71e11d066c
Song Shuai <songshuaishuai@tinylab.org> says: This series contains a cleanup for riscv_kexec_relocate() and two fixups for KEXEC_FILE and had passed the basic kexec test in my 64bit Qemu-virt. You can use this kexec-tools[3] to test the kexec-file-syscall and these patches. riscv: kexec: Cleanup riscv_kexec_relocate (patch1) ================================================== For readability and simplicity, cleanup the riscv_kexec_relocate code: - Re-sort the first 4 `mv` instructions against `riscv_kexec_method()` - Eliminate registers for debugging (s9,s10,s11) and storing const-value (s5,s6) - Replace `jalr` with `jr` for no-link jump riscv: kexec: Align the kexeced kernel entry (patch2) ================================================== The current riscv boot protocol requires 2MB alignment for RV64 and 4MB alignment for RV32. In KEXEC_FILE path, the elf_find_pbase() function should align the kexeced kernel entry according to the requirement, otherwise the kexeced kernel would silently BUG at the setup_vm(). riscv: kexec: Remove -fPIE for PURGATORY_CFLAGS (patch3) ================================================== With CONFIG_RELOCATABLE enabled, KBUILD_CFLAGS had a -fPIE option and then the purgatory/string.o was built to reference _ctype symbol via R_RISCV_GOT_HI20 relocations which can't be handled by purgatory. As a consequence, the kernel failed kexec_load_file() with: [ 880.386562] kexec_image: The entry point of kernel at 0x80200000 [ 880.388650] kexec_image: Unknown rela relocation: 20 [ 880.389173] kexec_image: Error loading purgatory ret=-8 So remove the -fPIE option for PURGATORY_CFLAGS to generate R_RISCV_PCREL_HI20 relocations type making puragtory work as it was. arch/riscv/kernel/elf_kexec.c | 8 ++++- arch/riscv/kernel/kexec_relocate.S | 52 +++++++++++++----------------- arch/riscv/purgatory/Makefile | 4 +++ 3 files changed, 34 insertions(+), 30 deletions(-) * b4-shazam-merge: riscv: kexec: Remove -fPIE for PURGATORY_CFLAGS riscv: kexec: Align the kexeced kernel entry riscv: kexec: Cleanup riscv_kexec_relocate Link: https://lore.kernel.org/r/20230907103304.590739-1-songshuaishuai@tinylab.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.