aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/uprobes.c (follow)
AgeCommit message (Collapse)AuthorFilesLines
2021-03-15x86/uprobes: Convert to insn_decode()Borislav Petkov1-4/+4
Simplify code, no functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210304174237.31945-16-bp@alien8.de
2020-12-14Merge tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-0/+2
Pull perf updates from Thomas Gleixner: "Core: - Better handling of page table leaves on archictectures which have architectures have non-pagetable aligned huge/large pages. For such architectures a leaf can actually be part of a larger entry. - Prevent a deadlock vs exec_update_mutex Architectures: - The related updates for page size calculation of leaf entries - The usual churn to support new CPUs - Small fixes and improvements all over the place" * tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) perf/x86/intel: Add Tremont Topdown support uprobes/x86: Fix fall-through warnings for Clang perf/x86: Fix fall-through warnings for Clang kprobes/x86: Fix fall-through warnings for Clang perf/x86/intel/lbr: Fix the return type of get_lbr_cycles() perf/x86/intel: Fix rtm_abort_event encoding on Ice Lake x86/kprobes: Restore BTF if the single-stepping is cancelled perf: Break deadlock involving exec_update_mutex sparc64/mm: Implement pXX_leaf_size() support powerpc/8xx: Implement pXX_leaf_size() support arm64/mm: Implement pXX_leaf_size() support perf/core: Fix arch_perf_get_page_size() mm: Introduce pXX_leaf_size() mm/gup: Provide gup_get_pte() more generic perf/x86/intel: Add event constraint for CYCLE_ACTIVITY.STALLS_MEM_ANY perf/x86/intel/uncore: Add Rocket Lake support perf/x86/msr: Add Rocket Lake CPU support perf/x86/cstate: Add Rocket Lake CPU support perf/x86/intel: Add Rocket Lake CPU support perf,mm: Handle non-page-table-aligned hugetlbfs ...
2020-12-09uprobes/x86: Fix fall-through warnings for ClangGustavo A. R. Silva1-0/+2
In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning by explicitly adding a break statement instead of letting the code fall through to the next case. Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://github.com/KSPP/linux/issues/115
2020-12-06x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytesMasami Hiramatsu1-4/+6
Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be insn.prefixes.bytes[i] != 0 and i < 4 instead of using insn.prefixes.nbytes. Introduce a for_each_insn_prefix() macro for this purpose. Debugged by Kees Cook <keescook@chromium.org>. [ bp: Massage commit message, sync with the respective header in tools/ and drop "we". ] Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@devnote2
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-2/+2
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2019-10-27x86/apic, x86/uprobes: Correct parameter names in kernel-doc commentsYi Wang1-1/+1
Rename parameter names to the correct ones used in the function. No functional changes. [ bp: Merge two patches into a single one. ] Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/1571816442-22494-1-git-send-email-wang.yi59@zte.com.cn
2019-08-26uprobes/x86: Fix detection of 32-bit user modeSebastian Mayr1-7/+10
32-bit processes running on a 64-bit kernel are not always detected correctly, causing the process to crash when uretprobes are installed. The reason for the crash is that in_ia32_syscall() is used to determine the process's mode, which only works correctly when called from a syscall. In the case of uretprobes, however, the function is called from a exception and always returns 'false' on a 64-bit kernel. In consequence this leads to corruption of the process's return address. Fix this by using user_64bit_mode() instead of in_ia32_syscall(), which is correct in any situation. [ tglx: Add a comment and the following historical info ] This should have been detected by the rename which happened in commit abfb9498ee13 ("x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()") which states in the changelog: The is_ia32_task()/is_x32_task() function names are a big misnomer: they suggests that the compat-ness of a system call is a task property, which is not true, the compatness of a system call purely depends on how it was invoked through the system call layer. ..... and then it went and blindly renamed every call site. Sadly enough this was already mentioned here: 8faaed1b9f50 ("uprobes/x86: Introduce sizeof_long(), cleanup adjust_ret_addr() and arch_uretprobe_hijack_return_addr()") where the changelog says: TODO: is_ia32_task() is not what we actually want, TS_COMPAT does not necessarily mean 32bit. Fortunately syscall-like insns can't be probed so it actually works, but it would be better to rename and use is_ia32_frame(). and goes all the way back to: 0326f5a94dde ("uprobes/core: Handle breakpoint and singlestep exceptions") Oh well. 7+ years until someone actually tried a uretprobe on a 32bit process on a 64bit kernel.... Fixes: 0326f5a94dde ("uprobes/core: Handle breakpoint and singlestep exceptions") Signed-off-by: Sebastian Mayr <me@sam.st> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190728152617.7308-1-me@sam.st
2019-07-08Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespaceLinus Torvalds1-1/+1
Pull force_sig() argument change from Eric Biederman: "A source of error over the years has been that force_sig has taken a task parameter when it is only safe to use force_sig with the current task. The force_sig function is built for delivering synchronous signals such as SIGSEGV where the userspace application caused a synchronous fault (such as a page fault) and the kernel responded with a signal. Because the name force_sig does not make this clear, and because the force_sig takes a task parameter the function force_sig has been abused for sending other kinds of signals over the years. Slowly those have been fixed when the oopses have been tracked down. This set of changes fixes the remaining abusers of force_sig and carefully rips out the task parameter from force_sig and friends making this kind of error almost impossible in the future" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits) signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus signal: Remove the signal number and task parameters from force_sig_info signal: Factor force_sig_info_to_task out of force_sig_info signal: Generate the siginfo in force_sig signal: Move the computation of force into send_signal and correct it. signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal signal: Remove the task parameter from force_sig_fault signal: Use force_sig_fault_to_task for the two calls that don't deliver to current signal: Explicitly call force_sig_fault on current signal/unicore32: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from __do_user_fault signal/arm: Remove tsk parameter from ptrace_break signal/nds32: Remove tsk parameter from send_sigtrap signal/riscv: Remove tsk parameter from do_trap signal/sh: Remove tsk parameter from force_sig_info_fault signal/um: Remove task parameter from send_sigtrap signal/x86: Remove task parameter from send_sigtrap signal: Remove task parameter from force_sig_mceerr signal: Remove task parameter from force_sig signal: Remove task parameter from force_sigsegv ...
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner1-14/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-27signal: Remove task parameter from force_sigEric W. Biederman1-1/+1
All of the remaining callers pass current into force_sig so remove the task parameter to make this obvious and to make misuse more difficult in the future. This also makes it clear force_sig passes current into force_sig_info. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2019-01-26x86/kernel: Mark expected switch-case fall-throughsGustavo A. R. Silva1-0/+1
In preparation to enable -Wimplicit-fallthrough by default, mark switch-case statements where fall-through is intentional, explicitly in order to fix a couple of -Wimplicit-fallthrough warnings. Warning level 3 was used: -Wimplicit-fallthrough=3. [ bp: Massasge and trim commit message. ] Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Baoquan He <bhe@redhat.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: David Wang <davidwang@zhaoxin.com> Cc: Douglas Anderson <dianders@chromium.org> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Beulich <JBeulich@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pu Wen <puwen@hygon.cn> Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190125183903.GA4712@embeddedor
2018-09-11signal: Properly deliver SIGSEGV from x86 uprobesEric W. Biederman1-1/+1
For userspace to tell the difference between an random signal and an exception, the exception must include siginfo information. Using SEND_SIG_FORCED for SIGSEGV is thus wrong, and it will result in userspace seeing si_code == SI_USER (like a random signal) instead of si_code == SI_KERNEL or a more specific si_code as all exceptions deliver. Therefore replace force_sig_info(SIGSEGV, SEND_SIG_FORCE, current) with force_sig(SIG_SEGV, current) which gets this right and is shorter and easier to type. Fixes: 791eca10107f ("uretprobes/x86: Hijack return address") Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-06-21uprobes/x86: Remove incorrect WARN_ON() in uprobe_init_insn()Oleg Nesterov1-1/+1
insn_get_length() has the side-effect of processing the entire instruction but only if it was decoded successfully, otherwise insn_complete() can fail and in this case we need to just return an error without warning. Reported-by: syzbot+30d675e3ca03c1c351e7@syzkaller.appspotmail.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: syzkaller-bugs@googlegroups.com Link: https://lkml.kernel.org/lkml/20180518162739.GA5559@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-04Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-2/+2
Pull x86 cleanups from Ingo Molnar: "Misc cleanups" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/apm: Fix spelling mistake: "caculate" -> "calculate" x86/mtrr: Rename main.c to mtrr.c and remove duplicate prefixes x86: Remove pr_fmt duplicate logging prefixes x86/early-quirks: Rename duplicate define of dev_err x86/bpf: Clean up non-standard comments, to make the code more readable
2018-05-13x86: Remove pr_fmt duplicate logging prefixesJoe Perches1-2/+2
Converting pr_fmt from a default simple #define to use KBUILD_MODNAME added some duplicate prefixes. Remove the duplicate prefixes. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Link: https://lkml.kernel.org/r/e7b709a2b040af7faa81b0aa2c3a125aed628a82.1525964383.git.joe@perches.com
2018-05-13uprobes/x86: Prohibit probing on MOV SS instructionMasami Hiramatsu1-0/+4
Since MOV SS and POP SS instructions will delay the exceptions until the next instruction is executed, single-stepping on it by uprobes must be prohibited. uprobe already rejects probing on POP SS (0x1f), but allows probing on MOV SS (0x8e and reg == 2). This checks the target instruction and if it is MOV SS or POP SS, returns -ENOTSUPP to reject probing. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Francis Deslauriers <francis.deslauriers@efficios.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Yonghong Song <yhs@fb.com> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "David S . Miller" <davem@davemloft.net> Link: https://lkml.kernel.org/r/152587072544.17316.5950935243917346341.stgit@devbox
2017-12-11uprobes/x86: Emulate push insns for uprobe on x86Yonghong Song1-4/+103
Uprobe is a tracing mechanism for userspace programs. Typical uprobe will incur overhead of two traps. First trap is caused by replaced trap insn, and the second trap is to execute the original displaced insn in user space. To reduce the overhead, kernel provides hooks for architectures to emulate the original insn and skip the second trap. In x86, emulation is done for certain branch insns. This patch extends the emulation to "push <reg>" insns. These insns are typical in the beginning of the function. For example, bcc in https://github.com/iovisor/bcc repo provides tools to measure funclantency, detect memleak, etc. The tools will place uprobes in the beginning of function and possibly uretprobes at the end of function. This patch is able to reduce the trap overhead for uprobe from 2 to 1. Without this patch, uretprobe will typically incur three traps. With this patch, if the function starts with "push" insn, the number of traps can be reduced from 3 to 2. An experiment was conducted on two local VMs, fedora 26 64-bit VM and 32-bit VM, both 4 processors and 4GB memory, booted with latest tip repo (and this patch). The host is MacBook with intel i7 processor. The test program looks like: #include <stdio.h> #include <stdlib.h> #include <time.h> #include <sys/time.h> static void test() __attribute__((noinline)); void test() {} int main() { struct timeval start, end; gettimeofday(&start, NULL); for (int i = 0; i < 1000000; i++) { test(); } gettimeofday(&end, NULL); printf("%ld\n", ((end.tv_sec * 1000000 + end.tv_usec) - (start.tv_sec * 1000000 + start.tv_usec))); return 0; } The program is compiled without optimization, and the first insn for function "test" is "push %rbp". The host is relatively idle. Before the test run, the uprobe is inserted as below for uprobe: echo 'p <binary>:<test_func_offset>' > /sys/kernel/debug/tracing/uprobe_events echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable and for uretprobe: echo 'r <binary>:<test_func_offset>' > /sys/kernel/debug/tracing/uprobe_events echo 1 > /sys/kernel/debug/tracing/events/uprobes/enable Unit: microsecond(usec) per loop iteration x86_64 W/ this patch W/O this patch uprobe 1.55 3.1 uretprobe 2.0 3.6 x86_32 W/ this patch W/O this patch uprobe 1.41 3.5 uretprobe 1.75 4.0 You can see that this patch significantly reduced the overhead, 50% for uprobe and 44% for uretprobe on x86_64, and even more on x86_32. Signed-off-by: Yonghong Song <yhs@fb.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-team@fb.com Link: http://lkml.kernel.org/r/20171201001202.3706564-1-yhs@fb.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-01uprobes/x86: Use existing definitions for segment override prefixesRicardo Neri1-6/+9
Rather than using hard-coded values of the segment override prefixes, leverage the existing definitions provided in inat.h. Suggested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: ricardo.neri@intel.com Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Jiri Slaby <jslaby@suse.cz> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Brian Gerst <brgerst@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Chen Yucong <slaoub@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/1509135945-13762-5-git-send-email-ricardo.neri-calderon@linux.intel.com
2016-08-12uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructionsDenys Vlasenko1-11/+11
Since instruction decoder now supports EVEX-encoded instructions, two fixes are needed to correctly handle them in uprobes. Extended bits for MODRM.rm field need to be sanitized just like we do it for VEX3, to avoid encoding wrong register for register-relative access. EVEX has _two_ extended bits: b and x. Theoretically, EVEX.x should be ignored by the CPU (since GPRs go only up to 15, not 31), but let's be paranoid here: proper encoding for register-relative access should have EVEX.x = 1. Secondly, we should fetch vex.vvvv for EVEX too. This is now super easy because instruction decoder populates vex_prefix.bytes[2] for all flavors of (e)vex encodings, even for VEX2. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> # v4.1+ Fixes: 8a764a875fe3 ("x86/asm/decoder: Create artificial 3rd byte for 2-byte VEX") Link: http://lkml.kernel.org/r/20160811154521.20469-1-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-16Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-1/+1
Pull x86 asm updates from Ingo Molnar: "The main changes in this cycle were: - MSR access API fixes and enhancements (Andy Lutomirski) - early exception handling improvements (Andy Lutomirski) - user-space FS/GS prctl usage fixes and improvements (Andy Lutomirski) - Remove the cpu_has_*() APIs and replace them with equivalents (Borislav Petkov) - task switch micro-optimization (Brian Gerst) - 32-bit entry code simplification (Denys Vlasenko) - enhance PAT handling in enumated CPUs (Toshi Kani) ... and lots of other cleanups/fixlets" * 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits) x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS x86/entry/32: Remove asmlinkage_protect() x86/entry/32: Remove GET_THREAD_INFO() from entry code x86/entry, sched/x86: Don't save/restore EFLAGS on task switch x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment x86/tls: Synchronize segment registers in set_thread_area() x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization x86/segments/64: When load_gs_index fails, clear the base x86/segments/64: When loadsegment(fs, ...) fails, clear the base x86/asm: Make asm/alternative.h safe from assembly x86/asm: Stop depending on ptrace.h in alternative.h x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall() x86/asm: Make sure verify_cpu() has a good stack x86/extable: Add a comment about early exception handlers x86/msr: Set the return value to zero when native_rdmsr_safe() fails x86/paravirt: Make "unsafe" MSR accesses unsafe even if PARAVIRT=y x86/paravirt: Add paravirt_{read,write}_msr() x86/msr: Carry on after a non-"safe" MSR access fails ...
2016-04-19x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()Dmitry Safonov1-1/+1
The is_ia32_task()/is_x32_task() function names are a big misnomer: they suggests that the compat-ness of a system call is a task property, which is not true, the compatness of a system call purely depends on how it was invoked through the system call layer. A task may call 32-bit and 64-bit and x32 system calls without changing any of its kernel visible state. This specific minomer is also actively dangerous, as it might cause kernel developers to use the wrong kind of security checks within system calls. So rename it to in_{ia32,x32}_syscall(). Suggested-by: Andy Lutomirski <luto@amacapital.net> Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> [ Expanded the changelog. ] Acked-by: Andy Lutomirski <luto@kernel.org> Cc: 0x7f454c46@gmail.com Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/1460987025-30360-1-git-send-email-dsafonov@virtuozzo.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-13uprobes/x86: Constify uprobe_xol_ops structuresJulia Lawall1-2/+2
The uprobe_xol_ops structures are never modified, so declare them as const. Done with the help of Coccinelle. Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/1460200649-32526-1-git-send-email-Julia.Lawall@lip6.fr Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-31uprobes/x86: Make arch_uretprobe_is_alive(RP_CHECK_CALL) more cleverOleg Nesterov1-1/+4
The previous change documents that cleanup_return_instances() can't always detect the dead frames, the stack can grow. But there is one special case which imho worth fixing: arch_uretprobe_is_alive() can return true when the stack didn't actually grow, but the next "call" insn uses the already invalidated frame. Test-case: #include <stdio.h> #include <setjmp.h> jmp_buf jmp; int nr = 1024; void func_2(void) { if (--nr == 0) return; longjmp(jmp, 1); } void func_1(void) { setjmp(jmp); func_2(); } int main(void) { func_1(); return 0; } If you ret-probe func_1() and func_2() prepare_uretprobe() hits the MAX_URETPROBE_DEPTH limit and "return" from func_2() is not reported. When we know that the new call is not chained, we can do the more strict check. In this case "sp" points to the new ret-addr, so every frame which uses the same "sp" must be dead. The only complication is that arch_uretprobe_is_alive() needs to know was it chained or not, so we add the new RP_CHECK_CHAIN_CALL enum and change prepare_uretprobe() to pass RP_CHECK_CALL only if !chained. Note: arch_uretprobe_is_alive() could also re-read *sp and check if this word is still trampoline_vaddr. This could obviously improve the logic, but I would like to avoid another copy_from_user() especially in the case when we can't avoid the false "alive == T" positives. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134028.GA4786@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-31uprobes: Add the "enum rp_check ctx" arg to arch_uretprobe_is_alive()Oleg Nesterov1-1/+2
arch/x86 doesn't care (so far), but as Pratyush Anand pointed out other architectures might want why arch_uretprobe_is_alive() was called and use different checks depending on the context. Add the new argument to distinguish 2 callers. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134026.GA4779@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-07-31uprobes/x86: Reimplement arch_uretprobe_is_alive()Oleg Nesterov1-0/+5
Add the x86 specific version of arch_uretprobe_is_alive() helper. It returns true if the stack frame mangled by prepare_uretprobe() is still on stack. So if it returns false, we know that the probed function has already returned. We add the new return_instance->stack member and change the generic code to initialize it in prepare_uretprobe, but it should be equally useful for other architectures. TODO: this assumes that the probed application can't use multiple stacks (say sigaltstack). We will try to improve this logic later. Tested-by: Pratyush Anand <panand@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Anton Arapov <arapov@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150721134018.GA4766@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-09x86: Make is_64bit_mm() widely availableDave Hansen1-9/+1
The uprobes code has a nice helper, is_64bit_mm(), that consults both the runtime and compile-time flags for 32-bit support. Instead of reinventing the wheel, pull it in to an x86 header so we can use it for MPX. I prefer passing the 'mm' around to test_thread_flag(TIF_IA32) because it makes it explicit where the context is coming from. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dave Hansen <dave@sr71.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150607183704.F0209999@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-23x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()'Andy Lutomirski1-1/+1
user_mode_vm() and user_mode() are now the same. Change all callers of user_mode_vm() to user_mode(). The next patch will remove the definition of user_mode_vm. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brad Spengler <spender@grsecurity.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/43b1f57f3df70df5a08b0925897c660725015554.1426728647.git.luto@kernel.org [ Merged to a more recent kernel. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18uprobes/x86: Fix 2-byte opcode tableDenys Vlasenko1-35/+17
Enabled probing of lar, lsl, popcnt, lddqu, prefetch insns. They should be safe to probe, they throw no exceptions. Enabled probing of 3-byte opcodes 0f 38-3f xx - these are vector isns, so should be safe. Enabled probing of many currently undefined 0f xx insns. At the rate new vector instructions are getting added, we don't want to constantly enable more bits. We want to only occasionally *disable* ones which for some reason can't be probed. This includes 0f 24,26 opcodes, which are undefined since Pentium. On 486, they were "mov to/from test register". Explained more fully what 0f 78,79 opcodes are. Explained what 0f ae opcode is. (It's unclear why we don't allow probing it, but let's not change it for now). Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1423768732-32194-3-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18uprobes/x86: Fix 1-byte opcode tablesDenys Vlasenko1-48/+18
This change fixes 1-byte opcode tables so that only insns for which we have real reasons to disallow probing are marked with unset bits. To that end: Set bits for all prefix bytes. Their setting is ignored anyway - we check the bitmap against OPCODE1(insn), not against first byte. Keeping them set to 0 only confuses code reader with "why we don't support that opcode" question. Thus: enable bytes c4,c5 in 64-bit mode (VEX prefixes). Byte 62 (EVEX prefix) is not yet enabled since insn decoder does not support that yet. For 32-bit mode, enable probing of opcodes 63 (arpl) and d6 (salc). They don't require any special handling. For 64-bit mode, disable 9a and ea - these undefined opcodes were mistakenly left enabled. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1423768732-32194-2-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18uprobes/x86: Add comment with insn opcodes, mnemonics and why we dont support themDenys Vlasenko1-19/+134
After adding these, it's clear we have some awkward choices there. Some valid instructions are prohibited from uprobing while several invalid ones are allowed. Hopefully future edits to the good-opcode tables will fix wrong bits or explain why those bits are not wrong. No actual code changes. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1423768732-32194-1-git-send-email-dvlasenk@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-18x86: Remove arbitrary instruction size limit in instruction decoderDave Hansen1-1/+1
The current x86 instruction decoder steps along through the instruction stream but always ensures that it never steps farther than the largest possible instruction size (MAX_INSN_SIZE). The MPX code is now going to be doing some decoding of userspace instructions. We copy those from userspace in to the kernel and they're obviously completely untrusted coming from userspace. In addition to the constraint that instructions can only be so long, we also have to be aware of how long the buffer is that came in from userspace. This _looks_ to be similar to what the perf and kprobes is doing, but it's unclear to me whether they are affected. The whole reason we need this is that it is perfectly valid to be executing an instruction within MAX_INSN_SIZE bytes of an unreadable page. We should be able to gracefully handle short reads in those cases. This adds support to the decoder to record how long the buffer being decoded is and to refuse to "validate" the instruction if we would have gone over the end of the buffer to decode it. The kprobes code probably needs to be looked at here a bit more carefully. This patch still respects the MAX_INSN_SIZE limit there but the kprobes code does look like it might be able to be a bit more strict than it currently is. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: x86@kernel.org Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Link: http://lkml.kernel.org/r/20141114153957.E6B01535@viggo.jf.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-06-05uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updatesOleg Nesterov1-19/+18
Purely cosmetic, no changes in .o, 1. As Jim pointed out arch_uprobe->def looks ambiguous, rename it to ->defparam. 2. Add the comment into default_post_xol_op() to explain "regs->sp +=". 3. Remove the stale part of the comment in arch_uprobe_analyze_insn(). Suggested-by: Jim Keniston <jkenisto@us.ibm.com> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-05-14uprobes/x86: Fix scratch register selection for rip-relative fixupsDenys Vlasenko1-51/+125
Before this patch, instructions such as div, mul, shifts with count in CL, cmpxchg are mishandled. This patch adds vex prefix handling. In particular, it avoids colliding with register operand encoded in vex.vvvv field. Since we need to avoid two possible register operands, the selection of scratch register needs to be from at least three registers. After looking through a lot of CPU docs, it looks like the safest choice is SI,DI,BX. Selecting BX needs care to not collide with implicit use of BX by cmpxchg8b. Test-case: #include <stdio.h> static const char *const pass[] = { "FAIL", "pass" }; long two = 2; void test1(void) { long ax = 0, dx = 0; asm volatile("\n" " xor %%edx,%%edx\n" " lea 2(%%edx),%%eax\n" // We divide 2 by 2. Result (in eax) should be 1: " probe1: .globl probe1\n" " divl two(%%rip)\n" // If we have a bug (eax mangled on entry) the result will be 2, // because eax gets restored by probe machinery. : "=a" (ax), "=d" (dx) /*out*/ : "0" (ax), "1" (dx) /*in*/ : "memory" /*clobber*/ ); dprintf(2, "%s: %s\n", __func__, pass[ax == 1] ); } long val2 = 0; void test2(void) { long old_val = val2; long ax = 0, dx = 0; asm volatile("\n" " mov val2,%%eax\n" // eax := val2 " lea 1(%%eax),%%edx\n" // edx := eax+1 // eax is equal to val2. cmpxchg should store edx to val2: " probe2: .globl probe2\n" " cmpxchg %%edx,val2(%%rip)\n" // If we have a bug (eax mangled on entry), val2 will stay unchanged : "=a" (ax), "=d" (dx) /*out*/ : "0" (ax), "1" (dx) /*in*/ : "memory" /*clobber*/ ); dprintf(2, "%s: %s\n", __func__, pass[val2 == old_val + 1] ); } long val3[2] = {0,0}; void test3(void) { long old_val = val3[0]; long ax = 0, dx = 0; asm volatile("\n" " mov val3,%%eax\n" // edx:eax := val3 " mov val3+4,%%edx\n" " mov %%eax,%%ebx\n" // ecx:ebx := edx:eax + 1 " mov %%edx,%%ecx\n" " add $1,%%ebx\n" " adc $0,%%ecx\n" // edx:eax is equal to val3. cmpxchg8b should store ecx:ebx to val3: " probe3: .globl probe3\n" " cmpxchg8b val3(%%rip)\n" // If we have a bug (edx:eax mangled on entry), val3 will stay unchanged. // If ecx:edx in mangled, val3 will get wrong value. : "=a" (ax), "=d" (dx) /*out*/ : "0" (ax), "1" (dx) /*in*/ : "cx", "bx", "memory" /*clobber*/ ); dprintf(2, "%s: %s\n", __func__, pass[val3[0] == old_val + 1 && val3[1] == 0] ); } int main(int argc, char **argv) { test1(); test2(); test3(); return 0; } Before this change all tests fail if probe{1,2,3} are probed. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-05-14uprobes/x86: Simplify rip-relative handlingDenys Vlasenko1-41/+30
It is possible to replace rip-relative addressing mode with addressing mode of the same length: (reg+disp32). This eliminates the need to fix up immediate and correct for changing instruction length. And we can kill arch_uprobe->def.riprel_target. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-04-30uprobes/x86: Simplify riprel_{pre,post}_xol() and make them similarOleg Nesterov1-16/+14
Ignoring the "correction" logic riprel_pre_xol() and riprel_post_xol() are very similar but look quite differently. 1. Add the "UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX" check at the start of riprel_pre_xol(), like the same check in riprel_post_xol(). 2. Add the trivial scratch_reg() helper which returns the address of scratch register pre_xol/post_xol need to change. 3. Change these functions to use the new helper and avoid copy-and-paste under if/else branches. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Kill the "autask" arg of riprel_pre_xol()Oleg Nesterov1-9/+9
default_pre_xol_op() passes &current->utask->autask to riprel_pre_xol() and this is just ugly because it still needs to load current->utask to read ->vaddr. Remove this argument, change riprel_pre_xol() to use current->utask. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Rename *riprel* helpers to make the naming consistentOleg Nesterov1-13/+11
handle_riprel_insn(), pre_xol_rip_insn() and handle_riprel_post_xol() look confusing and inconsistent. Rename them into riprel_analyze(), riprel_pre_xol(), and riprel_post_xol() respectively. No changes in compiled code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Cleanup the usage of UPROBE_FIX_IP/UPROBE_FIX_CALLOleg Nesterov1-16/+11
Now that UPROBE_FIX_IP/UPROBE_FIX_CALL are mutually exclusive we can use a single "fix_ip_or_call" enum instead of 2 fix_* booleans. This way the logic looks more understandable and clean to me. While at it, join "case 0xea" with other "ip is correct" ret/lret cases. Also change default_post_xol_op() to use "else if" for the same reason. Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-04-30uprobes/x86: Kill adjust_ret_addr(), simplify UPROBE_FIX_CALL logicOleg Nesterov1-21/+3
The only insn which could have both UPROBE_FIX_IP and UPROBE_FIX_CALL was 0xe8 "call relative", and now it is handled by branch_xol_ops. So we can change default_post_xol_op(UPROBE_FIX_CALL) to simply push the address of next insn == utask->vaddr + insn.length, just we need to record insn.length into the new auprobe->def.ilen member. Note: if/when we teach branch_xol_ops to support jcxz/loopz we can remove the "correction" logic, UPROBE_FIX_IP can use the same address. Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-04-30uprobes/x86: Introduce push_ret_address()Oleg Nesterov1-3/+12
Extract the "push return address" code from branch_emulate_op() into the new simple helper, push_ret_address(). It will have more users. Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-04-30uprobes/x86: Cleanup the usage of arch_uprobe->def.fixups, make it u8Oleg Nesterov1-7/+7
handle_riprel_insn() assumes that nobody else could modify ->fixups before. This is correct but fragile, change it to use "|=". Also make ->fixups u8, we are going to add the new members into the union. It is not clear why UPROBE_FIX_RIP_.X lived in the upper byte, redefine them so that they can fit into u8. Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2014-04-30uprobes/x86: Move default_xol_ops's data into arch_uprobe->defOleg Nesterov1-22/+21
Finally we can move arch_uprobe->fixups/rip_rela_target_address into the new "def" struct and place this struct in the union, they are only used by default_xol_ops paths. The patch also renames rip_rela_target_address to riprel_target just to make this name shorter. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
2014-04-30uprobes/x86: Move UPROBE_FIX_SETF logic from arch_uprobe_post_xol() to default_post_xol_op()Oleg Nesterov1-8/+12
UPROBE_FIX_SETF is only needed to handle "popf" correctly but it is processed by the generic arch_uprobe_post_xol() code. This doesn't allows us to make ->fixups private for default_xol_ops. 1 Change default_post_xol_op(UPROBE_FIX_SETF) to set ->saved_tf = T. "popf" always reads the flags from stack, it doesn't matter if TF was set or not before single-step. Ignoring the naming, this is even more logical, "saved_tf" means "owned by application" and we do not own this flag after "popf". 2. Change arch_uprobe_post_xol() to save ->saved_tf into the local "bool send_sigtrap" before ->post_xol(). 3. Change arch_uprobe_post_xol() to ignore UPROBE_FIX_SETF and just check ->saved_tf after ->post_xol(). With this patch ->fixups and ->rip_rela_target_address are only used by default_xol_ops hooks, we are ready to remove them from the common part of arch_uprobe. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
2014-04-30uprobes/x86: Don't use arch_uprobe_abort_xol() in arch_uprobe_post_xol()Oleg Nesterov1-8/+9
014940bad8e4 "uprobes/x86: Send SIGILL if arch_uprobe_post_xol() fails" changed arch_uprobe_post_xol() to use arch_uprobe_abort_xol() if ->post_xol fails. This was correct and helped to avoid the additional complications, we need to clear X86_EFLAGS_TF in this case. However, now that we have uprobe_xol_ops->abort() hook it would be better to avoid arch_uprobe_abort_xol() here. ->post_xol() should likely do what ->abort() does anyway, we should not do the same work twice. Currently only handle_riprel_post_xol() can be called twice, this is unnecessary but safe. Still this is not clean and can lead to the problems in future. Change arch_uprobe_post_xol() to clear X86_EFLAGS_TF and restore ->ip by hand and avoid arch_uprobe_abort_xol(). This temporary uglifies the usage of autask.saved_tf, we will cleanup this later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
2014-04-30uprobes/x86: Introduce uprobe_xol_ops->abort() and default_abort_op()Oleg Nesterov1-3/+11
arch_uprobe_abort_xol() calls handle_riprel_post_xol() even if auprobe->ops != default_xol_ops. This is fine correctness wise, only default_pre_xol_op() can set UPROBE_FIX_RIP_AX|UPROBE_FIX_RIP_CX and otherwise handle_riprel_post_xol() is nop. But this doesn't look clean and this doesn't allow us to move ->fixups into the union in arch_uprobe. Move this handle_riprel_post_xol() call into the new default_abort_op() hook and change arch_uprobe_abort_xol() accordingly. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
2014-04-30uprobes/x86: Don't change the task's state if ->pre_xol() failsOleg Nesterov1-2/+6
Currently this doesn't matter, the only ->pre_xol() hook can't fail, but we need to fix arch_uprobe_pre_xol() anyway. If ->pre_xol() fails we should not change regs->ip/flags, we should just return the error to make restart actually possible. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
2014-04-30uprobes/x86: Fix is_64bit_mm() with CONFIG_X86_X32Oleg Nesterov1-1/+1
is_64bit_mm() assumes that mm->context.ia32_compat means the 32-bit instruction set, this is not true if the task is TIF_X32. Change set_personality_ia32() to initialize mm->context.ia32_compat by TIF_X32 or TIF_IA32 instead of 1. This allows to fix is_64bit_mm() without affecting other users, they all treat ia32_compat as "bool". TIF_ in ->ia32_compat looks a bit strange, but this is grep-friendly and avoids the new define's. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Make good_insns_* depend on CONFIG_X86_*Oleg Nesterov1-24/+32
Add the suitable ifdef's around good_insns_* arrays. We do not want to add the ugly ifdef's into their only user, uprobe_init_insn(), so the "#else" branch simply defines them as NULL. This doesn't generate the extra code, gcc is smart enough, although the code is fine even if it could not detect that (without CONFIG_IA32_EMULATION) is_64bit_mm() is __builtin_constant_p(). The patch looks more complicated because it also moves good_insns_64 up close to good_insns_32. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Shift "insn_complete" from branch_setup_xol_ops() to uprobe_init_insn()Oleg Nesterov1-9/+4
Change uprobe_init_insn() to make insn_complete() == T, this makes other insn_get_*() calls unnecessary. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2014-04-30uprobes/x86: Add is_64bit_mm(), kill validate_insn_bits()Oleg Nesterov1-11/+9
1. Extract the ->ia32_compat check from 64bit validate_insn_bits() into the new helper, is_64bit_mm(), it will have more users. TODO: this checks is actually wrong if mm owner is X32 task, we need another fix which changes set_personality_ia32(). TODO: even worse, the whole 64-or-32-bit logic is very broken and the fix is not simple, we need the nontrivial changes in the core uprobes code. 2. Kill validate_insn_bits() and change its single caller to use uprobe_init_insn(is_64bit_mm(mm). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>