Giancarlo Ferrari reports the following oops while trying to use kexec: Unable to handle kernel paging request at virtual address 80112f38 pgd = fd7ef03e [80112f38] *pgd=0001141e(bad) Internal error: Oops: 80d [#1] PREEMPT SMP ARM ... This is caused by machine_kexec() trying to set the kernel text to be read/write, so it can poke values into the relocation code before copying it - and an interrupt occuring which changes the page tables. The subsequent writes then hit read-only sections that trigger a data abort resulting in the above oops. Fix this by copying the relocation code, and then writing the variables into the destination, thereby avoiding the need to make the kernel text read/write. Reported-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com> Tested-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Ensure that the signal page contains our poison instruction to increase the protection against ROP attacks and also contains well defined contents. Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Pull irq updates from Thomas Gleixner: "This is the second attempt after the first one failed miserably and got zapped to unblock the rest of the interrupt related patches. A treewide cleanup of interrupt descriptor (ab)use with all sorts of racy accesses, inefficient and disfunctional code. The goal is to remove the export of irq_to_desc() to prevent these things from creeping up again" * tag 'irq-core-2020-12-23' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) genirq: Restrict export of irq_to_desc() xen/events: Implement irq distribution xen/events: Reduce irq_info:: Spurious_cnt storage size xen/events: Only force affinity mask for percpu interrupts xen/events: Use immediate affinity setting xen/events: Remove disfunct affinity spreading xen/events: Remove unused bind_evtchn_to_irq_lateeoi() net/mlx5: Use effective interrupt affinity net/mlx5: Replace irq_to_desc() abuse net/mlx4: Use effective interrupt affinity net/mlx4: Replace irq_to_desc() abuse PCI: mobiveil: Use irq_data_get_irq_chip_data() PCI: xilinx-nwl: Use irq_data_get_irq_chip_data() NTB/msi: Use irq_has_action() mfd: ab8500-debugfs: Remove the racy fiddling with irq_desc pinctrl: nomadik: Use irq_has_action() drm/i915/pmu: Replace open coded kstat_irqs() copy drm/i915/lpe_audio: Remove pointless irq_to_desc() usage s390/irq: Use irq_desc_kstat_cpu() in show_msi_interrupt() parisc/irq: Use irq_desc_kstat_cpu() in show_interrupts() ...
Pull ARM updates from Russell King: - Rework phys/virt translation - Add KASan support - Move DT out of linear map region - Use more PC-relative addressing in assembly - Remove FP emulation handling while in kernel mode - Link with '-z norelro' - remove old check for GCC <= 4.2 in ARM unwinder code - disable big endian if using clang's linker * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (46 commits) ARM: 9027/1: head.S: explicitly map DT even if it lives in the first physical section ARM: 9038/1: Link with '-z norelro' ARM: 9037/1: uncompress: Add OF_DT_MAGIC macro ARM: 9036/1: uncompress: Fix dbgadtb size parameter name ARM: 9035/1: uncompress: Add be32tocpu macro ARM: 9033/1: arm/smp: Drop the macro S(x,s) ARM: 9032/1: arm/mm: Convert PUD level pgtable helper macros into functions ARM: 9031/1: hyp-stub: remove unused .L__boot_cpu_mode_offset symbol ARM: 9044/1: vfp: use undef hook for VFP support detection ARM: 9034/1: __div64_32(): straighten up inline asm constraints ARM: 9030/1: entry: omit FP emulation for UND exceptions taken in kernel mode ARM: 9029/1: Make iwmmxt.S support Clang's integrated assembler ARM: 9028/1: disable KASAN in call stack capturing routines ARM: 9026/1: unwind: remove old check for GCC <= 4.2 ARM: 9025/1: Kconfig: CPU_BIG_ENDIAN depends on !LD_IS_LLD ARM: 9024/1: Drop useless cast of "u64" to "long long" ARM: 9023/1: Spelling s/mmeory/memory/ ARM: 9022/1: Change arch/arm/lib/mem*.S to use WEAK instead of .weak ARM: kvm: replace open coded VA->PA calculations with adr_l call ARM: head.S: use PC relative insn sequence to calculate PHYS_OFFSET ...
The early ATAGS/DT mapping code uses SECTION_SHIFT to mask low order
bits of R2, and decides that no ATAGS/DTB were provided if the resulting
value is 0x0.
This means that on systems where DRAM starts at 0x0 (such as Raspberry
Pi), no explicit mapping of the DT will be created if R2 points into the
first 1 MB section of memory. This was not a problem before, because the
decompressed kernel is loaded at the base of DRAM and mapped using
sections as well, and so as long as the DT is referenced via a virtual
address that uses the same translation (the linear map, in this case),
things work fine.
However, commit 7a1be318f579 ("9012/1: move device tree mapping out of
linear region") changes this, and now the DT is referenced via a virtual
address that is disjoint from the linear mapping of DRAM, and so we need
the early code to create the DT mapping unconditionally.
So let's create the early DT mapping for any value of R2 != 0x0.
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Mapping between IPI type index and its string is direct without requiring an additional offset. Hence the existing macro S(x, s) is now redundant and can just be dropped. This also makes the code clean and simple. Cc: Marc Zyngier <maz@kernel.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Commit aaac3733171fca94 ("ARM: kvm: replace open coded VA->PA calculations
with adr_l call") removed all uses of .L__boot_cpu_mode_offset, so there
is no longer a need to define it.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe: "This sits on top of of the core entry/exit and x86 entry branch from the tip tree, which contains the generic and x86 parts of this work. Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL. With that done, we can get rid of JOBCTL_TASK_WORK from task_work and signal.c, and also remove a deadlock work-around in io_uring around knowing that signal based task_work waking is invoked with the sighand wait queue head lock. The motivation for this work is to decouple signal notify based task_work, of which io_uring is a heavy user of, from sighand. The sighand lock becomes a huge contention point, particularly for threaded workloads where it's shared between threads. Even outside of threaded applications it's slower than it needs to be. Roman Gershman <romger@amazon.com> reported that his networked workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all spent hammering on the sighand lock, showing 57% of the CPU time there [1]. There are further cleanups possible on top of this. One example is TIF_PATCH_PENDING, where a patch already exists to use TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more consolidation, but the work stands on its own as well" [1] https://github.com/axboe/liburing/issues/215 * tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits) io_uring: remove 'twa_signal_ok' deadlock work-around kernel: remove checking for TIF_NOTIFY_SIGNAL signal: kill JOBCTL_TASK_WORK io_uring: JOBCTL_TASK_WORK is no longer used by task_work task_work: remove legacy TWA_SIGNAL path sparc: add support for TIF_NOTIFY_SIGNAL riscv: add support for TIF_NOTIFY_SIGNAL nds32: add support for TIF_NOTIFY_SIGNAL ia64: add support for TIF_NOTIFY_SIGNAL h8300: add support for TIF_NOTIFY_SIGNAL c6x: add support for TIF_NOTIFY_SIGNAL alpha: add support for TIF_NOTIFY_SIGNAL xtensa: add support for TIF_NOTIFY_SIGNAL arm: add support for TIF_NOTIFY_SIGNAL microblaze: add support for TIF_NOTIFY_SIGNAL hexagon: add support for TIF_NOTIFY_SIGNAL csky: add support for TIF_NOTIFY_SIGNAL openrisc: add support for TIF_NOTIFY_SIGNAL sh: add support for TIF_NOTIFY_SIGNAL um: add support for TIF_NOTIFY_SIGNAL ...
Pull asm-generic cross-architecture timer cleanup from Arnd Bergmann: "This cleans up two ancient timer features that were never completed in the past, CONFIG_GENERIC_CLOCKEVENTS and CONFIG_ARCH_USES_GETTIMEOFFSET. There was only one user left for the ARCH_USES_GETTIMEOFFSET variant of clocksource implementations, the ARM EBSA110 platform. Rather than changing to use modern timekeeping, we remove the platform entirely as Russell no longer uses his machine and nobody else seems to have one any more. The conditional code for using arch_gettimeoffset() is removed as a result. For CONFIG_GENERIC_CLOCKEVENTS, there are still a couple of platforms not using clockevent drivers: parisc, ia64, most of m68k, and one Arm platform. These all do timer ticks slighly differently, and this gets cleaned up to the point they at least all call the same helper function. Instead of most platforms using 'select GENERIC_CLOCKEVENTS' in Kconfig, the polarity is now reversed, with the few remaining ones selecting LEGACY_TIMER_TICK instead" * tag 'asm-generic-timers-5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: timekeeping: default GENERIC_CLOCKEVENTS to enabled timekeeping: remove xtime_update m68k: remove timer_interrupt() function m68k: change remaining timers to legacy_timer_tick m68k: m68328: use legacy_timer_tick() m68k: sun3/sun3c: use legacy_timer_tick m68k: split heartbeat out of timer function m68k: coldfire: use legacy_timer_tick() parisc: use legacy_timer_tick ARM: rpc: use legacy_timer_tick ia64: convert to legacy_timer_tick timekeeping: add CONFIG_LEGACY_TIMER_TICK timekeeping: remove arch_gettimeoffset net: remove am79c961a driver ARM: remove ebsa110 platform