[PATCH v3 14/17] x86/crash: Simplify crash_load_segments() using crash_extra_elfcorehdr_size()

[Jinjie Ruan <ruanjinjie@huawei.com>]

Replace the open-coded elfcorehdr reservation logic in
crash_load_segments() with the generic crash_extra_elfcorehdr_size()
helper. The helper centralizes all PN_XNUM and memory range checks,
reducing code duplication.

The elfcorehdr_index is handled separately in crash_handle_hotplug_event()
during the first hotplug event, so it does not need to be set in
crash_load_segments().

Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
 arch/x86/kernel/crash.c | 32 +++++---------------------------
 1 file changed, 5 insertions(+), 27 deletions(-)

diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index afe2aea19f47..99eb8583d932 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -348,42 +348,20 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
 
 int crash_load_segments(struct kimage *image)
 {
-	int ret;
-	unsigned long pnum = 0;
 	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
 				  .buf_max = ULONG_MAX, .top_down = false };
+	unsigned long nr_ranges = 0;
+	int ret;
 
 	/* Prepare elf headers and add a segment */
 	ret = crash_prepare_headers(IS_ENABLED(CONFIG_X86_64), &kbuf.buffer,
-				    &kbuf.bufsz, &pnum);
+				    &kbuf.bufsz, &nr_ranges);
 	if (ret)
 		return ret;
 
 	image->elf_headers	= kbuf.buffer;
-	image->elf_headers_sz	= kbuf.bufsz;
-	kbuf.memsz		= kbuf.bufsz;
-
-#ifdef CONFIG_CRASH_HOTPLUG
-	/*
-	 * The elfcorehdr segment size accounts for VMCOREINFO, kernel_map,
-	 * maximum CPUs and maximum memory ranges.
-	 */
-	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
-		pnum = 2 + num_possible_cpus() + CONFIG_CRASH_MAX_MEMORY_RANGES;
-	else
-		pnum += 2 + num_possible_cpus();
-
-	if (pnum < (unsigned long)PN_XNUM) {
-		kbuf.memsz = elf64_phdr_size(pnum);
-
-		image->elfcorehdr_index = image->nr_segments;
-
-		/* Mark as usable to crash kernel, else crash kernel fails on boot */
-		image->elf_headers_sz = kbuf.memsz;
-	} else {
-		pr_err("number of Phdrs %lu exceeds max\n", pnum);
-	}
-#endif
+	kbuf.memsz = kbuf.bufsz + crash_extra_elfcorehdr_size(nr_ranges);
+	image->elf_headers_sz	= kbuf.memsz;
 
 	kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
 	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
-- 
2.34.1