linux-dev/arch/x86/kernel/kprobes, branch master

x86: kprobes: Remove unused macro stack_addr

2022-09-27T18:48:26Z

An unused macro reported by [-Wunused-macros]. This macro is used to access the sp in pt_regs because at that time x86_32 can only get sp by kernel_stack_pointer(regs). '3c88c692c287 ("x86/stackframe/32: Provide consistent pt_regs")' This commit have unified the pt_regs and from them we can get sp from pt_regs with regs->sp easily. Nowhere is using this macro anymore. Refrencing pt_regs directly is more clear. Remove this macro for code cleaning. Link: https://lkml.kernel.org/r/20220924072629.104759-1-chenzhongjin@huawei.com Signed-off-by: Chen Zhongjin Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google)

x86/kprobes: Fix JNG/JNLE emulation

2022-08-14T09:27:17Z

When kprobes emulates JNG/JNLE instructions on x86 it uses the wrong condition. For JNG (opcode: 0F 8E), according to Intel SDM, the jump is performed if (ZF == 1 or SF != OF). However the kernel emulation currently uses 'and' instead of 'or'. As a result, setting a kprobe on JNG/JNLE might cause the kernel to behave incorrectly whenever the kprobe is hit. Fix by changing the 'and' to 'or'. Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Signed-off-by: Nadav Amit Signed-off-by: Ingo Molnar Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220813225943.143767-1-namit@vmware.com

x86/kprobes: Update kcb status flag after singlestepping

2022-08-02T10:35:04Z

Fix kprobes to update kcb (kprobes control block) status flag to KPROBE_HIT_SSDONE even if the kp->post_handler is not set. This bug may cause a kernel panic if another INT3 user runs right after kprobes because kprobe_int3_handler() misunderstands the INT3 is kprobe's single stepping INT3. Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Reported-by: Daniel Müller Signed-off-by: Masami Hiramatsu (Google) Signed-off-by: Ingo Molnar Tested-by: Daniel Müller Cc: stable@vger.kernel.org Link: https://lore.kernel.org/all/20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9 Link: https://lore.kernel.org/r/165942025658.342061.12452378391879093249.stgit@devnote2

x86,kprobes: Fix optprobe trampoline to generate complete pt_regs

2022-03-29T02:38:51Z

Currently the optprobe trampoline template code ganerate an almost complete pt_regs on-stack, everything except regs->ss. The 'regs->ss' points to the top of stack, which is not a valid segment decriptor. As same as the rethook does, complete the job by also pushing ss. Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Masami Hiramatsu Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/164826166027.2455864.14759128090648961900.stgit@devnote2

x86,rethook,kprobes: Replace kretprobe with rethook on x86

2022-03-29T02:38:51Z

Replaces the kretprobe code with rethook on x86. With this patch, kretprobe on x86 uses the rethook instead of kretprobe specific trampoline code. Signed-off-by: Masami Hiramatsu Signed-off-by: Alexei Starovoitov Tested-by: Jiri Olsa Link: https://lore.kernel.org/bpf/164826163692.2455864.13745421016848209527.stgit@devnote2

x86/ibt: Annotate text references

2022-03-15T09:32:40Z

Annotate away some of the generic code references. This is things where we take the address of a symbol for exception handling or return addresses (eg. context switch). Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.877758523@infradead.org

x86/ibt,kprobes: Cure sym+0 equals fentry woes

2022-03-15T09:32:38Z

In order to allow kprobes to skip the ENDBR instructions at sym+0 for X86_KERNEL_IBT builds, change _kprobe_addr() to take an architecture callback to inspect the function at hand and modify the offset if needed. This streamlines the existing interface to cover more cases and require less hooks. Once PowerPC gets fully converted there will only be the one arch hook. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.405947704@infradead.org

x86/ibt,ftrace: Search for fentry location

2022-03-15T09:32:37Z

Currently a lot of ftrace code assumes __fentry__ is at sym+0. However with Intel IBT enabled the first instruction of a function will most likely be ENDBR. Change ftrace_location() to not only return the __fentry__ location when called for the __fentry__ location, but also when called for the sym+0 location. Then audit/update all callsites of this function to consistently use these new semantics. Suggested-by: Steven Rostedt Signed-off-by: Peter Zijlstra (Intel) Acked-by: Masami Hiramatsu Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220308154318.227581603@infradead.org

x86: Prepare inline-asm for straight-line-speculation

2021-12-08T18:23:12Z

Replace all ret/retq instructions with ASM_RET in preparation of making it more than a single instruction. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20211204134907.964635458@infradead.org

ftrace: disable preemption when recursion locked

2021-10-27T15:21:49Z

As the documentation explained, ftrace_test_recursion_trylock() and ftrace_test_recursion_unlock() were supposed to disable and enable preemption properly, however currently this work is done outside of the function, which could be missing by mistake. And since the internal using of trace_test_and_set_recursion() and trace_clear_recursion() also require preemption disabled, we can just merge the logical. This patch will make sure the preemption has been disabled when trace_test_and_set_recursion() return bit >= 0, and trace_clear_recursion() will enable the preemption if previously enabled. Link: https://lkml.kernel.org/r/13bde807-779c-aa4c-0672-20515ae365ea@linux.alibaba.com CC: Petr Mladek Cc: Guo Ren Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Michael Ellerman Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Thomas Gleixner Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: Josh Poimboeuf Cc: Jiri Kosina Cc: Joe Lawrence Cc: Masami Hiramatsu Cc: Nicholas Piggin Cc: Jisheng Zhang CC: Steven Rostedt CC: Miroslav Benes Reported-by: Abaci Suggested-by: Peter Zijlstra Signed-off-by: Michael Wang [ Removed extra line in comment - SDR ] Signed-off-by: Steven Rostedt (VMware)