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* ARM: 9410/1: vfp: Use asm volatile in fmrx/fmxr macrosCalvin Owens2024-08-201-22/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Floating point instructions in userspace can crash some arm kernels built with clang/LLD 17.0.6: BUG: unsupported FP instruction in kernel mode FPEXC == 0xc0000780 Internal error: Oops - undefined instruction: 0 [#1] ARM CPU: 0 PID: 196 Comm: vfp-reproducer Not tainted 6.10.0 #1 Hardware name: BCM2835 PC is at vfp_support_entry+0xc8/0x2cc LR is at do_undefinstr+0xa8/0x250 pc : [<c0101d50>] lr : [<c010a80c>] psr: a0000013 sp : dc8d1f68 ip : 60000013 fp : bedea19c r10: ec532b17 r9 : 00000010 r8 : 0044766c r7 : c0000780 r6 : ec532b17 r5 : c1c13800 r4 : dc8d1fb0 r3 : c10072c4 r2 : c0101c88 r1 : ec532b17 r0 : 0044766c Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 00c5387d Table: 0251c008 DAC: 00000051 Register r0 information: non-paged memory Register r1 information: vmalloc memory Register r2 information: non-slab/vmalloc memory Register r3 information: non-slab/vmalloc memory Register r4 information: 2-page vmalloc region Register r5 information: slab kmalloc-cg-2k Register r6 information: vmalloc memory Register r7 information: non-slab/vmalloc memory Register r8 information: non-paged memory Register r9 information: zero-size pointer Register r10 information: vmalloc memory Register r11 information: non-paged memory Register r12 information: non-paged memory Process vfp-reproducer (pid: 196, stack limit = 0x61aaaf8b) Stack: (0xdc8d1f68 to 0xdc8d2000) 1f60: 0000081f b6f69300 0000000f c10073f4 c10072c4 dc8d1fb0 1f80: ec532b17 0c532b17 0044766c b6f9ccd8 00000000 c010a80c 00447670 60000010 1fa0: ffffffff c1c13800 00c5387d c0100f10 b6f68af8 00448fc0 00000000 bedea188 1fc0: bedea314 00000001 00448ebc b6f9d000 00447608 b6f9ccd8 00000000 bedea19c 1fe0: bede9198 bedea188 b6e1061c 0044766c 60000010 ffffffff 00000000 00000000 Call trace: [<c0101d50>] (vfp_support_entry) from [<c010a80c>] (do_undefinstr+0xa8/0x250) [<c010a80c>] (do_undefinstr) from [<c0100f10>] (__und_usr+0x70/0x80) Exception stack(0xdc8d1fb0 to 0xdc8d1ff8) 1fa0: b6f68af8 00448fc0 00000000 bedea188 1fc0: bedea314 00000001 00448ebc b6f9d000 00447608 b6f9ccd8 00000000 bedea19c 1fe0: bede9198 bedea188 b6e1061c 0044766c 60000010 ffffffff Code: 0a000061 e3877202 e594003c e3a09010 (eef16a10) ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Fatal exception in interrupt ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- This is a minimal userspace reproducer on a Raspberry Pi Zero W: #include <stdio.h> #include <math.h> int main(void) { double v = 1.0; printf("%fn", NAN + *(volatile double *)&v); return 0; } Another way to consistently trigger the oops is: calvin@raspberry-pi-zero-w ~$ python -c "import json" The bug reproduces only when the kernel is built with DYNAMIC_DEBUG=n, because the pr_debug() calls act as barriers even when not activated. This is the output from the same kernel source built with the same compiler and DYNAMIC_DEBUG=y, where the userspace reproducer works as expected: VFP: bounce: trigger ec532b17 fpexc c0000780 VFP: emulate: INST=0xee377b06 SCR=0x00000000 VFP: bounce: trigger eef1fa10 fpexc c0000780 VFP: emulate: INST=0xeeb40b40 SCR=0x00000000 VFP: raising exceptions 30000000 calvin@raspberry-pi-zero-w ~$ ./vfp-reproducer nan Crudely grepping for vmsr/vmrs instructions in the otherwise nearly idential text for vfp_support_entry() makes the problem obvious: vmlinux.llvm.good [0xc0101cb8] <+48>: vmrs r7, fpexc vmlinux.llvm.good [0xc0101cd8] <+80>: vmsr fpexc, r0 vmlinux.llvm.good [0xc0101d20] <+152>: vmsr fpexc, r7 vmlinux.llvm.good [0xc0101d38] <+176>: vmrs r4, fpexc vmlinux.llvm.good [0xc0101d6c] <+228>: vmrs r0, fpscr vmlinux.llvm.good [0xc0101dc4] <+316>: vmsr fpexc, r0 vmlinux.llvm.good [0xc0101dc8] <+320>: vmrs r0, fpsid vmlinux.llvm.good [0xc0101dcc] <+324>: vmrs r6, fpscr vmlinux.llvm.good [0xc0101e10] <+392>: vmrs r10, fpinst vmlinux.llvm.good [0xc0101eb8] <+560>: vmrs r10, fpinst2 vmlinux.llvm.bad [0xc0101cb8] <+48>: vmrs r7, fpexc vmlinux.llvm.bad [0xc0101cd8] <+80>: vmsr fpexc, r0 vmlinux.llvm.bad [0xc0101d20] <+152>: vmsr fpexc, r7 vmlinux.llvm.bad [0xc0101d30] <+168>: vmrs r0, fpscr vmlinux.llvm.bad [0xc0101d50] <+200>: vmrs r6, fpscr <== BOOM! vmlinux.llvm.bad [0xc0101d6c] <+228>: vmsr fpexc, r0 vmlinux.llvm.bad [0xc0101d70] <+232>: vmrs r0, fpsid vmlinux.llvm.bad [0xc0101da4] <+284>: vmrs r10, fpinst vmlinux.llvm.bad [0xc0101df8] <+368>: vmrs r4, fpexc vmlinux.llvm.bad [0xc0101e5c] <+468>: vmrs r10, fpinst2 I think LLVM's reordering is valid as the code is currently written: the compiler doesn't know the instructions have side effects in hardware. Fix by using "asm volatile" in fmxr() and fmrx(), so they cannot be reordered with respect to each other. The original compiler now produces working kernels on my hardware with DYNAMIC_DEBUG=n. This is the relevant piece of the diff of the vfp_support_entry() text, from the original oopsing kernel to a working kernel with this patch: vmrs r0, fpscr tst r0, #4096 bne 0xc0101d48 tst r0, #458752 beq 0xc0101ecc orr r7, r7, #536870912 ldr r0, [r4, #0x3c] mov r9, #16 -vmrs r6, fpscr orr r9, r9, #251658240 add r0, r0, #4 str r0, [r4, #0x3c] mvn r0, #159 sub r0, r0, #-1207959552 and r0, r7, r0 vmsr fpexc, r0 vmrs r0, fpsid +vmrs r6, fpscr and r0, r0, #983040 cmp r0, #65536 bne 0xc0101d88 Fixes: 4708fb041346 ("ARM: vfp: Reimplement VFP exception entry in C code") Signed-off-by: Calvin Owens <calvin@wbinvd.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9327/1: vfp: Add missing VFP instructions to neon_support_hookMark-PK Tsai2023-12-051-0/+18
| | | | | | | | | | | | | | | | Add the missing "Unconditional Advanced SIMD and floating-point instructions" in [1] to the VFP undef hook. This commit addresses the issue reported in [2], where executing the vudot instruction on a platform with FEAT_DotProd support resulted in an undefined instruction error. Link: https://developer.arm.com/documentation/ddi0597/2023-06/?lang=en [1] Link: https://lore.kernel.org/lkml/20230920083907.30479-1-mark-pk.tsai@mediatek.com/ [2] Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com> Tested-by: Xuewen Yan <xuewen.yan@unisoc.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* Merge branch 'devel-stable' into for-nextRussell King (Oracle)2023-08-145-288/+162
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| * ARM: vfp: Use undef hook for handling VFP exceptionsArd Biesheuvel2023-05-173-88/+54
| | | | | | | | | | | | | | | | | | | | Now that the VFP support code has been reimplemented as a C function that takes a struct pt_regs pointer and an opcode, we can use the existing undef_hook framework to deal with undef exceptions triggered by VFP instructions instead of having special handling in assembler. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
| * ARM: vfp: Reimplement VFP exception entry in C codeArd Biesheuvel2023-05-174-216/+124
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | En/disabling softirqs from asm code turned out to be trickier than expected, so vfp_support_entry now returns by tail calling __local_enable_bh_ip() and passing the same arguments that a C call to local_bh_enable() would pass. However, this is slightly hacky, as we don't want to carry our own implementation of local_bh_enable(). So let's bite the bullet, and get rid of the asm logic in vfp_support_entry that reasons about whether or not to save and/or reload the VFP state, and about whether or not an FP exception is pending, and only keep the VFP loading logic as a function that is callable from C. Replicate the removed logic in vfp_entry(), and use the exact same reasoning as in the asm code. To emphasize the correspondence, retain some of the asm comments in the C version as well. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Linus Walleij <linus.walleij@linaro.org>
| * ARM: vfp: Remove workaround for Feroceon CPUsArd Biesheuvel2023-05-172-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Feroceon CPUs have a non-standard implementation of VFP which reports synchronous VFP exceptions using the async VFP flag. This requires a workaround which is difficult to reconcile with other implementations, making it tricky to support both versions in a single image. Since this is a v5 CPU, it is not supported by armhf and so the likelihood that anybody is using this with recent distros/kernels and rely on the VFP at the same time is extremely low. So let's just disable VFP support on these cores, so we can remove the workaround. This will help future development to support v5 and v6 CPUs with a single kernel image. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Nicolas Pitre <nico@fluxnic.net> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
| * ARM: vfp: Record VFP bounces as perf emulation faultsArd Biesheuvel2023-05-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | VFP 'bouncing' occurs when the VFP unit cannot complete the execution of a VFP instruction, either because it is not implemented at all, or because the values of the arguments are out of range for the hardware implementation, and the software needs to step in to complete the operation. To give some insight in how much certain programs rely on this bouncing, record the emulation of a VFP instruction in perf's emulation-faults counter. This can be used like so perf stat -e emulation-faults ./testfloat -all2 and the output will be something like Performance counter stats for './testfloat -all2': 259,277 emulation-faults:u 6.846432176 seconds time elapsed Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
* | Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2023-06-271-0/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull ARM updates from Russell King: - lots of build cleanups from Arnd spread throughout the arch/arm tree - replace strlcpy() with the preferred strscpy() - use sign_extend32() in the module linker - drop handle_irq() machine descriptor method * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9315/1: fiq: include asm/mach/irq.h for prototypes ARM: 9314/1: tcm: move tcm_init() prototype to asm/tcm.h ARM: 9313/1: vdso: add missing prototypes ARM: 9312/1: vfp: include asm/neon.h in vfpmodule.c ARM: 9311/1: decompressor: move function prototypes to misc.h ARM: 9310/1: xip-kernel: add __inflate_kernel_data prototype ARM: 9309/1: add missing syscall prototypes ARM: 9308/1: move setup functions to header ARM: 9307/1: nommu: include asm/idmap.h ARM: 9306/1: cacheflush: avoid __flush_anon_page() missing-prototype warning ARM: 9305/1: add clear/copy_user_highpage declarations ARM: 9304/1: add prototype for function called only from asm ARM: 9303/1: kprobes: avoid missing-declaration warnings ARM: 9302/1: traps: hide unused functions on NOMMU ARM: 9301/1: dma-mapping: hide unused dma_contiguous_early_fixup function ARM: 9300/1: Replace all non-returning strlcpy with strscpy ARM: 9299/1: module: use sign_extend32() to extend the signedness ARM: 9298/1: Drop custom mdesc->handle_irq()
| * ARM: 9312/1: vfp: include asm/neon.h in vfpmodule.cArnd Bergmann2023-06-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | Two functions defined here need the declaration in a header to avoid W=1 warnings: arch/arm/vfp/vfpmodule.c:735:6: error: no previous prototype for 'kernel_neon_begin' [-Werror=missing-prototypes] arch/arm/vfp/vfpmodule.c:768:6: error: no previous prototype for 'kernel_neon_end' [-Werror=missing-prototypes] Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* | ARM: 9297/1: vfp: avoid unbalanced stack on 'success' return pathArd Biesheuvel2023-05-102-4/+9
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c76c6c4ecbec0deb5 ("ARM: 9294/2: vfp: Fix broken softirq handling with instrumentation enabled") updated the VFP exception entry logic to go via a C function, so that we get the compiler's version of local_bh_disable(), which may be instrumented, and isn't generally callable from assembler. However, this assumes that passing an alternative 'success' return address works in C as it does in asm, and this is only the case if the C calls in question are tail calls, as otherwise, the stack will need some unwinding as well. I have already sent patches to the list that replace most of the asm logic with C code, and so it is preferable to have a minimal fix that addresses the issue and can be backported along with the commit that it fixes to v6.3 from v6.4. Hopefully, we can land the C conversion for v6.5. So instead of passing the 'success' return address as a function argument, pass the stack address from where to pop it so that both LR and SP have the expected value. Fixes: c76c6c4ecbec0deb5 ("ARM: 9294/2: vfp: Fix broken softirq handling with ...") Reported-by: syzbot+d4b00edc2d0c910d4bf4@syzkaller.appspotmail.com Tested-by: syzbot+d4b00edc2d0c910d4bf4@syzkaller.appspotmail.com Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Tested-by: Andre Przywara <andre.przywara@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9294/2: vfp: Fix broken softirq handling with instrumentation enabledArd Biesheuvel2023-04-123-21/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 62b95a7b44d1 ("ARM: 9282/1: vfp: Manipulate task VFP state with softirqs disabled") replaced the en/disable preemption calls inside the VFP state handling code with en/disabling of soft IRQs, which is necessary to allow kernel use of the VFP/SIMD unit when handling a soft IRQ. Unfortunately, when lockdep is enabled (or other instrumentation that enables TRACE_IRQFLAGS), the disable path implemented in asm fails to perform the lockdep and RCU related bookkeeping, resulting in spurious warnings and other badness. Set let's rework the VFP entry code a little bit so we can make the local_bh_disable() call from C, with all the instrumentations that happen to have been configured. Calling local_bh_enable() can be done from asm, as it is a simple wrapper around __local_bh_enable_ip(), which is always a callable function. Link: https://lore.kernel.org/all/ZBBYCSZUJOWBg1s8@localhost.localdomain/ Fixes: 62b95a7b44d1 ("ARM: 9282/1: vfp: Manipulate task VFP state with softirqs disabled") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9293/1: vfp: Pass successful return address via register R3Ard Biesheuvel2023-04-112-7/+8
| | | | | | | | | | | In preparation for reimplementing the do_vfp()->vfp_support_entry() handover in C code, switch to using R3 to pass the 'success' return address, rather than R9, as it cannot be used for parameter passing. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9292/1: vfp: Pass thread_info pointer to vfp_support_entryArd Biesheuvel2023-04-112-7/+8
| | | | | | | | | | | | | | | | Instead of dereferencing thread_info in do_vfp, pass the thread_info pointer to vfp_support_entry via R1. That way, we only use a single caller save register, which makes it easier to convert do_vfp to C code in a subsequent patch. Note that, unlike the CPU number, which can change due to preemption, passing the thread_info pointer can safely be done with preemption enabled. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9283/1: permit non-nested kernel mode NEON in softirq contextArd Biesheuvel2023-01-111-7/+6
| | | | | | | | | | | | | | | | | | | | | | We currently only permit kernel mode NEON in process context, to avoid the need to preserve/restore the NEON register file when taking an exception while running in the kernel. Like we did on arm64, we can relax this restriction substantially, by permitting kernel mode NEON from softirq context, while ensuring that softirq processing is disabled when the NEON is being used in task context. This guarantees that only NEON context belonging to user space needs to be preserved and restored, which is already taken care of. This is especially relevant for network encryption, where incoming frames are typically handled in softirq context, and deferring software decryption to a kernel thread or falling back to C code are both undesirable from a performance PoV. Tested-by: Martin Willi <martin@strongswan.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9282/1: vfp: Manipulate task VFP state with softirqs disabledArd Biesheuvel2023-01-113-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a subsequent patch, we will relax the kernel mode NEON policy, and permit kernel mode NEON to be used not only from task context, as is permitted today, but also from softirq context. Given that softirqs may trigger over the back of any IRQ unless they are explicitly disabled, we need to address the resulting races in the VFP state handling, by disabling softirq processing in two distinct but related cases: - kernel mode NEON will leave the FPU disabled after it completes, so any kernel code sequence that enables the FPU and subsequently accesses its registers needs to disable softirqs until it completes; - kernel_neon_begin() will preserve the userland VFP state in memory, and if it interrupts the ordinary VFP state preserve sequence, the latter will resume execution with the VFP registers corrupted, and happily continue saving them to memory. Given that disabling softirqs also disables preemption, we can replace the existing preempt_disable/enable occurrences in the VFP state handling asm code with new macros that dis/enable softirqs instead. In the VFP state handling C code, add local_bh_disable/enable() calls in those places where the VFP state is preserved. One thing to keep in mind is that, once we allow NEON use in softirq context, the result of any such interruption is that the FPEXC_EN bit in the FPEXC register will be cleared, and vfp_current_hw_state[cpu] will be NULL. This means that any sequence that [conditionally] clears FPEXC_EN and/or sets vfp_current_hw_state[cpu] to NULL does not need to run with softirqs disabled, as the result will be the same. Furthermore, the handling of THREAD_NOTIFY_SWITCH is guaranteed to run with IRQs disabled, and so it does not need protection from softirq interruptions either. Tested-by: Martin Willi <martin@strongswan.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MMAmit Daniel Kachhap2022-11-281-0/+6
| | | | | | | | | | | | Int8 matrix multiplication (FEAT_AA32I8MM) is a feature present in AArch32 state for Armv8 and is represented by ISAR6.I8MM identification register. This feature denotes the presence of VSMMLA, VSUDOT, VUMMLA, VUSMMLA and VUSDOT instructions and hence adding a hwcap will enable the userspace to check it before trying to use those instructions. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16Amit Daniel Kachhap2022-11-281-0/+6
| | | | | | | | | | | | | | Advanced SIMD BFloat16 (FEAT_AA32BF16) is a feature present in AArch32 state for Armv8 and is represented by ISAR6.BF16 identification register. This feature denotes the presence of VCVT, VCVTB, VCVTT, VDOT, VFMAB, VFMAT and VMMLA instructions and hence adding a hwcap will enable the userspace to check it before trying to use those instructions. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9270/1: vfp: Add hwcap for FEAT_FHMAmit Daniel Kachhap2022-11-281-0/+6
| | | | | | | | | | | | | Floating-point half-precision multiplication (FHM) is a feature present in AArch32 state for Armv8 and is represented by ISAR6.FHM identification register. This feature denotes the presence of VFMAL and VMFSL instructions and hence adding a hwcap will enable the userspace to check it before trying to use those instructions. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9269/1: vfp: Add hwcap for FEAT_DotProdAmit Daniel Kachhap2022-11-281-0/+10
| | | | | | | | | | | Advanced Dot product is a feature present in AArch32 state for Armv8 and is represented by ISAR6 identification register. This feature denotes the presence of UDOT and SDOT instructions and hence adding a hwcap will enable the userspace to check it before trying to use those instructions. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16Amit Daniel Kachhap2022-11-281-0/+4
| | | | | | | | | | | | Floating point half-precision (FPHP) and Advanced SIMD half-precision (ASIMDHP) are VFP features (FEAT_FP16) represented by MVFR1 identification register. These capabilities can optionally exist with VFPv3 and mandatory with VFPv4. Both these new features exist for Armv8 architecture in AArch32 state. These hwcaps may be useful for the userspace to add conditional check before trying to use FEAT_FP16 feature specific instructions. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
* printk: Userspace format indexing supportChris Down2021-07-191-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a number of systems industry-wide that have a subset of their functionality that works as follows: 1. Receive a message from local kmsg, serial console, or netconsole; 2. Apply a set of rules to classify the message; 3. Do something based on this classification (like scheduling a remediation for the machine), rinse, and repeat. As a couple of examples of places we have this implemented just inside Facebook, although this isn't a Facebook-specific problem, we have this inside our netconsole processing (for alarm classification), and as part of our machine health checking. We use these messages to determine fairly important metrics around production health, and it's important that we get them right. While for some kinds of issues we have counters, tracepoints, or metrics with a stable interface which can reliably indicate the issue, in order to react to production issues quickly we need to work with the interface which most kernel developers naturally use when developing: printk. Most production issues come from unexpected phenomena, and as such usually the code in question doesn't have easily usable tracepoints or other counters available for the specific problem being mitigated. We have a number of lines of monitoring defence against problems in production (host metrics, process metrics, service metrics, etc), and where it's not feasible to reliably monitor at another level, this kind of pragmatic netconsole monitoring is essential. As one would expect, monitoring using printk is rather brittle for a number of reasons -- most notably that the message might disappear entirely in a new version of the kernel, or that the message may change in some way that the regex or other classification methods start to silently fail. One factor that makes this even harder is that, under normal operation, many of these messages are never expected to be hit. For example, there may be a rare hardware bug which one wants to detect if it was to ever happen again, but its recurrence is not likely or anticipated. This precludes using something like checking whether the printk in question was printed somewhere fleetwide recently to determine whether the message in question is still present or not, since we don't anticipate that it should be printed anywhere, but still need to monitor for its future presence in the long-term. This class of issue has happened on a number of occasions, causing unhealthy machines with hardware issues to remain in production for longer than ideal. As a recent example, some monitoring around blk_update_request fell out of date and caused semi-broken machines to remain in production for longer than would be desirable. Searching through the codebase to find the message is also extremely fragile, because many of the messages are further constructed beyond their callsite (eg. btrfs_printk and other module-specific wrappers, each with their own functionality). Even if they aren't, guessing the format and formulation of the underlying message based on the aesthetics of the message emitted is not a recipe for success at scale, and our previous issues with fleetwide machine health checking demonstrate as much. This provides a solution to the issue of silently changed or deleted printks: we record pointers to all printk format strings known at compile time into a new .printk_index section, both in vmlinux and modules. At runtime, this can then be iterated by looking at <debugfs>/printk/index/<module>, which emits the following format, both readable by humans and able to be parsed by machines: $ head -1 vmlinux; shuf -n 5 vmlinux # <level[,flags]> filename:line function "format" <5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n" <4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n" <6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n" <6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n" <6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n" This mitigates the majority of cases where we have a highly-specific printk which we want to match on, as we can now enumerate and check whether the format changed or the printk callsite disappeared entirely in userspace. This allows us to catch changes to printks we monitor earlier and decide what to do about it before it becomes problematic. There is no additional runtime cost for printk callers or printk itself, and the assembly generated is exactly the same. Signed-off-by: Chris Down <chris@chrisdown.name> Cc: Petr Mladek <pmladek@suse.com> Cc: Jessica Yu <jeyu@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kees Cook <keescook@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Reported-by: kernel test robot <lkp@intel.com> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Jessica Yu <jeyu@kernel.org> # for module.{c,h} Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/e42070983637ac5e384f17fbdbe86d19c7b212a5.1623775748.git.chris@chrisdown.name
* ARM: 9044/1: vfp: use undef hook for VFP support detectionArd Biesheuvel2020-12-212-22/+20
| | | | | | | | | | | | | | | | | Commit f77ac2e378be9dd6 ("ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode") failed to take into account that there is in fact a case where we relied on this code path: during boot, the VFP detection code issues a read of FPSID, which will trigger an undef exception on cores that lack VFP support. So let's reinstate this logic using an undef hook which is registered only for the duration of the initcall to vpf_init(), and which sets VFP_arch to a non-zero value - as before - if no VFP support is present. Fixes: f77ac2e378be9dd6 ("ARM: 9030/1: entry: omit FP emulation for UND ...") Reported-by: "kernelci.org bot" <bot@kernelci.org> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel modeArd Biesheuvel2020-12-082-7/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are a couple of problems with the exception entry code that deals with FP exceptions (which are reported as UND exceptions) when building the kernel in Thumb2 mode: - the conditional branch to vfp_kmode_exception in vfp_support_entry() may be out of range for its target, depending on how the linker decides to arrange the sections; - when the UND exception is taken in kernel mode, the emulation handling logic is entered via the 'call_fpe' label, which means we end up using the wrong value/mask pairs to match and detect the NEON opcodes. Since UND exceptions in kernel mode are unlikely to occur on a hot path (as opposed to the user mode version which is invoked for VFP support code and lazy restore), we can use the existing undef hook machinery for any kernel mode instruction emulation that is needed, including calling the existing vfp_kmode_exception() routine for unexpected cases. So drop the call to call_fpe, and instead, install an undef hook that will get called for NEON and VFP instructions that trigger an UND exception in kernel mode. While at it, make sure that the PC correction is accurate for the execution mode where the exception was taken, by checking the PSR Thumb bit. Cc: Dmitry Osipenko <digetx@gmail.com> Cc: Kees Cook <keescook@chromium.org> Fixes: eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input sections") Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* ARM: 8991/1: use VFP assembler mnemonics if availableStefan Agner2020-07-212-4/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The integrated assembler of Clang 10 and earlier do not allow to access the VFP registers through the coprocessor load/store instructions: arch/arm/vfp/vfpmodule.c:342:2: error: invalid operand for instruction fmxr(FPEXC, fpexc & ~(FPEXC_EX|FPEXC_DEX|FPEXC_FP2V|FPEXC_VV|FPEXC_TRAP_MASK)); ^ arch/arm/vfp/vfpinstr.h:79:6: note: expanded from macro 'fmxr' asm("mcr p10, 7, %0, " vfpreg(_vfp_) ", cr0, 0 @ fmxr " #_vfp_ ", %0" ^ <inline asm>:1:6: note: instantiated into assembly here mcr p10, 7, r0, cr8, cr0, 0 @ fmxr FPEXC, r0 ^ This has been addressed with Clang 11 [0]. However, to support earlier versions of Clang and for better readability use of VFP assembler mnemonics still is preferred. Ideally we would replace this code with the unified assembler language mnemonics vmrs/vmsr on call sites along with .fpu assembler directives. The GNU assembler supports the .fpu directive at least since 2.17 (when documentation has been added). Since Linux requires binutils 2.21 it is safe to use .fpu directive. However, binutils does not allow to use FPINST or FPINST2 as an argument to vmrs/vmsr instructions up to binutils 2.24 (see binutils commit 16d02dc907c5): arch/arm/vfp/vfphw.S: Assembler messages: arch/arm/vfp/vfphw.S:162: Error: operand 0 must be FPSID or FPSCR pr FPEXC -- `vmsr FPINST,r6' arch/arm/vfp/vfphw.S:165: Error: operand 0 must be FPSID or FPSCR pr FPEXC -- `vmsr FPINST2,r8' arch/arm/vfp/vfphw.S:235: Error: operand 1 must be a VFP extension System Register -- `vmrs r3,FPINST' arch/arm/vfp/vfphw.S:238: Error: operand 1 must be a VFP extension System Register -- `vmrs r12,FPINST2' Use as-instr in Kconfig to check if FPINST/FPINST2 can be used. If they can be used make use of .fpu directives and UAL VFP mnemonics for register access. This allows to build vfpmodule.c with Clang and its integrated assembler. [0] https://reviews.llvm.org/D59733 Link: https://github.com/ClangBuiltLinux/linux/issues/905 Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* ARM: 8989/1: use .fpu assembler directives instead of assembler argumentsStefan Agner2020-07-212-12/+20
| | | | | | | | | | | | | | | | | | | Explicit FPU selection has been introduced in commit 1a6be26d5b1a ("[ARM] Enable VFP to be built when non-VFP capable CPUs are selected") to make use of assembler mnemonics for VFP instructions. However, clang currently does not support passing assembler flags like this and errors out with: clang-10: error: the clang compiler does not support '-Wa,-mfpu=softvfp+vfp' Make use of the .fpu assembler directives to select the floating point hardware selectively. Also use the new unified assembler language mnemonics. This allows to build these procedures with Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/762 Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner2019-06-195-20/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2019-05-211-0/+1
| | | | | | | | | | | | | | Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'spectre' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2018-11-141-1/+1
|\ | | | | | | | | | | | | | | | | Pull ARM fix from Russell King: "It was noticed that one of Julien's patches contained an error, this fixes that up" * 'spectre' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 8810/1: vfp: Fix wrong assignement to ufp_exc
| * ARM: 8810/1: vfp: Fix wrong assignement to ufp_excJulien Thierry2018-11-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | In vfp_preserve_user_clear_hwstate, ufp_exc->fpinst2 gets assigned to itself. It should actually be hwstate->fpinst2 that gets assigned to the ufp_exc field. Fixes commit 3aa2df6ec2ca6bc143a65351cca4266d03a8bc41 ("ARM: 8791/1: vfp: use __copy_to_user() when saving VFP state"). Reported-by: David Binderman <dcb314@hotmail.com> Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | Merge branch 'siginfo-linus' of ↵Linus Torvalds2018-10-241-8/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull siginfo updates from Eric Biederman: "I have been slowly sorting out siginfo and this is the culmination of that work. The primary result is in several ways the signal infrastructure has been made less error prone. The code has been updated so that manually specifying SEND_SIG_FORCED is never necessary. The conversion to the new siginfo sending functions is now complete, which makes it difficult to send a signal without filling in the proper siginfo fields. At the tail end of the patchset comes the optimization of decreasing the size of struct siginfo in the kernel from 128 bytes to about 48 bytes on 64bit. The fundamental observation that enables this is by definition none of the known ways to use struct siginfo uses the extra bytes. This comes at the cost of a small user space observable difference. For the rare case of siginfo being injected into the kernel only what can be copied into kernel_siginfo is delivered to the destination, the rest of the bytes are set to 0. For cases where the signal and the si_code are known this is safe, because we know those bytes are not used. For cases where the signal and si_code combination is unknown the bits that won't fit into struct kernel_siginfo are tested to verify they are zero, and the send fails if they are not. I made an extensive search through userspace code and I could not find anything that would break because of the above change. If it turns out I did break something it will take just the revert of a single change to restore kernel_siginfo to the same size as userspace siginfo. Testing did reveal dependencies on preferring the signo passed to sigqueueinfo over si->signo, so bit the bullet and added the complexity necessary to handle that case. Testing also revealed bad things can happen if a negative signal number is passed into the system calls. Something no sane application will do but something a malicious program or a fuzzer might do. So I have fixed the code that performs the bounds checks to ensure negative signal numbers are handled" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (80 commits) signal: Guard against negative signal numbers in copy_siginfo_from_user32 signal: Guard against negative signal numbers in copy_siginfo_from_user signal: In sigqueueinfo prefer sig not si_signo signal: Use a smaller struct siginfo in the kernel signal: Distinguish between kernel_siginfo and siginfo signal: Introduce copy_siginfo_from_user and use it's return value signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE signal: Fail sigqueueinfo if si_signo != sig signal/sparc: Move EMT_TAGOVF into the generic siginfo.h signal/unicore32: Use force_sig_fault where appropriate signal/unicore32: Generate siginfo in ucs32_notify_die signal/unicore32: Use send_sig_fault where appropriate signal/arc: Use force_sig_fault where appropriate signal/arc: Push siginfo generation into unhandled_exception signal/ia64: Use force_sig_fault where appropriate signal/ia64: Use the force_sig(SIGSEGV,...) in ia64_rt_sigreturn signal/ia64: Use the generic force_sigsegv in setup_frame signal/arm/kvm: Use send_sig_mceerr signal/arm: Use send_sig_fault where appropriate signal/arm: Use force_sig_fault where appropriate ...
| * | signal/arm: Use send_sig_fault where appropriateEric W. Biederman2018-09-271-8/+3
| | | | | | | | | | | | Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* | | Merge branches 'fixes', 'misc' and 'spectre' into for-nextRussell King2018-10-101-12/+8
|\ \ \ | |/ / |/| / | |/
| * ARM: 8791/1: vfp: use __copy_to_user() when saving VFP stateJulien Thierry2018-10-051-12/+8
| | | | | | | | | | | | | | | | | | | | Use __copy_to_user() rather than __put_user_error() for individual members when saving VFP state. This has the benefit of disabling/enabling PAN once per copied struct intead of once per write. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| |
| \
*-. | Merge branches 'fixes', 'misc' and 'spectre' into for-linusRussell King2018-08-132-14/+8
|\ \| | | | | | | | | | | | | | | | | | | Conflicts: arch/arm/include/asm/uaccess.h Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| | * ARM: vfp: use __copy_from_user() when restoring VFP stateRussell King2018-08-021-10/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __get_user_error() is used as a fast accessor to make copying structure members in the signal handling path as efficient as possible. However, with software PAN and the recent Spectre variant 1, the efficiency is reduced as these are no longer fast accessors. In the case of software PAN, it has to switch the domain register around each access, and with Spectre variant 1, it would have to repeat the access_ok() check for each access. Use __copy_from_user() rather than __get_user_err() for individual members when restoring VFP state. Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| * | ARM: 8782/1: vfp: clean up arch/arm/vfp/MakefileMasahiro Yamada2018-07-301-4/+1
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 799c43415442 ("kbuild: thin archives make default for all archs"), $(AR) is used instead of $(LD) to combine object files. The following code in arch/arm/vfp/Makefile: LDFLAGS +=--no-warn-mismatch ... is no longer used. Also, arch/arm/Makefile already guards arch/arm/vfp/ by a boolean symbol, CONFIG_VFP, like this: core-$(CONFIG_VFP) += arch/arm/vfp/ So, $(CONFIG_VFP) is always evaluated to y in arch/arm/vfp/Makefile. There is no point to use pseudo object, vfp.o, which never becomes a module. Add all objects to obj-y directly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* | Merge branch 'siginfo-linus' of ↵Linus Torvalds2018-06-051-2/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull siginfo updates from Eric Biederman: "This set of changes close the known issues with setting si_code to an invalid value, and with not fully initializing struct siginfo. There remains work to do on nds32, arc, unicore32, powerpc, arm, arm64, ia64 and x86 to get the code that generates siginfo into a simpler and more maintainable state. Most of that work involves refactoring the signal handling code and thus careful code review. Also not included is the work to shrink the in kernel version of struct siginfo. That depends on getting the number of places that directly manipulate struct siginfo under control, as it requires the introduction of struct kernel_siginfo for the in kernel things. Overall this set of changes looks like it is making good progress, and with a little luck I will be wrapping up the siginfo work next development cycle" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits) signal/sh: Stop gcc warning about an impossible case in do_divide_error signal/mips: Report FPE_FLTUNK for undiagnosed floating point exceptions signal/um: More carefully relay signals in relay_signal. signal: Extend siginfo_layout with SIL_FAULT_{MCEERR|BNDERR|PKUERR} signal: Remove unncessary #ifdef SEGV_PKUERR in 32bit compat code signal/signalfd: Add support for SIGSYS signal/signalfd: Remove __put_user from signalfd_copyinfo signal/xtensa: Use force_sig_fault where appropriate signal/xtensa: Consistenly use SIGBUS in do_unaligned_user signal/um: Use force_sig_fault where appropriate signal/sparc: Use force_sig_fault where appropriate signal/sparc: Use send_sig_fault where appropriate signal/sh: Use force_sig_fault where appropriate signal/s390: Use force_sig_fault where appropriate signal/riscv: Replace do_trap_siginfo with force_sig_fault signal/riscv: Use force_sig_fault where appropriate signal/parisc: Use force_sig_fault where appropriate signal/parisc: Use force_sig_mceerr where appropriate signal/openrisc: Use force_sig_fault where appropriate signal/nios2: Use force_sig_fault where appropriate ...
| * | signal: Ensure every siginfo we send has all bits initializedEric W. Biederman2018-04-251-2/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Call clear_siginfo to ensure every stack allocated siginfo is properly initialized before being passed to the signal sending functions. Note: It is not safe to depend on C initializers to initialize struct siginfo on the stack because C is allowed to skip holes when initializing a structure. The initialization of struct siginfo in tracehook_report_syscall_exit was moved from the helper user_single_step_siginfo into tracehook_report_syscall_exit itself, to make it clear that the local variable siginfo gets fully initialized. In a few cases the scope of struct siginfo has been reduced to make it clear that siginfo siginfo is not used on other paths in the function in which it is declared. Instances of using memset to initialize siginfo have been replaced with calls clear_siginfo for clarity. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* / ARM: fix kill( ,SIGFPE) breakageRussell King2018-05-191-1/+1
|/ | | | | | | | | | | | | Commit 7771c6645700 ("signal/arm: Document conflicts with SI_USER and SIGFPE") broke the siginfo structure for userspace triggered signals, causing the strace testsuite to regress. Fix this by eliminating the FPE_FIXME definition (which is at the root of the breakage) and use FPE_FLTINV instead for the case where the hardware appears to be reporting nonsense. Fixes: 7771c6645700 ("signal/arm: Document conflicts with SI_USER and SIGFPE") Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* ARM: 8746/1: vfp: Go back to clearing vfp_current_hw_state[]Fabio Estevam2018-03-241-1/+1
| | | | | | | | | | | | | | | | Commit 384b38b66947 ("ARM: 7873/1: vfp: clear vfp_current_hw_state for dying cpu") fixed the cpu dying notifier by clearing vfp_current_hw_state[]. However commit e5b61bafe704 ("arm: Convert VFP hotplug notifiers to state machine") incorrectly used the original vfp_force_reload() function in the cpu dying notifier. Fix it by going back to clearing vfp_current_hw_state[]. Fixes: e5b61bafe704 ("arm: Convert VFP hotplug notifiers to state machine") Cc: linux-stable <stable@vger.kernel.org> Reported-by: Kohji Okuno <okuno.kohji@jp.panasonic.com> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
* signal/arm: Document conflicts with SI_USER and SIGFPEEric W. Biederman2018-01-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Setting si_code to 0 results in a userspace seeing an si_code of 0. This is the same si_code as SI_USER. Posix and common sense requires that SI_USER not be a signal specific si_code. As such this use of 0 for the si_code is a pretty horribly broken ABI. Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a value of __SI_KILL and now sees a value of SIL_KILL with the result that uid and pid fields are copied and which might copying the si_addr field by accident but certainly not by design. Making this a very flakey implementation. Utilizing FPE_FIXME, siginfo_layout will now return SIL_FAULT and the appropriate fields will be reliably copied. Possible ABI fixes includee: - Send the signal without siginfo - Don't generate a signal - Possibly assign and use an appropriate si_code - Don't handle cases which can't happen Cc: Russell King <rmk@flint.arm.linux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Ref: 451436b7bbb2 ("[ARM] Add support code for ARM hardware vector floating point") History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-1/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/signal.h> We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* cpu/hotplug: Cleanup state namesThomas Gleixner2016-12-251-1/+1
| | | | | | | | | | | | | | | | | When the state names got added a script was used to add the extra argument to the calls. The script basically converted the state constant to a string, but the cleanup to convert these strings into meaningful ones did not happen. Replace all the useless strings with 'subsys/xxx/yyy:state' strings which are used in all the other places already. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Link: http://lkml.kernel.org/r/20161221192112.085444152@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* ARM: 8629/1: vfp: properly tag assembly function declarations in C codeNicolas Pitre2016-11-222-9/+9
| | | | | | | | | This is good for consistency even if there is no difference in compiled code. LTO might rely on this eventually. No need to preserve the extern attribute as it is the default with function prototypes. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* arm: Convert VFP hotplug notifiers to state machineThomas Gleixner2016-07-151-11/+17
| | | | | | | | | | | | | | | | Straight forward conversion plus commentary why code which is executed in hotplug callbacks needs to be invoked before installing them. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153335.713612993@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* exit_thread: accept a task parameter to be exitedJiri Slaby2016-05-211-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to call exit_thread from copy_process in a fail path. So make it accept task_struct as a parameter. [v2] * s390: exit_thread_runtime_instr doesn't make sense to be called for non-current tasks. * arm: fix the comment in vfp_thread_copy * change 'me' to 'tsk' for task_struct * now we can change only archs that actually have exit_thread [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Aurelien Jacquiot <a-jacquiot@ti.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Howells <dhowells@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Haavard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Hogan <james.hogan@imgtec.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonas Bonn <jonas@southpole.se> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Mark Salter <msalter@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mikael Starvik <starvik@axis.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Kuo <rkuo@codeaurora.org> Cc: Richard Weinberger <richard@nod.at> Cc: Russell King <linux@arm.linux.org.uk> Cc: Steven Miao <realmz6@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* ARM: vfp: Add vfp_disable for problematic platformsFlorian Fainelli2015-05-211-0/+13
| | | | | | | | | Some platforms might not be able to fully utilize VFP when e.g: one CPU out of two in a SMP complex lacks a VFP unit. Adding code to migrate task to the CPU which has a VFP unit would be cumbersome and not performant, instead, just add the ability to disable VFP. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
* ARM: convert printk(KERN_* to pr_*Russell King2014-11-211-1/+1
| | | | | | | | | | | Convert many (but not all) printk(KERN_* to pr_* to simplify the code. We take the opportunity to join some printk lines together so we don't split the message across several lines, and we also add a few levels to some messages which were previously missing them. Tested-by: Andrew Lunn <andrew@lunn.ch> Tested-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 8215/1: vfp: Silence mvfr0 variable unused warningStephen Boyd2014-11-211-23/+22
| | | | | | | | | | | | | | | | | Stephen Rothwell reports that commit 3f4c9f8f0a20 ("ARM: 8197/1: vfp: Fix VFPv3 hwcap detection on CPUID based cpus") introduced a variable unused warning. arch/arm/vfp/vfpmodule.c: In function 'vfp_init': arch/arm/vfp/vfpmodule.c:725:6: warning: unused variable 'mvfr0' [-Wunused-variable] u32 mvfr0; Silence this warning by using IS_ENABLED instead of ifdefs. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 8197/1: vfp: Fix VFPv3 hwcap detection on CPUID based cpusStephen Boyd2014-11-211-41/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The subarchitecture field in the fpsid register is 7 bits wide on ARM CPUs using the CPUID identification scheme, spanning bits 22 to 16. The topmost bit is used to designate that the subarchitecture designer is not ARM when it is set to 1. On non-CPUID scheme CPUs the subarchitecture field is only 4 bits wide and the higher bits are used to indicate no double precision support (bit 20) and the FTSMX/FLDMX format (bits 21-22). The VFP support code only looks at bits 19-16 to determine the VFP version. On Qualcomm's processors (Krait and Scorpion) we should see that we have HWCAP_VFPv3 but we don't because bit 22 is set to 1 to indicate that the subarchitecture is not implemented by ARM and the rest of the bits are left as 0 because this is the first subarchitecture that Qualcomm has designed. Unfortunately we can't just widen the FPSID subarchitecture bitmask to consider all the bits on a CPUID scheme because there may be CPUs without the CPUID scheme that have VFP without double precision support and then the version would be a very wrong and large number. Instead, update the version detection logic to consider if the CPU is using the CPUID scheme. If the CPU is using CPUID scheme, use the MVFR registers to determine what version of VFP is supported. We already do this for VFPv4, so do something similar for VFPv3 and look for single or double precision support in MVFR0. Otherwise fall back to using FPSID to detect VFP support on non-CPUID scheme CPUs. We know that VFPv3 is only present in CPUs that have support for the CPUID scheme so this should be equivalent. Tested-by: Rob Clark <robdclark@gmail.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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