kernel.git/arch/mips/kernel, branch linux-5.16.y

MIPS: fix fortify panic when copying asm exception handlers

2022-04-13T18:03:05Z

[ Upstream commit d17b66417308996e7e64b270a3c7f3c1fbd4cfc8 ] With KCFLAGS="-O3", I was able to trigger a fortify-source memcpy() overflow panic on set_vi_srs_handler(). Although O3 level is not supported in the mainline, under some conditions that may've happened with any optimization settings, it's just a matter of inlining luck. The panic itself is correct, more precisely, 50/50 false-positive and not at the same time. From the one side, no real overflow happens. Exception handler defined in asm just gets copied to some reserved places in the memory. But the reason behind is that C code refers to that exception handler declares it as `char`, i.e. something of 1 byte length. It's obvious that the asm function itself is way more than 1 byte, so fortify logics thought we are going to past the symbol declared. The standard way to refer to asm symbols from C code which is not supposed to be called from C is to declare them as `extern const u8[]`. This is fully correct from any point of view, as any code itself is just a bunch of bytes (including 0 as it is for syms like _stext/_etext/etc.), and the exact size is not known at the moment of compilation. Adjust the type of the except_vec_vi_*() and related variables. Make set_handler() take `const` as a second argument to avoid cast-away warnings and give a little more room for optimization. Signed-off-by: Alexander Lobakin Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: smp: fill in sibling and core maps earlier

2022-03-19T12:48:43Z

[ Upstream commit f2703def339c793674010cc9f01bfe4980231808 ] After enabling CONFIG_SCHED_CORE (landed during 5.14 cycle), 2-core 2-thread-per-core interAptiv (CPS-driven) started emitting the following: [ 0.025698] CPU1 revision is: 0001a120 (MIPS interAptiv (multi)) [ 0.048183] ------------[ cut here ]------------ [ 0.048187] WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6025 sched_core_cpu_starting+0x198/0x240 [ 0.048220] Modules linked in: [ 0.048233] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 5.17.0-rc3+ #35 b7b319f24073fd9a3c2aa7ad15fb7993eec0b26f [ 0.048247] Stack : 817f0000 00000004 327804c8 810eb050 00000000 00000004 00000000 c314fdd1 [ 0.048278] 830cbd64 819c0000 81800000 817f0000 83070bf4 00000001 830cbd08 00000000 [ 0.048307] 00000000 00000000 815fcbc4 00000000 00000000 00000000 00000000 00000000 [ 0.048334] 00000000 00000000 00000000 00000000 817f0000 00000000 00000000 817f6f34 [ 0.048361] 817f0000 818a3c00 817f0000 00000004 00000000 00000000 4dc33260 0018c933 [ 0.048389] ... [ 0.048396] Call Trace: [ 0.048399] [<8105a7bc>] show_stack+0x3c/0x140 [ 0.048424] [<8131c2a0>] dump_stack_lvl+0x60/0x80 [ 0.048440] [<8108b5c0>] __warn+0xc0/0xf4 [ 0.048454] [<8108b658>] warn_slowpath_fmt+0x64/0x10c [ 0.048467] [<810bd418>] sched_core_cpu_starting+0x198/0x240 [ 0.048483] [<810c6514>] sched_cpu_starting+0x14/0x80 [ 0.048497] [<8108c0f8>] cpuhp_invoke_callback_range+0x78/0x140 [ 0.048510] [<8108d914>] notify_cpu_starting+0x94/0x140 [ 0.048523] [<8106593c>] start_secondary+0xbc/0x280 [ 0.048539] [ 0.048543] ---[ end trace 0000000000000000 ]--- [ 0.048636] Synchronize counters for CPU 1: done. ...for each but CPU 0/boot. Basic debug printks right before the mentioned line say: [ 0.048170] CPU: 1, smt_mask: So smt_mask, which is sibling mask obviously, is empty when entering the function. This is critical, as sched_core_cpu_starting() calculates core-scheduling parameters only once per CPU start, and it's crucial to have all the parameters filled in at that moment (at least it uses cpu_smt_mask() which in fact is `&cpu_sibling_map[cpu]` on MIPS). A bit of debugging led me to that set_cpu_sibling_map() performing the actual map calculation, was being invocated after notify_cpu_start(), and exactly the latter function starts CPU HP callback round (sched_core_cpu_starting() is basically a CPU HP callback). While the flow is same on ARM64 (maps after the notifier, although before calling set_cpu_online()), x86 started calculating sibling maps earlier than starting the CPU HP callbacks in Linux 4.14 (see [0] for the reference). Neither me nor my brief tests couldn't find any potential caveats in calculating the maps right after performing delay calibration, but the WARN splat is now gone. The very same debug prints now yield exactly what I expected from them: [ 0.048433] CPU: 1, smt_mask: 0-1 [0] https://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git/commit/?id=76ce7cfe35ef Signed-off-by: Alexander Lobakin Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

mips: setup: fix setnocoherentio() boolean setting

2022-03-08T18:14:12Z

commit 1e6ae0e46e32749b130f1823da30cea9aa2a59a0 upstream. Correct a typo/pasto: setnocoherentio() should set dma_default_coherent to false, not true. Fixes: 14ac09a65e19 ("MIPS: refactor the runtime coherent vs noncoherent DMA indicators") Signed-off-by: Randy Dunlap Cc: Christoph Hellwig Cc: Thomas Bogendoerfer Cc: linux-mips@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: Fix build error due to PTR used in more places

2022-02-16T11:58:18Z

[ Upstream commit fa62f39dc7e25fc16371b958ac59b9a6fd260bea ] Use PTR_WD instead of PTR to avoid clashes with other parts. Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

MIPS: loongson64: fix FTLB configuration

2021-11-25T15:46:31Z

It turns out that 'decode_configs' -> 'set_ftlb_enable' is called under c->cputype unset, which leaves FTLB disabled on BOTH 3A2000 and 3A3000 Fix it by calling "decode_configs" after c->cputype is initialized Fixes: da1bd29742b1 ("MIPS: Loongson64: Probe CPU features via CPUCFG") Signed-off-by: Huang Pei Signed-off-by: Thomas Bogendoerfer

MIPS: Fix using smp_processor_id() in preemptible in show_cpuinfo()

2021-11-25T15:45:58Z

There exists the following issue under DEBUG_PREEMPT: BUG: using smp_processor_id() in preemptible [00000000] code: systemd/1 caller is show_cpuinfo+0x460/0xea0 ... Call Trace: [] show_stack+0x94/0x128 [] dump_stack_lvl+0x94/0xd8 [] check_preemption_disabled+0x104/0x110 [] show_cpuinfo+0x460/0xea0 [] seq_read_iter+0xfc/0x4f8 [] new_sync_read+0x110/0x1b8 [] vfs_read+0x1b4/0x1d0 [] ksys_read+0xd0/0x110 [] syscall_common+0x34/0x58 We can see the following call trace: show_cpuinfo() cpu_has_fpu current_cpu_data smp_processor_id() $ addr2line -f -e vmlinux 0xffffffff802209c8 show_cpuinfo arch/mips/kernel/proc.c:188 $ head -188 arch/mips/kernel/proc.c | tail -1 if (cpu_has_fpu) arch/mips/include/asm/cpu-features.h # define cpu_has_fpu (current_cpu_data.options & MIPS_CPU_FPU) arch/mips/include/asm/cpu-info.h #define current_cpu_data cpu_data[smp_processor_id()] Based on the above analysis, fix the issue by using raw_cpu_has_fpu which calls raw_smp_processor_id() in show_cpuinfo(). Fixes: 626bfa037299 ("MIPS: kernel: proc: add CPU option reporting") Signed-off-by: Tiezhu Yang Signed-off-by: Thomas Bogendoerfer

MIPS: syscalls: Wire up futex_waitv syscall

2021-11-16T08:25:48Z

Wire up the futex_waitv syscall. Fix Build warning: #warning syscall futex_waitv not implemented [-Wcpp] Signed-off-by: Wang Haojun Signed-off-by: Thomas Bogendoerfer

Merge tag 'mips_5.16_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

2021-11-13T17:11:33Z

Pull more MIPS updates from Thomas Bogendoerfer: - Config updates for BMIPS platform - Build fixes - Makefile cleanups * tag 'mips_5.16_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: mips: decompressor: do not copy source files while building MIPS: boot/compressed/: add __bswapdi2() to target for ZSTD decompression MIPS: fix duplicated slashes for Platform file path MIPS: fix *-pkg builds for loongson2ef platform PCI: brcmstb: Allow building for BMIPS_GENERIC MIPS: BMIPS: Enable PCI Kconfig MIPS: VDSO: remove -nostdlib compiler flag mips: BCM63XX: ensure that CPU_SUPPORTS_32BIT_KERNEL is set MIPS: Update bmips_stb_defconfig MIPS: Allow modules to set board_be_handler

Merge branch 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2021-11-11T00:15:54Z

Pull exit cleanups from Eric Biederman: "While looking at some issues related to the exit path in the kernel I found several instances where the code is not using the existing abstractions properly. This set of changes introduces force_fatal_sig a way of sending a signal and not allowing it to be caught, and corrects the misuse of the existing abstractions that I found. A lot of the misuse of the existing abstractions are silly things such as doing something after calling a no return function, rolling BUG by hand, doing more work than necessary to terminate a kernel thread, or calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL). In the review a deficiency in force_fatal_sig and force_sig_seccomp where ptrace or sigaction could prevent the delivery of the signal was found. I have added a change that adds SA_IMMUTABLE to change that makes it impossible to interrupt the delivery of those signals, and allows backporting to fix force_sig_seccomp And Arnd found an issue where a function passed to kthread_run had the wrong prototype, and after my cleanup was failing to build." * 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits) soc: ti: fix wkup_m3_rproc_boot_thread return type signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) exit/r8188eu: Replace the macro thread_exit with a simple return 0 exit/rtl8712: Replace the macro thread_exit with a simple return 0 exit/rtl8723bs: Replace the macro thread_exit with a simple return 0 signal/x86: In emulate_vsyscall force a signal instead of calling do_exit signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails exit/syscall_user_dispatch: Send ordinary signals on failure signal: Implement force_fatal_sig exit/kthread: Have kernel threads return instead of calling do_exit signal/s390: Use force_sigsegv in default_trap_handler signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved. signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON signal/sparc: In setup_tsb_params convert open coded BUG into BUG signal/powerpc: On swapcontext failure force SIGSEGV signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT signal/sparc32: Remove unreachable do_exit in do_sparc_fault ...

MIPS: Allow modules to set board_be_handler

2021-11-09T15:07:26Z

After making the brcmstb_gisb driver modular with 707a4cdf86e5 ("bus: brcmstb_gisb: Allow building as module") Guenter reported that mips allmodconfig failed to link because board_be_handler was referenced. Thomas indicated that if we were to continue making the brcmstb_gisb driver modular for MIPS we would need to introduce a function that allows setting the board_be_handler and export that function towards modules. This is what is being done here: board_be_handler is made static and is now settable with a mips_set_be_handler() function which is exported. Reported-by: Guenter Roeck Suggested-by: Thomas Bogendoerfer Fixes: 707a4cdf86e5 ("bus: brcmstb_gisb: Allow building as module") Signed-off-by: Florian Fainelli Tested-by: Guenter Roeck Signed-off-by: Thomas Bogendoerfer