On 1/12/23 11:23, Eric DeVolder wrote:
On 1/8/23 23:05, Sourabh Jain wrote:
On 09/12/22 21:06, Eric DeVolder wrote:
At the outcome of this patch set, the crash_prepare_elf64_headers()
is utilized on both the kexec_file_load() and kexec_load() paths. As
such, need to move this function out of kexec_file.c and into a
common location crash_core.c.
No functionality change.
Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
---
kernel/crash_core.c | 100 ++++++++++++++++++++++++++++++++++++++++++++
kernel/kexec_file.c | 99 -------------------------------------------
2 files changed, 100 insertions(+), 99 deletions(-)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a0eb4d5cf557..46c160d14045 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -10,6 +10,7 @@
#include <linux/utsname.h>
#include <linux/vmalloc.h>
#include <linux/sizes.h>
+#include <linux/kexec.h>
#include <asm/page.h>
#include <asm/sections.h>
@@ -314,6 +315,105 @@ static int __init parse_crashkernel_dummy(char *arg)
}
early_param("crashkernel", parse_crashkernel_dummy);
+int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
+ void **addr, unsigned long *sz)
+{
+ Elf64_Ehdr *ehdr;
+ Elf64_Phdr *phdr;
+ unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
+ unsigned char *buf;
+ unsigned int cpu, i;
+ unsigned long long notes_addr;
+ unsigned long mstart, mend;
+
+ /* extra phdr for vmcoreinfo ELF note */
+ nr_phdr = nr_cpus + 1;
+ nr_phdr += mem->nr_ranges;
+
+ /*
+ * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
+ * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
+ * I think this is required by tools like gdb. So same physical
+ * memory will be mapped in two ELF headers. One will contain kernel
+ * text virtual addresses and other will have __va(physical) addresses.
+ */
+
+ nr_phdr++;
+ elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
+ elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
Seems like above function is out of CONFIG_KEXEC_FILE but some of the
structure/attributes like crash_mem and ELF_CORE_HEADER_ALIGN are
still defined under CONFIG_KEXEC_FILE (look for include/linux/kexec.h).
This leads to kernel build issue when CONFIG_KEXEC_FILE is disabled.
Thanks,
Sourabh Jain
After looking into this for a bit, to allow hotplug without kexec_file would require quite a bit of
code movement. Why? Because hotplug is basically built on top of (part of) the infrastructure that
was needed for kexec_file.
I'd be inclined to suggest that KEXEC_FILE be a required dependency for CRASH_HOTPLUG, ie:
config CRASH_HOTPLUG
bool "Update the crash elfcorehdr on system configuration changes"
default n
- depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG)
+ depends on CRASH_DUMP && KEXEC_FILE && (HOTPLUG_CPU || MEMORY_HOTPLUG)
If that isn't feasible, then it would appear quite a bit of surgery is needed to properly separate
out the items hotplug needs from kexec_file.
Thoughts?
eric
I completed the changes necessary to move code around to allow this to work outside of KEXEC_FILE;
in the end it wasn't too bad. I'll include these changes in the next version.
eric
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