kernel.git/arch/loongarch/include/uapi, branch linux-6.10.y

LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h

2024-08-19T04:05:37Z

commit 7697a0fe0154468f5df35c23ebd7aa48994c2cdc upstream. Chromium sandbox apparently wants to deny statx [1] so it could properly inspect arguments after the sandboxed process later falls back to fstat. Because there's currently not a "fd-only" version of statx, so that the sandbox has no way to ensure the path argument is empty without being able to peek into the sandboxed process's memory. For architectures able to do newfstatat though, glibc falls back to newfstatat after getting -ENOSYS for statx, then the respective SIGSYS handler [2] takes care of inspecting the path argument, transforming allowed newfstatat's into fstat instead which is allowed and has the same type of return value. But, as LoongArch is the first architecture to not have fstat nor newfstatat, the LoongArch glibc does not attempt falling back at all when it gets -ENOSYS for statx -- and you see the problem there! Actually, back when the LoongArch port was under review, people were aware of the same problem with sandboxing clone3 [3], so clone was eventually kept. Unfortunately it seemed at that time no one had noticed statx, so besides restoring fstat/newfstatat to LoongArch uapi (and postponing the problem further), it seems inevitable that we would need to tackle seccomp deep argument inspection. However, this is obviously a decision that shouldn't be taken lightly, so we just restore fstat/newfstatat by defining __ARCH_WANT_NEW_STAT in unistd.h. This is the simplest solution for now, and so we hope the community will tackle the long-standing problem of seccomp deep argument inspection in the future [4][5]. Also add "newstat" to syscall_abis_64 in Makefile.syscalls due to upstream asm-generic changes. More infomation please reading this thread [6]. [1] https://chromium-review.googlesource.com/c/chromium/src/+/2823150 [2] https://chromium.googlesource.com/chromium/src/sandbox/+/c085b51940bd/linux/seccomp-bpf-helpers/sigsys_handlers.cc#355 [3] https://lore.kernel.org/linux-arch/20220511211231.GG7074@brightrain.aerifal.cx/ [4] https://lwn.net/Articles/799557/ [5] https://lpc.events/event/4/contributions/560/attachments/397/640/deep-arg-inspection.pdf [6] https://lore.kernel.org/loongarch/20240226-granit-seilschaft-eccc2433014d@brauner/T/#t Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: KVM: Add software breakpoint support

2024-05-06T14:00:47Z

When VM runs in kvm mode, system will not exit to host mode when executing a general software breakpoint instruction such as INSN_BREAK, trap exception happens in guest mode rather than host mode. In order to debug guest kernel on host side, one mechanism should be used to let VM exit to host mode. Here a hypercall instruction with a special code is used for software breakpoint usage. VM exits to host mode and kvm hypervisor identifies the special hypercall code and sets exit_reason with KVM_EXIT_DEBUG. And then let qemu handle it. Idea comes from ppc kvm, one api KVM_REG_LOONGARCH_DEBUG_INST is added to get the hypercall code. VMM needs get sw breakpoint instruction with this api and set the corresponding sw break point for guest kernel. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

kvm: replace __KVM_HAVE_READONLY_MEM with Kconfig symbol

2024-02-08T13:41:06Z

KVM uses __KVM_HAVE_* symbols in the architecture-dependent uapi/asm/kvm.h to mask unused definitions in include/uapi/linux/kvm.h. __KVM_HAVE_READONLY_MEM however was nothing but a misguided attempt to define KVM_CAP_READONLY_MEM only on architectures where KVM_CHECK_EXTENSION(KVM_CAP_READONLY_MEM) could possibly return nonzero. This however does not make sense, and it prevented userspace from supporting this architecture-independent feature without recompilation. Therefore, these days __KVM_HAVE_READONLY_MEM does not mask anything and is only used in virt/kvm/kvm_main.c. Userspace does not need to test it and there should be no need for it to exist. Remove it and replace it with a Kconfig symbol within Linux source code. Signed-off-by: Paolo Bonzini

LoongArch: KVM: Add LSX (128bit SIMD) support

2023-12-19T02:48:28Z

This patch adds LSX (128bit SIMD) support for LoongArch KVM. There will be LSX exception in KVM when guest use the LSX instructions. KVM will enable LSX and restore the vector registers for guest and then return to guest to continue running. Signed-off-by: Tianrui Zhao Signed-off-by: Huacai Chen

LoongArch: KVM: Add kvm related header files

2023-10-02T02:01:20Z

Add LoongArch KVM related header files, including kvm.h, kvm_host.h and kvm_types.h. All of those are about LoongArch virtualization features and kvm interfaces. Reviewed-by: Bibo Mao Tested-by: Huacai Chen Signed-off-by: Tianrui Zhao Signed-off-by: Huacai Chen

LoongArch: Add Loongson Binary Translation (LBT) extension support

2023-09-06T14:53:55Z

Loongson Binary Translation (LBT) is used to accelerate binary translation, which contains 4 scratch registers (scr0 to scr3), x86/ARM eflags (eflags) and x87 fpu stack pointer (ftop). This patch support kernel to save/restore these registers, handle the LBT exception and maintain sigcontext. Signed-off-by: Qi Hu Signed-off-by: Huacai Chen

Merge tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2023-07-06T17:06:04Z

Pull asm-generic updates from Arnd Bergmann: "These are cleanups for architecture specific header files: - the comments in include/linux/syscalls.h have gone out of sync and are really pointless, so these get removed - The asm/bitsperlong.h header no longer needs to be architecture specific on modern compilers, so use a generic version for newer architectures that use new enough userspace compilers - A cleanup for virt_to_pfn/virt_to_bus to have proper type checking, forcing the use of pointers" * tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: syscalls: Remove file path comments from headers tools arch: Remove uapi bitsperlong.h of hexagon and microblaze asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch m68k/mm: Make pfn accessors static inlines arm64: memory: Make virt_to_pfn() a static inline ARM: mm: Make virt_to_pfn() a static inline asm-generic/page.h: Make pfn accessors static inlines xen/netback: Pass (void *) to virt_to_page() netfs: Pass a pointer to virt_to_page() cifs: Pass a pointer to virt_to_page() in cifsglob cifs: Pass a pointer to virt_to_page() riscv: mm: init: Pass a pointer to virt_to_page() ARC: init: Pass a pointer to virt_to_pfn() in init m68k: Pass a pointer to virt_to_pfn() virt_to_page() fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

LoongArch: Introduce hardware page table walker

2023-06-29T12:58:44Z

Loongson-3A6000 and newer processors have hardware page table walker (PTW) support. PTW can handle all fastpaths of TLBI/TLBL/TLBS/TLBM exceptions by hardware, software only need to handle slowpaths (page faults). BTW, PTW doesn't append _PAGE_MODIFIED for page table entries, so we change pmd_dirty() and pte_dirty() to also check _PAGE_DIRTY for the "dirty" attribute. Signed-off-by: Liang Gao Signed-off-by: Jun Yi Signed-off-by: Huacai Chen

LoongArch: Add vector extensions support

2023-06-29T12:58:43Z

Add LoongArch's vector extensions support, which including 128bit LSX (i.e., Loongson SIMD eXtension) and 256bit LASX (i.e., Loongson Advanced SIMD eXtension). Linux kernel doesn't use vector itself, it only handle exceptions and context save/restore. So it only needs a subset of these instructions: * Vector load/store: vld vst vldx vstx xvld xvst xvldx xvstx * 8bit-elements move: vpickve2gr.b xvpickve2gr.b vinsgr2vr.b xvinsgr2vr.b * 16bit-elements move: vpickve2gr.h xvpickve2gr.h vinsgr2vr.h xvinsgr2vr.h * 32bit-elements move: vpickve2gr.w xvpickve2gr.w vinsgr2vr.w xvinsgr2vr.w * 64bit-elements move: vpickve2gr.d xvpickve2gr.d vinsgr2vr.d xvinsgr2vr.d * Elements permute: vpermi.w vpermi.d xvpermi.w xvpermi.d xvpermi.q Introduce AS_HAS_LSX_EXTENSION and AS_HAS_LASX_EXTENSION to avoid non- vector toolchains complains unsupported instructions. Signed-off-by: Huacai Chen

asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch

2023-06-22T15:04:36Z

Now we specify the minimal version of GCC as 5.1 and Clang/LLVM as 11.0.0 in Documentation/process/changes.rst, __CHAR_BIT__ and __SIZEOF_LONG__ are usable, it is probably fine to unify the definition of __BITS_PER_LONG as (__CHAR_BIT__ * __SIZEOF_LONG__) in asm-generic uapi bitsperlong.h. In order to keep safe and avoid regression, only unify uapi bitsperlong.h for some archs such as arm64, riscv and loongarch which are using newer toolchains that have the definitions of __CHAR_BIT__ and __SIZEOF_LONG__. Suggested-by: Xi Ruoyao Link: https://lore.kernel.org/all/d3e255e4746de44c9903c4433616d44ffcf18d1b.camel@xry111.site/ Suggested-by: Arnd Bergmann Link: https://lore.kernel.org/linux-arch/a3a4f48a-07d4-4ed9-bc53-5d383428bdd2@app.fastmail.com/ Signed-off-by: Tiezhu Yang Signed-off-by: Arnd Bergmann