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

mm: z3fold: deprecate CONFIG_Z3FOLD

2024-10-10T10:01:09Z

[ Upstream commit 7a2369b74abf76cd3e54c45b30f6addb497f831b ] The z3fold compressed pages allocator is rarely used, most users use zsmalloc. The only disadvantage of zsmalloc in comparison is the dependency on MMU, and zbud is a more common option for !MMU as it was the default zswap allocator for a long time. Historically, zsmalloc had worse latency than zbud and z3fold but offered better memory savings. This is no longer the case as shown by a simple recent analysis [1]. That analysis showed that z3fold does not have any advantage over zsmalloc or zbud considering both performance and memory usage. In a kernel build test on tmpfs in a limited cgroup, z3fold took 3% more time and used 1.8% more memory. The latency of zswap_load() was 7% higher, and that of zswap_store() was 10% higher. Zsmalloc is better in all metrics. Moreover, z3fold apparently has latent bugs, which was made noticeable by a recent soft lockup bug report with z3fold [2]. Switching to zsmalloc not only fixed the problem, but also reduced the swap usage from 6~8G to 1~2G. Other users have also reported being bitten by mistakenly enabling z3fold. Other than hurting users, z3fold is repeatedly causing wasted engineering effort. Apart from investigating the above bug, it came up in multiple development discussions (e.g. [3]) as something we need to handle, when there aren't any legit users (at least not intentionally). The natural course of action is to deprecate z3fold, and remove in a few cycles if no objections are raised from active users. Next on the list should be zbud, as it offers marginal latency gains at the cost of huge memory waste when compared to zsmalloc. That one will need to wait until zsmalloc does not depend on MMU. Rename the user-visible config option from CONFIG_Z3FOLD to CONFIG_Z3FOLD_DEPRECATED so that users with CONFIG_Z3FOLD=y get a new prompt with explanation during make oldconfig. Also, remove CONFIG_Z3FOLD=y from defconfigs. [1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/ [2]https://lore.kernel.org/lkml/EF0ABD3E-A239-4111-A8AB-5C442E759CF3@gmail.com/ [3]https://lore.kernel.org/lkml/CAJD7tkbnmeVugfunffSovJf9FAgy9rhBVt_tx=nxUveLUfqVsA@mail.gmail.com/ [arnd@arndb.de: deprecate ZSWAP_ZPOOL_DEFAULT_Z3FOLD as well] Link: https://lkml.kernel.org/r/20240909202625.1054880-1-arnd@kernel.org Link: https://lkml.kernel.org/r/20240904233343.933462-1-yosryahmed@google.com Signed-off-by: Yosry Ahmed Signed-off-by: Arnd Bergmann Acked-by: Chris Down Acked-by: Nhat Pham Acked-by: Johannes Weiner Acked-by: Vitaly Wool Acked-by: Christoph Hellwig Cc: Aneesh Kumar K.V Cc: Christophe Leroy Cc: Huacai Chen Cc: Miaohe Lin Cc: Michael Ellerman Cc: Naveen N. Rao Cc: Nicholas Piggin Cc: Sergey Senozhatsky Cc: WANG Xuerui Cc: Signed-off-by: Andrew Morton (cherry picked from commit 7a2369b74abf76cd3e54c45b30f6addb497f831b) Signed-off-by: Sasha Levin

Revert "LoongArch: KVM: Invalidate guest steal time address on vCPU reset"

2024-10-04T14:33:29Z

This reverts commit 05969a6944713f159e8f28be2388500174521818 which is commit 4956e07f05e239b274d042618a250c9fa3e92629 upstream. LoongArch's PV steal time support is add after 6.10, so 6.10.y doesn't need this fix. Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: KVM: Invalidate guest steal time address on vCPU reset

2024-09-30T14:29:28Z

[ Upstream commit 4956e07f05e239b274d042618a250c9fa3e92629 ] If ParaVirt steal time feature is enabled, there is a percpu gpa address passed from guest vCPU and host modifies guest memory space with this gpa address. When vCPU is reset normally, it will notify host and invalidate gpa address. However if VM is crashed and VMM reboots VM forcely, the vCPU reboot notification callback will not be called in VM. Host needs invalidate the gpa address, else host will modify guest memory during VM reboots. Here it is invalidated from the vCPU KVM_REG_LOONGARCH_VCPU_RESET ioctl interface. Also funciton kvm_reset_timer() is removed at vCPU reset stage, since SW emulated timer is only used in vCPU block state. When a vCPU is removed from the block waiting queue, kvm_restore_timer() is called and SW timer is cancelled. And the timer register is also cleared at VMM when a vCPU is reset. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

LoongArch: Define ARCH_IRQ_INIT_FLAGS as IRQ_NOPROBE

2024-09-30T14:29:28Z

[ Upstream commit 274ea3563e5ab9f468c15bfb9d2492803a66d9be ] Currently we call irq_set_noprobe() in a loop for all IRQs, but indeed it only works for IRQs below NR_IRQS_LEGACY because at init_IRQ() only legacy interrupts have been allocated. Instead, we can define ARCH_IRQ_INIT_FLAGS as IRQ_NOPROBE in asm/hwirq.h and the core will automatically set the flag for all interrupts. Reviewed-by: Thomas Gleixner Signed-off-by: Huacai Chen Signed-off-by: Tianyang Zhang Signed-off-by: Sasha Levin

LoongArch: Use accessors to page table entries instead of direct dereference

2024-09-12T09:13:13Z

commit 4574815abf43e2bf05643e1b3f7a2e5d6df894f0 upstream. As very well explained in commit 20a004e7b017cce282 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when accessing page tables"), an architecture whose page table walker can modify the PTE in parallel must use READ_ONCE()/ WRITE_ONCE() macro to avoid any compiler transformation. So apply that to LoongArch which is such an architecture, in order to avoid potential problems. Similar to commit edf955647269422e ("riscv: Use accessors to page table entries instead of direct dereference"). Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Use correct API to map cmdline in relocate_kernel()

2024-09-12T09:13:03Z

[ Upstream commit 0124fbb4c6dba23dbdf80c829be68adbccde2722 ] fw_arg1 is in memory space rather than I/O space, so we should use early_memremap_ro() instead of early_ioremap() to map the cmdline. Moreover, we should unmap it after using. Suggested-by: Jiaxun Yang Reviewed-by: Jiaxun Yang Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

LoongArch: Add ifdefs to fix LSX and LASX related warnings

2024-09-04T11:29:55Z

commit 80376323e2b6a4559f86b2b4d864848ac25cb054 upstream. There exist some warnings when building kernel if CONFIG_CPU_HAS_LBT is set but CONFIG_CPU_HAS_LSX and CONFIG_CPU_HAS_LASX are not set. In this case, there are no definitions of _restore_lsx & _restore_lasx and there are also no definitions of kvm_restore_lsx & kvm_restore_lasx in fpu.S and switch.S respectively, just add some ifdefs to fix these warnings. AS arch/loongarch/kernel/fpu.o arch/loongarch/kernel/fpu.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0 arch/loongarch/kernel/fpu.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0 AS [M] arch/loongarch/kvm/switch.o arch/loongarch/kvm/switch.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0 arch/loongarch/kvm/switch.o: warning: objtool: unexpected relocation symbol type in .rela.discard.func_stack_frame_non_standard: 0 MODPOST Module.symvers ERROR: modpost: "kvm_restore_lsx" [arch/loongarch/kvm/kvm.ko] undefined! ERROR: modpost: "kvm_restore_lasx" [arch/loongarch/kvm/kvm.ko] undefined! Cc: stable@vger.kernel.org # 6.9+ Fixes: cb8a2ef0848c ("LoongArch: Add ORC stack unwinder support") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202408120955.qls5oNQY-lkp@intel.com/ Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Remove the unused dma-direct.h

2024-09-04T11:29:55Z

commit 58aec91efb93338d1cc7acc0a93242613a2a4e5f upstream. dma-direct.h is introduced in commit d4b6f1562a3c3284 ("LoongArch: Add Non-Uniform Memory Access (NUMA) support"). In commit c78c43fe7d42524c ("LoongArch: Use acpi_arch_dma_setup() and remove ARCH_HAS_PHYS_TO_DMA"), ARCH_HAS_PHYS_TO_DMA was deselected and the coresponding phys_to_dma()/ dma_to_phys() functions were removed. However, the unused dma-direct.h was left behind, which is removed by this patch. Cc: Fixes: c78c43fe7d42 ("LoongArch: Use acpi_arch_dma_setup() and remove ARCH_HAS_PHYS_TO_DMA") Signed-off-by: Miao Wang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

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: Enable general EFI poweroff method

2024-08-14T13:34:32Z

commit e688c220732e518c2eb1639e9ef77d4a9311713c upstream. efi_shutdown_init() can register a general sys_off handler named efi_power_off(). Enable this by providing efi_poweroff_required(), like arm and x86. Since EFI poweroff is also supported on LoongArch, and the enablement makes the poweroff function usable for hardwares which lack ACPI S5. We prefer ACPI poweroff rather than EFI poweroff (like x86), so we only require EFI poweroff if acpi_gbl_reduced_hardware or acpi_no_s5 is true. Cc: stable@vger.kernel.org Acked-by: Ard Biesheuvel Signed-off-by: Miao Wang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman