This routine provides a means to tune the size of the elfcorehdr
buffer segment, taking into account the --hotplug and
--elfcorehdrsz options. The possibilities are:
no --elfcorehdrsz w/ --elfcorehdrsz
no --hotplug just-large-enough user-specified
w/ --hotplug maximum-size user-specified
Where just-large-enough is the min_size parameter, computed based
upon the existing CPUs and memory regions in the system.
Where maximum-size is computed based upon the maximum number of
CPUs and memory regions possible in the system.
Signed-off-by: Eric DeVolder <[email protected]>
---
include/elf.h | 2 ++
kexec/crashdump.c | 33 +++++++++++++++++++++++++++++++++
kexec/crashdump.h | 4 ++++
3 files changed, 39 insertions(+)
diff --git a/include/elf.h b/include/elf.h
index 1c8d2cc..2c5884d 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -163,6 +163,8 @@ typedef struct
#define EI_PAD 9 /* Byte index of padding bytes */
+#define PN_XNUM 0xffff /* Maximum number of headers in e_phnum */
+
/* Legal values for e_type (object file type). */
#define ET_NONE 0 /* No file type */
diff --git a/kexec/crashdump.c b/kexec/crashdump.c
index 0b363c5..4210c53 100644
--- a/kexec/crashdump.c
+++ b/kexec/crashdump.c
@@ -53,6 +53,9 @@
#undef EHDR
#undef FUNC
+#define MIN(x, y) ((x) < (y) ? (x) : (y))
+#define MAX(x, y) ((x) > (y) ? (x) : (y))
+
unsigned long crash_architecture(struct crash_elf_info *elf_info)
{
if (xen_present())
@@ -157,3 +160,33 @@ int get_kernel_vmcoreinfo(uint64_t *addr, uint64_t *len)
{
return get_vmcoreinfo("/sys/kernel/vmcoreinfo", addr, len);
}
+
+unsigned long get_elfcorehdrsz(struct crash_elf_info *elf_info,
+ unsigned long min_size,
+ unsigned long nr_memory_ranges)
+{
+ /* Size elfcorehdr appropriately */
+ unsigned long sz = min_size;
+
+ if (elfcorehdrsz) {
+ /* Utilize option value */
+ sz = elfcorehdrsz;
+ } else {
+ /* Compute maximum for hotplug */
+ if (do_hotplug) {
+ long int nr_cpus = get_nr_cpus();
+ sz = nr_cpus + nr_memory_ranges;
+ sz = MIN(sz, PN_XNUM);
+ if (elf_info->class == ELFCLASS32) {
+ sz *= sizeof(Elf32_Phdr);
+ sz += sizeof(Elf32_Ehdr);
+ } else {
+ sz *= sizeof(Elf64_Phdr);
+ sz += sizeof(Elf64_Ehdr);
+ }
+ }
+ /* else default is min_size */
+ }
+ sz = MAX(min_size, sz);
+ return sz;
+}
diff --git a/kexec/crashdump.h b/kexec/crashdump.h
index 28d3278..e4cedce 100644
--- a/kexec/crashdump.h
+++ b/kexec/crashdump.h
@@ -53,6 +53,10 @@ int crash_create_elf64_headers(struct kexec_info *info,
unsigned long crash_architecture(struct crash_elf_info *elf_info);
+unsigned long get_elfcorehdrsz(struct crash_elf_info *elf_info,
+ unsigned long min_size,
+ unsigned long nr_memory_ranges);
+
unsigned long phys_to_virt(struct crash_elf_info *elf_info,
unsigned long long paddr);
--
2.31.1
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