If the default state of the interrupt controllers in the first kernel
don't mask any interrupts, it may cause the second kernel to potentially
receive interrupts (which were previously allocated by the first kernel)
immediately after a CPU becomes online during its boot process. These
interrupts cannot be properly routed, leading to bad IRQ issues.
This patch calls machine_kexec_mask_interrupts() to mask all interrupts
during the kexec/kdump process.
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Consolidate the machine_kexec_mask_interrupts implementation into a common
function located in a new file: kernel/irq/kexec.c. This removes duplicate
implementations from architecture-specific files in arch/arm, arch/arm64,
arch/powerpc, and arch/riscv, reducing code duplication and improving
maintainability.
The new implementation retains architecture-specific behavior for
CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD, which was previously implemented
for ARM64. When enabled (currently for ARM64), it clears the active state
of interrupts forwarded to virtual machines (VMs) before handling other
interrupt masking operations.
Signed-off-by: Eliav Farber <farbere@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241204142003.32859-2-farbere@amazon.com
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The current LoongArch BPF trampoline implementation is incompatible
with tracing functions in kernel modules. This causes several severe
and user-visible problems:
* The `bpf_selftests/module_attach` test fails consistently.
* Kernel lockup when a BPF program is attached to a module function [1].
* Critical kernel modules like WireGuard experience traffic disruption
when their functions are traced with fentry [2].
Given the severity and the potential for other unknown side-effects, it
is safest to disable the feature entirely for now. This patch prevents
the BPF subsystem from allowing trampoline attachments to kernel module
functions on LoongArch.
This is a temporary mitigation until the core issues in the trampoline
code for kernel module handling can be identified and fixed.
[root@fedora bpf]# ./test_progs -a module_attach -v
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_module_attach:PASS:skel_open 0 nsec
test_module_attach:PASS:set_attach_target 0 nsec
test_module_attach:PASS:set_attach_target_explicit 0 nsec
test_module_attach:PASS:skel_load 0 nsec
libbpf: prog 'handle_fentry': failed to attach: -ENOTSUPP
libbpf: prog 'handle_fentry': failed to auto-attach: -ENOTSUPP
test_module_attach:FAIL:skel_attach skeleton attach failed: -524
Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
Successfully unloaded bpf_testmod.ko.
[1]: https://lore.kernel.org/loongarch/CAK3+h2wDmpC-hP4u4pJY8T-yfKyk4yRzpu2LMO+C13FMT58oqQ@mail.gmail.com/
[2]: https://lore.kernel.org/loongarch/CAK3+h2wYcpc+OwdLDUBvg2rF9rvvyc5amfHT-KcFaK93uoELPg@mail.gmail.com/
Cc: stable@vger.kernel.org
Fixes: f9b6b41f0cf3 ("LoongArch: BPF: Add basic bpf trampoline support")
Acked-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
If there is no valid cache info detected (may happen in virtual machine)
for pci_dfl_cache_line_size, kernel shouldn't panic. Because in the PCI
core it will be evaluated to (L1_CACHE_BYTES >> 2).
Cc: <stable@vger.kernel.org>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
On physical machine, NUMA node id comes from high bit 44:48 of physical
address. However it is not true on virt machine. With general method, it
comes from ACPI SRAT table.
Here the common function numa_memblks_init() is used to parse NUMA node
information with numa_memblks.
Cc: <stable@vger.kernel.org>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
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 <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The kernel UAPI headers already contain fixed-width integer types, there
is no need to rely on the libc types. There may not be a libc available
or the libc may not provides the <stdint.h>, like for example on nolibc.
This also aligns the header with the rest of the LoongArch UAPI headers.
Fixes: 803b0fc5c3f2 ("LoongArch: Add process management")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Now there 5 places which calculate max_pfn & max_low_pfn:
1. in fdt_setup() for FDT systems;
2. in memblock_init() for ACPI systems;
3. in init_numa_memory() for NUMA systems;
4. in arch_mem_init() to recalculate for "mem=" cmdline;
5. in paging_init() to recalculate for NUMA systems.
Since memblock_init() is called both for ACPI and FDT systems, move the
calculation out of the for_each_efi_memory_desc() loop can eliminate the
first case. The last case is very questionable (may be derived from the
MIPS/Loongson code) and breaks the "mem=" cmdline, so should be removed.
And then the NUMA version of paging_init() can be also eliminated.
After consolidation there are 3 places of calculation:
1. in memblock_init() for both ACPI and FDT systems;
2. in init_numa_memory() to recalculate for NUMA systems;
3. in arch_mem_init() to recalculate for the "mem=" cmdline.
For all cases the calculation is:
max_pfn = PFN_DOWN(memblock_end_of_DRAM());
max_low_pfn = min(PFN_DOWN(HIGHMEM_START), max_pfn);
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When specifying '-d' for kexec_file_load interface, loaded locations of
kernel/initrd/cmdline etc can be printed out to help debug.
Commit eb7622d908a0 ("kexec_file, riscv: print out debugging message if
required") fixes the same issue on RISC-V.
So, remove kexec_image_info() because the content has been printed out
in generic code.
And on Loongson-3A5000, the printed messages look like below:
kexec_file: kernel: 00000000d9aad283 kernel_size: 0x2e77f30
kexec_file(EFI): No LoongArch PE image header.
kexec_file: Loaded initrd at 0x80000000 bufsz=0x1637cd0 memsz=0x1638000
kexec_file(ELF): Loaded kernel at 0x9c20000 bufsz=0x27f1800 memsz=0x2950000
kexec_file: nr_segments = 2
kexec_file: segment[0]: buf=0x00000000cc3e6c33 bufsz=0x27f1800 mem=0x9c20000 memsz=0x2950000
kexec_file: segment[1]: buf=0x00000000bb75a541 bufsz=0x1637cd0 mem=0x80000000 memsz=0x1638000
kexec_file: kexec_file_load: type:0, start:0xb15d000 head:0x18db60002 flags:0x8
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The kexec_buf structure was previously declared without initialization.
commit bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
added a field that is always read but not consistently populated by all
architectures. This un-initialized field will contain garbage.
This is also triggering a UBSAN warning when the uninitialized data is
accessed:
------------[ cut here ]------------
UBSAN: invalid-load in ./include/linux/kexec.h:210:10
load of value 252 is not a valid value for type '_Bool'
Zero-initializing kexec_buf at declaration ensures all fields are
cleanly set, preventing future instances of uninitialized memory being
used.
Fixes: bf454ec31add ("kexec_file: allow to place kexec_buf randomly")
Link: https://lore.kernel.org/r/20250827-kbuf_all-v1-2-1df9882bb01a@debian.org
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
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 <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Remove the unnecessary __GFP_HIGHMEM masking in pud_alloc_one(), which
was introduced with commit 382739797f79ec2 ("loongarch: convert various
functions to use ptdescs"). GFP_KERNEL doesn't contain __GFP_HIGHMEM.
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Now if the PTE/PMD is dirty with _PAGE_DIRTY but without _PAGE_MODIFIED,
after {pte,pmd}_modify() we lose _PAGE_DIRTY, then {pte,pmd}_dirty()
return false and lead to data loss. This can happen in certain scenarios
such as HW PTW doesn't set _PAGE_MODIFIED automatically, so here we need
_PAGE_MODIFIED to record the dirty status (_PAGE_DIRTY).
The new modification involves checking whether the original PTE/PMD has
the _PAGE_DIRTY flag. If it exists, the _PAGE_MODIFIED bit is also set,
ensuring that the {pte,pmd}_dirty() interface can always return accurate
information.
Cc: stable@vger.kernel.org
Co-developed-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Liupu Wang <wangliupu@loongson.cn>
Signed-off-by: Tianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
1. Use phys_addr_t instead of u64, which can work for both 32/64 bits.
2. Check whether the input physical address is above TO_PHYS_MASK (and
return NULL if yes) for the DMW version.
Note: In theory early_ioremap() also need the TO_PHYS_MASK checking, but
the UEFI BIOS pass some DMW virtual addresses.
Cc: stable@vger.kernel.org
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Now we use virtual addresses to fill CSR_MERRENTRY/CSR_TLBRENTRY, but
hardware hope physical addresses. Now it works well because the high
bits are ignored above PA_BITS (48 bits), but explicitly use physical
addresses can avoid potential bugs. So fix it.
Cc: stable@vger.kernel.org
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
LoongArch's MSG interrupt features are used across multiple subsystems.
Clarify these features to avoid misuse, existing users will be adjusted
if necessary.
MSGINT: Infrastructure, means the CPU core supports message interupts.
Indicated by CPUCFG1.MSGINT.
AVECINT: AVEC interrupt controller based on MSGINT, means the CPU chip
supports direct message interrupts. Indicated by IOCSR.FEATURES.DMSI.
REDIRECTINT: REDIRECT interrupt controller based on MSGINT and AVECINT,
means the CPU chip supports redirect message interrupts. Indicated by
IOCSR.FEATURES.RMSI.
For example:
Loongson-3A5000/3C5000 doesn't support MSGINT/AVECINT/REDIRECTINT;
Loongson-3A6000 supports MSGINT but doesn't support AVECINT/REDIRECTINT;
Loongson-3C6000 supports MSGINT/AVECINT/REDIRECTINT.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The HD-audio codec driver configs have been updated again the drivers
got split with different kconfigs.
Enable all Realtek HD-audio codecs and HDMI codecs (except for
NVIDIA_MCP and TEGRA) per request.
Fixes: 1d8dd982c409 ("ALSA: hda/realtek: Enable drivers as default")
Fixes: 81231ad173d8 ("ALSA: hda/hdmi: Enable drivers as default")
Cc: loongarch@lists.linux.dev
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250731091109.16901-3-tiwai@suse.de
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When attach fentry/fexit BPF programs, __arch_prepare_bpf_trampoline()
is called twice with different `struct bpf_tramp_image *im`:
bpf_trampoline_update()
-> arch_bpf_trampoline_size()
-> __arch_prepare_bpf_trampoline()
-> arch_prepare_bpf_trampoline()
-> __arch_prepare_bpf_trampoline()
Use move_imm() will emit unstable instruction sequences, so let's use
move_addr() instead to prevent subtle bugs.
(I observed this while debugging other issues with printk.)
Cc: stable@vger.kernel.org
Tested-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The current implementation of bpf_arch_text_poke() requires 5 nops
at patch site which is not applicable for kernel/module functions.
Because LoongArch reserves ONLY 2 nops at the function entry. With
CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS=y, this can be done by ftrace
instead.
See the following commit for details:
* commit b91e014f078e ("bpf: Make BPF trampoline use register_ftrace_direct() API")
* commit 9cdc3b6a299c ("LoongArch: ftrace: Add direct call support")
Cc: stable@vger.kernel.org
Tested-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
In __arch_prepare_bpf_trampoline(), retval_off is meaningful only when
save_ret is not 0, so the current logic is correct. But it may cause a
build warning:
arch/loongarch/net/bpf_jit.c:1547 __arch_prepare_bpf_trampoline() error: uninitialized symbol 'retval_off'.
So initialize retval_off unconditionally to fix it.
Cc: stable@vger.kernel.org
Fixes: f9b6b41f0cf3 ("LoongArch: BPF: Add basic bpf trampoline support")
Closes: https://lore.kernel.org/r/202508191020.PBBh07cK-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The atomic instructions sc.q, llacq.{w/d}, screl.{w/d} were newly added
in the LoongArch Reference Manual v1.10, it is necessary to handle them
in insns_not_supported() to avoid putting a breakpoint in the middle of
a ll/sc atomic sequence, otherwise it will loop forever for kprobes and
uprobes.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Attempt VMA lock-based page fault handling first, and fall back to the
existing mmap_lock-based handling if that fails.
The "ebizzy -mTRp" test on Loongson-3A6000 shows that PER_VMA_LOCK can
improve the benchmark by about 17.9% (97837.7 to 115430.8).
This is the LoongArch variant of "x86/mm: try VMA lock-based page fault
handling first".
Signed-off-by: Wentao Guan <guanwentao@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Automatically disable kaslr when the kernel loads from kexec_file.
kexec_file loads the secondary kernel image to a non-linked address,
inherently providing KASLR-like randomization.
However, on LoongArch where System RAM may be non-contiguous, enabling
KASLR for the second kernel may relocate it to an invalid memory region
and cause a boot failure. Thus, we disable KASLR when "kexec_file" is
detected in the command line.
To ensure compatibility with older kernels loaded via kexec_file, this
patch should be backported to stable branches.
Cc: stable@vger.kernel.org
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Enabling crash dump (kdump) includes:
- Prepare contents of ELF header of a core dump file, /proc/vmcore,
using crash_prepare_elf64_headers().
- Add "mem=size@start" parameter to the command line and pass it to the
capture kernel. Limit the runtime memory area of the captured kernel
to avoid disrupting the production kernel's runtime state.
- Add "elfcorehdr=size@start" parameter to the cmdline.
The basic usage for kdump (add the cmdline parameter crashkernel=512M
to grub.cfg for production kernel):
1) Load capture kernel image (vmlinux.efi or vmlinux can both be used):
# kexec -s -p vmlinuz.efi --initrd=initrd.img --reuse-cmdline
2) Do something to crash, like:
# echo c > /proc/sysrq-trigger
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
This patch creates kexec_elf_ops to load ELF binary file for
kexec_file_load() syscall.
However, for `kbuf->memsz` and `kbuf->buf_min`, special handling is
required, and the generic `kexec_elf_load()` cannot be used directly.
$ readelf -l vmlinux
...
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000010000 0x9000000000200000 0x9000000000200000
0x0000000002747a00 0x000000000287a0d8 RWE 0x10000
NOTE 0x0000000000000000 0x0000000000000000 0x0000000000000000
0x0000000000000000 0x0000000000000000 R 0x8
phdr->p_paddr should have been a physical address, but it is a virtual
address on the current LoongArch. This will cause kexec_file to fail
when loading the kernel and need to be converted to a physical address.
From the above MemSiz, it can be seen that 0x287a0d8 isn't page aligned.
Although kexec_add_buffer() will perform PAGE_SIZE alignment on kbuf->
memsz, there is still a stampeding in the loaded kernel space and initrd
space. The initrd resolution failed when starting the second kernel.
It can be known from the link script vmlinux.lds.S that,
BSS_SECTION(0, SZ_64K, 8)
. = ALIGN(PECOFF_SEGMENT_ALIGN);
It needs to be aligned according to SZ_64K, so that after alignment, its
size is consistent with _kernel_asize.
The basic usage (vmlinux):
1) Load second kernel image:
# kexec -s -l vmlinux --initrd=initrd.img --reuse-cmdline
2) Startup second kernel:
# kexec -e
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
This patch creates kexec_efi_ops to load EFI binary file for
kexec_file_load() syscall.
The efi_kexec_load() as two parts:
- the first part loads the kernel image (vmlinuz.efi or vmlinux.efi)
- the second part loads other segments (e.g: initrd, cmdline, etc)
Currently, pez (vmlinuz.efi) and pei (vmlinux.efi) format images are
supported.
The basic usage (vmlinuz.efi or vmlinux.efi):
1) Load second kernel image:
# kexec -s -l vmlinuz.efi --initrd=initrd.img --reuse-cmdline
2) Startup second kernel:
# kexec -e
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Add some preparatory infrastructure:
- Add command line processing.
- Add support for loading other segments.
- Other minor modifications.
This initrd will be passed to the second kernel via the command line
'initrd=start,size'.
The 'kexec_file' command line parameter indicates that the kernel is
loaded via kexec_file.
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Define a dedicated image header structure for LoongArch architecture to
standardize kernel loading in bootloaders (primarily for kexec_file).
This header includes critical metadata, such as PE/DOS signature, kernel
entry points, kernel image size and load address offset, etc.
Signed-off-by: Youling Tang <tangyouling@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
For power saving or debugging purpose, we usually want to limit the SIMD
(LSX/LASX) usage on a rich feature platform. So allow specify SIMD width
via kernel parameters "simd=".
Allowed values of "simd=" are any integers, and recommended values are:
0: Disable all SIMD features;
128: Enable at most 128bit SIMD features;
256: Enable at most 256bit SIMD features;
-1(default): Enable as many as possible SIMD features automatically.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Commit b15212824a01 ("LoongArch: Make LTO case independent in Makefile")
moves "KBUILD_LDFLAGS += -mllvm --loongarch-annotate-tablejump" out of
CONFIG_CC_HAS_ANNOTATE_TABLEJUMP, which breaks the build for LLVM-18, as
'--loongarch-annotate-tablejump' is unimplemented there:
ld.lld: error: -mllvm: ld.lld: Unknown command line argument '--loongarch-annotate-tablejump'.
Call ld-option to detect '--loongarch-annotate-tablejump' before use, so
as to fix the build error.
Fixes: b15212824a01 ("LoongArch: Make LTO case independent in Makefile")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build
Suggested-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Currently, when compiling with GCC, there is no "break 7" instruction
for zero division due to using the option -mno-check-zero-division, but
the compiler still generates "break 0" instruction for zero division.
Here is a simple example:
$ cat test.c
int div(int a)
{
return a / 0;
}
$ gcc -O2 -S test.c -o test.s
GCC generates "break 0" on LoongArch and "ud2" on x86, objtool decodes
"ud2" as INSN_BUG for x86, so decode "break 0" as INSN_BUG can fix the
objtool warnings for LoongArch, but this is not the intention.
When decoding "break 0" as INSN_TRAP in the previous commit, the aim is
to handle "break 0" as a trap. The generated "break 0" for zero division
by GCC is not proper, it should generate a break instruction with proper
bug type, so add the GCC option -fno-isolate-erroneous-paths-dereference
to avoid generating the unexpected "break 0" instruction for now.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202509200413.7uihAxJ5-lkp@intel.com/
Fixes: baad7830ee9a ("objtool/LoongArch: Mark types based on break immediate code")
Suggested-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Add a NULL-pointer check after the kcalloc() call in init_vdso(). If
allocation fails, return -ENOMEM to prevent a possible dereference of
vdso_info.code_mapping.pages when it is NULL.
Cc: stable@vger.kernel.org
Fixes: 2ed119aef60d ("LoongArch: Set correct size for vDSO code mapping")
Signed-off-by: Guangshuo Li <202321181@mail.sdu.edu.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When testing the kernel live patching with "modprobe livepatch-sample",
there is a timeout over 15 seconds from "starting patching transition"
to "patching complete". The dmesg command shows "unreliable stack" for
user tasks in debug mode, here is one of the messages:
livepatch: klp_try_switch_task: bash:1193 has an unreliable stack
The "unreliable stack" is because it can not unwind from do_syscall()
to its previous frame handle_syscall(). It should use fp to find the
original stack top due to secondary stack in do_syscall(), but fp is
not used for some other functions, then fp can not be restored by the
next frame of do_syscall(), so it is necessary to save fp if task is
not current, in order to get the stack top of do_syscall().
Here are the call chains:
klp_enable_patch()
klp_try_complete_transition()
klp_try_switch_task()
klp_check_and_switch_task()
klp_check_stack()
stack_trace_save_tsk_reliable()
arch_stack_walk_reliable()
When executing "rmmod livepatch-sample", there exists a similar issue.
With this patch, it takes a short time for patching and unpatching.
Before:
# modprobe livepatch-sample
# dmesg -T | tail -3
[Sat Sep 6 11:00:20 2025] livepatch: 'livepatch_sample': starting patching transition
[Sat Sep 6 11:00:35 2025] livepatch: signaling remaining tasks
[Sat Sep 6 11:00:36 2025] livepatch: 'livepatch_sample': patching complete
# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
# rmmod livepatch_sample
rmmod: ERROR: Module livepatch_sample is in use
# rmmod livepatch_sample
# dmesg -T | tail -3
[Sat Sep 6 11:06:05 2025] livepatch: 'livepatch_sample': starting unpatching transition
[Sat Sep 6 11:06:20 2025] livepatch: signaling remaining tasks
[Sat Sep 6 11:06:21 2025] livepatch: 'livepatch_sample': unpatching complete
After:
# modprobe livepatch-sample
# dmesg -T | tail -2
[Tue Sep 16 16:19:30 2025] livepatch: 'livepatch_sample': starting patching transition
[Tue Sep 16 16:19:31 2025] livepatch: 'livepatch_sample': patching complete
# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
# rmmod livepatch_sample
# dmesg -T | tail -2
[Tue Sep 16 16:19:36 2025] livepatch: 'livepatch_sample': starting unpatching transition
[Tue Sep 16 16:19:37 2025] livepatch: 'livepatch_sample': unpatching complete
Cc: stable@vger.kernel.org # v6.9+
Fixes: 199cc14cb4f1 ("LoongArch: Add kernel livepatching support")
Reported-by: Xi Zhang <zhangxi@kylinos.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
As Documentation/filesystems/sysfs.rst suggested, show() should only use
sysfs_emit() or sysfs_emit_at() when formatting the value to be returned
to user space.
No functional change intended.
Cc: stable@vger.kernel.org
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
ARCH_STRICT_ALIGN is used for hardware without UAL, now it only control
the -mstrict-align flag. However, ACPI structures are packed by default
so will cause unaligned accesses.
To avoid this, define ACPI_MISALIGNMENT_NOT_SUPPORTED in asm/acenv.h to
align ACPI structures if ARCH_STRICT_ALIGN enabled.
Cc: stable@vger.kernel.org
Reported-by: Binbin Zhou <zhoubinbin@loongson.cn>
Suggested-by: Xi Ruoyao <xry111@xry111.site>
Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Loongson-3A6000 and 3C6000 CPUs also support unaligned memory access, so
the current description is out of date to some extent.
Actually, all of Loongson-3 series processors based on LoongArch support
unaligned memory access, this hardware capability is indicated by the bit
20 (UAL) of CPUCFG1 register, update the help info to reflect the reality.
Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with LLVM and CONFIG_RUST is set, there exist objtool
warnings in rust/core.o and rust/kernel.o, like this:
rust/core.o: warning: objtool:
_RNvXs1_NtNtCs5QSdWC790r4_4core5ascii10ascii_charNtB5_9AsciiCharNtNtB9_3fmt5Debug3fmt+0x54:
sibling call from callable instruction with modified stack frame
For this special case, the related object file shows that there is no
generated relocation section '.rela.discard.tablejump_annotate' for the
table jump instruction jirl, thus objtool can not know that what is the
actual destination address.
If rustc has the option "-Cllvm-args=--loongarch-annotate-tablejump",
pass the option to enable jump tables for objtool, otherwise it should
pass "-Zno-jump-tables" to keep compatibility with older rustc.
How to test:
$ rustup component add rust-src
$ make LLVM=1 rustavailable
$ make ARCH=loongarch LLVM=1 clean defconfig
$ scripts/config -d MODVERSIONS \
-e RUST -e SAMPLES -e SAMPLES_RUST \
-e SAMPLE_RUST_CONFIGFS -e SAMPLE_RUST_MINIMAL \
-e SAMPLE_RUST_MISC_DEVICE -e SAMPLE_RUST_PRINT \
-e SAMPLE_RUST_DMA -e SAMPLE_RUST_DRIVER_PCI \
-e SAMPLE_RUST_DRIVER_PLATFORM -e SAMPLE_RUST_DRIVER_FAUX \
-e SAMPLE_RUST_DRIVER_AUXILIARY -e SAMPLE_RUST_HOSTPROGS
$ make ARCH=loongarch LLVM=1 olddefconfig all
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When compiling with LLVM and CONFIG_LTO_CLANG is set, there exist many
objtool warnings "sibling call from callable instruction with modified
stack frame".
For this special case, the related object file shows that there is no
generated relocation section '.rela.discard.tablejump_annotate' for the
table jump instruction jirl, thus objtool can not know that what is the
actual destination address.
It needs to do something on the LLVM side to make sure that there is the
relocation section '.rela.discard.tablejump_annotate' if LTO is enabled,
but in order to maintain compatibility for the current LLVM compiler,
this can be done in the kernel Makefile for now. Ensure it is aware of
linker with LTO, '--loongarch-annotate-tablejump' needs to be passed via
'-mllvm' to ld.lld.
Note that it should also pass the compiler option -mannotate-tablejump
rather than only pass '-mllvm --loongarch-annotate-tablejump' to ld.lld
if LTO is enabled, otherwise there are no jump info for some table jump
instructions.
Fixes: e20ab7d454ee ("LoongArch: Enable jump table for objtool")
Closes: https://lore.kernel.org/loongarch/20250731175655.GA1455142@ax162/
Reported-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Co-developed-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Huacai Chen