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path: root/arch/x86/kernel/kprobes/opt.c
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2025-04-11x86/alternatives: Rename 'text_poke_sync()' to 'smp_text_poke_sync_each_cpu()'Ingo Molnar
Unlike sync_core(), text_poke_sync() is a very heavy operation, as it sends an IPI to every online CPU in the system and waits for completion. Reflect this in the name. Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250411054105.2341982-41-mingo@kernel.org
2025-04-11x86/alternatives: Rename 'text_poke_bp()' to 'smp_text_poke_single()'Ingo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Juergen Gross <jgross@suse.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20250411054105.2341982-7-mingo@kernel.org
2024-01-10x86/bugs: Rename CONFIG_RETPOLINE => CONFIG_MITIGATION_RETPOLINEBreno Leitao
Step 5/10 of the namespace unification of CPU mitigations related Kconfig options. [ mingo: Converted a few more uses in comments/messages as well. ] Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ariel Miculas <amiculas@cisco.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20231121160740.1249350-6-leitao@debian.org
2023-08-14x86/retpoline,kprobes: Skip optprobe check for indirect jumps with ↵Petr Pavlu
retpolines and IBT The kprobes optimization check can_optimize() calls insn_is_indirect_jump() to detect indirect jump instructions in a target function. If any is found, creating an optprobe is disallowed in the function because the jump could be from a jump table and could potentially land in the middle of the target optprobe. With retpolines, insn_is_indirect_jump() additionally looks for calls to indirect thunks which the compiler potentially used to replace original jumps. This extra check is however unnecessary because jump tables are disabled when the kernel is built with retpolines. The same is currently the case with IBT. Based on this observation, remove the logic to look for calls to indirect thunks and skip the check for indirect jumps altogether if the kernel is built with retpolines or IBT. Remove subsequently the symbols __indirect_thunk_start and __indirect_thunk_end which are no longer needed. Dropping this logic indirectly fixes a problem where the range [__indirect_thunk_start, __indirect_thunk_end] wrongly included also the return thunk. It caused that machines which used the return thunk as a mitigation and didn't have it patched by any alternative ended up not being able to use optprobes in any regular function. Fixes: 0b53c374b9ef ("x86/retpoline: Use -mfunction-return") Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Petr Pavlu <petr.pavlu@suse.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Link: https://lore.kernel.org/r/20230711091952.27944-3-petr.pavlu@suse.com
2023-02-21x86/kprobes: Fix arch_check_optimized_kprobe check within optimized_kprobe rangeYang Jihong
When arch_prepare_optimized_kprobe calculating jump destination address, it copies original instructions from jmp-optimized kprobe (see __recover_optprobed_insn), and calculated based on length of original instruction. arch_check_optimized_kprobe does not check KPROBE_FLAG_OPTIMATED when checking whether jmp-optimized kprobe exists. As a result, setup_detour_execution may jump to a range that has been overwritten by jump destination address, resulting in an inval opcode error. For example, assume that register two kprobes whose addresses are <func+9> and <func+11> in "func" function. The original code of "func" function is as follows: 0xffffffff816cb5e9 <+9>: push %r12 0xffffffff816cb5eb <+11>: xor %r12d,%r12d 0xffffffff816cb5ee <+14>: test %rdi,%rdi 0xffffffff816cb5f1 <+17>: setne %r12b 0xffffffff816cb5f5 <+21>: push %rbp 1.Register the kprobe for <func+11>, assume that is kp1, corresponding optimized_kprobe is op1. After the optimization, "func" code changes to: 0xffffffff816cc079 <+9>: push %r12 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp Now op1->flags == KPROBE_FLAG_OPTIMATED; 2. Register the kprobe for <func+9>, assume that is kp2, corresponding optimized_kprobe is op2. register_kprobe(kp2) register_aggr_kprobe alloc_aggr_kprobe __prepare_optimized_kprobe arch_prepare_optimized_kprobe __recover_optprobed_insn // copy original bytes from kp1->optinsn.copied_insn, // jump address = <func+14> 3. disable kp1: disable_kprobe(kp1) __disable_kprobe ... if (p == orig_p || aggr_kprobe_disabled(orig_p)) { ret = disarm_kprobe(orig_p, true) // add op1 in unoptimizing_list, not unoptimized orig_p->flags |= KPROBE_FLAG_DISABLED; // op1->flags == KPROBE_FLAG_OPTIMATED | KPROBE_FLAG_DISABLED ... 4. unregister kp2 __unregister_kprobe_top ... if (!kprobe_disabled(ap) && !kprobes_all_disarmed) { optimize_kprobe(op) ... if (arch_check_optimized_kprobe(op) < 0) // because op1 has KPROBE_FLAG_DISABLED, here not return return; p->kp.flags |= KPROBE_FLAG_OPTIMIZED; // now op2 has KPROBE_FLAG_OPTIMIZED } "func" code now is: 0xffffffff816cc079 <+9>: int3 0xffffffff816cc07a <+10>: push %rsp 0xffffffff816cc07b <+11>: jmp 0xffffffffa0210000 0xffffffff816cc080 <+16>: incl 0xf(%rcx) 0xffffffff816cc083 <+19>: xchg %eax,%ebp 0xffffffff816cc084 <+20>: (bad) 0xffffffff816cc085 <+21>: push %rbp 5. if call "func", int3 handler call setup_detour_execution: if (p->flags & KPROBE_FLAG_OPTIMIZED) { ... regs->ip = (unsigned long)op->optinsn.insn + TMPL_END_IDX; ... } The code for the destination address is 0xffffffffa021072c: push %r12 0xffffffffa021072e: xor %r12d,%r12d 0xffffffffa0210731: jmp 0xffffffff816cb5ee <func+14> However, <func+14> is not a valid start instruction address. As a result, an error occurs. Link: https://lore.kernel.org/all/20230216034247.32348-3-yangjihong1@huawei.com/ Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-02-21x86/kprobes: Fix __recover_optprobed_insn check optimizing logicYang Jihong
Since the following commit: commit f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") modified the update timing of the KPROBE_FLAG_OPTIMIZED, a optimized_kprobe may be in the optimizing or unoptimizing state when op.kp->flags has KPROBE_FLAG_OPTIMIZED and op->list is not empty. The __recover_optprobed_insn check logic is incorrect, a kprobe in the unoptimizing state may be incorrectly determined as unoptimizing. As a result, incorrect instructions are copied. The optprobe_queued_unopt function needs to be exported for invoking in arch directory. Link: https://lore.kernel.org/all/20230216034247.32348-2-yangjihong1@huawei.com/ Fixes: f66c0447cca1 ("kprobes: Set unoptimized flag after unoptimizing code") Cc: stable@vger.kernel.org Signed-off-by: Yang Jihong <yangjihong1@huawei.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2022-12-27x86/kprobes: Fix optprobe optimization check with CONFIG_RETHUNKMasami Hiramatsu (Google)
Since the CONFIG_RETHUNK and CONFIG_SLS will use INT3 for stopping speculative execution after function return, kprobe jump optimization always fails on the functions with such INT3 inside the function body. (It already checks the INT3 padding between functions, but not inside the function) To avoid this issue, as same as kprobes, check whether the INT3 comes from kgdb or not, and if so, stop decoding and make it fail. The other INT3 will come from CONFIG_RETHUNK/CONFIG_SLS and those can be treated as a one-byte instruction. Fixes: e463a09af2f0 ("x86: Add straight-line-speculation mitigation") Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/167146051929.1374301.7419382929328081706.stgit@devnote3
2022-03-28x86,kprobes: Fix optprobe trampoline to generate complete pt_regsMasami Hiramatsu
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) <peterz@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/164826166027.2455864.14759128090648961900.stgit@devnote2
2021-09-30kprobes: treewide: Use 'kprobe_opcode_t *' for the code address in ↵Masami Hiramatsu
get_optimized_kprobe() Since get_optimized_kprobe() is only used inside kprobes, it doesn't need to use 'unsigned long' type for 'addr' parameter. Make it use 'kprobe_opcode_t *' for the 'addr' parameter and subsequent call of arch_within_optimized_kprobe() also should use 'kprobe_opcode_t *'. Note that MAX_OPTIMIZED_LENGTH and RELATIVEJUMP_SIZE are defined by byte-size, but the size of 'kprobe_opcode_t' depends on the architecture. Therefore, we must be careful when calculating addresses using those macros. Link: https://lkml.kernel.org/r/163163040680.489837.12133032364499833736.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2021-03-31x86: Add insn_decode_kernel()Peter Zijlstra
Add a helper to decode kernel instructions; there's no point in endlessly repeating those last two arguments. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210326151259.379242587@infradead.org
2021-03-15x86/kprobes: Convert to insn_decode()Borislav Petkov
Simplify code, improve decoding error checking. Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20210304174237.31945-12-bp@alien8.de
2020-12-12x86/kprobes: Fix optprobe to detect INT3 padding correctlyMasami Hiramatsu
Commit 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes") changed the padding bytes between functions from NOP to INT3. However, when optprobe decodes a target function it finds INT3 and gives up the jump optimization. Instead of giving up any INT3 detection, check whether the rest of the bytes to the end of the function are INT3. If all of them are INT3, those come from the linker. In that case, continue the optprobe jump optimization. [ bp: Massage commit message. ] Fixes: 7705dc855797 ("x86/vmlinux: Use INT3 instead of NOP for linker fill bytes") Reported-by: Adam Zabrocki <pi3@pi3.com.pl> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/160767025681.3880685.16021570341428835411.stgit@devnote2
2020-10-14Merge tag 'objtool-core-2020-10-13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: "Most of the changes are cleanups and reorganization to make the objtool code more arch-agnostic. This is in preparation for non-x86 support. Other changes: - KASAN fixes - Handle unreachable trap after call to noreturn functions better - Ignore unreachable fake jumps - Misc smaller fixes & cleanups" * tag 'objtool-core-2020-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) perf build: Allow nested externs to enable BUILD_BUG() usage objtool: Allow nested externs to enable BUILD_BUG() objtool: Permit __kasan_check_{read,write} under UACCESS objtool: Ignore unreachable trap after call to noreturn functions objtool: Handle calling non-function symbols in other sections objtool: Ignore unreachable fake jumps objtool: Remove useless tests before save_reg() objtool: Decode unwind hint register depending on architecture objtool: Make unwind hint definitions available to other architectures objtool: Only include valid definitions depending on source file type objtool: Rename frame.h -> objtool.h objtool: Refactor jump table code to support other architectures objtool: Make relocation in alternative handling arch dependent objtool: Abstract alternative special case handling objtool: Move macros describing structures to arch-dependent code objtool: Make sync-check consider the target architecture objtool: Group headers to check in a single list objtool: Define 'struct orc_entry' only when needed objtool: Skip ORC entry creation for non-text sections objtool: Move ORC logic out of check() ...
2020-10-12Merge tag 'x86-paravirt-2020-10-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 paravirt cleanup from Ingo Molnar: "Clean up the paravirt code after the removal of 32-bit Xen PV support" * tag 'x86-paravirt-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/paravirt: Avoid needless paravirt step clearing page table entries x86/paravirt: Remove set_pte_at() pv-op x86/entry/32: Simplify CONFIG_XEN_PV build dependency x86/paravirt: Use CONFIG_PARAVIRT_XXL instead of CONFIG_PARAVIRT x86/paravirt: Clean up paravirt macros x86/paravirt: Remove 32-bit support from CONFIG_PARAVIRT_XXL
2020-09-10objtool: Rename frame.h -> objtool.hJulien Thierry
Header frame.h is getting more code annotations to help objtool analyze object files. Rename the file to objtool.h. [ jpoimboe: add objtool.h to MAINTAINERS ] Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-01static_call: Avoid kprobes on inline static_call()sPeter Zijlstra
Similar to how we disallow kprobes on any other dynamic text (ftrace/jump_label) also disallow kprobes on inline static_call()s. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200818135804.744920586@infradead.org
2020-08-15x86/paravirt: Remove 32-bit support from CONFIG_PARAVIRT_XXLJuergen Gross
The last 32-bit user of stuff under CONFIG_PARAVIRT_XXL is gone. Remove 32-bit specific parts. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200815100641.26362-2-jgross@suse.com
2020-07-02Merge branch 'perf/vlbr'Peter Zijlstra
2020-06-17maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofaultChristoph Hellwig
Better describe what these functions do. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-15perf/x86: Add perf text poke events for kprobesAdrian Hunter
Add perf text poke events for kprobes. That includes: - the replaced instruction(s) which are executed out-of-line i.e. arch_copy_kprobe() and arch_remove_kprobe() - the INT3 that activates the kprobe i.e. arch_arm_kprobe() and arch_disarm_kprobe() - optimised kprobe function i.e. arch_prepare_optimized_kprobe() and __arch_remove_optimized_kprobe() - optimised kprobe i.e. arch_optimize_kprobes() and arch_unoptimize_kprobe() Resulting in 8 possible text_poke events: 0: NULL -> probe.ainsn.insn (if ainsn.boostable && !kp.post_handler) arch_copy_kprobe() 1: old0 -> INT3 arch_arm_kprobe() // boosted kprobe active 2: NULL -> optprobe_trampoline arch_prepare_optimized_kprobe() 3: INT3,old1,old2,old3,old4 -> JMP32 arch_optimize_kprobes() // optprobe active 4: JMP32 -> INT3,old1,old2,old3,old4 // optprobe disabled and kprobe active (this sometimes goes back to 3) arch_unoptimize_kprobe() 5: optprobe_trampoline -> NULL arch_remove_optimized_kprobe() // boosted kprobe active 6: INT3 -> old0 arch_disarm_kprobe() 7: probe.ainsn.insn -> NULL (if ainsn.boostable && !kp.post_handler) arch_remove_kprobe() Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20200512121922.8997-6-adrian.hunter@intel.com
2020-06-11x86/entry: Unbreak __irqentry_text_start/end magicThomas Gleixner
The entry rework moved interrupt entry code from the irqentry to the noinstr section which made the irqentry section empty. This breaks boundary checks which rely on the __irqentry_text_start/end markers to find out whether a function in a stack trace is interrupt/exception entry code. This affects the function graph tracer and filter_irq_stacks(). As the IDT entry points are all sequentialy emitted this is rather simple to unbreak by injecting __irqentry_text_start/end as global labels. To make this work correctly: - Remove the IRQENTRY_TEXT section from the x86 linker script - Define __irqentry so it breaks the build if it's used - Adjust the entry mirroring in PTI - Remove the redundant kprobes and unwinder bound checks Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2020-06-09mm: reorder includes after introduction of linux/pgtable.hMike Rapoport
The replacement of <asm/pgrable.h> with <linux/pgtable.h> made the include of the latter in the middle of asm includes. Fix this up with the aid of the below script and manual adjustments here and there. import sys import re if len(sys.argv) is not 3: print "USAGE: %s <file> <header>" % (sys.argv[0]) sys.exit(1) hdr_to_move="#include <linux/%s>" % sys.argv[2] moved = False in_hdrs = False with open(sys.argv[1], "r") as f: lines = f.readlines() for _line in lines: line = _line.rstrip(' ') if line == hdr_to_move: continue if line.startswith("#include <linux/"): in_hdrs = True elif not moved and in_hdrs: moved = True print hdr_to_move print line Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-4-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-09mm: introduce include/linux/pgtable.hMike Rapoport
The include/linux/pgtable.h is going to be the home of generic page table manipulation functions. Start with moving asm-generic/pgtable.h to include/linux/pgtable.h and make the latter include asm/pgtable.h. Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-3-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-03-20x86/optprobe: Fix OPTPROBE vs UACCESSPeter Zijlstra
While looking at an objtool UACCESS warning, it suddenly occurred to me that it is entirely possible to have an OPTPROBE right in the middle of an UACCESS region. In this case we must of course clear FLAGS.AC while running the KPROBE. Luckily the trampoline already saves/restores [ER]FLAGS, so all we need to do is inject a CLAC. Unfortunately we cannot use ALTERNATIVE() in the trampoline text, so we have to frob that manually. Fixes: ca0bbc70f147 ("sched/x86_64: Don't save flags on context switch") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20200305092130.GU2596@hirez.programming.kicks-ass.net
2019-11-27x86/kprobe: Add comments to arch_{,un}optimize_kprobes()Peter Zijlstra
Add a few words describing how it is safe to overwrite the 4 bytes after a kprobe. In specific it is possible the JMP.d32 required for the optimized kprobe overwrites multiple instructions. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> 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> Link: https://lkml.kernel.org/r/20191111132458.401696663@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-27x86/kprobes: Fix ordering while text-patchingPeter Zijlstra
Kprobes does something like: register: arch_arm_kprobe() text_poke(INT3) /* guarantees nothing, INT3 will become visible at some point, maybe */ kprobe_optimizer() /* guarantees the bytes after INT3 are unused */ synchronize_rcu_tasks(); text_poke_bp(JMP32); /* implies IPI-sync, kprobe really is enabled */ unregister: __disarm_kprobe() unoptimize_kprobe() text_poke_bp(INT3 + tail); /* implies IPI-sync, so tail is guaranteed visible */ arch_disarm_kprobe() text_poke(old); /* guarantees nothing, old will maybe become visible */ synchronize_rcu() free-stuff Now the problem is that on register, the synchronize_rcu_tasks() does not imply sufficient to guarantee all CPUs have already observed INT3 (although in practice this is exceedingly unlikely not to have happened) (similar to how MEMBARRIER_CMD_PRIVATE_EXPEDITED does not imply MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE). Worse, even if it did, we'd have to do 2 synchronize calls to provide the guarantee we're looking for, the first to ensure INT3 is visible, the second to guarantee nobody is then still using the instruction bytes after INT3. Similar on unregister; the synchronize_rcu() between __unregister_kprobe_top() and __unregister_kprobe_bottom() does not guarantee all CPUs are free of the INT3 (and observe the old text). Therefore, sprinkle some IPI-sync love around. This guarantees that all CPUs agree on the text and RCU once again provides the required guaranteed. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Paul E. McKenney <paulmck@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> 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> Link: https://lkml.kernel.org/r/20191111132458.162172862@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-27x86/kprobes: Convert to text-patching.hPeter Zijlstra
Convert kprobes to the new text-poke naming. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> 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> Link: https://lkml.kernel.org/r/20191111132458.103959370@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-27x86/alternatives: Add and use text_gen_insn() helperPeter Zijlstra
Provide a simple helper function to create common instruction encodings. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191111132457.703538332@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-15x86/alternatives: Teach text_poke_bp() to emulate instructionsPeter Zijlstra
In preparation for static_call and variable size jump_label support, teach text_poke_bp() to emulate instructions, namely: JMP32, JMP8, CALL, NOP2, NOP_ATOMIC5, INT3 The current text_poke_bp() takes a @handler argument which is used as a jump target when the temporary INT3 is hit by a different CPU. When patching CALL instructions, this doesn't work because we'd miss the PUSH of the return address. Instead, teach poke_int3_handler() to emulate an instruction, typically the instruction we're patching in. This fits almost all text_poke_bp() users, except arch_unoptimize_kprobe() which restores random text, and for that site we have to build an explicit emulate instruction. Tested-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191111132457.529086974@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> (cherry picked from commit 8c7eebc10687af45ac8e40ad1bac0cf7893dba9f) Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-09-02x86: Correct misc typosMarco Ammon
Correct spelling typos in comments in different files under arch/x86/. [ bp: Merge into a single patch, massage. ] Signed-off-by: Marco Ammon <marco.ammon@fau.de> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nadav Amit <namit@vmware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pu Wen <puwen@hygon.cn> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: trivial@kernel.org Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190902102436.27396-1-marco.ammon@fau.de
2019-07-08Merge branch 'x86-paravirt-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 paravirt updates from Ingo Molnar: "A handful of paravirt patching code enhancements to make it more robust against patching failures, and related cleanups and not so related cleanups - by Thomas Gleixner and myself" * 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/paravirt: Rename paravirt_patch_site::instrtype to paravirt_patch_site::type x86/paravirt: Standardize 'insn_buff' variable names x86/paravirt: Match paravirt patchlet field definition ordering to initialization ordering x86/paravirt: Replace the paravirt patch asm magic x86/paravirt: Unify the 32/64 bit paravirt patching code x86/paravirt: Detect over-sized patching bugs in paravirt_patch_call() x86/paravirt: Detect over-sized patching bugs in paravirt_patch_insns() x86/paravirt: Remove bogus extern declarations
2019-06-25x86/stackframe/32: Provide consistent pt_regsPeter Zijlstra
Currently pt_regs on x86_32 has an oddity in that kernel regs (!user_mode(regs)) are short two entries (esp/ss). This means that any code trying to use them (typically: regs->sp) needs to jump through some unfortunate hoops. Change the entry code to fix this up and create a full pt_regs frame. This then simplifies various trampolines in ftrace and kprobes, the stack unwinder, ptrace, kdump and kgdb. Much thanks to Josh for help with the cleanups! Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-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> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner
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>
2019-04-29x86/paravirt: Standardize 'insn_buff' variable namesIngo Molnar
We currently have 6 (!) separate naming variants to name temporary instruction buffers that are used for code patching: - insnbuf - insnbuff - insn_buff - insn_buffer - ibuf - ibuffer These are used as local variables, percpu fields and function parameters. Standardize all the names to a single variant: 'insn_buff'. Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juergen Gross <jgross@suse.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-13x86/kprobes: Move trampoline code into RODATAMasami Hiramatsu
Move optprobe trampoline code into RODATA since it is not executed, but copied and modified to be used on a trampoline buffer. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/154998790744.31052.3016106262944915510.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-02-13x86/kprobes: Prohibit probing on optprobe template codeMasami Hiramatsu
Prohibit probing on optprobe template code, since it is not a code but a template instruction sequence. If we modify this template, copied template must be broken. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrea Righi <righi.andrea@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Fixes: 9326638cbee2 ("kprobes, x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation") Link: http://lkml.kernel.org/r/154998787911.31052.15274376330136234452.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-04kprobes/x86: Fix instruction patching corruption when copying more than one ↵Masami Hiramatsu
RIP-relative instruction After copy_optimized_instructions() copies several instructions to the working buffer it tries to fix up the real RIP address, but it adjusts the RIP-relative instruction with an incorrect RIP address for the 2nd and subsequent instructions due to a bug in the logic. This will break the kernel pretty badly (with likely outcomes such as a kernel freeze, a crash, or worse) because probed instructions can refer to the wrong data. For example putting kprobes on cpumask_next() typically hits this bug. cpumask_next() is normally like below if CONFIG_CPUMASK_OFFSTACK=y (in this case nr_cpumask_bits is an alias of nr_cpu_ids): <cpumask_next>: 48 89 f0 mov %rsi,%rax 8b 35 7b fb e2 00 mov 0xe2fb7b(%rip),%esi # ffffffff82db9e64 <nr_cpu_ids> 55 push %rbp ... If we put a kprobe on it and it gets jump-optimized, it gets patched by the kprobes code like this: <cpumask_next>: e9 95 7d 07 1e jmpq 0xffffffffa000207a 7b fb jnp 0xffffffff81f8a2e2 <cpumask_next+2> e2 00 loop 0xffffffff81f8a2e9 <cpumask_next+9> 55 push %rbp This shows that the first two MOV instructions were copied to a trampoline buffer at 0xffffffffa000207a. Here is the disassembled result of the trampoline, skipping the optprobe template instructions: # Dump of assembly code from 0xffffffffa000207a to 0xffffffffa00020ea: 54 push %rsp ... 48 83 c4 08 add $0x8,%rsp 9d popfq 48 89 f0 mov %rsi,%rax 8b 35 82 7d db e2 mov -0x1d24827e(%rip),%esi # 0xffffffff82db9e67 <nr_cpu_ids+3> This dump shows that the second MOV accesses *(nr_cpu_ids+3) instead of the original *nr_cpu_ids. This leads to a kernel freeze because cpumask_next() always returns 0 and for_each_cpu() never ends. Fix this by adding 'len' correctly to the real RIP address while copying. [ mingo: Improved the changelog. ] Reported-by: Michael Rodin <michael@rodin.online> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org # v4.15+ Fixes: 63fef14fc98a ("kprobes/x86: Make insn buffer always ROX and use text_poke()") Link: http://lkml.kernel.org/r/153504457253.22602.1314289671019919596.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-10-22kprobes/x86: Use preempt_enable() in optimized_callback()Masami Hiramatsu
The following commit: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) removed local_irq_save/restore() from optimized_callback(), the handler might be interrupted by the rescheduling interrupt and might be rescheduled - so we must not use the preempt_enable_no_resched() macro. Use preempt_enable() instead, to not lose preemption events. [ mingo: Improved the changelog. ] Reported-by: Nadav Amit <namit@vmware.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dwmw@amazon.co.uk Fixes: a19b2e3d7839 ("kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes”) Link: http://lkml.kernel.org/r/154002887331.7627.10194920925792947001.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes/x86: Do not disable preempt on int3 pathMasami Hiramatsu
Since int3 and debug exception(for singlestep) are run with IRQ disabled and while running single stepping we drop IF from regs->flags, that path must not be preemptible. So we can remove the preempt disable/enable calls from that path. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/lkml/152942497779.15209.2879580696589868291.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-21Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 pti fixes from Thomas Gleixner: "A small set of fixes for the meltdown/spectre mitigations: - Make kprobes aware of retpolines to prevent probes in the retpoline thunks. - Make the machine check exception speculation protected. MCE used to issue an indirect call directly from the ASM entry code. Convert that to a direct call into a C-function and issue the indirect call from there so the compiler can add the retpoline protection, - Make the vmexit_fill_RSB() assembly less stupid - Fix a typo in the PTI documentation" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/retpoline: Optimize inline assembler for vmexit_fill_RSB x86/pti: Document fix wrong index kprobes/x86: Disable optimizing on the function jumps to indirect thunk kprobes/x86: Blacklist indirect thunk functions for kprobes retpoline: Introduce start/end markers of indirect thunk x86/mce: Make machine check speculation protected
2018-01-19kprobes/x86: Disable optimizing on the function jumps to indirect thunkMasami Hiramatsu
Since indirect jump instructions will be replaced by jump to __x86_indirect_thunk_*, those jmp instruction must be treated as an indirect jump. Since optprobe prohibits to optimize probes in the function which uses an indirect jump, it also needs to find out the function which jump to __x86_indirect_thunk_* and disable optimization. Add a check that the jump target address is between the __indirect_thunk_start/end when optimizing kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Woodhouse <dwmw@amazon.co.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/151629212062.10241.6991266100233002273.stgit@devbox
2017-09-28kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobesMasami Hiramatsu
Kkprobes don't need to disable IRQs if they are called from the ftrace/jump trampoline code, because Documentation/kprobes.txt says: ----- Probe handlers are run with preemption disabled. Depending on the architecture and optimization state, handlers may also run with interrupts disabled (e.g., kretprobe handlers and optimized kprobe handlers run without interrupt disabled on x86/x86-64). ----- So let's remove IRQ disabling from those handlers. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581534039.32348.11331736206004264553.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Disable preemption in optprobeMasami Hiramatsu
Disable preemption in optprobe handler as described in Documentation/kprobes.txt, which says: "Probe handlers are run with preemption disabled." Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581525942.32348.6359217983269060829.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Move the get_kprobe_ctlblk() into irq-disabled blockMasami Hiramatsu
Since get_kprobe_ctlblk() accesses per-cpu variables which calls smp_processor_id(), it must be called under preempt-disabled or irq-disabled. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@fb.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/150581517952.32348.2655896843219158446.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Remove addressof() operatorsMasami Hiramatsu
The following commit: 54a7d50b9205 ("x86: mark kprobe templates as character arrays, not single characters") changed optprobe_template_* to arrays, so we can remove the addressof() operators from those symbols. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.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/150304469798.17009.15886717935027472863.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-09-28kprobes/x86: Make insn buffer always ROX and use text_poke()Masami Hiramatsu
Make insn buffer always ROX and use text_poke() to write the copied instructions instead of set_memory_*(). This makes instruction buffer stronger against other kernel subsystems because there is no window time to modify the buffer. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.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/150304463032.17009.14195368040691676813.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-08-10kprobes/x86: Do not jump-optimize kprobes on irq entry codeMasami Hiramatsu
Since the kernel segment registers are not prepared at the entry of irq-entry code, if a kprobe on such code is jump-optimized, accessing per-CPU variables may cause a kernel panic. However, if the kprobe is not optimized, it triggers an int3 exception and sets segment registers correctly. With this patch we check the probe-address and if it is in the irq-entry code, it prohibits optimizing such kprobes. This means we can continue probing such interrupt handlers by kprobes but it is not optimized anymore. Reported-by: Francis Deslauriers <francis.deslauriers@efficios.com> Tested-by: Francis Deslauriers <francis.deslauriers@efficios.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Chris Zankel <chris@zankel.net> Cc: David S . Miller <davem@davemloft.net> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: linux-arch@vger.kernel.org Cc: linux-cris-kernel@axis.com Cc: mathieu.desnoyers@efficios.com Link: http://lkml.kernel.org/r/150172795654.27216.9824039077047777477.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-30objtool, x86: Add several functions and files to the objtool whitelistJosh Poimboeuf
In preparation for an objtool rewrite which will have broader checks, whitelist functions and files which cause problems because they do unusual things with the stack. These whitelists serve as a TODO list for which functions and files don't yet have undwarf unwinder coverage. Eventually most of the whitelists can be removed in favor of manual CFI hint annotations or objtool improvements. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/7f934a5d707a574bda33ea282e9478e627fb1829.1498659915.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-08treewide: decouple cacheflush.h and set_memory.hLaura Abbott
Now that all call sites, completely decouple cacheflush.h and set_memory.h [sfr@canb.auug.org.au: kprobes/x86: merge fix for set_memory.h decoupling] Link: http://lkml.kernel.org/r/20170418180903.10300fd3@canb.auug.org.au Link: http://lkml.kernel.org/r/1488920133-27229-17-git-send-email-labbott@redhat.com Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-04-12kprobes/x86: Consolidate insn decoder users for copying codeMasami Hiramatsu
Consolidate x86 instruction decoder users on the path of copying original code for kprobes. Kprobes decodes the same instruction a maximum of 3 times when preparing the instruction buffer: - The first time for getting the length of the instruction, - the 2nd for adjusting displacement, - and the 3rd for checking whether the instruction is boostable or not. For each time, the actual decoding target address is slightly different (1st is original address or recovered instruction buffer, 2nd and 3rd are pointing to the copied buffer), but all have the same instruction. Thus, this patch also changes the target address to the copied buffer at first and reuses the decoded "insn" for displacement adjusting and checking boostability. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David S . Miller <davem@davemloft.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ye Xiaolong <xiaolong.ye@intel.com> Link: http://lkml.kernel.org/r/149076389643.22469.13151892839998777373.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
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