korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-29 07:04:10 +08:00
Code Issues Packages Projects Releases Wiki Activity

Urgent RISC-V fix for v5.3

Browse Source 
Last week, Palmer and I learned that there was an error in the RISC-V
 kernel image header format that could make it less compatible with the
 ARM64 kernel image header format.  I had missed this error during my
 original reviews of the patch.
 
 The kernel image header format is an interface that impacts
 bootloaders, QEMU, and other user tools.  Those packages must be
 updated to align with whatever is merged in the kernel.  We would like
 to avoid proliferating these image formats by keeping the RISC-V
 header as close as possible to the existing ARM64 header.  Since the
 arch/riscv patch that adds support for the image header was merged
 with our v5.3-rc1 pull request as commit 0f327f2aaa ("RISC-V: Add
 an Image header that boot loader can parse."), we think it wise to try
 to fix this error before v5.3 is released.
 
 The fix itself should be backwards-compatible with any project that
 has already merged support for premature versions of this interface.
 It primarily involves ensuring that the RISC-V image header has
 something useful in the same field as the ARM64 image header.
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCgAdFiEElRDoIDdEz9/svf2Kx4+xDQu9KksFAl1870sACgkQx4+xDQu9
 Kkt33A//SG4fTIyz0rIGTZpJPKV3nXacBq6XvOFxFsHRHlEvD2f/JkSK1Ab+hV5R
 vmTkVGCSCVz1C/OEA+KWsjuiJEglII6eOLIRqST1Wm6KumwAwLc78xdgEb1Sm/SC
 E7OTYtSqbUjCqzzD1BFcXfbP4mGF/9IBjWI3OcCnb1UcLuL29Mt35gvxI9fF1FB6
 +EU96MBQbk4gVUYjKXObTvaAZwWIYrMkOFQmdRgb4jqk42i0hLmKx//WkI1Ajlp8
 FDjE2nIo2NAt0N7pImJ/QtqxkOsQjMtOyOscoTyhB4eGJW0+fTyVrt6FpUdYQDQq
 vZI/WS2RFYUi2wfj+JNQ959MgsWZZ8z21KbFWwR0HC4k2xRZaxCO48g/VweJA/QW
 3f6+CMxYgwF5KzToHvUjlo0wNMW2Xo/FX9bky3gb8rJPWnSx9uu9lfoh17FUD4Ty
 cEknaLtmMALA8Lgr8hwTKbZLg7J1ih5r1SPj0UvjpjEmwDUl2doA0EONuuBroEHM
 KDerGitg6D0g4B4VlGsHuLMd6Gj/5r2teno97tPoaf5J9mCZ1v2/Q5OL0QwBYd84
 5cp+Ox1aQTY6SJq8gftBOD3MmW2lKCC5tT6H0bJvKBAE7tJaLPv5YIj6dp1jfXKB
 klzJUdGRsL60EwlL/cbFOurDfhBeQlq8akdzG5Cg5e8q+mISSTE=
 =Jt6U
 -----END PGP SIGNATURE-----

Merge tag 'riscv/for-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V fix from Paul Walmsley:
 "Last week, Palmer and I learned that there was an error in the RISC-V
  kernel image header format that could make it less compatible with the
  ARM64 kernel image header format. I had missed this error during my
  original reviews of the patch.

  The kernel image header format is an interface that impacts
  bootloaders, QEMU, and other user tools. Those packages must be
  updated to align with whatever is merged in the kernel. We would like
  to avoid proliferating these image formats by keeping the RISC-V
  header as close as possible to the existing ARM64 header. Since the
  arch/riscv patch that adds support for the image header was merged
  with our v5.3-rc1 pull request as commit 0f327f2aaa ("RISC-V: Add
  an Image header that boot loader can parse."), we think it wise to try
  to fix this error before v5.3 is released.

  The fix itself should be backwards-compatible with any project that
  has already merged support for premature versions of this interface.
  It primarily involves ensuring that the RISC-V image header has
  something useful in the same field as the ARM64 image header"

* tag 'riscv/for-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: modify the Image header to improve compatibility with the ARM64 header
This commit is contained in:
Linus Torvalds 2019-09-14 15:58:02 -07:00
commit b03c036e6f
3 changed files with 15 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
Documentation/riscv/boot-image-header.txt
View File

@ -18,7 +18,7 @@ The following 64-byte header is present in decompressed Linux kernel image.
u32 res1 = 0; /* Reserved */
u64 res2 = 0; /* Reserved */
u64 magic = 0x5643534952; /* Magic number, little endian, "RISCV" */
u32 res3; /* Reserved for additional RISC-V specific header */
u32 magic2 = 0x56534905; /* Magic number 2, little endian, "RSC\x05" */
u32 res4; /* Reserved for PE COFF offset */
This header format is compliant with PE/COFF header and largely inspired from
@ -37,13 +37,14 @@ Notes:
Bits 16:31 - Major version
This preserves compatibility across newer and older version of the header.
The current version is defined as 0.1.
The current version is defined as 0.2.
- res3 is reserved for offset to any other additional fields. This makes the
header extendible in future. One example would be to accommodate ISA
extension for RISC-V in future. For current version, it is set to be zero.
- The "magic" field is deprecated as of version 0.2. In a future
release, it may be removed. This originally should have matched up
with the ARM64 header "magic" field, but unfortunately does not.
The "magic2" field replaces it, matching up with the ARM64 header.
- In current header, the flag field has only one field.
- In current header, the flags field has only one field.
Bit 0: Kernel endianness. 1 if BE, 0 if LE.
- Image size is mandatory for boot loader to load kernel image. Booting will

12
arch/riscv/include/asm/image.h
View File

@ -3,7 +3,8 @@
#ifndef __ASM_IMAGE_H
#define __ASM_IMAGE_H
#define RISCV_IMAGE_MAGIC "RISCV"
#define RISCV_IMAGE_MAGIC "RISCV\0\0\0"
#define RISCV_IMAGE_MAGIC2 "RSC\x05"
#define RISCV_IMAGE_FLAG_BE_SHIFT 0
#define RISCV_IMAGE_FLAG_BE_MASK 0x1
@ -23,7 +24,7 @@
#define __HEAD_FLAGS (__HEAD_FLAG(BE))
#define RISCV_HEADER_VERSION_MAJOR 0
#define RISCV_HEADER_VERSION_MINOR 1
#define RISCV_HEADER_VERSION_MINOR 2
#define RISCV_HEADER_VERSION (RISCV_HEADER_VERSION_MAJOR << 16 | \
RISCV_HEADER_VERSION_MINOR)
@ -39,9 +40,8 @@
* @version: version
* @res1: reserved
* @res2: reserved
* @magic: Magic number
* @res3: reserved (will be used for additional RISC-V specific
* header)
* @magic: Magic number (RISC-V specific; deprecated)
* @magic2: Magic number 2 (to match the ARM64 'magic' field pos)
* @res4: reserved (will be used for PE COFF offset)
*
* The intention is for this header format to be shared between multiple
@ -58,7 +58,7 @@ struct riscv_image_header {
u32 res1;
u64 res2;
u64 magic;
u32 res3;
u32 magic2;
u32 res4;
};
#endif /* __ASSEMBLY__ */

4
arch/riscv/kernel/head.S
View File

@ -39,9 +39,9 @@ ENTRY(_start)
.word RISCV_HEADER_VERSION
.word 0
.dword 0
.asciz RISCV_IMAGE_MAGIC
.word 0
.ascii RISCV_IMAGE_MAGIC
.balign 4
.ascii RISCV_IMAGE_MAGIC2
.word 0
.global _start_kernel