linux-dev/arch/arm64/kernel/probes, branch master

arm64/kprobe: Optimize the performance of patching single-step slot

2022-09-30T08:17:15Z

Single-step slot would not be used until kprobe is enabled, that means no race condition occurs on it under SMP, hence it is safe to pacth ss slot without stopping machine. Since I and D caches are coherent within single-step slot from aarch64_insn_patch_text_nosync(), hence no need to do it again via flush_icache_range(). Acked-by: Will Deacon Acked-by: Masami Hiramatsu (Google) Signed-off-by: Liao Chang Link: https://lore.kernel.org/r/20220927022435.129965-4-liaochang1@huawei.com Signed-off-by: Catalin Marinas

arm64: Treat ESR_ELx as a 64-bit register

2022-04-29T18:26:27Z

In the initial release of the ARM Architecture Reference Manual for ARMv8-A, the ESR_ELx registers were defined as 32-bit registers. This changed in 2018 with version D.a (ARM DDI 0487D.a) of the architecture, when they became 64-bit registers, with bits [63:32] defined as RES0. In version G.a, a new field was added to ESR_ELx, ISS2, which covers bits [36:32]. This field is used when the Armv8.7 extension FEAT_LS64 is implemented. As a result of the evolution of the register width, Linux stores it as both a 64-bit value and a 32-bit value, which hasn't affected correctness so far as Linux only uses the lower 32 bits of the register. Make the register type consistent and always treat it as 64-bit wide. The register is redefined as an "unsigned long", which is an unsigned double-word (64-bit quantity) for the LP64 machine (aapcs64 [1], Table 1, page 14). The type was chosen because "unsigned int" is the most frequent type for ESR_ELx and because FAR_ELx, which is used together with ESR_ELx in exception handling, is also declared as "unsigned long". The 64-bit type also makes adding support for architectural features that use fields above bit 31 easier in the future. The KVM hypervisor will receive a similar update in a subsequent patch. [1] https://github.com/ARM-software/abi-aa/releases/download/2021Q3/aapcs64.pdf Signed-off-by: Alexandru Elisei Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20220425114444.368693-4-alexandru.elisei@arm.com Signed-off-by: Catalin Marinas

arm64: kprobes: Make a frame pointer on __kretprobe_trampoline

2021-10-22T16:16:53Z

Make a frame pointer (make the x29 register points the address of pt_regs->regs[29]) on __kretprobe_trampoline. This frame pointer will be used by the stacktracer when it is called from the kretprobe handlers. In this case, the stack tracer will unwind stack to trampoline_probe_handler() and find the next frame pointer in the stack frame of the __kretprobe_trampoline(). Signed-off-by: Masami Hiramatsu Acked-by: Will Deacon Signed-off-by: Steven Rostedt (VMware)

arm64: kprobes: Record frame pointer with kretprobe instance

2021-10-22T16:16:53Z

Record the frame pointer instead of stack address with kretprobe instance as the identifier on the instance list. Since arm64 always enable CONFIG_FRAME_POINTER, we can use the actual frame pointer (x29). This will allow the stacktrace code to find the original return address from the FP alone. Signed-off-by: Masami Hiramatsu Acked-by: Will Deacon Acked-by: Mark Rutland Signed-off-by: Steven Rostedt (VMware)

kprobes: treewide: Make it harder to refer kretprobe_trampoline directly

2021-10-01T01:24:06Z

Since now there is kretprobe_trampoline_addr() for referring the address of kretprobe trampoline code, we don't need to access kretprobe_trampoline directly. Make it harder to refer by renaming it to __kretprobe_trampoline(). Link: https://lkml.kernel.org/r/163163045446.489837.14510577516938803097.stgit@devnote2 Suggested-by: Ingo Molnar Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()

2021-10-01T01:24:06Z

The __kretprobe_trampoline_handler() callback, called from low level arch kprobes methods, has the 'trampoline_address' parameter, which is entirely superfluous as it basically just replicates: dereference_kernel_function_descriptor(kretprobe_trampoline) In fact we had bugs in arch code where it wasn't replicated correctly. So remove this superfluous parameter and use kretprobe_trampoline_addr() instead. Link: https://lkml.kernel.org/r/163163044546.489837.13505751885476015002.stgit@devnote2 Signed-off-by: Masami Hiramatsu Tested-by: Andrii Nakryiko Signed-off-by: Steven Rostedt (VMware)

kprobes: treewide: Cleanup the error messages for kprobes

2021-10-01T01:24:05Z

This clean up the error/notification messages in kprobes related code. Basically this defines 'pr_fmt()' macros for each files and update the messages which describes - what happened, - what is the kernel going to do or not do, - is the kernel fine, - what can the user do about it. Also, if the message is not needed (e.g. the function returns unique error code, or other error message is already shown.) remove it, and replace the message with WARN_*() macros if suitable. Link: https://lkml.kernel.org/r/163163036568.489837.14085396178727185469.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2021-06-28T21:04:24Z

Pull arm64 updates from Will Deacon: "There's a reasonable amount here and the juicy details are all below. It's worth noting that the MTE/KASAN changes strayed outside of our usual directories due to core mm changes and some associated changes to some other architectures; Andrew asked for us to carry these [1] rather that take them via the -mm tree. Summary: - Optimise SVE switching for CPUs with 128-bit implementations. - Fix output format from SVE selftest. - Add support for versions v1.2 and 1.3 of the SMC calling convention. - Allow Pointer Authentication to be configured independently for kernel and userspace. - PMU driver cleanups for managing IRQ affinity and exposing event attributes via sysfs. - KASAN optimisations for both hardware tagging (MTE) and out-of-line software tagging implementations. - Relax frame record alignment requirements to facilitate 8-byte alignment with KASAN and Clang. - Cleanup of page-table definitions and removal of unused memory types. - Reduction of ARCH_DMA_MINALIGN back to 64 bytes. - Refactoring of our instruction decoding routines and addition of some missing encodings. - Move entry code moved into C and hardened against harmful compiler instrumentation. - Update booting requirements for the FEAT_HCX feature, added to v8.7 of the architecture. - Fix resume from idle when pNMI is being used. - Additional CPU sanity checks for MTE and preparatory changes for systems where not all of the CPUs support 32-bit EL0. - Update our kernel string routines to the latest Cortex Strings implementation. - Big cleanup of our cache maintenance routines, which were confusingly named and inconsistent in their implementations. - Tweak linker flags so that GDB can understand vmlinux when using RELR relocations. - Boot path cleanups to enable early initialisation of per-cpu operations needed by KCSAN. - Non-critical fixes and miscellaneous cleanup" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (150 commits) arm64: tlb: fix the TTL value of tlb_get_level arm64: Restrict undef hook for cpufeature registers arm64/mm: Rename ARM64_SWAPPER_USES_SECTION_MAPS arm64: insn: avoid circular include dependency arm64: smp: Bump debugging information print down to KERN_DEBUG drivers/perf: fix the missed ida_simple_remove() in ddr_perf_probe() perf/arm-cmn: Fix invalid pointer when access dtc object sharing the same IRQ number arm64: suspend: Use cpuidle context helpers in cpu_suspend() PSCI: Use cpuidle context helpers in psci_cpu_suspend_enter() arm64: Convert cpu_do_idle() to using cpuidle context helpers arm64: Add cpuidle context save/restore helpers arm64: head: fix code comments in set_cpu_boot_mode_flag arm64: mm: drop unused __pa(__idmap_text_start) arm64: mm: fix the count comments in compute_indices arm64/mm: Fix ttbr0 values stored in struct thread_info for software-pan arm64: mm: Pass original fault address to handle_mm_fault() arm64/mm: Drop SECTION_[SHIFT|SIZE|MASK] arm64/mm: Use CONT_PMD_SHIFT for ARM64_MEMSTART_SHIFT arm64/mm: Drop SWAPPER_INIT_MAP_SIZE arm64: Conditionally configure PTR_AUTH key of the kernel. ...

Merge branch 'for-next/insn' into for-next/core

2021-06-24T13:03:24Z

Refactoring of our instruction decoding routines and addition of some missing encodings. * for-next/insn: arm64: insn: avoid circular include dependency arm64: insn: move AARCH64_INSN_SIZE into arm64: insn: decouple patching from insn code arm64: insn: Add load/store decoding helpers arm64: insn: Add some opcodes to instruction decoder arm64: insn: Add barrier encodings arm64: insn: Add SVE instruction class arm64: Move instruction encoder/decoder under lib/ arm64: Move aarch32 condition check functions arm64: Move patching utilities out of instruction encoding/decoding

arm64: insn: decouple patching from insn code

2021-06-11T10:19:27Z

Currently, includes . We intend that will be usable from userspace, so it doesn't make sense to include headers for kernel-only features such as the patching routines, and we'd intended to restrict to instruction encoding details. Let's decouple the patching code from , and explicitly include where it is needed. Since isn't included from assembly, we can drop the __ASSEMBLY__ guards. At the same time, sort the kprobes includes so that it's easier to see what is and isn't incldued. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Will Deacon Link: https://lore.kernel.org/r/20210609102301.17332-2-mark.rutland@arm.com Signed-off-by: Will Deacon