[PATCH v5 3/6] crash: add phdr for possible CPUs in elfcorehdr
From: Sourabh Jain <hidden>
Date: 2022-11-20 23:28:16
Also in:
kexec
Subsystem:
kdump, the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
On architectures like PowerPC the crash notes are available for all possible CPUs. So let's populate the elfcorehdr for all possible CPUs having crash notes to avoid updating elfcorehdr during in-kernel crash update on CPU hotplug events. The similar technique was used in kexec-tool for kexec_load case. Signed-off-by: Sourabh Jain <redacted> --- kernel/crash_core.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index bca1b198d9e55..f6cccdcadc9f3 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c@@ -364,16 +364,19 @@ int crash_prepare_elf64_headers(struct kimage *image, struct crash_mem *mem, ehdr->e_ehsize = sizeof(Elf64_Ehdr); ehdr->e_phentsize = sizeof(Elf64_Phdr); - /* Prepare one phdr of type PT_NOTE for each present CPU */ - for_each_present_cpu(cpu) { + /* Prepare one phdr of type PT_NOTE for possible CPU with crash note. */ + for_each_possible_cpu(cpu) { if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) { /* Skip the soon-to-be offlined cpu */ if (image->hotplug_event && (cpu == image->offlinecpu)) continue; } - phdr->p_type = PT_NOTE; notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu)); + if (!notes_addr) + continue; + + phdr->p_type = PT_NOTE; phdr->p_offset = phdr->p_paddr = notes_addr; phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t); (ehdr->e_phnum)++;
--
2.38.1