wireguard-linux/arch/powerpc/kernel/entry_64.S, branch jd/unified-crypt-queue

powerpc/64: make buildable without CONFIG_COMPAT

2020-04-02T13:10:00Z

There are numerous references to 32bit functions in generic and 64bit code so ifdef them out. Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e5619617020ef3a1f54f0c076e7d74cb9ec9f3bf.1584699455.git.msuchanek@suse.de

powerpc/64/syscall: Reconcile interrupts

2020-04-01T02:42:14Z

This reconciles interrupts in the system call case like all other interrupts. This allows system_call_common to be shared with the scv system call implementation in a subsequent patch. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-31-npiggin@gmail.com

powerpc/64s/exception: Remove lite interrupt return

2020-04-01T02:42:14Z

Regular interrupt return restores NVGPRS whereas lite returns do not. This is clumsy: most interrupts can return without restoring NVGPRS in most of the time, but there are special cases that require it (when registers have been modified by the kernel). So change interrupt return to not restore NVGPRS, and have interrupt handlers restore them explicitly in the cases that requires it. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-30-npiggin@gmail.com

powerpc/64s: Implement interrupt exit logic in C

2020-04-01T02:42:14Z

Implement the bulk of interrupt return logic in C. The asm return code must handle a few cases: restoring full GPRs, and emulating stack store. The stack store emulation is significantly simplfied, rather than creating a new return frame and switching to that before performing the store, it uses the PACA to keep a scratch register around to perform the store. The asm return code is moved into 64e for now. The new logic has made allowance for 64e, but I don't have a full environment that works well to test it, and even booting in emulated qemu is not great for stress testing. 64e shouldn't be too far off working with this, given a bit more testing and auditing of the logic. This is slightly faster on a POWER9 (page fault speed increases about 1.1%), probably due to reduced mtmsrd. mpe: Includes fixes from Nick for _TIF_EMULATE_STACK_STORE handling (including the fast_interrupt_return path), to remove trace_hardirqs_on(), and fixes the interrupt-return part of the MSR_VSX restore bug caught by tm-unavailable selftest. mpe: Incorporate fix from Nick: The return-to-kernel path has to replay any soft-pending interrupts if it is returning to a context that had interrupts soft-enabled. It has to do this carefully and avoid plain enabling interrupts if this is an irq context, which can cause multiple nesting of interrupts on the stack, and other unexpected issues. The code which avoided this case got the soft-mask state wrong, and marked interrupts as enabled before going around again to retry. This seems to be mostly harmless except when PREEMPT=y, this calls preempt_schedule_irq with irqs apparently enabled and runs into a BUG in kernel/sched/core.c Signed-off-by: Nicholas Piggin Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-29-npiggin@gmail.com

powerpc/64/syscall: Zero volatile registers when returning

2020-04-01T02:42:13Z

Kernel addresses and potentially other sensitive data could be leaked in volatile registers after a syscall. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-27-npiggin@gmail.com

powerpc/64/sycall: Implement syscall entry/exit logic in C

2020-04-01T02:42:13Z

System call entry and particularly exit code is beyond the limit of what is reasonable to implement in asm. This conversion moves all conditional branches out of the asm code, except for the case that all GPRs should be restored at exit. Null syscall test is about 5% faster after this patch, because the exit work is handled under local_irq_disable, and the hard mask and pending interrupt replay is handled after that, which avoids games with MSR. mpe: Includes subsequent fixes from Nick: This fixes 4 issues caught by TM selftests. First was a tm-syscall bug that hit due to tabort_syscall being called after interrupts were reconciled (in a subsequent patch), which led to interrupts being enabled before tabort_syscall was called. Rather than going through an un-reconciling interrupts for the return, I just go back to putting the test early in asm, the C-ification of that wasn't a big win anyway. Second is the syscall return _TIF_USER_WORK_MASK check would go into an infinite loop if _TIF_RESTORE_TM became set. The asm code uses _TIF_USER_WORK_MASK to brach to slowpath which includes restore_tm_state. Third is system call return was not calling restore_tm_state, I missed this completely (alhtough it's in the return from interrupt C conversion because when the asm syscall code encountered problems it would branch to the interrupt return code. Fourth is MSR_VEC missing from restore_math, which was caught by tm-unavailable selftest taking an unexpected facility unavailable interrupt when testing VSX unavailble exception with MSR.FP=1 MSR.VEC=1. Fourth case also has a fixup in a subsequent patch. Signed-off-by: Nicholas Piggin Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-26-npiggin@gmail.com

powerpc/64/syscall: Remove non-volatile GPR save optimisation

2020-04-01T02:42:13Z

powerpc has an optimisation where interrupts avoid saving the non-volatile (or callee saved) registers to the interrupt stack frame if they are not required. Two problems with this are that an interrupt does not always know whether it will need non-volatiles; and if it does need them, they can only be saved from the entry-scoped asm code (because we don't control what the C compiler does with these registers). system calls are the most difficult: some system calls always require all registers (e.g., fork, to copy regs into the child). Sometimes registers are only required under certain conditions (e.g., tracing, signal delivery). These cases require ugly logic in the call chains (e.g., ppc_fork), and require a lot of logic to be implemented in asm. So remove the optimisation for system calls, and always save NVGPRs on entry. Modern high performance CPUs are not so sensitive, because the stores are dense in cache and can be hidden by other expensive work in the syscall path -- the null syscall selftests benchmark on POWER9 is not slowed (124.40ns before and 123.64ns after, i.e., within the noise). Other interrupts retain the NVGPR optimisation for now. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-24-npiggin@gmail.com

Merge tag 'powerpc-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2020-02-04T13:06:46Z

Pull powerpc updates from Michael Ellerman: "A pretty small batch for us, and apologies for it being a bit late, I wanted to sneak Christophe's user_access_begin() series in. Summary: - Implement user_access_begin() and friends for our platforms that support controlling kernel access to userspace. - Enable CONFIG_VMAP_STACK on 32-bit Book3S and 8xx. - Some tweaks to our pseries IOMMU code to allow SVMs ("secure" virtual machines) to use the IOMMU. - Add support for CLOCK_{REALTIME/MONOTONIC}_COARSE to the 32-bit VDSO, and some other improvements. - A series to use the PCI hotplug framework to control opencapi card's so that they can be reset and re-read after flashing a new FPGA image. As well as other minor fixes and improvements as usual. Thanks to: Alastair D'Silva, Alexandre Ghiti, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Bai Yingjie, Chen Zhou, Christophe Leroy, Frederic Barrat, Greg Kurz, Jason A. Donenfeld, Joel Stanley, Jordan Niethe, Julia Lawall, Krzysztof Kozlowski, Laurent Dufour, Laurentiu Tudor, Linus Walleij, Michael Bringmann, Nathan Chancellor, Nicholas Piggin, Nick Desaulniers, Oliver O'Halloran, Peter Ujfalusi, Pingfan Liu, Ram Pai, Randy Dunlap, Russell Currey, Sam Bobroff, Sebastian Andrzej Siewior, Shawn Anastasio, Stephen Rothwell, Steve Best, Sukadev Bhattiprolu, Thiago Jung Bauermann, Tyrel Datwyler, Vaibhav Jain" * tag 'powerpc-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (131 commits) powerpc: configs: Cleanup old Kconfig options powerpc/configs/skiroot: Enable some more hardening options powerpc/configs/skiroot: Disable xmon default & enable reboot on panic powerpc/configs/skiroot: Enable security features powerpc/configs/skiroot: Update for symbol movement only powerpc/configs/skiroot: Drop default n CONFIG_CRYPTO_ECHAINIV powerpc/configs/skiroot: Drop HID_LOGITECH powerpc/configs: Drop NET_VENDOR_HP which moved to staging powerpc/configs: NET_CADENCE became NET_VENDOR_CADENCE powerpc/configs: Drop CONFIG_QLGE which moved to staging powerpc: Do not consider weak unresolved symbol relocations as bad powerpc/32s: Fix kasan_early_hash_table() for CONFIG_VMAP_STACK powerpc: indent to improve Kconfig readability powerpc: Provide initial documentation for PAPR hcalls powerpc: Implement user_access_save() and user_access_restore() powerpc: Implement user_access_begin and friends powerpc/32s: Prepare prevent_user_access() for user_access_end() powerpc/32s: Drop NULL addr verification powerpc/kuap: Fix set direction in allow/prevent_user_access() powerpc/32s: Fix bad_kuap_fault() ...

powerpc/64: Use {SAVE,REST}_NVGPRS macros

2020-01-06T05:25:26Z

In entry_64.S there are places that open code saving and restoring the non-volatile registers. There are already macros for doing this so use them. Signed-off-by: Jordan Niethe Reviewed-by: Andrew Donnellan Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191211023552.16480-1-jniethe5@gmail.com

sched/rt, powerpc: Use CONFIG_PREEMPTION

2019-12-08T13:37:32Z

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the entry code over to use CONFIG_PREEMPTION. [bigeasy: +Kconfig] Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Michael Ellerman Cc: Christophe Leroy Cc: Linus Torvalds Cc: Paul Mackerras Cc: Peter Zijlstra Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20191024160458.vlnf3wlcyjl2ich7@linutronix.de Signed-off-by: Ingo Molnar