@@ -73,13 +73,15 @@ The decompressed kernel image contains a 64-byte header as follows:
u32 code0; /* Executable code */
u32 code1; /* Executable code */
u64 text_offset; /* Image load offset */
- u64 res0 = 0; /* reserved */
- u64 res1 = 0; /* reserved */
- u64 res2 = 0; /* reserved */
+ u8 byte_order; /* 1=LSB (little endian), 2=MSB (big endian) */
+ u8[3] res1; /* reserved */
+ u32 res2 = 0; /* reserved */
u64 res3 = 0; /* reserved */
u64 res4 = 0; /* reserved */
+ u64 res5 = 0; /* reserved */
+ u64 res6 = 0; /* reserved */
u32 magic = 0x644d5241; /* Magic number, little endian, "ARM\x64" */
- u32 res5 = 0; /* reserved */
+ u32 res7 = 0; /* reserved */
Header notes:
@@ -111,7 +111,12 @@
b stext // branch to kernel start, magic
.long 0 // reserved
.quad TEXT_OFFSET // Image load offset from start of RAM
- .quad 0 // reserved
+ CPU_LE(.byte 1) // 1=LSB (little endian)
+ CPU_BE(.byte 2) // 2=MSB (big endian)
+ .byte 0 // reserved
+ .byte 0 // reserved
+ .byte 0 // reserved
+ .word 0 // reserved
.quad 0 // reserved
.quad 0 // reserved
.quad 0 // reserved
When working with a raw arm64 image one needs to know the byte order of the image header to properly interpret the multi-byte values of the header. Add a character value to the image header indicating the byte order the image was built with: 1=LSB (little endian), 2=MSB (big endian), 0=no support. A zero value will indicate a kernel that pre-dates this change. Signed-off-by: Geoff Levand <geoff@infradead.org> --- Hi, I noticed there was a change to the image header for COFF compatibility that conflicted with my old patch. Here's an update that also changes booting.txt. I'll also post a patch that adds a new file asm/image.h to describe the header. -Geoff Documentation/arm64/booting.txt | 10 ++++++---- arch/arm64/kernel/head.S | 7 ++++++- 2 files changed, 12 insertions(+), 5 deletions(-)