kernel/linux.git/arch/loongarch/include/asm, branch v6.18.34

ring-buffer: Flush and stop persistent ring buffer on panic

2026-06-01T15:50:44+00:00

commit a494d3c8d5392bcdff83c2a593df0c160ff9f322 upstream. On real hardware, panic and machine reboot may not flush hardware cache to memory. This means the persistent ring buffer, which relies on a coherent state of memory, may not have its events written to the buffer and they may be lost. Moreover, there may be inconsistency with the counters which are used for validation of the integrity of the persistent ring buffer which may cause all data to be discarded. To avoid this issue, stop recording of the ring buffer on panic and flush the cache of the ring buffer's memory. Fixes: e645535a954a ("tracing: Add option to use memmapped memory for trace boot instance") Cc: stable@vger.kernel.org Cc: Will Deacon Cc: Mathieu Desnoyers Cc: Ian Rogers Link: https://patch.msgid.link/177751969602.2136606.12031934362587643488.stgit@mhiramat.tok.corp.google.com Signed-off-by: Masami Hiramatsu (Google) Acked-by: Catalin Marinas Acked-by: Geert Uytterhoeven Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

LoongArch: KVM: Compile switch.S directly into the kernel

2026-05-17T15:15:35+00:00

commit 5203012fa6045aac4b69d4e7c212e16dcf38ef10 upstream. If we directly compile the switch.S file into the kernel, the address of the kvm_exc_entry function will definitely be within the DMW memory area. Therefore, we will no longer need to perform a copy relocation of the kvm_exc_entry. So this patch compiles switch.S directly into the kernel, and then remove the copy relocation execution logic for the kvm_exc_entry function. Cc: stable@vger.kernel.org Signed-off-by: Xianglai Li Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Fix SYM_SIGFUNC_START definition for 32BIT

2026-05-14T13:30:15+00:00

commit 98b8aebb14fdc0133939fd8fe07d0d98333dc976 upstream. The SYM_SIGFUNC_START definition should match sigcontext that the length of GPRs are 8 bytes for both 32BIT and 64BIT. So replace SZREG with 8 to fix it. Cc: stable@vger.kernel.org Fixes: e4878c37f6679fde ("LoongArch: vDSO: Emit GNU_EH_FRAME correctly") Suggested-by: Xi Ruoyao Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: vDSO: Emit GNU_EH_FRAME correctly

2026-04-02T11:23:24+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: Give more information if kmem access failed

2026-03-25T10:10:31+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: Handle percpu handler address for ORC unwinder

2026-03-12T11:09:33+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: Make cpumask_of_node() robust against NUMA_NO_NODE

2026-03-04T12:21:26+00:00

[ Upstream commit 94b0c831eda778ae9e4f2164a8b3de485d8977bb ] The arch definition of cpumask_of_node() cannot handle NUMA_NO_NODE - which is a valid index - so add a check for this. Cc: stable@vger.kernel.org Signed-off-by: John Garry Signed-off-by: Huacai Chen Signed-off-by: Sasha Levin

LoongArch: Use pmd()/pte() for swap entry conversions

2026-01-08T09:17:06+00:00

commit 4a71df151e703b5e7e85b33369cee59ef2665e61 upstream. The __pmd() and __pte() helper macros provide the correct initialization syntax and abstraction for the pmd_t and pte_t types. Use __pmd() to fix follow warning about __swp_entry_to_pmd() with gcc-15 under specific configs [1] : In file included from ./include/linux/pgtable.h:6, from ./include/linux/mm.h:31, from ./include/linux/pagemap.h:8, from arch/loongarch/mm/init.c:14: ./include/linux/swapops.h: In function ‘swp_entry_to_pmd’: ./arch/loongarch/include/asm/pgtable.h:302:34: error: missing braces around initializer [-Werror=missing-braces] 302 | #define __swp_entry_to_pmd(x) ((pmd_t) { (x).val | _PAGE_HUGE }) | ^ ./include/linux/swapops.h:559:16: note: in expansion of macro ‘__swp_entry_to_pmd’ 559 | return __swp_entry_to_pmd(arch_entry); | ^~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors Also update __swp_entry_to_pte() to use __pte() for consistency. [1]. https://download.01.org/0day-ci/archive/20251119/202511190316.luI90kAo-lkp@intel.com/config Cc: stable@vger.kernel.org Signed-off-by: Yuli Wang Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman

LoongArch: Consolidate CPU names in /proc/cpuinfo

2025-11-20T06:42:05+00:00

Some processors have no IOCSR.VENDOR and IOCSR.CPUNAME, some processors have these registers but there is no valid information. Consolidate CPU names in /proc/cpuinfo: 1. Add "PRID" to display the PRID & Core-Name; 2. Let "Model Name" display "Unknown" if no valid name. Signed-off-by: Huacai Chen

LoongArch: Use correct accessor to read FWPC/MWPC

2025-11-10T00:37:06+00:00

CSR.FWPC and CSR.MWPC are 32bit registers, so use csr_read32() rather than csr_read64() to read the values of FWPC/MWPC. Cc: stable@vger.kernel.org Fixes: edffa33c7bb5a73 ("LoongArch: Add hardware breakpoints/watchpoints support") Signed-off-by: Huacai Chen