarch.c b/kexec/arch/loongarch/kexec-loongarch.c
index ac75030..ee7b9f1 100644
--- a/kexec/arch/loongarch/kexec-loongarch.c
+++ b/kexec/arch/loongarch/kexec-loongarch.c
@@ -381,3 +381,8 @@ unsigned long add_buffer(struct kexec_info *info, const void *buf,
return add_buffer_phys_virt(info, buf, bufsz, memsz, buf_align,
buf_min, buf_max, buf_end, 1);
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/m68k/kexec-m68k.c b/kexec/arch/m68k/kexec-m68k.c
index cb54927..0c7dbaf 100644
--- a/kexec/arch/m68k/kexec-m68k.c
+++ b/kexec/arch/m68k/kexec-m68k.c
@@ -108,3 +108,8 @@ void add_segment(struct kexec_info *info, const void *buf, size_t bufsz,
{
add_segment_phys_virt(info, buf, bufsz, base, memsz, 1);
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/mips/kexec-mips.c b/kexec/arch/mips/kexec-mips.c
index d8cbea8..94224ee 100644
--- a/kexec/arch/mips/kexec-mips.c
+++ b/kexec/arch/mips/kexec-mips.c
@@ -189,3 +189,7 @@ unsigned long add_buffer(struct kexec_info *info, const void *buf,
buf_min, buf_max, buf_end, 1);
}
+int arch_do_exclude_segment(const void *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/ppc/kexec-ppc.c b/kexec/arch/ppc/kexec-ppc.c
index 03bec36..c8af870 100644
--- a/kexec/arch/ppc/kexec-ppc.c
+++ b/kexec/arch/ppc/kexec-ppc.c
@@ -966,3 +966,7 @@ void arch_update_purgatory(struct kexec_info *UNUSED(info))
{
}
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/ppc64/kexec-ppc64.c b/kexec/arch/ppc64/kexec-ppc64.c
index bd5274c..fb27b6b 100644
--- a/kexec/arch/ppc64/kexec-ppc64.c
+++ b/kexec/arch/ppc64/kexec-ppc64.c
@@ -967,3 +967,8 @@ int arch_compat_trampoline(struct kexec_info *UNUSED(info))
void arch_update_purgatory(struct kexec_info *UNUSED(info))
{
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/s390/kexec-s390.c b/kexec/arch/s390/kexec-s390.c
index 33ba6b9..0561ee7 100644
--- a/kexec/arch/s390/kexec-s390.c
+++ b/kexec/arch/s390/kexec-s390.c
@@ -267,3 +267,8 @@ int get_crash_kernel_load_range(uint64_t *start, uint64_t *end)
{
return parse_iomem_single("Crash kernel\n", start, end);
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/sh/kexec-sh.c b/kexec/arch/sh/kexec-sh.c
index ce341c8..f84c40c 100644
--- a/kexec/arch/sh/kexec-sh.c
+++ b/kexec/arch/sh/kexec-sh.c
@@ -257,3 +257,8 @@ unsigned long add_buffer(struct kexec_info *info, const void *buf,
return add_buffer_phys_virt(info, buf, bufsz, memsz, buf_align,
buf_min, buf_max, buf_end, 1);
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/arch/x86_64/kexec-x86_64.c b/kexec/arch/x86_64/kexec-x86_64.c
index ffd84f0..42af90a 100644
--- a/kexec/arch/x86_64/kexec-x86_64.c
+++ b/kexec/arch/x86_64/kexec-x86_64.c
@@ -188,3 +188,8 @@ void arch_update_purgatory(struct kexec_info *info)
elf_rel_set_symbol(&info->rhdr, "panic_kernel",
&panic_kernel, sizeof(panic_kernel));
}
+
+int arch_do_exclude_segment(struct kexec_segment *UNUSED(seg_ptr), struct kexec_info *UNUSED(info))
+{
+ return 0;
+}
diff --git a/kexec/kexec-syscall.h b/kexec/kexec-syscall.h
index 73e5254..4675c46 100644
--- a/kexec/kexec-syscall.h
+++ b/kexec/kexec-syscall.h
@@ -112,7 +112,7 @@ static inline long kexec_file_load(int kernel_fd, int initrd_fd,
#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
/* Flags for kexec file based system call */
diff --git a/kexec/kexec.c b/kexec/kexec.c
index 222f79e..034cea6 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -701,10 +701,13 @@ static void update_purgatory(struct kexec_info *info)
continue;
}
- /* Don't include elfcorehdr in the checksum, if hotplug
- * support enabled.
+ /*
+ * Let architecture decide which segments to exclude from checksum
+ * if hotplug support is enabled.
*/
- if (do_hotplug && (info->segment[i].mem == (void *)info->elfcorehdr)) {
+ if (do_hotplug && arch_do_exclude_segment(&info->segment[i], info)) {
+ dbgprintf("Skipping segment mem: 0x%lx from SHA calculation\n",
+ (unsigned long)info->segment[i].mem);
continue;
}
@@ -1651,7 +1654,6 @@ int main(int argc, char *argv[])
die("--load-live-update can only be used with xen\n");
}
- /* NOTE: Xen KEXEC_LIVE_UPDATE and KEXEC_UPDATE_ELFCOREHDR collide */
if (do_hotplug) {
const char *ces = "/sys/kernel/crash_elfcorehdr_size";
char *buf, *endptr = NULL;
@@ -1665,8 +1667,8 @@ int main(int argc, char *argv[])
if (!elfcorehdrsz || (endptr && *endptr != '\0'))
die("Path %s does not exist, the kernel needs CONFIG_CRASH_HOTPLUG\n", ces);
dbgprintf("ELFCOREHDR_SIZE %lu\n", elfcorehdrsz);
- /* Indicate to the kernel it is ok to modify the elfcorehdr */
- kexec_flags |= KEXEC_UPDATE_ELFCOREHDR;
+ /* Indicate to the kernel it is ok to modify the relevant kexec segments */
+ kexec_flags |= KEXEC_CRASH_HOTPLUG_SUPPORT;
}
fileind = optind;
diff --git a/kexec/kexec.h b/kexec/kexec.h
index 1004aff..2d758c9 100644
--- a/kexec/kexec.h
+++ b/kexec/kexec.h
@@ -307,6 +307,8 @@ extern int do_hotplug;
#define BOOTLOADER_VERSION PACKAGE_VERSION
void arch_usage(void);
+/* Return non-zero if segment needs to be excluded from SHA calculation, else 0. */
+int arch_do_exclude_segment(struct kexec_segment *seg_ptr, struct kexec_info *info);
int arch_process_options(int argc, char **argv);
int arch_compat_trampoline(struct kexec_info *info);
void arch_update_purgatory(struct kexec_info *info);
--
2.45.1
More information about the kexec
mailing list