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

Fix mis-uses of 'cc-option' for warning disablement

2025-04-23T17:08:29Z

This was triggered by one of my mis-uses causing odd build warnings on sparc in linux-next, but while figuring out why the "obviously correct" use of cc-option caused such odd breakage, I found eight other cases of the same thing in the tree. The root cause is that 'cc-option' doesn't work for checking negative warning options (ie things like '-Wno-stringop-overflow') because gcc will silently accept options it doesn't recognize, and so 'cc-option' ends up thinking they are perfectly fine. And it all works, until you have a situation where _another_ warning is emitted. At that point the compiler will go "Hmm, maybe the user intended to disable this warning but used that wrong option that I didn't recognize", and generate a warning for the unrecognized negative option. Which explains why we have several cases of this in the tree: the 'cc-option' test really doesn't work for this situation, but most of the time it simply doesn't matter that ity doesn't work. The reason my recently added case caused problems on sparc was pointed out by Thomas Weißschuh: the sparc build had a previous explicit warning that then triggered the new one. I think the best fix for this would be to make 'cc-option' a bit smarter about this sitation, possibly by adding an intentional warning to the test case that then triggers the unrecognized option warning reliably. But the short-term fix is to replace 'cc-option' with an existing helper designed for this exact case: 'cc-disable-warning', which picks the negative warning but uses the positive form for testing the compiler support. Reported-by: Stephen Rothwell Link: https://lore.kernel.org/all/20250422204718.0b4e3f81@canb.auug.org.au/ Explained-by: Thomas Weißschuh Signed-off-by: Linus Torvalds

LoongArch: Add debugfs entries to switch SFB/TSO state

2025-01-26T13:49:59Z

We need to switch SFB (Store Fill Buffer) and TSO (Total Store Order) state at runtime to debug memory management and KVM virtualization, so add two debugfs entries "sfb_state" and "tso_state" under the directory /sys/kernel/debug/loongarch. Query SFB: cat /sys/kernel/debug/loongarch/sfb_state Enable SFB: echo 1 > /sys/kernel/debug/loongarch/sfb_state Disable SFB: echo 0 > /sys/kernel/debug/loongarch/sfb_state Query TSO: cat /sys/kernel/debug/loongarch/tso_state Switch TSO: echo [TSO] > /sys/kernel/debug/loongarch/tso_state Available [TSO] states: 0 (No Load No Store) 1 (All Load No Store) 3 (Same Load No Store) 4 (No Load All Store) 5 (All Load All Store) 7 (Same Load All Store) Signed-off-by: Huacai Chen

loongarch: Use new fallback IO memcpy/memset

2024-10-28T21:44:29Z

Use the new fallback memcpy_{from,to}io and memset_io functions from lib/iomem_copy.c on the loongarch processor architecture. Reviewed-by: Yann Sionneau Signed-off-by: Julian Vetter Signed-off-by: Arnd Bergmann

LoongArch: KVM: Add PV IPI support on guest side

2024-05-06T14:00:47Z

PARAVIRT config option and PV IPI is added for the guest side, function pv_ipi_init() is used to add IPI sending and IPI receiving hooks. This function firstly checks whether system runs in VM mode, and if kernel runs in VM mode, it will call function kvm_para_available() to detect the current hypervirsor type (now only KVM type detection is supported). The paravirt functions can work only if current hypervisor type is KVM, since there is only KVM supported on LoongArch now. PV IPI uses virtual IPI sender and virtual IPI receiver functions. With virtual IPI sender, IPI message is stored in memory rather than emulated HW. IPI multicast is also supported, and 128 vcpus can received IPIs at the same time like X86 KVM method. Hypercall method is used for IPI sending. With virtual IPI receiver, HW SWI0 is used rather than real IPI HW. Since VCPU has separate HW SWI0 like HW timer, there is no trap in IPI interrupt acknowledge. Since IPI message is stored in memory, there is no trap in getting IPI message. Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

LoongArch: Add ORC stack unwinder support

2024-03-11T14:23:47Z

The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is similar in concept to a DWARF unwinder. The difference is that the format of the ORC data is much simpler than DWARF, which in turn allows the ORC unwinder to be much simpler and faster. The ORC data consists of unwind tables which are generated by objtool. After analyzing all the code paths of a .o file, it determines information about the stack state at each instruction address in the file and outputs that information to the .orc_unwind and .orc_unwind_ip sections. The per-object ORC sections are combined at link time and are sorted and post-processed at boot time. The unwinder uses the resulting data to correlate instruction addresses with their stack states at run time. Most of the logic are similar with x86, in order to get ra info before ra is saved into stack, add ra_reg and ra_offset into orc_entry. At the same time, modify some arch-specific code to silence the objtool warnings. Co-developed-by: Jinyang He Signed-off-by: Jinyang He Co-developed-by: Youling Tang Signed-off-by: Youling Tang Signed-off-by: Tiezhu Yang Signed-off-by: Huacai Chen

loongarch, kexec: change dependency of object files

2023-12-13T01:20:17Z

Patch series "kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC". The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be dropped, then compiling errors will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === E.g on mips, below link error are seen: -------------------------------------------------------------------- mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free': kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup' mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec': kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec' mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec': kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown' mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec' -------------------------------------------------------------------- Here, change the incorrect dependency of building kexec_core related object files, and the ifdeffery on architectures from CONFIG_KEXEC to CONFIG_KEXEC_CORE. Testing: ======== Passed on mips and loognarch with the LKP reproducer. This patch (of 5): Currently, in arch/loongarch/kernel/Makefile, building machine_kexec.o relocate_kernel.o depends on CONFIG_KEXEC. Whereas, since we will drop the select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec, compiling error will be triggered if below config items are set: === CONFIG_CRASH_CORE=y CONFIG_KEXEC_CORE=y CONFIG_CRASH_DUMP=y === --------------------------------------------------------------- loongarch64-linux-ld: kernel/kexec_core.o: in function `.L209': >> kexec_core.c:(.text+0x1660): undefined reference to `machine_kexec_cleanup' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L287': >> kexec_core.c:(.text+0x1c5c): undefined reference to `machine_crash_shutdown' >> loongarch64-linux-ld: kexec_core.c:(.text+0x1c64): undefined reference to `machine_kexec' loongarch64-linux-ld: kernel/kexec_core.o: in function `.L2^B5': >> kexec_core.c:(.text+0x2090): undefined reference to `machine_shutdown' loongarch64-linux-ld: kexec_core.c:(.text+0x20a0): undefined reference to `machine_kexec' --------------------------------------------------------------- Here, change the dependency of machine_kexec.o relocate_kernel.o to CONFIG_KEXEC_CORE can fix above building error. Link: https://lkml.kernel.org/r/20231208073036.7884-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20231208073036.7884-2-bhe@redhat.com Signed-off-by: Baoquan He Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202311300946.kHE9Iu71-lkp@intel.com/ Cc: Eric DeVolder Cc: Ignat Korchagin Cc: Stephen Rothwell Signed-off-by: Andrew Morton

LoongArch: Fix some build warnings with W=1

2023-09-20T06:26:28Z

There are some building warnings when building LoongArch kernel with W=1 as following, this patch fixes them. arch/loongarch/kernel/acpi.c:284:13: warning: no previous prototype for ‘acpi_numa_arch_fixup’ [-Wmissing-prototypes] 284 | void __init acpi_numa_arch_fixup(void) {} | ^~~~~~~~~~~~~~~~~~~~ arch/loongarch/kernel/time.c:32:13: warning: no previous prototype for ‘constant_timer_interrupt’ [-Wmissing-prototypes] 32 | irqreturn_t constant_timer_interrupt(int irq, void *data) | ^~~~~~~~~~~~~~~~~~~~~~~~ arch/loongarch/kernel/traps.c:496:25: warning: no previous prototype for 'do_fpe' [-Wmissing-prototypes] 496 | asmlinkage void noinstr do_fpe(struct pt_regs *regs | ^~~~~~ arch/loongarch/kernel/traps.c:813:22: warning: variable ‘opcode’ set but not used [-Wunused-but-set-variable] 813 | unsigned int opcode; | ^~~~~~ arch/loongarch/kernel/signal.c:895:14: warning: no previous prototype for ‘get_sigframe’ [-Wmissing-prototypes] 895 | void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, | ^~~~~~~~~~~~ arch/loongarch/kernel/syscall.c:21:40: warning: initialized field overwritten [-Woverride-init] 21 | #define __SYSCALL(nr, call) [nr] = (call), | ^ arch/loongarch/kernel/syscall.c:40:14: warning: no previous prototype for ‘do_syscall’ [-Wmissing-prototypes] 40 | void noinstr do_syscall(struct pt_regs *regs) | ^~~~~~~~~~ arch/loongarch/kernel/smp.c:502:17: warning: no previous prototype for ‘start_secondary’ [-Wmissing-prototypes] 502 | asmlinkage void start_secondary(void) | ^~~~~~~~~~~~~~~ arch/loongarch/kernel/process.c:309:15: warning: no previous prototype for ‘arch_align_stack’ [-Wmissing-prototypes] 309 | unsigned long arch_align_stack(unsigned long sp) | ^~~~~~~~~~~~~~~~ arch/loongarch/kernel/topology.c:13:5: warning: no previous prototype for ‘arch_register_cpu’ [-Wmissing-prototypes] 13 | int arch_register_cpu(int cpu) | ^~~~~~~~~~~~~~~~~ arch/loongarch/kernel/topology.c:27:6: warning: no previous prototype for ‘arch_unregister_cpu’ [-Wmissing-prototypes] 27 | void arch_unregister_cpu(int cpu) | ^~~~~~~~~~~~~~~~~~~ arch/loongarch/kernel/module-sections.c:103:5: warning: no previous prototype for ‘module_frob_arch_sections’ [-Wmissing-prototypes] 103 | int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, | ^~~~~~~~~~~~~~~~~~~~~~~~~ arch/loongarch/mm/hugetlbpage.c:56:5: warning: no previous prototype for ‘is_aligned_hugepage_range’ [-Wmissing-prototypes] 56 | int is_aligned_hugepage_range(unsigned long addr, unsigned long len) | ^~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Bibo Mao Signed-off-by: Huacai Chen

LoongArch: Add KASAN (Kernel Address Sanitizer) support

2023-09-06T14:54:16Z

1/8 of kernel addresses reserved for shadow memory. But for LoongArch, There are a lot of holes between different segments and valid address space (256T available) is insufficient to map all these segments to kasan shadow memory with the common formula provided by kasan core, saying (addr >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET So LoongArch has a arch-specific mapping formula, different segments are mapped individually, and only limited space lengths of these specific segments are mapped to shadow. At early boot stage the whole shadow region populated with just one physical page (kasan_early_shadow_page). Later, this page is reused as readonly zero shadow for some memory that kasan currently don't track. After mapping the physical memory, pages for shadow memory are allocated and mapped. Functions like memset()/memcpy()/memmove() do a lot of memory accesses. If bad pointer passed to one of these function it is important to be caught. Compiler's instrumentation cannot do this since these functions are written in assembly. KASan replaces memory functions with manually instrumented variants. Original functions declared as weak symbols so strong definitions in mm/kasan/kasan.c could replace them. Original functions have aliases with '__' prefix in names, so we could call non-instrumented variant if needed. Signed-off-by: Qing Zhang Signed-off-by: Huacai Chen

LoongArch: Add basic KGDB & KDB support

2023-09-06T14:53:55Z

KGDB is intended to be used as a source level debugger for the Linux kernel. It is used along with gdb to debug a Linux kernel. GDB can be used to "break in" to the kernel to inspect memory, variables and regs similar to the way an application developer would use GDB to debug an application. KDB is a frontend of KGDB which is similar to GDB. By now, in addition to the generic KGDB features, the LoongArch KGDB implements the following features: - Hardware breakpoints/watchpoints; - Software single-step support for KDB. Signed-off-by: Qing Zhang # Framework & CoreFeature Signed-off-by: Binbin Zhou # BreakPoint & SingleStep Signed-off-by: Hui Li # Some Minor Improvements Signed-off-by: Randy Dunlap # Some Build Error Fixes 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