[PATCH v13 09/15] 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.mari...@arm.com>
Reviewed-by: Sourabh Jain <sourabhj...@linux.ibm.com>
Acked-by: Baoquan He <b...@redhat.com>
Acked-by: Mike Rapoport (Microsoft) <r...@kernel.org>
Signed-off-by: Jinjie Ruan <ruanjin...@huawei.com>
---
 arch/arm64/kernel/machine_kexec_file.c | 46 ++++++++------------------
 1 file changed, 14 insertions(+), 32 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec_file.c 
b/arch/arm64/kernel/machine_kexec_file.c
index a67e7b1abbab..8d72038f206d 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
-static 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 (cmem->nr_ranges >= cmem->max_nr_ranges) {
-                       ret = -ENOMEM;
-                       goto out;
-               }
+               if (cmem->nr_ranges >= cmem->max_nr_ranges)
+                       return -ENOMEM;
 
                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
 
@@ -114,7 +96,7 @@ int load_other_segments(struct kimage *image,
        void *headers;
        unsigned long headers_sz;
        if (image->type == KEXEC_TYPE_CRASH) {
-               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");
                        goto out_err;
-- 
2.34.1