linux/arch/loongarch/kernel/Makefile, branch master

LoongArch: Add ELF binary support for kexec_file

2025-10-02T14:39:08Z

This patch creates kexec_elf_ops to load ELF binary file for kexec_file_load() syscall. However, for `kbuf->memsz` and `kbuf->buf_min`, special handling is required, and the generic `kexec_elf_load()` cannot be used directly. $ readelf -l vmlinux ... Type Offset VirtAddr PhysAddr FileSiz MemSiz Flags Align LOAD 0x0000000000010000 0x9000000000200000 0x9000000000200000 0x0000000002747a00 0x000000000287a0d8 RWE 0x10000 NOTE 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 0x0000000000000000 R 0x8 phdr->p_paddr should have been a physical address, but it is a virtual address on the current LoongArch. This will cause kexec_file to fail when loading the kernel and need to be converted to a physical address. From the above MemSiz, it can be seen that 0x287a0d8 isn't page aligned. Although kexec_add_buffer() will perform PAGE_SIZE alignment on kbuf-> memsz, there is still a stampeding in the loaded kernel space and initrd space. The initrd resolution failed when starting the second kernel. It can be known from the link script vmlinux.lds.S that, BSS_SECTION(0, SZ_64K, 8) . = ALIGN(PECOFF_SEGMENT_ALIGN); It needs to be aligned according to SZ_64K, so that after alignment, its size is consistent with _kernel_asize. The basic usage (vmlinux): 1) Load second kernel image: # kexec -s -l vmlinux --initrd=initrd.img --reuse-cmdline 2) Startup second kernel: # kexec -e Signed-off-by: Youling Tang Signed-off-by: Huacai Chen

LoongArch: Add EFI binary support for kexec_file

2025-10-02T14:39:07Z

This patch creates kexec_efi_ops to load EFI binary file for kexec_file_load() syscall. The efi_kexec_load() as two parts: - the first part loads the kernel image (vmlinuz.efi or vmlinux.efi) - the second part loads other segments (e.g: initrd, cmdline, etc) Currently, pez (vmlinuz.efi) and pei (vmlinux.efi) format images are supported. The basic usage (vmlinuz.efi or vmlinux.efi): 1) Load second kernel image: # kexec -s -l vmlinuz.efi --initrd=initrd.img --reuse-cmdline 2) Startup second kernel: # kexec -e Signed-off-by: Youling Tang Signed-off-by: Huacai Chen

LoongArch: Add preparatory infrastructure for kexec_file

2025-10-02T14:39:07Z

Add some preparatory infrastructure: - Add command line processing. - Add support for loading other segments. - Other minor modifications. This initrd will be passed to the second kernel via the command line 'initrd=start,size'. The 'kexec_file' command line parameter indicates that the kernel is loaded via kexec_file. Signed-off-by: Youling Tang Signed-off-by: Huacai Chen

arch: use always-$(KBUILD_BUILTIN) for vmlinux.lds

2025-06-07T05:38:07Z

The extra-y syntax is deprecated. Instead, use always-$(KBUILD_BUILTIN), which behaves equivalently. Signed-off-by: Masahiro Yamada Acked-by: Johannes Berg Reviewed-by: Nicolas Schier

Fix mis-uses of 'cc-option' for warning disablement

2025-04-23T17:08:29Z

This was triggered by one of my mis-uses causing odd build warnings on sparc in linux-next, but while figuring out why the "obviously correct" use of cc-option caused such odd breakage, I found eight other cases of the same thing in the tree. The root cause is that 'cc-option' doesn't work for checking negative warning options (ie things like '-Wno-stringop-overflow') because gcc will silently accept options it doesn't recognize, and so 'cc-option' ends up thinking they are perfectly fine. And it all works, until you have a situation where _another_ warning is emitted. At that point the compiler will go "Hmm, maybe the user intended to disable this warning but used that wrong option that I didn't recognize", and generate a warning for the unrecognized negative option. Which explains why we have several cases of this in the tree: the 'cc-option' test really doesn't work for this situation, but most of the time it simply doesn't matter that ity doesn't work. The reason my recently added case caused problems on sparc was pointed out by Thomas Weißschuh: the sparc build had a previous explicit warning that then triggered the new one. I think the best fix for this would be to make 'cc-option' a bit smarter about this sitation, possibly by adding an intentional warning to the test case that then triggers the unrecognized option warning reliably. But the short-term fix is to replace 'cc-option' with an existing helper designed for this exact case: 'cc-disable-warning', which picks the negative warning but uses the positive form for testing the compiler support. Reported-by: Stephen Rothwell Link: https://lore.kernel.org/all/20250422204718.0b4e3f81@canb.auug.org.au/ Explained-by: Thomas Weißschuh Signed-off-by: Linus Torvalds

LoongArch: Add debugfs entries to switch SFB/TSO state

2025-01-26T13:49:59Z

We need to switch SFB (Store Fill Buffer) and TSO (Total Store Order) state at runtime to debug memory management and KVM virtualization, so add two debugfs entries "sfb_state" and "tso_state" under the directory /sys/kernel/debug/loongarch. Query SFB: cat /sys/kernel/debug/loongarch/sfb_state Enable SFB: echo 1 > /sys/kernel/debug/loongarch/sfb_state Disable SFB: echo 0 > /sys/kernel/debug/loongarch/sfb_state Query TSO: cat /sys/kernel/debug/loongarch/tso_state Switch TSO: echo [TSO] > /sys/kernel/debug/loongarch/tso_state Available [TSO] states: 0 (No Load No Store) 1 (All Load No Store) 3 (Same Load No Store) 4 (No Load All Store) 5 (All Load All Store) 7 (Same Load All Store) Signed-off-by: Huacai Chen

loongarch: Use new fallback IO memcpy/memset

2024-10-28T21:44:29Z

Use the new fallback memcpy_{from,to}io and memset_io functions from lib/iomem_copy.c on the loongarch processor architecture. Reviewed-by: Yann Sionneau Signed-off-by: Julian Vetter Signed-off-by: Arnd Bergmann

LoongArch: KVM: Add PV IPI support on guest side

2024-05-06T14:00:47Z

PARAVIRT config option and PV IPI is added for the guest side, function pv_ipi_init() is used to add IPI sending and IPI receiving hooks. This function firstly checks whether system runs in VM mode, and if kernel runs in VM mode, it will call function kvm_para_available() to detect the current hypervirsor type (now only KVM type detection is supported). The paravirt functions can work only if current hypervisor type is KVM, since there is only KVM supported on LoongArch now. PV IPI uses virtual IPI sender and virtual IPI receiver functions. With virtual IPI sender, IPI message is stored in memory rather than emulated HW. IPI multicast is also supported, and 128 vcpus can received IPIs at the same time like X86 KVM method. Hypercall method is used for IPI sending. With virtual IPI receiver, HW SWI0 is used rather than real IPI HW. Since VCPU has separate HW SWI0 like HW timer, there is no trap in IPI interrupt acknowledge. Since IPI message is stored in memory, there is no trap in getting IPI message. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

LoongArch: Add ORC stack unwinder support

2024-03-11T14:23:47Z

The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is similar in concept to a DWARF unwinder. The difference is that the format of the ORC data is much simpler than DWARF, which in turn allows the ORC unwinder to be much simpler and faster. The ORC data consists of unwind tables which are generated by objtool. After analyzing all the code paths of a .o file, it determines information about the stack state at each instruction address in the file and outputs that information to the .orc_unwind and .orc_unwind_ip sections. The per-object ORC sections are combined at link time and are sorted and post-processed at boot time. The unwinder uses the resulting data to correlate instruction addresses with their stack states at run time. Most of the logic are similar with x86, in order to get ra info before ra is saved into stack, add ra_reg and ra_offset into orc_entry. At the same time, modify some arch-specific code to silence the objtool warnings. Co-developed-by: Jinyang He Signed-off-by: Jinyang He Co-developed-by: Youling Tang Signed-off-by: Youling Tang Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen

loongarch, kexec: change dependency of object files

2023-12-13T01:20:17Z

Patch series "kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC". The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === E.g on mips, below link error are seen: -------------------------------------------------------------------- mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free': kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup' mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec': kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec' mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec': kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec' -------------------------------------------------------------------- Here, change the incorrect dependency of building kexec_core related object files, and the ifdeffery on architectures from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Testing: ======== Passed on mips and loognarch with the LKP reproducer. This patch (of 5): Currently, in arch/loongarch/kernel/Makefile, building machine_kexec.o relocate_kernel.o depends on CONFIG_KEXEC. Whereas, since we will drop the select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec, compiling error will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === --------------------------------------------------------------- loongarch64-linux-ld: kernel/kexec_core.o: in function `.L209': >> kexec_core.c:(.text+0x1660): undefined reference to `machine_kexec_cleanup' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L287': >> kexec_core.c:(.text+0x1c5c): undefined reference to `machine_crash_shutdown' >> loongarch64-linux-ld: kexec_core.c:(.text+0x1c64): undefined reference to `machine_kexec' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L2^B5': >> kexec_core.c:(.text+0x2090): undefined reference to `machine_shutdown' loongarch64-linux-ld: kexec_core.c:(.text+0x20a0): undefined reference to `machine_kexec' --------------------------------------------------------------- Here, change the dependency of machine_kexec.o relocate_kernel.o to CONFIG_KEXEC_CORE can fix above building error. Link: https://lkml.kernel.org/r/20231208073036.7884-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20231208073036.7884-2-bhe@redhat.com Signed-off-by: Baoquan He Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202311300946.kHE9Iu71-lkp@intel.com/ Cc: Eric DeVolder Cc: Ignat Korchagin Cc: Stephen Rothwell Signed-off-by: Andrew Morton