summaryrefslogtreecommitdiffstats
path: root/arch/riscv
diff options
context:
space:
mode:
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/include/asm/image.h65
-rw-r--r--arch/riscv/kernel/head.S32
2 files changed, 97 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/image.h b/arch/riscv/include/asm/image.h
new file mode 100644
index 000000000000..ef28e106f247
--- /dev/null
+++ b/arch/riscv/include/asm/image.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __ASM_IMAGE_H
+#define __ASM_IMAGE_H
+
+#define RISCV_IMAGE_MAGIC "RISCV"
+
+#define RISCV_IMAGE_FLAG_BE_SHIFT 0
+#define RISCV_IMAGE_FLAG_BE_MASK 0x1
+
+#define RISCV_IMAGE_FLAG_LE 0
+#define RISCV_IMAGE_FLAG_BE 1
+
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#error conversion of header fields to LE not yet implemented
+#else
+#define __HEAD_FLAG_BE RISCV_IMAGE_FLAG_LE
+#endif
+
+#define __HEAD_FLAG(field) (__HEAD_FLAG_##field << \
+ RISCV_IMAGE_FLAG_##field##_SHIFT)
+
+#define __HEAD_FLAGS (__HEAD_FLAG(BE))
+
+#define RISCV_HEADER_VERSION_MAJOR 0
+#define RISCV_HEADER_VERSION_MINOR 1
+
+#define RISCV_HEADER_VERSION (RISCV_HEADER_VERSION_MAJOR << 16 | \
+ RISCV_HEADER_VERSION_MINOR)
+
+#ifndef __ASSEMBLY__
+/**
+ * struct riscv_image_header - riscv kernel image header
+ * @code0: Executable code
+ * @code1: Executable code
+ * @text_offset: Image load offset (little endian)
+ * @image_size: Effective Image size (little endian)
+ * @flags: kernel flags (little endian)
+ * @version: version
+ * @res1: reserved
+ * @res2: reserved
+ * @magic: Magic number
+ * @res3: reserved (will be used for additional RISC-V specific
+ * header)
+ * @res4: reserved (will be used for PE COFF offset)
+ *
+ * The intention is for this header format to be shared between multiple
+ * architectures to avoid a proliferation of image header formats.
+ */
+
+struct riscv_image_header {
+ u32 code0;
+ u32 code1;
+ u64 text_offset;
+ u64 image_size;
+ u64 flags;
+ u32 version;
+ u32 res1;
+ u64 res2;
+ u64 magic;
+ u32 res3;
+ u32 res4;
+};
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_IMAGE_H */
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index e368106f2228..0f1ba17e476f 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -11,9 +11,41 @@
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/csr.h>
+#include <asm/image.h>
__INIT
ENTRY(_start)
+ /*
+ * Image header expected by Linux boot-loaders. The image header data
+ * structure is described in asm/image.h.
+ * Do not modify it without modifying the structure and all bootloaders
+ * that expects this header format!!
+ */
+ /* jump to start kernel */
+ j _start_kernel
+ /* reserved */
+ .word 0
+ .balign 8
+#if __riscv_xlen == 64
+ /* Image load offset(2MB) from start of RAM */
+ .dword 0x200000
+#else
+ /* Image load offset(4MB) from start of RAM */
+ .dword 0x400000
+#endif
+ /* Effective size of kernel image */
+ .dword _end - _start
+ .dword __HEAD_FLAGS
+ .word RISCV_HEADER_VERSION
+ .word 0
+ .dword 0
+ .asciz RISCV_IMAGE_MAGIC
+ .word 0
+ .balign 4
+ .word 0
+
+.global _start_kernel
+_start_kernel:
/* Mask all interrupts */
csrw CSR_SIE, zero
csrw CSR_SIP, zero