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Subject[PATCH v16 10/16] arm64: kexec_file: load initrd and device-tree
Date
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.akashi@linaro.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
---
arch/arm64/include/asm/kexec.h | 17 +++
arch/arm64/kernel/machine_kexec_file.c | 185 +++++++++++++++++++++++++
2 files changed, 202 insertions(+)

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index e17f0529a882..bbb5f505b0ba 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -93,6 +93,23 @@ 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 {
+ void *dtb;
+ unsigned long dtb_mem;
+};
+
+struct kimage;
+
+extern int arch_kimage_file_post_load_cleanup(struct kimage *image);
+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);
+#endif
+
#endif /* __ASSEMBLY__ */

#endif
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index c38a8048ed00..b433d947d486 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -5,12 +5,197 @@
* Copyright (C) 2018 Linaro Limited
* Author: AKASHI Takahiro <takahiro.akashi@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/string.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+/* relevant device tree properties */
+#define FDT_PSTR_INITRD_STA "linux,initrd-start"
+#define FDT_PSTR_INITRD_END "linux,initrd-end"
+#define FDT_PSTR_BOOTARGS "bootargs"

const struct kexec_file_ops * const kexec_file_loaders[] = {
NULL
};
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+ vfree(image->arch.dtb);
+ image->arch.dtb = 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, void *dtb)
+{
+ int nodeoffset;
+ int ret;
+
+ nodeoffset = fdt_path_offset(dtb, "/chosen");
+ if (nodeoffset < 0)
+ return -EINVAL;
+
+ /* add bootargs */
+ if (cmdline) {
+ ret = fdt_setprop_string(dtb, nodeoffset, FDT_PSTR_BOOTARGS,
+ cmdline);
+ if (ret)
+ return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+ } else {
+ ret = fdt_delprop(dtb, nodeoffset, FDT_PSTR_BOOTARGS);
+ if (ret && (ret != -FDT_ERR_NOTFOUND))
+ return -EINVAL;
+ }
+
+ /* add initrd-* */
+ if (initrd_load_addr) {
+ ret = fdt_setprop_u64(dtb, nodeoffset, FDT_PSTR_INITRD_STA,
+ initrd_load_addr);
+ if (ret)
+ return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+
+ ret = fdt_setprop_u64(dtb, nodeoffset, FDT_PSTR_INITRD_END,
+ initrd_load_addr + initrd_len);
+ if (ret)
+ return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+ } else {
+ ret = fdt_delprop(dtb, nodeoffset, FDT_PSTR_INITRD_STA);
+ if (ret && (ret != -FDT_ERR_NOTFOUND))
+ return -EINVAL;
+
+ ret = fdt_delprop(dtb, nodeoffset, FDT_PSTR_INITRD_END);
+ if (ret && (ret != -FDT_ERR_NOTFOUND))
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/*
+ * More space needed so that we can add initrd and bootargs.
+ */
+#define DTB_EXTRA_SPACE 0x1000
+
+static int create_dtb(struct kimage *image,
+ unsigned long initrd_load_addr, unsigned long initrd_len,
+ char *cmdline, void **dtb)
+{
+ void *buf;
+ size_t buf_size;
+ int ret;
+
+ buf_size = fdt_totalsize(initial_boot_params)
+ + strlen(cmdline) + DTB_EXTRA_SPACE;
+
+ for (;;) {
+ buf = vmalloc(buf_size);
+ if (!buf)
+ return -ENOMEM;
+
+ /* duplicate a device tree blob */
+ ret = fdt_open_into(initial_boot_params, buf, buf_size);
+ if (ret)
+ return -EINVAL;
+
+ ret = setup_dtb(image, initrd_load_addr, initrd_len,
+ cmdline, buf);
+ if (ret) {
+ vfree(buf);
+ if (ret == -ENOMEM) {
+ /* unlikely, but just in case */
+ buf_size += DTB_EXTRA_SPACE;
+ continue;
+ } else {
+ return ret;
+ }
+ }
+
+ /* trim it */
+ fdt_pack(buf);
+ *dtb = buf;
+
+ return 0;
+ }
+}
+
+int load_other_segments(struct kimage *image,
+ unsigned long kernel_load_addr,
+ unsigned long kernel_size,
+ char *initrd, unsigned long initrd_len,
+ char *cmdline)
+{
+ struct kexec_buf kbuf;
+ void *dtb = NULL;
+ unsigned long initrd_load_addr = 0, dtb_len;
+ 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.mem = 0;
+ 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 */
+ ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
+ if (ret) {
+ pr_err("Preparing for new dtb failed\n");
+ goto out_err;
+ }
+
+ dtb_len = fdt_totalsize(dtb);
+ kbuf.buffer = dtb;
+ kbuf.bufsz = dtb_len;
+ kbuf.mem = 0;
+ 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 = dtb;
+ image->arch.dtb_mem = kbuf.mem;
+
+ 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;
+}
--
2.19.0
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