[PATCH v14 10/17] 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/kernel/kexec_image.c        |  6 +---
 arch/arm64/kernel/machine_kexec_file.c | 44 ++++++++------------------
 2 files changed, 14 insertions(+), 36 deletions(-)

diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index 884e446f08e3..770a4c7bf573 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -12,7 +12,6 @@
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/kexec.h>
-#include <linux/memory_hotplug.h>
 #include <linux/pe.h>
 #include <linux/string.h>
 #include <asm/byteorder.h>
@@ -97,14 +96,11 @@ static void *image_load(struct kimage *image,
 
 #ifdef CONFIG_CRASH_DUMP
 	if (image->type == KEXEC_TYPE_CRASH) {
-		get_online_mems();
-		ret = prepare_elf_headers(&headers, &headers_sz);
+		ret = crash_prepare_headers_locked(true, &headers, &headers_sz, NULL);
 		if (ret) {
 			pr_err("Preparing elf core header failed\n");
-			put_online_mems();
 			return ERR_PTR(ret);
 		}
-		put_online_mems();
 		image->elf_headers = headers;
 		image->elf_headers_sz = headers_sz;
 	}
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index c0ace89ded92..66fbfbaec1c6 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -40,51 +40,33 @@ 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;
+	unsigned int nr_ranges = 2; /* for exclusion of crashkernel region */
 	phys_addr_t start, end;
+	u64 i;
 
-	nr_ranges = 2; /* for exclusion of crashkernel region */
 	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 (WARN_ON_ONCE(cmem->nr_ranges >= cmem->max_nr_ranges)) {
-			ret = -EAGAIN;
-			goto out;
-		}
+		if (WARN_ON_ONCE(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