- 06 Dec, 2019 4 commits
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Heyi Guo authored
Stack overflow checking can be done by testing sp & (1 << THREAD_SHIFT) only for the stacks are aligned to (2 << THREAD_SHIFT) with size of (1 << THREAD_SIZE), and this is the case when CONFIG_VMAP_STACK is set. Fix the code comment to avoid confusion. Cc: Will Deacon <will@kernel.org> Acked-by:
Mark Rutland <mark.rutland@arm.com> Signed-off-by:
Heyi Guo <guoheyi@huawei.com> [catalin.marinas@arm.com: Updated comment following Mark's suggestion] Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
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Mark Rutland authored
When I tweaked the ftrace entry assembly in commit: 3b23e499 ("arm64: implement ftrace with regs") ... my ifdeffery tweaks left ftrace_graph_caller undefined for CONFIG_DYNAMIC_FTRACE && CONFIG_FUNCTION_GRAPH_TRACER when ftrace is based on mcount. The kbuild test robot reported that this issue is detected at link time: | arch/arm64/kernel/entry-ftrace.o: In function `skip_ftrace_call': | arch/arm64/kernel/entry-ftrace.S:238: undefined reference to `ftrace_graph_caller' | arch/arm64/kernel/entry-ftrace.S:238:(.text+0x3c): relocation truncated to fit: R_AARCH64_CONDBR19 against undefined symbol | `ftrace_graph_caller' | arch/arm64/kernel/entry-ftrace.S:243: undefined reference to `ftrace_graph_caller' | arch/arm64/kernel/entry-ftrace.S:243:(.text+0x54): relocation truncated to fit: R_AARCH64_CONDBR19 against undefined symbol | `ftrace_graph_caller' This patch fixes the ifdeffery so that the mcount version of ftrace_graph_caller doesn't depend on CONFIG_DYNAMIC_FTRACE. At the same time, a redundant #else is removed from the ifdeffery for the patchable-function-entry version of ftrace_graph_caller. Fixes: 3b23e499 ("arm64: implement ftrace with regs") Reported-by:
kbuild test robot <lkp@intel.com> Signed-off-by:
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Sebastian Andrzej Siewior authored
compute_layout() is invoked as part of an alternative fixup under stop_machine(). This function invokes get_random_long() which acquires a sleeping lock on -RT which can not be acquired in this context. Rename compute_layout() to kvm_compute_layout() and invoke it before stop_machine() applies the alternatives. Add a __init prefix to kvm_compute_layout() because the caller has it, too (and so the code can be discarded after boot). Reviewed-by:
James Morse <james.morse@arm.com> Acked-by:
Marc Zyngier <maz@kernel.org> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by:
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Catalin Marinas authored
__range_ok(), invoked from access_ok(), clears the tag of the user address only if CONFIG_ARM64_TAGGED_ADDR_ABI is enabled and the thread opted in to the relaxed ABI. The latter sets the TIF_TAGGED_ADDR thread flag. In the case of asynchronous I/O (e.g. io_submit()), the access_ok() may be called from a kernel thread. Since kernel threads don't have TIF_TAGGED_ADDR set, access_ok() will fail for valid tagged user addresses. Example from the ffs_user_copy_worker() thread: use_mm(io_data->mm); ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data); unuse_mm(io_data->mm); Relax the __range_ok() check to always untag the user address if called in the context of a kernel thread. The user pointers would have already been checked via aio_setup_rw() -> import_{single_range,iovec}() at the time of the asynchronous I/O request. Fixes: 63f0c603 ("arm64: Introduce prctl() options to control the tagged user addresses ABI") Cc: <stable@vger.kernel.org> # 5.4.x- Cc: Will Deacon <will@kernel.org> Reported-by:Evgenii Stepanov <eugenis@google.com> Tested-by:
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- 04 Dec, 2019 3 commits
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Mark Brown authored
UXN is the only individual PTE bit other than the PTE_ATTRINDX_MASK ones which doesn't have both a set and a clear value provided, meaning that the columns in the table won't all be aligned. The PTE_ATTRINDX_MASK values are all both mutually exclusive and longer so are listed last to make a single final column for those values. Ensure everything is aligned by providing a clear value for UXN. Acked-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
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Mark Rutland authored
A kernel built with KASAN && FTRACE_WITH_REGS && !MODULES, produces a boot-time splat in the bowels of ftrace: | [ 0.000000] ftrace: allocating 32281 entries in 127 pages | [ 0.000000] ------------[ cut here ]------------ | [ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2019 ftrace_bug+0x27c/0x328 | [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.0-rc3-00008-g7f08ae53 #13 | [ 0.000000] Hardware name: linux,dummy-virt (DT) | [ 0.000000] pstate: 60000085 (nZCv daIf -PAN -UAO) | [ 0.000000] pc : ftrace_bug+0x27c/0x328 | [ 0.000000] lr : ftrace_init+0x640/0x6cc | [ 0.000000] sp : ffffa000120e7e00 | [ 0.000000] x29: ffffa000120e7e00 x28: ffff00006ac01b10 | [ 0.000000] x27: ffff00006ac898c0 x26: dfffa00000000000 | [ 0.000000] x25: ffffa000120ef290 x24: ffffa0001216df40 | [ 0.000000] x23: 000000000000018d x22: ffffa0001244c700 | [ 0.000000] x21: ffffa00011bf393c x20: ffff00006ac898c0 | [ 0.000000] x19: 00000000ffffffff x18: 0000000000001584 | [ 0.000000] x17: 0000000000001540 x16: 0000000000000007 | [ 0.000000] x15: 0000000000000000 x14: ffffa00010432770 | [ 0.000000] x13: ffff940002483519 x12: 1ffff40002483518 | [ 0.000000] x11: 1ffff40002483518 x10: ffff940002483518 | [ 0.000000] x9 : dfffa00000000000 x8 : 0000000000000001 | [ 0.000000] x7 : ffff940002483519 x6 : ffffa0001241a8c0 | [ 0.000000] x5 : ffff940002483519 x4 : ffff940002483519 | [ 0.000000] x3 : ffffa00011780870 x2 : 0000000000000001 | [ 0.000000] x1 : 1fffe0000d591318 x0 : 0000000000000000 | [ 0.000000] Call trace: | [ 0.000000] ftrace_bug+0x27c/0x328 | [ 0.000000] ftrace_init+0x640/0x6cc | [ 0.000000] start_kernel+0x27c/0x654 | [ 0.000000] random: get_random_bytes called from print_oops_end_marker+0x30/0x60 with crng_init=0 | [ 0.000000] ---[ end trace 0000000000000000 ]--- | [ 0.000000] ftrace faulted on writing | [ 0.000000] [<ffffa00011bf393c>] _GLOBAL__sub_D_65535_0___tracepoint_initcall_level+0x4/0x28 | [ 0.000000] Initializing ftrace call sites | [ 0.000000] ftrace record flags: 0 | [ 0.000000] (0) | [ 0.000000] expected tramp: ffffa000100b3344 This is due to an unfortunate combination of several factors. Building with KASAN results in the compiler generating anonymous functions to register/unregister global variables against the shadow memory. These functions are placed in .text.startup/.text.exit, and given mangled names like _GLOBAL__sub_{I,D}_65535_0_$OTHER_SYMBOL. The kernel linker script places these in .init.text and .exit.text respectively, which are both discarded at runtime as part of initmem. Building with FTRACE_WITH_REGS uses -fpatchable-function-entry=2, which also instruments KASAN's anonymous functions. When these are discarded with the rest of initmem, ftrace removes dangling references to these call sites. Building without MODULES implicitly disables STRICT_MODULE_RWX, and causes arm64's patch_map() function to treat any !core_kernel_text() symbol as something that can be modified in-place. As core_kernel_text() is only true for .text and .init.text, with the latter depending on system_state < SYSTEM_RUNNING, we'll treat .exit.text as something that can be patched in-place. However, .exit.text is mapped read-only. Hence in this configuration the ftrace init code blows up while trying to patch one of the functions generated by KASAN. We could try to filter out the call sites in .exit.text rather than initializing them, but this would be inconsistent with how we handle .init.text, and requires hooking into core bits of ftrace. The behaviour of patch_map() is also inconsistent today, so instead let's clean that up and have it consistently handle .exit.text. This patch teaches patch_map() to handle .exit.text at init time, preventing the boot-time splat above. The flow of patch_map() is reworked to make the logic clearer and minimize redundant conditionality. Fixes: 3b23e499 ("arm64: implement ftrace with regs") Signed-off-by:
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Will Deacon authored
John reports that the recently merged commit 1a8e1cef ("arm64: use both ZONE_DMA and ZONE_DMA32") breaks the boot on his DB845C board: | Booting Linux on physical CPU 0x0000000000 [0x517f803c] | Linux version 5.4.0-mainline-10675-g957a03b9e38f | Machine model: Thundercomm Dragonboard 845c | [...] | Built 1 zonelists, mobility grouping on. Total pages: -188245 | Kernel command line: earlycon | firmware_class.path=/vendor/firmware/ androidboot.hardware=db845c | init=/init androidboot.boot_devices=soc/1d84000.ufshc | printk.devkmsg=on buildvariant=userdebug root=/dev/sda2 | androidboot.bootdevice=1d84000.ufshc androidboot.serialno=c4e1189c | androidboot.baseband=sda | msm_drm.dsi_display0=dsi_lt9611_1080_video_display: | androidboot.slot_suffix=_a skip_initramfs rootwait ro init=/init | | <hangs indefinitely here> This is because, when CONFIG_NUMA=n, zone_sizes_init() fails to handle memblocks that fall entirely within the ZONE_DMA region and erroneously ends up trying to add a negatively-sized region into the following ZONE_DMA32, which is later interpreted as a large unsigned region by the core MM code. Rework the non-NUMA implementation of zone_sizes_init() so that the start address of the memblock being processed is adjusted according to the end of the previous zone, which is then range-checked before updating the hole information of subsequent zones. Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Link: https://lore.kernel.org/lkml/CALAqxLVVcsmFrDKLRGRq7GewcW405yTOxG=KR3csVzQ6bXutkA@mail.gmail.com Fixes: 1a8e1cef ("arm64: use both ZONE_DMA and ZONE_DMA32") Reported-by:
John Stultz <john.stultz@linaro.org> Tested-by:
Will Deacon <will@kernel.org> Signed-off-by:
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- 14 Nov, 2019 1 commit
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Anders Roxell authored
When building allmodconfig KCONFIG_ALLCONFIG=$(pwd)/arch/arm64/configs/defconfig CONFIG_CPU_BIG_ENDIAN gets enabled. Which tends not to be what most people want. Another concern that has come up is that ACPI isn't built for an allmodconfig kernel today since that also depends on !CPU_BIG_ENDIAN. Rework so that we introduce a 'choice' and default the choice to CPU_LITTLE_ENDIAN. That means that when we build an allmodconfig kernel it will default to CPU_LITTLE_ENDIAN that most people tends to want. Reviewed-by:
John Garry <john.garry@huawei.com> Acked-by:
Anders Roxell <anders.roxell@linaro.org> Signed-off-by:
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- 11 Nov, 2019 3 commits
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Colin Ian King authored
There is a spelling mistake in an error message literal string. Fix it. Fixes: f96bf434 ("kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils") Signed-off-by:
Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Anders Roxell authored
When building allmodconfig KCONFIG_ALLCONFIG=$(pwd)/arch/arm64/configs/defconfig CONFIG_CMDLINE_FORCE gets enabled. Which forces the user to pass the full cmdline to CONFIG_CMDLINE="...". Rework so that CONFIG_CMDLINE_FORCE gets set only if CONFIG_CMDLINE is set to something except an empty string. Suggested-by:
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Catalin Marinas authored
Since these are tests specific to the arm64 architecture, it makes sense for the arm64 maintainers to gatekeep the corresponding changes. Cc: Shuah Khan <shuah@kernel.org> Cc: Will Deacon <will@kernel.org> Signed-off-by:
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- 08 Nov, 2019 16 commits
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Catalin Marinas authored
Merge branches 'for-next/elf-hwcap-docs', 'for-next/smccc-conduit-cleanup', 'for-next/zone-dma', 'for-next/relax-icc_pmr_el1-sync', 'for-next/double-page-fault', 'for-next/misc', 'for-next/kselftest-arm64-signal' and 'for-next/kaslr-diagnostics' into for-next/core * for-next/elf-hwcap-docs: : Update the arm64 ELF HWCAP documentation docs/arm64: cpu-feature-registers: Rewrite bitfields that don't follow [e, s] docs/arm64: cpu-feature-registers: Documents missing visible fields docs/arm64: elf_hwcaps: Document HWCAP_SB docs/arm64: elf_hwcaps: sort the HWCAP{, 2} documentation by ascending value * for-next/smccc-conduit-cleanup: : SMC calling convention conduit clean-up firmware: arm_sdei: use common SMCCC_CONDUIT_* firmware/psci: use common SMCCC_CONDUIT_* arm: spectre-v2: use arm_smccc_1_1_get_conduit() arm64: errata: use arm_smccc_1_1_get_conduit() arm/arm64: smccc/psci: add arm_smccc_1_1_get_conduit() * for-next/zone-dma: : Reintroduction of ZONE_DMA for Raspberry Pi 4 support arm64: mm: reserve CMA and crashkernel in ZONE_DMA32 dma/direct: turn ARCH_ZONE_DMA_BITS into a variable arm64: Make arm64_dma32_phys_limit static arm64: mm: Fix unused variable warning in zone_sizes_init mm: refresh ZONE_DMA and ZONE_DMA32 comments in 'enum zone_type' arm64: use both ZONE_DMA and ZONE_DMA32 arm64: rename variables used to calculate ZONE_DMA32's size arm64: mm: use arm64_dma_phys_limit instead of calling max_zone_dma_phys() * for-next/relax-icc_pmr_el1-sync: : Relax ICC_PMR_EL1 (GICv3) accesses when ICC_CTLR_EL1.PMHE is clear arm64: Document ICC_CTLR_EL3.PMHE setting requirements arm64: Relax ICC_PMR_EL1 accesses when ICC_CTLR_EL1.PMHE is clear * for-next/double-page-fault: : Avoid a double page fault in __copy_from_user_inatomic() if hw does not support auto Access Flag mm: fix double page fault on arm64 if PTE_AF is cleared x86/mm: implement arch_faults_on_old_pte() stub on x86 arm64: mm: implement arch_faults_on_old_pte() on arm64 arm64: cpufeature: introduce helper cpu_has_hw_af() * for-next/misc: : Various fixes and clean-ups arm64: kpti: Add NVIDIA's Carmel core to the KPTI whitelist arm64: mm: Remove MAX_USER_VA_BITS definition arm64: mm: simplify the page end calculation in __create_pgd_mapping() arm64: print additional fault message when executing non-exec memory arm64: psci: Reduce the waiting time for cpu_psci_cpu_kill() arm64: pgtable: Correct typo in comment arm64: docs: cpu-feature-registers: Document ID_AA64PFR1_EL1 arm64: cpufeature: Fix typos in comment arm64/mm: Poison initmem while freeing with free_reserved_area() arm64: use generic free_initrd_mem() arm64: simplify syscall wrapper ifdeffery * for-next/kselftest-arm64-signal: : arm64-specific kselftest support with signal-related test-cases kselftest: arm64: fake_sigreturn_misaligned_sp kselftest: arm64: fake_sigreturn_bad_size kselftest: arm64: fake_sigreturn_duplicated_fpsimd kselftest: arm64: fake_sigreturn_missing_fpsimd kselftest: arm64: fake_sigreturn_bad_size_for_magic0 kselftest: arm64: fake_sigreturn_bad_magic kselftest: arm64: add helper get_current_context kselftest: arm64: extend test_init functionalities kselftest: arm64: mangle_pstate_invalid_mode_el[123][ht] kselftest: arm64: mangle_pstate_invalid_daif_bits kselftest: arm64: mangle_pstate_invalid_compat_toggle and common utils kselftest: arm64: extend toplevel skeleton Makefile * for-next/kaslr-diagnostics: : Provide diagnostics on boot for KASLR arm64: kaslr: Check command line before looking for a seed arm64: kaslr: Announce KASLR status on boot -
Mark Brown authored
Now that we print diagnostics at boot the reason why we do not initialise KASLR matters. Currently we check for a seed before we check if the user has explicitly disabled KASLR on the command line which will result in misleading diagnostics so reverse the order of those checks. We still parse the seed from the DT early so that if the user has both provided a seed and disabled KASLR on the command line we still mask the seed on the command line. Signed-off-by:
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Mark Brown authored
Currently the KASLR code is silent at boot unless it forces on KPTI in which case a message will be printed for that. This can lead to users incorrectly believing their system has the feature enabled when it in fact does not, and if they notice the problem the lack of any diagnostics makes it harder to understand the problem. Add an initcall which prints a message showing the status of KASLR during boot to make the status clear. This is particularly useful in cases where we don't have a seed. It seems to be a relatively common error for system integrators and administrators to enable KASLR in their configuration but not provide the seed at runtime, often due to seed provisioning breaking at some later point after it is initially enabled and verified. Signed-off-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which places a valid sigframe on a non-16 bytes aligned SP. Expects a SIGSEGV on test PASS. Reviewed-by:
Dave Martin <Dave.Martin@arm.com> Signed-off-by:
Cristian Marussi <cristian.marussi@arm.com> Signed-off-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which builds a ucontext_t with a badly sized header that causes a overrun in the __reserved area and place it onto the stack. Expects a SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which builds a ucontext_t with an anomalous additional fpsimd_context and place it onto the stack. Expects a SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which builds a ucontext_t without the required fpsimd_context and place it onto the stack. Expects a SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which builds a ucontext_t with a badly sized terminator record and place it onto the stack. Expects a SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add a simple fake_sigreturn testcase which builds a ucontext_t with a bad magic header and place it onto the stack. Expects a SIGSEGV on test PASS. Introduce a common utility assembly trampoline function to invoke a sigreturn while placing the provided sigframe at wanted alignment and also an helper to make space when needed inside the sigframe reserved area. Reviewed-by:
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Cristian Marussi authored
Introduce a new common utility function get_current_context() which can be used to grab a ucontext without the help of libc, and also to detect if such ucontext has been successfully used by placing it on the stack as a fake sigframe. Reviewed-by:
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Cristian Marussi authored
Extend signal testing framework to allow the definition of a custom per test initialization function to be run at the end of the common test_init after test setup phase has completed and before test-run routine. This custom per-test initialization function also enables the test writer to decide on its own when forcibly skip the test itself using standard KSFT mechanism. Reviewed-by:
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Cristian Marussi authored
Add 6 simple mangle testcases that mess with the ucontext_t from within the signal handler, trying to toggle PSTATE mode bits to trick the system into switching to EL1/EL2/EL3 using both SP_EL0(t) and SP_ELx(h). Expects SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add a simple mangle testcase which messes with the ucontext_t from within the signal handler, trying to set PSTATE DAIF bits to an invalid value (masking everything). Expects SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Add some arm64/signal specific boilerplate and utility code to help further testcases' development. Introduce also one simple testcase mangle_pstate_invalid_compat_toggle and some related helpers: it is a simple mangle testcase which messes with the ucontext_t from within the signal handler, trying to toggle PSTATE state bits to switch the system between 32bit/64bit execution state. Expects SIGSEGV on test PASS. Reviewed-by:
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Cristian Marussi authored
Modify KSFT arm64 toplevel Makefile to maintain arm64 kselftests organized by subsystem, keeping them into distinct subdirectories under arm64 custom KSFT directory: tools/testing/selftests/arm64/ Add to such toplevel Makefile a mechanism to guess the effective location of Kernel headers as installed by KSFT framework. Fit existing arm64 tags kselftest into this new schema moving them into their own subdirectory (arm64/tags). Reviewed-by:
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Catalin Marinas authored
- Support for additional PMU topologies on HiSilicon platforms - Support for CCN-512 interconnect PMU - Support for AXI ID filtering in the IMX8 DDR PMU - Support for the CCPI2 uncore PMU in ThunderX2 - Driver cleanup to use devm_platform_ioremap_resource() * for-next/perf: drivers/perf: hisi: update the sccl_id/ccl_id for certain HiSilicon platform perf/imx_ddr: Dump AXI ID filter info to userspace docs/perf: Add AXI ID filter capabilities information perf/imx_ddr: Add driver for DDR PMU in i.MX8MPlus perf/imx_ddr: Add enhanced AXI ID filter support bindings: perf: imx-ddr: Add new compatible string docs/perf: Add explanation for DDR_CAP_AXI_ID_FILTER_ENHANCED quirk arm64: perf: Simplify the ARMv8 PMUv3 event attributes drivers/perf: Add CCPI2 PMU support in ThunderX2 UNCORE driver. Documentation: perf: Update documentation for ThunderX2 PMU uncore driver Documentation: Add documentation for CCN-512 DTS binding perf: arm-ccn: Enable stats for CCN-512 interconnect perf/smmuv3: use devm_platform_ioremap_resource() to simplify code perf/arm-cci: use devm_platform_ioremap_resource() to simplify code perf/arm-ccn: use devm_platform_ioremap_resource() to simplify code perf: xgene: use devm_platform_ioremap_resource() to simplify code perf: hisi: use devm_platform_ioremap_resource() to simplify code
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- 07 Nov, 2019 3 commits
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Shaokun Zhang authored
For some HiSilicon platform, the originally designed SCCL_ID and CCL_ID are not satisfied with much rich topology when the MT is set, so we extend the SCCL_ID to MPIDR[aff3] and CCL_ID to MPIDR[aff2]. Let's update this for HiSilicon uncore PMU driver. Cc: John Garry <john.garry@huawei.com> Cc: Hanjun Guo <guohanjun@huawei.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by:
Shaokun Zhang <zhangshaokun@hisilicon.com> Signed-off-by:
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Catalin Marinas authored
Merge branch 'arm64/ftrace-with-regs' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux into for-next/core FTRACE_WITH_REGS support for arm64. * 'arm64/ftrace-with-regs' of git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux: arm64: ftrace: minimize ifdeffery arm64: implement ftrace with regs arm64: asm-offsets: add S_FP arm64: insn: add encoder for MOV (register) arm64: module/ftrace: intialize PLT at load time arm64: module: rework special section handling module/ftrace: handle patchable-function-entry ftrace: add ftrace_init_nop()
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Nicolas Saenz Julienne authored
With the introduction of ZONE_DMA in arm64 we moved the default CMA and crashkernel reservation into that area. This caused a regression on big machines that need big CMA and crashkernel reservations. Note that ZONE_DMA is only 1GB big. Restore the previous behavior as the wide majority of devices are OK with reserving these in ZONE_DMA32. The ones that need them in ZONE_DMA will configure it explicitly. Fixes: 1a8e1cef ("arm64: use both ZONE_DMA and ZONE_DMA32") Reported-by:
Qian Cai <cai@lca.pw> Signed-off-by:
Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by:
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- 06 Nov, 2019 10 commits
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Mark Rutland authored
Now that we no longer refer to mod->arch.ftrace_trampolines in the body of ftrace_make_call(), we can use IS_ENABLED() rather than ifdeffery, and make the code easier to follow. Likewise in ftrace_make_nop(). Let's do so. Signed-off-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by:
Torsten Duwe <duwe@suse.de> Tested-by:
Amit Daniel Kachhap <amit.kachhap@arm.com> Tested-by:
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Torsten Duwe authored
This patch implements FTRACE_WITH_REGS for arm64, which allows a traced function's arguments (and some other registers) to be captured into a struct pt_regs, allowing these to be inspected and/or modified. This is a building block for live-patching, where a function's arguments may be forwarded to another function. This is also necessary to enable ftrace and in-kernel pointer authentication at the same time, as it allows the LR value to be captured and adjusted prior to signing. Using GCC's -fpatchable-function-entry=N option, we can have the compiler insert a configurable number of NOPs between the function entry point and the usual prologue. This also ensures functions are AAPCS compliant (e.g. disabling inter-procedural register allocation). For example, with -fpatchable-function-entry=2, GCC 8.1.0 compiles the following: | unsigned long bar(void); | | unsigned long foo(void) | { | return bar() + 1; | } ... to: | <foo>: | nop | nop | stp x29, x30, [sp, #-16]! | mov x29, sp | bl 0 <bar> | add x0, x0, #0x1 | ldp x29, x30, [sp], #16 | ret This patch builds the kernel with -fpatchable-function-entry=2, prefixing each function with two NOPs. To trace a function, we replace these NOPs with a sequence that saves the LR into a GPR, then calls an ftrace entry assembly function which saves this and other relevant registers: | mov x9, x30 | bl <ftrace-entry> Since patchable functions are AAPCS compliant (and the kernel does not use x18 as a platform register), x9-x18 can be safely clobbered in the patched sequence and the ftrace entry code. There are now two ftrace entry functions, ftrace_regs_entry (which saves all GPRs), and ftrace_entry (which saves the bare minimum). A PLT is allocated for each within modules. Signed-off-by: -
Mark Rutland authored
So that assembly code can more easily manipulate the FP (x29) within a pt_regs, add an S_FP asm-offsets definition. Signed-off-by:
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Mark Rutland authored
For FTRACE_WITH_REGS, we're going to want to generate a MOV (register) instruction as part of the callsite intialization. As MOV (register) is an alias for ORR (shifted register), we can generate this with aarch64_insn_gen_logical_shifted_reg(), but it's somewhat verbose and difficult to read in-context. Add a aarch64_insn_gen_move_reg() wrapper for this case so that we can write callers in a more straightforward way. Signed-off-by:
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Mark Rutland authored
Currently we lazily-initialize a module's ftrace PLT at runtime when we install the first ftrace call. To do so we have to apply a number of sanity checks, transiently mark the module text as RW, and perform an IPI as part of handling Neoverse-N1 erratum #1542419. We only expect the ftrace trampoline to point at ftrace_caller() (AKA FTRACE_ADDR), so let's simplify all of this by intializing the PLT at module load time, before the module loader marks the module RO and performs the intial I-cache maintenance for the module. Thus we can rely on the module having been correctly intialized, and can simplify the runtime work necessary to install an ftrace call in a module. This will also allow for the removal of module_disable_ro(). Tested by forcing ftrace_make_call() to use the module PLT, and then loading up a module after setting up ftrace with: | echo ":mod:<module-name>" > set_ftrace_filter; | echo function > current_tracer; | modprobe <module-name> Since FTRACE_ADDR is only defined when CONFIG_DYNAMIC_FTRACE is selected, we wrap its use along with most of module_init_ftrace_plt() with ifdeffery rather than using IS_ENABLED(). Signed-off-by:
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Mark Rutland authored
When we load a module, we have to perform some special work for a couple of named sections. To do this, we iterate over all of the module's sections, and perform work for each section we recognize. To make it easier to handle the unexpected absence of a section, and to make the section-specific logic easer to read, let's factor the section search into a helper. Similar is already done in the core module loader, and other architectures (and ideally we'd unify these in future). If we expect a module to have an ftrace trampoline section, but it doesn't have one, we'll now reject loading the module. When ARM64_MODULE_PLTS is selected, any correctly built module should have one (and this is assumed by arm64's ftrace PLT code) and the absence of such a section implies something has gone wrong at build time. Subsequent patches will make use of the new helper. Signed-off-by:
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Mark Rutland authored
When using patchable-function-entry, the compiler will record the callsites into a section named "__patchable_function_entries" rather than "__mcount_loc". Let's abstract this difference behind a new FTRACE_CALLSITE_SECTION, so that architectures don't have to handle this explicitly (e.g. with custom module linker scripts). As parisc currently handles this explicitly, it is fixed up accordingly, with its custom linker script removed. Since FTRACE_CALLSITE_SECTION is only defined when DYNAMIC_FTRACE is selected, the parisc module loading code is updated to only use the definition in that case. When DYNAMIC_FTRACE is not selected, modules shouldn't have this section, so this removes some redundant work in that case. To make sure that this is keep up-to-date for modules and the main kernel, a comment is added to vmlinux.lds.h, with the existing ifdeffery simplified for legibility. I built parisc generic-{32,64}bit_defconfig with DYNAMIC_FTRACE enabled, and verified that the section made it into the .ko files for modules. Signed-off-by:Helge Deller <deller@gmx.de> Acked-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by:
Sven Schnelle <svens@stackframe.org> Tested-by:
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Mark Rutland authored
Architectures may need to perform special initialization of ftrace callsites, and today they do so by special-casing ftrace_make_nop() when the expected branch address is MCOUNT_ADDR. In some cases (e.g. for patchable-function-entry), we don't have an mcount-like symbol and don't want a synthetic MCOUNT_ADDR, but we may need to perform some initialization of callsites. To make it possible to separate initialization from runtime modification, and to handle cases without an mcount-like symbol, this patch adds an optional ftrace_init_nop() function that architectures can implement, which does not pass a branch address. Where an architecture does not provide ftrace_init_nop(), we will fall back to the existing behaviour of calling ftrace_make_nop() with MCOUNT_ADDR. At the same time, ftrace_code_disable() is renamed to ftrace_nop_initialize() to make it clearer that it is intended to intialize a callsite into a disabled state, and is not for disabling a callsite that has been runtime enabled. The kerneldoc description of rec arguments is updated to cover non-mcount callsites. Signed-off-by:
Miroslav Benes <mbenes@suse.cz> Reviewed-by:
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Rich Wiley authored
NVIDIA Carmel CPUs don't implement ID_AA64PFR0_EL1.CSV3 but aren't susceptible to Meltdown, so add Carmel to kpti_safe_list[]. Signed-off-by:
Rich Wiley <rwiley@nvidia.com> Signed-off-by:
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Bhupesh Sharma authored
commit 9b31cf49 ("arm64: mm: Introduce MAX_USER_VA_BITS definition") introduced the MAX_USER_VA_BITS definition, which was used to support the arm64 mm use-cases where the user-space could use 52-bit virtual addresses whereas the kernel-space would still could a maximum of 48-bit virtual addressing. But, now with commit b6d00d47 ("arm64: mm: Introduce 52-bit Kernel VAs"), we removed the 52-bit user/48-bit kernel kconfig option and hence there is no longer any scenario where user VA != kernel VA size (even with CONFIG_ARM64_FORCE_52BIT enabled, the same is true). Hence we can do away with the MAX_USER_VA_BITS macro as it is equal to VA_BITS (maximum VA space size) in all possible use-cases. Note that even though the 'vabits_actual' value would be 48 for arm64 hardware which don't support LVA-8.2 extension (even when CONFIG_ARM64_VA_BITS_52 is enabled), VA_BITS would still be set to a value 52. Hence this change would be safe in all possible VA address space combinations. Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Steve Capper <steve.capper@arm.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: linux-kernel@vger.kernel.org Cc: kexec@lists.infradead.org Reviewed-by:
Bhupesh Sharma <bhsharma@redhat.com> Signed-off-by:
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