Linux kernel development work - see feature branches https://git.zx2c4.com/linux-dev/atom/arch/loongarch/kernel?h=master 2022-10-29T08:29:31Z 2022-10-29T08:29:31Z Jinyang He hejinyang@loongson.cn 2022-10-29T08:29:31Z urn:sha1:b40fa75e1542e069a4eb9b33d62061d4ae734537 The current LoongArch kernel stack is padded as if obeying the MIPS o32 calling convention (32 bytes), signifying the port's MIPS lineage but no longer making sense. Remove the padding for clarity. Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-16T22:27:07Z Linus Torvalds torvalds@linux-foundation.org 2022-10-16T22:27:07Z urn:sha1:f1947d7c8a61db1cb0ef909a6512ede0b1f2115b Pull more random number generator updates from Jason Donenfeld: "This time with some large scale treewide cleanups. The intent of this pull is to clean up the way callers fetch random integers. The current rules for doing this right are: - If you want a secure or an insecure random u64, use get_random_u64() - If you want a secure or an insecure random u32, use get_random_u32() The old function prandom_u32() has been deprecated for a while now and is just a wrapper around get_random_u32(). Same for get_random_int(). - If you want a secure or an insecure random u16, use get_random_u16() - If you want a secure or an insecure random u8, use get_random_u8() - If you want secure or insecure random bytes, use get_random_bytes(). The old function prandom_bytes() has been deprecated for a while now and has long been a wrapper around get_random_bytes() - If you want a non-uniform random u32, u16, or u8 bounded by a certain open interval maximum, use prandom_u32_max() I say "non-uniform", because it doesn't do any rejection sampling or divisions. Hence, it stays within the prandom_*() namespace, not the get_random_*() namespace. I'm currently investigating a "uniform" function for 6.2. We'll see what comes of that. By applying these rules uniformly, we get several benefits: - By using prandom_u32_max() with an upper-bound that the compiler can prove at compile-time is ≤65536 or ≤256, internally get_random_u16() or get_random_u8() is used, which wastes fewer batched random bytes, and hence has higher throughput. - By using prandom_u32_max() instead of %, when the upper-bound is not a constant, division is still avoided, because prandom_u32_max() uses a faster multiplication-based trick instead. - By using get_random_u16() or get_random_u8() in cases where the return value is intended to indeed be a u16 or a u8, we waste fewer batched random bytes, and hence have higher throughput. This series was originally done by hand while I was on an airplane without Internet. Later, Kees and I worked on retroactively figuring out what could be done with Coccinelle and what had to be done manually, and then we split things up based on that. So while this touches a lot of files, the actual amount of code that's hand fiddled is comfortably small" * tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: prandom: remove unused functions treewide: use get_random_bytes() when possible treewide: use get_random_u32() when possible treewide: use get_random_{u8,u16}() when possible, part 2 treewide: use get_random_{u8,u16}() when possible, part 1 treewide: use prandom_u32_max() when possible, part 2 treewide: use prandom_u32_max() when possible, part 1 2022-10-12T17:35:20Z Linus Torvalds torvalds@linux-foundation.org 2022-10-12T17:35:20Z urn:sha1:95b8b5953a315081eadbadf49200e57d7e05aae7 Pull LoongArch updates from Huacai Chen: - Use EXPLICIT_RELOCS (ABIv2.0) - Use generic BUG() handler - Refactor TLB/Cache operations - Add qspinlock support - Add perf events support - Add kexec/kdump support - Add BPF JIT support - Add ACPI-based laptop driver - Update the default config file * tag 'loongarch-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (25 commits) LoongArch: Update Loongson-3 default config file LoongArch: Add ACPI-based generic laptop driver LoongArch: Add BPF JIT support LoongArch: Add some instruction opcodes and formats LoongArch: Move {signed,unsigned}_imm_check() to inst.h LoongArch: Add kdump support LoongArch: Add kexec support LoongArch: Use generic BUG() handler LoongArch: Add SysRq-x (TLB Dump) support LoongArch: Add perf events support LoongArch: Add qspinlock support LoongArch: Use TLB for ioremap() LoongArch: Support access filter to /dev/mem interface LoongArch: Refactor cache probe and flush methods LoongArch: mm: Refactor TLB exception handlers LoongArch: Support R_LARCH_GOT_PC_{LO12,HI20} in modules LoongArch: Support PC-relative relocations in modules LoongArch: Define ELF relocation types added in ABIv2.0 LoongArch: Adjust symbol addressing for AS_HAS_EXPLICIT_RELOCS LoongArch: Add Kconfig option AS_HAS_EXPLICIT_RELOCS ... 2022-10-12T08:36:19Z Tiezhu Yang yangtiezhu@loongson.cn 2022-10-12T08:36:19Z urn:sha1:8a34228eb30308f6e223c6f2b87e2381d45056e2 {signed,unsigned}_imm_check() will also be used in the bpf jit, so move them from module.c to inst.h, this is preparation for later patches. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:19Z Youling Tang tangyouling@loongson.cn 2022-10-12T08:36:19Z urn:sha1:4e62d1d86585e1b62b4f96ee586881dd45a443dc This patch adds support for kdump. In kdump case the normal kernel will reserve a region for the crash kernel and jump there on panic. Arch-specific functions are added to allow for implementing a crash dump file interface, /proc/vmcore, which can be viewed as a ELF file. A user-space tool, such as kexec-tools, is responsible for allocating a separate region for the core's ELF header within the crash kdump kernel memory and filling it in when executing kexec_load(). Then, its location will be advertised to the crash dump kernel via a command line argument "elfcorehdr=", and the crash dump kernel will preserve this region for later use with arch_reserve_vmcore() at boot time. At the same time, the crash kdump kernel is also limited within the "crashkernel" area via a command line argument "mem=", so as not to destroy the original kernel dump data. In the crash dump kernel environment, /proc/vmcore is used to access the primary kernel's memory with copy_oldmem_page(). I tested kdump on LoongArch machines (Loongson-3A5000) and it works as expected (suggested crashkernel parameter is "crashkernel=512M@2560M"), you may test it by triggering a crash through /proc/sysrq-trigger: $ sudo kexec -p /boot/vmlinux-kdump --reuse-cmdline --append="nr_cpus=1" # echo c > /proc/sysrq-trigger Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:19Z Youling Tang tangyouling@loongson.cn 2022-10-12T08:36:19Z urn:sha1:4a03b2ac06a5bcae29371866d9d11f5bfd4c9188 Add three new files, kexec.h, machine_kexec.c and relocate_kernel.S to the LoongArch architecture, so as to add support for the kexec re-boot mechanism (CONFIG_KEXEC) on LoongArch platforms. Kexec supports loading vmlinux.elf in ELF format and vmlinux.efi in PE format. I tested kexec on LoongArch machines (Loongson-3A5000) and it works as expected: $ sudo kexec -l /boot/vmlinux.efi --reuse-cmdline $ sudo kexec -e Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:19Z Youling Tang tangyouling@loongson.cn 2022-10-12T08:36:19Z urn:sha1:2d2c395217d2233e752dbddcae3c5d94050b48c1 Inspired by commit 9fb7410f955("arm64/BUG: Use BRK instruction for generic BUG traps"), do similar for LoongArch to use generic BUG() handler. This patch uses the BREAK software breakpoint instruction to generate a trap instead, similarly to most other arches, with the generic BUG code generating the dmesg boilerplate. This allows bug metadata to be moved to a separate table and reduces the amount of inline code at BUG() and WARN() sites. This also avoids clobbering any registers before they can be dumped. To mitigate the size of the bug table further, this patch makes use of the existing infrastructure for encoding addresses within the bug table as 32-bit relative pointers instead of absolute pointers. (Note: this limits the max kernel size to 2GB.) Before patch: [ 3018.338013] lkdtm: Performing direct entry BUG [ 3018.342445] Kernel bug detected[#5]: [ 3018.345992] CPU: 2 PID: 865 Comm: cat Tainted: G D 6.0.0-rc6+ #35 After patch: [ 125.585985] lkdtm: Performing direct entry BUG [ 125.590433] ------------[ cut here ]------------ [ 125.595020] kernel BUG at drivers/misc/lkdtm/bugs.c:78! [ 125.600211] Oops - BUG[#1]: [ 125.602980] CPU: 3 PID: 410 Comm: cat Not tainted 6.0.0-rc6+ #36 Out-of-line file/line data information obtained compared to before. Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:14Z Huacai Chen chenhuacai@loongson.cn 2022-10-12T08:36:14Z urn:sha1:dea2df3cc72555633cc7858ce1daa4b757f843ad Add SysRq-x (TLB Dump) support for LoongArch, which is useful for debugging. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:14Z Huacai Chen chenhuacai@loongson.cn 2022-10-12T08:36:14Z urn:sha1:b37042b2bb7cd751f03b73afb90364a418d870f4 The perf events infrastructure of LoongArch is very similar to old MIPS- based Loongson, so most of the codes are derived from MIPS. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2022-10-12T08:36:14Z Huacai Chen chenhuacai@loongson.cn 2022-10-12T08:36:14Z urn:sha1:d279134168c78ac2caa1f7cd2a846579da1c93ac We can support more cache attributes (e.g., CC, SUC and WUC) and page protection when we use TLB for ioremap(). The implementation is based on GENERIC_IOREMAP. The existing simple ioremap() implementation has better performance so we keep it and introduce ARCH_IOREMAP to control the selection. We move pagetable_init() earlier to make early ioremap() works, and we modify the PCI ecam mapping because the TLB-based version of ioremap() will actually take the size into account. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>