From: Sourabh Jain <sourabhjain@linux.ibm.com>
To: linuxppc-dev@ozlabs.org, mpe@ellerman.id.au
Cc: eric.devolder@oracle.com, bhe@redhat.com,
mahesh@linux.vnet.ibm.com, kexec@lists.infradead.org,
ldufour@linux.ibm.com, hbathini@linux.ibm.com
Subject: [PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr
Date: Sun, 15 Jan 2023 20:32:02 +0530 [thread overview]
Message-ID: <20230115150206.431528-5-sourabhjain@linux.ibm.com> (raw)
In-Reply-To: <20230115150206.431528-1-sourabhjain@linux.ibm.com>
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 is used in kexec-tool for kexec_load case.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
---
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 910d377ea317e..19f987b3851e8 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -364,8 +364,8 @@ 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) {
#ifdef CONFIG_CRASH_HOTPLUG
if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
/* Skip the soon-to-be offlined cpu */
@@ -373,8 +373,11 @@ int crash_prepare_elf64_headers(struct kimage *image, struct crash_mem *mem,
continue;
}
#endif
- 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)++;
--
2.39.0
next prev parent reply other threads:[~2023-01-15 15:07 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-15 15:01 [PATCH v7 0/8] In kernel handling of CPU hotplug events for crash kernel Sourabh Jain
2023-01-15 15:01 ` [PATCH v7 1/8] powerpc/kexec: turn some static helper functions public Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 2/8] powerpc/crash hp: introduce a new config option CRASH_HOTPLUG Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 3/8] powerpc/crash: update kimage_arch struct Sourabh Jain
2023-01-19 18:57 ` Laurent Dufour
2023-01-23 5:23 ` Sourabh Jain
2023-01-15 15:02 ` Sourabh Jain [this message]
2023-01-19 18:29 ` [PATCH v7 4/8] crash: add phdr for possible CPUs in elfcorehdr Laurent Dufour
2023-01-20 11:39 ` Laurent Dufour
2023-01-23 5:27 ` Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 5/8] crash: pass hotplug action type to arch crash hotplug handler Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 6/8] powerpc/crash: add crash CPU hotplug support Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 7/8] crash: forward memory_notify args to arch crash hotplug handler Sourabh Jain
2023-01-15 15:02 ` [PATCH v7 8/8] powerpc/kexec: add crash memory hotplug support Sourabh Jain
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