kernel.git/arch/loongarch/kernel, branch linux-6.15.y

LoongArch: Avoid in-place string operation on FDT content

2025-08-20T16:35:45Z

commit 70a2365e18affc5ebdaab1ca6a0b3c4f3aac2ee8 upstream. In init_cpu_fullname(), a constant pointer to "model" property is retrieved. It's later modified by the strsep() function, which is illegal and corrupts kernel's FDT copy. This is shown by dmesg, OF: fdt: not creating '/sys/firmware/fdt': CRC check failed Create a mutable copy of the model property and do in-place operations on the mutable copy instead. loongson_sysconf.cpuname lives across the kernel lifetime, thus manually releasing isn't necessary. Also move the of_node_put() call for the root node after the usage of its property, since of_node_put() decreases the reference counter thus usage after the call is unsafe. Cc: stable@vger.kernel.org Fixes: 44a01f1f726a ("LoongArch: Parsing CPU-related information from DTS") Reviewed-by: Jiaxun Yang Signed-off-by: Yao Zi Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Make relocate_new_kernel_size be a .quad value

2025-08-20T16:35:45Z

commit a1a81b5477196ca1290b367404a461e046e647d5 upstream. Now relocate_new_kernel_size is a .long value, which means 32bit, so its high 32bit is undefined. This causes memcpy((void *)reboot_code_buffer, relocate_new_kernel, relocate_new_kernel_size) in machine_kexec_prepare() access out of range memories in some cases, and then end up with an ADE exception. So make relocate_new_kernel_size be a .quad value, which means 64bit, to avoid such errors. Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Don't use %pK through printk() in unwinder

2025-08-20T16:35:45Z

commit 2362e8124ed21445c6886806e5deaee717629ddd upstream. In the past %pK was preferable to %p as it would not leak raw pointer values into the kernel log. Since commit ad67b74d2469 ("printk: hash addresses printed with %p") the regular %p has been improved to avoid this issue. Furthermore, restricted pointers ("%pK") were never meant to be used through printk(). They can still unintentionally leak raw pointers or acquire sleeping locks in atomic contexts. Switch to the regular pointer formatting which is safer and easier to reason about. Cc: stable@vger.kernel.org Signed-off-by: Thomas Weißschuh Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: uprobes: Remove redundant code about resume_era

2025-05-14T14:18:10Z

arch_uprobe_skip_sstep() returns true if instruction was emulated, that is to say, there is no need to single step for the emulated instructions. regs->csr_era will point to the destination address directly after the exception, so the resume_era related code is redundant, just remove them. Cc: stable@vger.kernel.org Fixes: 19bc6cb64092 ("LoongArch: Add uprobes support") Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen

LoongArch: uprobes: Remove user_{en,dis}able_single_step()

2025-05-14T14:18:10Z

When executing the "perf probe" and "perf stat" test cases about some cryptographic algorithm, the output shows that "Trace/breakpoint trap". This is because it uses the software singlestep breakpoint for uprobes on LoongArch, and no need to use the hardware singlestep. So just remove the related function call to user_{en,dis}able_single_step() for uprobes on LoongArch. How to reproduce: Please make sure CONFIG_UPROBE_EVENTS is set and openssl supports sm2 algorithm, then execute the following command. cd tools/perf && make ./perf probe -x /usr/lib64/libcrypto.so BN_mod_mul_montgomery ./perf stat -e probe_libcrypto:BN_mod_mul_montgomery openssl speed sm2 Cc: stable@vger.kernel.org Fixes: 19bc6cb64092 ("LoongArch: Add uprobes support") Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen

LoongArch: Save and restore CSR.CNTC for hibernation

2025-05-14T14:17:52Z

Save and restore CSR.CNTC for hibernation which is similar to suspend. For host this is unnecessary because sched clock is ensured continuous, but for kvm guest sched clock isn't enough because rdtime.d should also be continuous. Host::rdtime.d = Host::CSR.CNTC + counter Guest::rdtime.d = Host::CSR.CNTC + Host::CSR.GCNTC + Guest::CSR.CNTC + counter so, Guest::rdtime.d = Host::rdtime.d + Host::CSR.GCNTC + Guest::CSR.CNTC To ensure Guest::rdtime.d continuous, Host::rdtime.d should be at first continuous, while Host::CSR.GCNTC / Guest::CSR.CNTC is maintained by KVM. Cc: stable@vger.kernel.org Signed-off-by: Xianglai Li Signed-off-by: Huacai Chen

LoongArch: Move __arch_cpu_idle() to .cpuidle.text section

2025-05-14T14:17:52Z

Now arch_cpu_idle() is annotated with __cpuidle which means it is in the .cpuidle.text section, but __arch_cpu_idle() isn't. Thus, fix the missing .cpuidle.text section assignment for __arch_cpu_idle() in order to correct backtracing with nmi_backtrace(). The principle is similar to the commit 97c8580e85cf81c ("MIPS: Annotate cpu_wait implementations with __cpuidle") Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen

LoongArch: Prevent cond_resched() occurring within kernel-fpu

2025-05-14T14:17:43Z

When CONFIG_PREEMPT_COUNT is not configured (i.e. CONFIG_PREEMPT_NONE/ CONFIG_PREEMPT_VOLUNTARY), preempt_disable() / preempt_enable() merely acts as a barrier(). However, in these cases cond_resched() can still trigger a context switch and modify the CSR.EUEN, resulting in do_fpu() exception being activated within the kernel-fpu critical sections, as demonstrated in the following path: dcn32_calculate_wm_and_dlg() DC_FP_START() dcn32_calculate_wm_and_dlg_fpu() dcn32_find_dummy_latency_index_for_fw_based_mclk_switch() dcn32_internal_validate_bw() dcn32_enable_phantom_stream() dc_create_stream_for_sink() kzalloc(GFP_KERNEL) __kmem_cache_alloc_node() __cond_resched() DC_FP_END() This patch is similar to commit d02198550423a0b (x86/fpu: Improve crypto performance by making kernel-mode FPU reliably usable in softirqs). It uses local_bh_disable() instead of preempt_disable() for non-RT kernels so it can avoid the cond_resched() issue, and also extend the kernel-fpu application scenarios to the softirq context. Cc: stable@vger.kernel.org Signed-off-by: Tianyang Zhang Signed-off-by: Huacai Chen

Merge tag 'loongarch-fixes-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

2025-04-26T16:02:41Z

Pull LoongArch fixes from Huacai Chen: "Add a missing Kconfig option, fix some bugs in exception handlers, memory management and KVM" * tag 'loongarch-fixes-6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: LoongArch: KVM: Fix PMU pass-through issue if VM exits to host finally LoongArch: KVM: Fully clear some CSRs when VM reboot LoongArch: KVM: Fix multiple typos of KVM code LoongArch: Return NULL from huge_pte_offset() for invalid PMD LoongArch: Remove a bogus reference to ZONE_DMA LoongArch: Handle fp, lsx, lasx and lbt assembly symbols LoongArch: Make do_xyz() exception handlers more robust LoongArch: Make regs_irqs_disabled() more clear LoongArch: Select ARCH_USE_MEMTEST

LoongArch: Handle fp, lsx, lasx and lbt assembly symbols

2025-04-26T01:58:12Z

Like the other relevant symbols, export some fp, lsx, lasx and lbt assembly symbols and put the function declarations in header files rather than source files. While at it, use "asmlinkage" for the other existing C prototypes of assembly functions and also do not use the "extern" keyword with function declarations according to the document coding-style.rst. Cc: stable@vger.kernel.org # 6.6+ Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen