kernel/linux.git/arch/loongarch, branch v6.12.80

LoongArch: vDSO: Emit GNU_EH_FRAME correctly

2026-04-02T11:09:49+00:00

commit e4878c37f6679fdea91b27a0f4e60a871f0b7bad upstream. With -fno-asynchronous-unwind-tables and --no-eh-frame-hdr (the default of the linker), the GNU_EH_FRAME segment (specified by vdso.lds.S) is empty. This is not valid, as the current DWARF specification mandates the first byte of the EH frame to be the version number 1. It causes some unwinders to complain, for example the ClickHouse query profiler spams the log with messages: clickhouse-server[365854]: libunwind: unsupported .eh_frame_hdr version: 127 at 7ffffffb0000 Here "127" is just the byte located at the p_vaddr (0, i.e. the beginning of the vDSO) of the empty GNU_EH_FRAME segment. Cross- checking with /proc/365854/maps has also proven 7ffffffb0000 is the start of vDSO in the process VM image. In LoongArch the -fno-asynchronous-unwind-tables option seems just a MIPS legacy, and MIPS only uses this option to satisfy the MIPS-specific "genvdso" program, per the commit cfd75c2db17e ("MIPS: VDSO: Explicitly use -fno-asynchronous-unwind-tables"). IIRC it indicates some inherent limitation of the MIPS ELF ABI and has nothing to do with LoongArch. So we can simply flip it over to -fasynchronous-unwind-tables and pass --eh-frame-hdr for linking the vDSO, allowing the profilers to unwind the stack for statistics even if the sample point is taken when the PC is in the vDSO. However simply adjusting the options above would exploit an issue: when the libgcc unwinder saw the invalid GNU_EH_FRAME segment, it silently falled back to a machine-specific routine to match the code pattern of rt_sigreturn() and extract the registers saved in the sigframe if the code pattern is matched. As unwinding from signal handlers is vital for libgcc to support pthread cancellation etc., the fall-back routine had been silently keeping the LoongArch Linux systems functioning since Linux 5.19. But when we start to emit GNU_EH_FRAME with the correct format, fall-back routine will no longer be used and libgcc will fail to unwind the sigframe, and unwinding from signal handlers will no longer work, causing dozens of glibc test failures. To make it possible to unwind from signal handlers again, it's necessary to code the unwind info in __vdso_rt_sigreturn via .cfi_* directives. The offsets in the .cfi_* directives depend on the layout of struct sigframe, notably the offset of sigcontext in the sigframe. To use the offset in the assembly file, factor out struct sigframe into a header to allow asm-offsets.c to output the offset for assembly. To work around a long-term issue in the libgcc unwinder (the pc is unconditionally substracted by 1: doing so is technically incorrect for a signal frame), a nop instruction is included with the two real instructions in __vdso_rt_sigreturn in the same FDE PC range. The same hack has been used on x86 for a long time. Cc: stable@vger.kernel.org Fixes: c6b99bed6b8f ("LoongArch: Add VDSO and VSYSCALL support") Signed-off-by: Xi Ruoyao Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: KVM: Make kvm_get_vcpu_by_cpuid() more robust

2026-04-02T11:09:46+00:00

commit 2db06c15d8c7a0ccb6108524e16cd9163753f354 upstream. kvm_get_vcpu_by_cpuid() takes a cpuid parameter whose type is int, so cpuid can be negative. Let kvm_get_vcpu_by_cpuid() return NULL for this case so as to make it more robust. This fix an out-of-bounds access to kvm_arch::phyid_map::phys_map[]. Cc: Fixes: 73516e9da512adc ("LoongArch: KVM: Add vcpu mapping from physical cpuid") Reported-by: Aurelien Jarno Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1131431 Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Workaround LS2K/LS7A GPU DMA hang bug

2026-04-02T11:09:46+00:00

commit 95db0c9f526d583634cddb2e5914718570fbac87 upstream. 1. Hardware limitation: GPU, DC and VPU are typically PCI device 06.0, 06.1 and 06.2. They share some hardware resources, so when configure the PCI 06.0 device BAR1, DMA memory access cannot be performed through this BAR, otherwise it will cause hardware abnormalities. 2. In typical scenarios of reboot or S3/S4, DC access to memory through BAR is not prohibited, resulting in GPU DMA hangs. 3. Workaround method: When configuring the 06.0 device BAR1, turn off the memory access of DC, GPU and VPU (via DC's CRTC registers). Cc: stable@vger.kernel.org Signed-off-by: Qianhai Wu Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Fix missing NULL checks for kstrdup()

2026-04-02T11:09:46+00:00

commit 3a28daa9b7d7c2ddf2c722e9e95d7e0928bf0cd1 upstream. 1. Replace "of_find_node_by_path("/")" with "of_root" to avoid multiple calls to "of_node_put()". 2. Fix a potential kernel oops during early boot when memory allocation fails while parsing CPU model from device tree. Cc: stable@vger.kernel.org Signed-off-by: Li Jun Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

Revert "LoongArch: Add machine_kexec_mask_interrupts() implementation"

2026-03-27T09:52:52+00:00

This reverts commit 429bf3f04c24a1590ed18cd7bf802cf63f937a0f. 6.12.78 backported "kexec: Consolidate machine_kexec_mask_interrupts() implementation" so the arch-specific implementation is redundant. Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Give more information if kmem access failed

2026-03-25T10:08:47+00:00

commit a47f0754bdd01f971c9715acdbdd3a07515c8f83 upstream. If memory access such as copy_{from, to}_kernel_nofault() failed, its users do not know what happened, so it is very useful to print the exception code for such cases. Furthermore, it is better to print the caller function to know where is the entry. Here are the low level call chains: copy_from_kernel_nofault() copy_from_kernel_nofault_loop() __get_kernel_nofault() copy_to_kernel_nofault() copy_to_kernel_nofault_loop() __put_kernel_nofault() Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Remove some extern variables in source files

2026-03-13T16:20:31+00:00

[ Upstream commit 0e6f596d6ac635e80bb265d587b2287ef8fa1cd6 ] There are declarations of the variable "eentry", "pcpu_handlers[]" and "exception_handlers[]" in asm/setup.h, the source files already include this header file directly or indirectly, so no need to declare them in the source files, just remove the code. Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

LoongArch: Handle percpu handler address for ORC unwinder

2026-03-13T16:20:31+00:00

[ Upstream commit 055c7e75190e0be43037bd663a3f6aced194416e ] After commit 4cd641a79e69 ("LoongArch: Remove unnecessary checks for ORC unwinder"), the system can not boot normally under some configs (such as enable KASAN), there are many error messages "cannot find unwind pc". The kernel boots normally with the defconfig, so no problem found out at the first time. Here is one way to reproduce: cd linux make mrproper defconfig -j"$(nproc)" scripts/config -e KASAN make olddefconfig all -j"$(nproc)" sudo make modules_install sudo make install sudo reboot The address that can not unwind is not a valid kernel address which is between "pcpu_handlers[cpu]" and "pcpu_handlers[cpu] + vec_sz" due to the code of eentry was copied to the new area of pcpu_handlers[cpu] in setup_tlb_handler(), handle this special case to get the valid address to unwind normally. Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

LoongArch: Remove unnecessary checks for ORC unwinder

2026-03-13T16:20:31+00:00

[ Upstream commit 4cd641a79e69270a062777f64a0dd330abb9044a ] According to the following function definitions, __kernel_text_address() already checks __module_text_address(), so it should remove the check of __module_text_address() in bt_address() at least. int __kernel_text_address(unsigned long addr) { if (kernel_text_address(addr)) return 1; ... return 0; } int kernel_text_address(unsigned long addr) { bool no_rcu; int ret = 1; ... if (is_module_text_address(addr)) goto out; ... return ret; } bool is_module_text_address(unsigned long addr) { guard(rcu)(); return __module_text_address(addr) != NULL; } Furthermore, there are two checks of __kernel_text_address(), one is in bt_address() and the other is after calling bt_address(), it looks like redundant. Handle the exception address first and then use __kernel_text_address() to validate the calculated address for exception or the normal address in bt_address(), then it can remove the check of __kernel_text_address() after calling bt_address(). Just remove unnecessary checks, no functional changes intended. Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen Stable-dep-of: 055c7e75190e ("LoongArch: Handle percpu handler address for ORC unwinder") Signed-off-by: Sasha Levin

LoongArch/orc: Use RCU in all users of __module_address().

2026-03-13T16:20:30+00:00

[ Upstream commit f99d27d9feb755aee9350fc89f57814d7e1b4880 ] __module_address() can be invoked within a RCU section, there is no requirement to have preemption disabled. Replace the preempt_disable() section around __module_address() with RCU. Cc: Huacai Chen Cc: WANG Xuerui Cc: loongarch@lists.linux.dev Signed-off-by: Sebastian Andrzej Siewior Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250108090457.512198-19-bigeasy@linutronix.de Signed-off-by: Petr Pavlu Stable-dep-of: 055c7e75190e ("LoongArch: Handle percpu handler address for ORC unwinder") Signed-off-by: Sasha Levin