kernel.git/arch/arm64/kernel/insn.c, branch linux-4.9.y

arm64: patch_text: Fixup last cpu should be master

2022-04-20T07:06:44Z

commit 31a099dbd91e69fcab55eef4be15ed7a8c984918 upstream. These patch_text implementations are using stop_machine_cpuslocked infrastructure with atomic cpu_count. The original idea: When the master CPU patch_text, the others should wait for it. But current implementation is using the first CPU as master, which couldn't guarantee the remaining CPUs are waiting. This patch changes the last CPU as the master to solve the potential risk. Fixes: ae16480785de ("arm64: introduce interfaces to hotpatch kernel and module code") Signed-off-by: Guo Ren Signed-off-by: Guo Ren Reviewed-by: Catalin Marinas Reviewed-by: Masami Hiramatsu Cc: Link: https://lore.kernel.org/r/20220407073323.743224-2-guoren@kernel.org Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman

arm64: Add helper to decode register from instruction

2022-04-12T05:52:15Z

commit 8c2dcbd2c4443bad0b4242fb62baa47b260b8f79 upstream. Add a helper to extract the register field from a given instruction. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Reviewed-by: Catalin Marinas Signed-off-by: Suzuki K Poulose Signed-off-by: Will Deacon Signed-off-by: James Morse Signed-off-by: Greg Kroah-Hartman

arm64: insn: Add helpers for adrp offsets

2016-09-09T14:03:28Z

Adds helpers for decoding/encoding the PC relative addresses for adrp. This will be used for handling dynamic patching of 'adrp' instructions in alternative code patching. Cc: Mark Rutland Cc: Will Deacon Cc: Catalin Marinas Cc: Marc Zyngier Signed-off-by: Suzuki K Poulose Signed-off-by: Will Deacon

arm64: always enable DEBUG_RODATA and remove the Kconfig option

2016-08-26T09:13:41Z

Follow the example set by x86 in commit 9ccaf77cf05915f5 ("x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option"), and make these protections a fundamental security feature rather than an opt-in. This also results in a minor code simplification. For those rare cases when users wish to disable this protection (e.g. for debugging), this can be done by passing 'rodata=off' on the command line. As DEBUG_RODATA_ALIGN is only intended to address a performance/memory tradeoff, and does not affect correctness, this is left user-selectable. DEBUG_MODULE_RONX is also left user-selectable until the core code provides a boot-time option to disable the protection for debugging use-cases. Cc: Catalin Marinas Acked-by: Ard Biesheuvel Acked-by: Kees Cook Acked-by: Laura Abbott Signed-off-by: Mark Rutland Signed-off-by: Will Deacon

arm64: kprobes instruction simulation support

2016-07-19T14:03:21Z

Kprobes needs simulation of instructions that cannot be stepped from a different memory location, e.g.: those instructions that uses PC-relative addressing. In simulation, the behaviour of the instruction is implemented using a copy of pt_regs. The following instruction categories are simulated: - All branching instructions(conditional, register, and immediate) - Literal access instructions(load-literal, adr/adrp) Conditional execution is limited to branching instructions in ARM v8. If conditions at PSTATE do not match the condition fields of opcode, the instruction is effectively NOP. Thanks to Will Cohen for assorted suggested changes. Signed-off-by: Sandeepa Prabhu Signed-off-by: William Cohen Signed-off-by: David A. Long Acked-by: Masami Hiramatsu [catalin.marinas@arm.com: removed linux/module.h include] Signed-off-by: Catalin Marinas

arm64: add conditional instruction simulation support

2016-07-19T14:03:19Z

Cease using the arm32 arm_check_condition() function and replace it with a local version for use in deprecated instruction support on arm64. Also make the function table used by this available for future use by kprobes and/or uprobes. This function is derived from code written by Sandeepa Prabhu. Signed-off-by: Sandeepa Prabhu Signed-off-by: David A. Long Acked-by: Masami Hiramatsu Signed-off-by: Catalin Marinas

arm64: Add more test functions to insn.c

2016-07-19T14:03:19Z

Certain instructions are hard to execute correctly out-of-line (as in kprobes). Test functions are added to insn.[hc] to identify these. The instructions include any that use PC-relative addressing, change the PC, or change interrupt masking. For efficiency and simplicity test functions are also added for small collections of related instructions. Signed-off-by: David A. Long Acked-by: Masami Hiramatsu Signed-off-by: Catalin Marinas

arm64: insn: avoid virt_to_page() translations on core kernel symbols

2016-04-14T15:31:49Z

Before restricting virt_to_page() to the linear mapping, ensure that the text patching code does not use it to resolve references into the core kernel text, which is mapped in the vmalloc area. Signed-off-by: Ard Biesheuvel Signed-off-by: Will Deacon

arm64: insn: remove BUG_ON from codegen

2016-01-18T00:15:26Z

During code generation, we used to BUG_ON unknown/unsupported encoding or invalid parameters. Instead, now we report these as errors and simply return the instruction AARCH64_BREAK_FAULT. Users of these codegen helpers should check for and handle this failure condition as appropriate. Otherwise, unhandled codegen failure will result in trapping at run-time due to AARCH64_BREAK_FAULT, which is arguably better than a BUG_ON. Signed-off-by: Zi Shen Lim Acked-by: Will Deacon Signed-off-by: David S. Miller

arm64: convert patch_lock to raw lock

2015-10-05T17:30:29Z

When running kprobe test on arm64 rt kernel, it reports the below warning: root@qemu7:~# modprobe kprobe_example BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 0, irqs_disabled(): 128, pid: 484, name: modprobe CPU: 0 PID: 484 Comm: modprobe Not tainted 4.1.6-rt5 #2 Hardware name: linux,dummy-virt (DT) Call trace: [] dump_backtrace+0x0/0x128 [] show_stack+0x20/0x30 [] dump_stack+0x1c/0x28 [] ___might_sleep+0x120/0x198 [] rt_spin_lock+0x28/0x40 [] __aarch64_insn_write+0x28/0x78 [] aarch64_insn_patch_text_nosync+0x18/0x48 [] aarch64_insn_patch_text_cb+0x70/0xa0 [] aarch64_insn_patch_text_sync+0x28/0x48 [] arch_arm_kprobe+0x38/0x48 [] arm_kprobe+0x34/0x50 [] register_kprobe+0x4cc/0x5b8 [] kprobe_init+0x38/0x7c [kprobe_example] [] do_one_initcall+0x90/0x1b0 [] do_init_module+0x6c/0x1cc [] load_module+0x17f8/0x1db0 [] SyS_finit_module+0xb4/0xc8 Convert patch_lock to raw loc kto avoid this issue. Although the problem is found on rt kernel, the fix should be applicable to mainline kernel too. Acked-by: Steven Rostedt Signed-off-by: Yang Shi Signed-off-by: Will Deacon