[PATCH v15 16/23] arm64: kexec_file: Use crash_prepare_headers() helper to simplify code

[Jinjie Ruan]

Use the newly introduced crash_prepare_headers() function to replace
the existing prepare_elf_headers(), allocate cmem and exclude crash
kernel memory in the crash core, which reduce code duplication.

Only the following two architecture functions need to be implemented:
- arch_get_system_nr_ranges(). Use for_each_mem_range() to traverse
  and pre-count the max number of memory ranges.

- arch_crash_populate_cmem(). Use for_each_mem_range to traverse
  and collect the memory ranges and fills them into cmem.

Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Reviewed-by: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
Acked-by: Baoquan He <bhe@xxxxxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
 arch/arm64/include/asm/kexec.h         |  1 -
 arch/arm64/kernel/kexec_image.c        |  2 +-
 arch/arm64/kernel/machine_kexec_file.c | 46 ++++++++------------------
 3 files changed, 15 insertions(+), 34 deletions(-)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 7ffa2ff5fcfd..892e5bebda95 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -128,7 +128,6 @@ extern int load_other_segments(struct kimage *image,
 		unsigned long kernel_load_addr, unsigned long kernel_size,
 		char *initrd, unsigned long initrd_len,
 		char *cmdline);
-extern int prepare_elf_headers(void **addr, unsigned long *sz);
 #endif
 
 #endif /* __ASSEMBLER__ */
diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 424b9527db09..93c36a3aa618 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -95,7 +95,7 @@ static void *image_load(struct kimage *image,
 		unsigned long headers_sz;
 		void *headers;
 
-		ret = prepare_elf_headers(&headers, &headers_sz);
+		ret = crash_prepare_headers(true, &headers, &headers_sz, NULL);
 		if (ret) {
 			pr_err("Preparing elf core header failed\n");
 			return ERR_PTR(ret);
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 8a96fb68b88d..14e65351133e 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -40,52 +40,34 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
 }
 
 #ifdef CONFIG_CRASH_DUMP
-int prepare_elf_headers(void **addr, unsigned long *sz)
+unsigned int arch_get_system_nr_ranges(void)
 {
-	struct crash_mem *cmem;
-	unsigned int nr_ranges;
-	int ret;
-	u64 i;
+	/* for exclusion of crashkernel region */
+	unsigned int nr_ranges = 2 + CRASH_HOTPLUG_SAFETY_PADDING;
 	phys_addr_t start, end;
+	u64 i;
 
-	/* for exclusion of crashkernel region */
-	nr_ranges = 2 + CRASH_HOTPLUG_SAFETY_PADDING;
 	for_each_mem_range(i, &start, &end)
 		nr_ranges++;
 
-	cmem = kmalloc_flex(*cmem, ranges, nr_ranges);
-	if (!cmem)
-		return -ENOMEM;
+	return nr_ranges;
+}
+
+int arch_crash_populate_cmem(struct crash_mem *cmem)
+{
+	phys_addr_t start, end;
+	u64 i;
 
-	cmem->max_nr_ranges = nr_ranges;
-	cmem->nr_ranges = 0;
 	for_each_mem_range(i, &start, &end) {
-		if (unlikely(cmem->nr_ranges >= cmem->max_nr_ranges)) {
-			ret = -EAGAIN;
-			goto out;
-		}
+		if (unlikely(cmem->nr_ranges >= cmem->max_nr_ranges))
+			return -EAGAIN;
 
 		cmem->ranges[cmem->nr_ranges].start = start;
 		cmem->ranges[cmem->nr_ranges].end = end - 1;
 		cmem->nr_ranges++;
 	}
 
-	/* Exclude crashkernel region */
-	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
-	if (ret)
-		goto out;
-
-	if (crashk_low_res.end) {
-		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
-		if (ret)
-			goto out;
-	}
-
-	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
-
-out:
-	kfree(cmem);
-	return ret;
+	return 0;
 }
 #endif
 
-- 
2.34.1