BMC/Intel-BMC/linux.git/arch/mips/kernel/process.c, branch dev-4.7

MIPS: Avoid a BUG warning during prctl(PR_SET_FP_MODE, ...)

2016-09-30T08:12:47+00:00

commit b244614a60ab7ce54c12a9cbe15cfbf8d79d0967 upstream. cpu_has_fpu macro uses smp_processor_id() and is currently executed with preemption enabled, that triggers the warning at runtime. It is assumed throughout the kernel that if any CPU has an FPU, then all CPUs would have an FPU as well, so it is safe to perform the check with preemption enabled - change the code to use raw_ variant of the check to avoid the warning. Signed-off-by: Marcin Nowakowski Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14125/ Signed-off-by: Ralf Baechle Signed-off-by: Greg Kroah-Hartman

Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

2016-05-28T23:41:39+00:00

Pull more MIPS updates from Ralf Baechle: "This is the secondnd batch of MIPS patches for 4.7. Summary: CPS: - Copy EVA configuration when starting secondary VPs. EIC: - Clear Status IPL. Lasat: - Fix a few off by one bugs. lib: - Mark intrinsics notrace. Not only are the intrinsics uninteresting, it would cause infinite recursion. MAINTAINERS: - Add file patterns for MIPS BRCM device tree bindings. - Add file patterns for mips device tree bindings. MT7628: - Fix MT7628 pinmux typos. - wled_an pinmux gpio. - EPHY LEDs pinmux support. Pistachio: - Enable KASLR VDSO: - Build microMIPS VDSO for microMIPS kernels. - Fix aliasing warning by building with `-fno-strict-aliasing' for debugging but also tracing them might result in recursion. Misc: - Add missing FROZEN hotplug notifier transitions. - Fix clk binding example for varioius PIC32 devices. - Fix cpu interrupt controller node-names in the DT files. - Fix XPA CPU feature separation. - Fix write_gc0_* macros when writing zero. - Add inline asm encoding helpers. - Add missing VZ accessor microMIPS encodings. - Fix little endian microMIPS MSA encodings. - Add 64-bit HTW fields and fix its configuration. - Fix sigreturn via VDSO on microMIPS kernel. - Lots of typo fixes. - Add definitions of SegCtl registers and use them" * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (49 commits) MIPS: Add missing FROZEN hotplug notifier transitions MIPS: Build microMIPS VDSO for microMIPS kernels MIPS: Fix sigreturn via VDSO on microMIPS kernel MIPS: devicetree: fix cpu interrupt controller node-names MIPS: VDSO: Build with `-fno-strict-aliasing' MIPS: Pistachio: Enable KASLR MIPS: lib: Mark intrinsics notrace MIPS: Fix 64-bit HTW configuration MIPS: Add 64-bit HTW fields MAINTAINERS: Add file patterns for mips device tree bindings MAINTAINERS: Add file patterns for mips brcm device tree bindings MIPS: Simplify DSP instruction encoding macros MIPS: Add missing tlbinvf/XPA microMIPS encodings MIPS: Fix little endian microMIPS MSA encodings MIPS: Add missing VZ accessor microMIPS encodings MIPS: Add inline asm encoding helpers MIPS: Spelling fix lets -> let's MIPS: VR41xx: Fix typo MIPS: oprofile: Fix typo MIPS: math-emu: Fix typo ...

MIPS: kernel: Fix typo

2016-05-28T10:35:08+00:00

Signed-off-by: Andrea Gelmini Cc: paul.burton@imgtec.com Cc: macro@imgtec.com Cc: james.hogan@imgtec.com Cc: jslaby@suse.cz Cc: adam.buchbinder@gmail.com Cc: trivial@kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/13330/ Signed-off-by: Ralf Baechle

exit_thread: remove empty bodies

2016-05-21T00:58:30+00:00

Define HAVE_EXIT_THREAD for archs which want to do something in exit_thread. For others, let's define exit_thread as an empty inline. This is a cleanup before we change the prototype of exit_thread to accept a task parameter. [akpm@linux-foundation.org: fix mips] Signed-off-by: Jiri Slaby Cc: "David S. Miller" Cc: "H. Peter Anvin" Cc: "James E.J. Bottomley" Cc: Aurelien Jacquiot Cc: Benjamin Herrenschmidt Cc: Catalin Marinas Cc: Chen Liqin Cc: Chris Metcalf Cc: Chris Zankel Cc: David Howells Cc: Fenghua Yu Cc: Geert Uytterhoeven Cc: Guan Xuetao Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Heiko Carstens Cc: Helge Deller Cc: Ingo Molnar Cc: Ivan Kokshaysky Cc: James Hogan Cc: Jeff Dike Cc: Jesper Nilsson Cc: Jiri Slaby Cc: Jonas Bonn Cc: Koichi Yasutake Cc: Lennox Wu Cc: Ley Foon Tan Cc: Mark Salter Cc: Martin Schwidefsky Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Mikael Starvik Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Ralf Baechle Cc: Rich Felker Cc: Richard Henderson Cc: Richard Kuo Cc: Richard Weinberger Cc: Russell King Cc: Steven Miao Cc: Thomas Gleixner Cc: Tony Luck Cc: Vineet Gupta Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

MIPS: Force CPUs to lose FP context during mode switches

2016-05-13T13:30:25+00:00

Commit 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") added support for the PR_SET_FP_MODE prctl, which allows a userland program to modify its FP mode at runtime. This is most notably required if dynamic linking leads to the FP mode requirement changing at runtime from that indicated in the initial executable's ELF header. In order to avoid overhead in the general FP context restore code, it aimed to have threads in the process become unable to enable the FPU during a mode switch & have the thread calling the prctl syscall wait for all other threads in the process to be context switched at least once. Once that happens we can know that no thread in the process whose mode will be switched has live FP context, and it's safe to perform the mode switch. However in the (rare) case of modeswitches occurring in multithreaded programs this can lead to indeterminate delays for the thread invoking the prctl syscall, and the code monitoring for those context switches was woefully inadequate for all but the simplest cases. Fix this by broadcasting an IPI if other CPUs may have live FP context for an affected thread, with a handler causing those CPUs to relinquish their FPU ownership. Threads will then be allowed to continue running but will stall on the wait_on_atomic_t in enable_restore_fp_context if they attempt to use FP again whilst the mode switch is still in progress. The end result is less fragile poking at scheduler context switch counts & a more expedient completion of the mode switch. Signed-off-by: Paul Burton Fixes: 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") Reviewed-by: Maciej W. Rozycki Cc: Adam Buchbinder Cc: James Hogan Cc: stable # v4.0+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13145/ Signed-off-by: Ralf Baechle

MIPS: Disable preemption during prctl(PR_SET_FP_MODE, ...)

2016-05-13T13:30:25+00:00

Whilst a PR_SET_FP_MODE prctl is performed there are decisions made based upon whether the task is executing on the current CPU. This may change if we're preempted, so disable preemption to avoid such changes for the lifetime of the mode switch. Signed-off-by: Paul Burton Fixes: 9791554b45a2 ("MIPS,prctl: add PR_[GS]ET_FP_MODE prctl options for MIPS") Reviewed-by: Maciej W. Rozycki Tested-by: Aurelien Jarno Cc: Adam Buchbinder Cc: James Hogan Cc: stable # v4.0+ Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/13144/ Signed-off-by: Ralf Baechle

MIPS: Make flush_thread

2016-05-13T12:01:54+00:00

Avoids function calls to an empty function. Signed-off-by: Ralf Baechle

MIPS: Don't unwind to user mode with EVA

2016-05-09T10:00:02+00:00

When unwinding through IRQs and exceptions, the unwinding only continues if the PC is a kernel text address, however since EVA it is possible for user and kernel address ranges to overlap, potentially allowing unwinding to continue to user mode if the user PC happens to be in the kernel text address range. Adjust the check to also ensure that the register state from before the exception is actually running in kernel mode, i.e. !user_mode(regs). I don't believe any harm can come of this problem, since the PC is only output, the stack pointer is checked to ensure it resides within the task's stack page before it is dereferenced in search of the return address, and the return address register is similarly only output (if the PC is in a leaf function or the beginning of a non-leaf function). However unwind_stack() is only meant for unwinding kernel code, so to be correct the unwind should stop there. Signed-off-by: James Hogan Reviewed-by: Leonid Yegoshin Cc: linux-mips@linux-mips.org Cc: # 3.15+ Patchwork: https://patchwork.linux-mips.org/patch/11700/ Signed-off-by: Ralf Baechle

MIPS: Fix misspellings in comments.

2016-04-03T10:32:09+00:00

Signed-off-by: Adam Buchbinder Cc: linux-mips@linux-mips.org Cc: trivial@kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12617/ Signed-off-by: Ralf Baechle

MIPS: Properly disable FPU in start_thread()

2016-02-01T22:36:03+00:00

start_thread() (called for execve(2)) clears the TIF_USEDFPU flag without atomically disabling the FPU. With a preemptive kernel, an unfortunately timed preemption after this could result in another task (or KVM guest) being scheduled in with the FPU still enabled, since lose_fpu_inatomic() only turns it off if TIF_USEDFPU is set. Use lose_fpu(0) instead of the separate FPU / MSA management, which should do the right thing (drop FPU properly and atomically without saving state) and will be more future proof. Signed-off-by: James Hogan Reviewed-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12302/ Signed-off-by: Ralf Baechle