load_other_segments() is expected to allocate and place all the necessary
memory segments other than kernel, including initrd and device-tree
blob (and elf core header for crash).
While most of the code was borrowed from kexec-tools' counterpart,
users may not be allowed to specify dtb explicitly, instead, the dtb
presented by the original boot loader is reused.

arch_kimage_kernel_post_load_cleanup() is responsible for freeing arm64-
specific data allocated in load_other_segments().

Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
---
 arch/arm64/include/asm/kexec.h         |  16 +++
 arch/arm64/kernel/machine_kexec_file.c | 184 +++++++++++++++++++++++++
 2 files changed, 200 insertions(+)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index e17f0529a882..01bbf6cebf12 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -93,6 +93,22 @@ static inline void crash_prepare_suspend(void) {}
 static inline void crash_post_resume(void) {}
 #endif
 
+#ifdef CONFIG_KEXEC_FILE
+#define ARCH_HAS_KIMAGE_ARCH
+
+struct kimage_arch {
+       phys_addr_t dtb_mem;
+       void *dtb_buf;
+};
+
+struct kimage;
+
+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, unsigned long cmdline_len);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif
diff --git a/arch/arm64/kernel/machine_kexec_file.c 
b/arch/arm64/kernel/machine_kexec_file.c
index c38a8048ed00..ca00681c25c6 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -5,12 +5,196 @@
  * Copyright (C) 2018 Linaro Limited
  * Author: AKASHI Takahiro <takahiro.aka...@linaro.org>
  *
+ * Most code is derived from arm64 port of kexec-tools
  */
 
 #define pr_fmt(fmt) "kexec_file: " fmt
 
+#include <linux/ioport.h>
+#include <linux/kernel.h>
 #include <linux/kexec.h>
+#include <linux/libfdt.h>
+#include <linux/memblock.h>
+#include <linux/of_fdt.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
 
 const struct kexec_file_ops * const kexec_file_loaders[] = {
        NULL
 };
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+       vfree(image->arch.dtb_buf);
+       image->arch.dtb_buf = NULL;
+
+       return kexec_image_post_load_cleanup_default(image);
+}
+
+static int setup_dtb(struct kimage *image,
+               unsigned long initrd_load_addr, unsigned long initrd_len,
+               char *cmdline, unsigned long cmdline_len,
+               char **dtb_buf, size_t *dtb_buf_len)
+{
+       char *buf = NULL;
+       size_t buf_size;
+       int nodeoffset;
+       u64 value;
+       int ret;
+
+       /* duplicate dt blob */
+       buf_size = fdt_totalsize(initial_boot_params);
+
+       if (initrd_load_addr) {
+               /* can be redundant, but trimmed at the end */
+               buf_size += fdt_prop_len("linux,initrd-start", sizeof(u64));
+               buf_size += fdt_prop_len("linux,initrd-end", sizeof(u64));
+       }
+
+       if (cmdline)
+               /* can be redundant, but trimmed at the end */
+               buf_size += fdt_prop_len("bootargs", cmdline_len + 1);
+
+       buf = vmalloc(buf_size);
+       if (!buf) {
+               ret = -ENOMEM;
+               goto out_err;
+       }
+
+       ret = fdt_open_into(initial_boot_params, buf, buf_size);
+       if (ret) {
+               ret = -EINVAL;
+               goto out_err;
+       }
+
+       nodeoffset = fdt_path_offset(buf, "/chosen");
+       if (nodeoffset < 0) {
+               ret = -EINVAL;
+               goto out_err;
+       }
+
+       /* add bootargs */
+       if (cmdline) {
+               ret = fdt_setprop_string(buf, nodeoffset, "bootargs", cmdline);
+               if (ret) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+       } else {
+               ret = fdt_delprop(buf, nodeoffset, "bootargs");
+               if (ret && (ret != -FDT_ERR_NOTFOUND)) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+       }
+
+       /* add initrd-* */
+       if (initrd_load_addr) {
+               value = cpu_to_fdt64(initrd_load_addr);
+               ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-start",
+                                                       value);
+               if (ret) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+
+               value = cpu_to_fdt64(initrd_load_addr + initrd_len);
+               ret = fdt_setprop_u64(buf, nodeoffset, "linux,initrd-end",
+                                                       value);
+               if (ret) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+       } else {
+               ret = fdt_delprop(buf, nodeoffset, "linux,initrd-start");
+               if (ret && (ret != -FDT_ERR_NOTFOUND)) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+
+               ret = fdt_delprop(buf, nodeoffset, "linux,initrd-end");
+               if (ret && (ret != -FDT_ERR_NOTFOUND)) {
+                       ret = -EINVAL;
+                       goto out_err;
+               }
+       }
+
+       /* trim a buffer */
+       fdt_pack(buf);
+       *dtb_buf = buf;
+       *dtb_buf_len = fdt_totalsize(buf);
+
+       return 0;
+
+out_err:
+       vfree(buf);
+       return ret;
+}
+
+int load_other_segments(struct kimage *image,
+                       unsigned long kernel_load_addr,
+                       unsigned long kernel_size,
+                       char *initrd, unsigned long initrd_len,
+                       char *cmdline, unsigned long cmdline_len)
+{
+       struct kexec_buf kbuf;
+       unsigned long initrd_load_addr = 0;
+       char *dtb = NULL;
+       unsigned long dtb_len = 0;
+       int ret = 0;
+
+       kbuf.image = image;
+       /* not allocate anything below the kernel */
+       kbuf.buf_min = kernel_load_addr + kernel_size;
+
+       /* load initrd */
+       if (initrd) {
+               kbuf.buffer = initrd;
+               kbuf.bufsz = initrd_len;
+               kbuf.memsz = initrd_len;
+               kbuf.buf_align = 0;
+               /* within 1GB-aligned window of up to 32GB in size */
+               kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
+                                               + (unsigned long)SZ_1G * 32;
+               kbuf.top_down = false;
+
+               ret = kexec_add_buffer(&kbuf);
+               if (ret)
+                       goto out_err;
+               initrd_load_addr = kbuf.mem;
+
+               pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+                               initrd_load_addr, initrd_len, initrd_len);
+       }
+
+       /* load dtb blob */
+       ret = setup_dtb(image, initrd_load_addr, initrd_len,
+                               cmdline, cmdline_len, &dtb, &dtb_len);
+       if (ret) {
+               pr_err("Preparing for new dtb failed\n");
+               goto out_err;
+       }
+
+       kbuf.buffer = dtb;
+       kbuf.bufsz = dtb_len;
+       kbuf.memsz = dtb_len;
+       /* not across 2MB boundary */
+       kbuf.buf_align = SZ_2M;
+       kbuf.buf_max = ULONG_MAX;
+       kbuf.top_down = true;
+
+       ret = kexec_add_buffer(&kbuf);
+       if (ret)
+               goto out_err;
+       image->arch.dtb_mem = kbuf.mem;
+       image->arch.dtb_buf = dtb;
+
+       pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+                       kbuf.mem, dtb_len, dtb_len);
+
+       return 0;
+
+out_err:
+       vfree(dtb);
+       return ret;
+}
-- 
2.17.0


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