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2024-02-01x86/objtool: Teach objtool about ERET[US]H. Peter Anvin (Intel)1-5/+14
Update the objtool decoder to know about the ERET[US] instructions (type INSN_CONTEXT_SWITCH). Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com> Signed-off-by: Xin Li <xin3.li@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: Shan Kang <shan.kang@intel.com> Link: https://lore.kernel.org/r/20231205105030.8698-11-xin3.li@intel.com
2023-10-03objtool: Use 'the fallthrough' pseudo-keywordRuan Jinjie1-3/+3
Replace the existing /* fallthrough */ comments with the new 'fallthrough' pseudo-keyword macro: https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org
2023-08-16x86/cpu: Rename original retbleed methodsPeter Zijlstra1-1/+1
Rename the original retbleed return thunk and untrain_ret to retbleed_return_thunk() and retbleed_untrain_ret(). No functional changes. Suggested-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230814121148.909378169@infradead.org
2023-08-16x86/cpu: Clean up SRSO return thunk messPeter Zijlstra1-1/+1
Use the existing configurable return thunk. There is absolute no justification for having created this __x86_return_thunk alternative. To clarify, the whole thing looks like: Zen3/4 does: srso_alias_untrain_ret: nop2 lfence jmp srso_alias_return_thunk int3 srso_alias_safe_ret: // aliasses srso_alias_untrain_ret just so add $8, %rsp ret int3 srso_alias_return_thunk: call srso_alias_safe_ret ud2 While Zen1/2 does: srso_untrain_ret: movabs $foo, %rax lfence call srso_safe_ret (jmp srso_return_thunk ?) int3 srso_safe_ret: // embedded in movabs instruction add $8,%rsp ret int3 srso_return_thunk: call srso_safe_ret ud2 While retbleed does: zen_untrain_ret: test $0xcc, %bl lfence jmp zen_return_thunk int3 zen_return_thunk: // embedded in the test instruction ret int3 Where Zen1/2 flush the BTB entry using the instruction decoder trick (test,movabs) Zen3/4 use BTB aliasing. SRSO adds a return sequence (srso_safe_ret()) which forces the function return instruction to speculate into a trap (UD2). This RET will then mispredict and execution will continue at the return site read from the top of the stack. Pick one of three options at boot (evey function can only ever return once). [ bp: Fixup commit message uarch details and add them in a comment in the code too. Add a comment about the srso_select_mitigation() dependency on retbleed_select_mitigation(). Add moar ifdeffery for 32-bit builds. Add a dummy srso_untrain_ret_alias() definition for 32-bit alternatives needing the symbol. ] Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230814121148.842775684@infradead.org
2023-08-16objtool/x86: Fix SRSO messPeter Zijlstra1-4/+7
Objtool --rethunk does two things: - it collects all (tail) call's of __x86_return_thunk and places them into .return_sites. These are typically compiler generated, but RET also emits this same. - it fudges the validation of the __x86_return_thunk symbol; because this symbol is inside another instruction, it can't actually find the instruction pointed to by the symbol offset and gets upset. Because these two things pertained to the same symbol, there was no pressing need to separate these two separate things. However, alas, along comes SRSO and more crazy things to deal with appeared. The SRSO patch itself added the following symbol names to identify as rethunk: 'srso_untrain_ret', 'srso_safe_ret' and '__ret' Where '__ret' is the old retbleed return thunk, 'srso_safe_ret' is a new similarly embedded return thunk, and 'srso_untrain_ret' is completely unrelated to anything the above does (and was only included because of that INT3 vs UD2 issue fixed previous). Clear things up by adding a second category for the embedded instruction thing. Fixes: fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20230814121148.704502245@infradead.org
2023-07-27x86/srso: Add a Speculative RAS Overflow mitigationBorislav Petkov (AMD)1-1/+4
Add a mitigation for the speculative return address stack overflow vulnerability found on AMD processors. The mitigation works by ensuring all RET instructions speculate to a controlled location, similar to how speculation is controlled in the retpoline sequence. To accomplish this, the __x86_return_thunk forces the CPU to mispredict every function return using a 'safe return' sequence. To ensure the safety of this mitigation, the kernel must ensure that the safe return sequence is itself free from attacker interference. In Zen3 and Zen4, this is accomplished by creating a BTB alias between the untraining function srso_untrain_ret_alias() and the safe return function srso_safe_ret_alias() which results in evicting a potentially poisoned BTB entry and using that safe one for all function returns. In older Zen1 and Zen2, this is accomplished using a reinterpretation technique similar to Retbleed one: srso_untrain_ret() and srso_safe_ret(). Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
2023-06-07objtool: Get rid of reloc->addendJosh Poimboeuf1-2/+2
Get the addend from the embedded GElf_Rel[a] struct. With allyesconfig + CONFIG_DEBUG_INFO: - Before: peak heap memory consumption: 42.10G - After: peak heap memory consumption: 40.37G Link: https://lore.kernel.org/r/ad2354f95d9ddd86094e3f7687acfa0750657784.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-06-07objtool: Get rid of reloc->typeJosh Poimboeuf1-1/+1
Get the type from the embedded GElf_Rel[a] struct. Link: https://lore.kernel.org/r/d1c1f8da31e4f052a2478aea585fcf355cacc53a.1685464332.git.jpoimboe@kernel.org Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
2023-02-23objtool: Make instruction::stack_ops a single-linked listPeter Zijlstra1-2/+2
struct instruction { struct list_head list; /* 0 16 */ struct hlist_node hash; /* 16 16 */ struct list_head call_node; /* 32 16 */ struct section * sec; /* 48 8 */ long unsigned int offset; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ unsigned int len; /* 64 4 */ enum insn_type type; /* 68 4 */ long unsigned int immediate; /* 72 8 */ u16 dead_end:1; /* 80: 0 2 */ u16 ignore:1; /* 80: 1 2 */ u16 ignore_alts:1; /* 80: 2 2 */ u16 hint:1; /* 80: 3 2 */ u16 save:1; /* 80: 4 2 */ u16 restore:1; /* 80: 5 2 */ u16 retpoline_safe:1; /* 80: 6 2 */ u16 noendbr:1; /* 80: 7 2 */ u16 entry:1; /* 80: 8 2 */ /* XXX 7 bits hole, try to pack */ s8 instr; /* 82 1 */ u8 visited; /* 83 1 */ /* XXX 4 bytes hole, try to pack */ struct alt_group * alt_group; /* 88 8 */ struct symbol * call_dest; /* 96 8 */ struct instruction * jump_dest; /* 104 8 */ struct instruction * first_jump_src; /* 112 8 */ struct reloc * jump_table; /* 120 8 */ /* --- cacheline 2 boundary (128 bytes) --- */ struct reloc * reloc; /* 128 8 */ struct list_head alts; /* 136 16 */ struct symbol * sym; /* 152 8 */ - struct list_head stack_ops; /* 160 16 */ - struct cfi_state * cfi; /* 176 8 */ + struct stack_op * stack_ops; /* 160 8 */ + struct cfi_state * cfi; /* 168 8 */ - /* size: 184, cachelines: 3, members: 29 */ - /* sum members: 178, holes: 1, sum holes: 4 */ + /* size: 176, cachelines: 3, members: 29 */ + /* sum members: 170, holes: 1, sum holes: 4 */ /* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 7 bits */ - /* last cacheline: 56 bytes */ + /* last cacheline: 48 bytes */ }; pre: 5:58.22 real, 226.69 user, 131.22 sys, 26221520 mem post: 5:58.50 real, 229.64 user, 128.65 sys, 26221520 mem Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> # build only Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run Link: https://lore.kernel.org/r/20230208172245.362196959@infradead.org
2023-02-23objtool: Change arch_decode_instruction() signaturePeter Zijlstra1-53/+52
In preparation to changing struct instruction around a bit, avoid passing it's members by pointer and instead pass the whole thing. A cleanup in it's own right too. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org> # build only Tested-by: Thomas Weißschuh <linux@weissschuh.net> # compile and run Link: https://lore.kernel.org/r/20230208172245.291087549@infradead.org
2022-12-19Merge tag 'powerpc-6.2-1' of ↵Linus Torvalds1-0/+5
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: - Add powerpc qspinlock implementation optimised for large system scalability and paravirt. See the merge message for more details - Enable objtool to be built on powerpc to generate mcount locations - Use a temporary mm for code patching with the Radix MMU, so the writable mapping is restricted to the patching CPU - Add an option to build the 64-bit big-endian kernel with the ELFv2 ABI - Sanitise user registers on interrupt entry on 64-bit Book3S - Many other small features and fixes Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET, Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang, Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A. R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin, Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng, XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu, and Wolfram Sang. * tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits) powerpc/code-patching: Fix oops with DEBUG_VM enabled powerpc/qspinlock: Fix 32-bit build powerpc/prom: Fix 32-bit build powerpc/rtas: mandate RTAS syscall filtering powerpc/rtas: define pr_fmt and convert printk call sites powerpc/rtas: clean up includes powerpc/rtas: clean up rtas_error_log_max initialization powerpc/pseries/eeh: use correct API for error log size powerpc/rtas: avoid scheduling in rtas_os_term() powerpc/rtas: avoid device tree lookups in rtas_os_term() powerpc/rtasd: use correct OF API for event scan rate powerpc/rtas: document rtas_call() powerpc/pseries: unregister VPA when hot unplugging a CPU powerpc/pseries: reset the RCU watchdogs after a LPM powerpc: Take in account addition CPU node when building kexec FDT powerpc: export the CPU node count powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state powerpc/dts/fsl: Fix pca954x i2c-mux node names cxl: Remove unnecessary cxl_pci_window_alignment() selftests/powerpc: Fix resource leaks ...
2022-11-18objtool: Add arch specific function arch_ftrace_match()Sathvika Vasireddy1-0/+5
Add architecture specific function to look for relocation records pointing to architecture specific symbols. Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu> Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Sathvika Vasireddy <sv@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221114175754.1131267-15-sv@linux.ibm.com
2022-10-17objtool: Allow !PC relative relocationsPeter Zijlstra1-0/+24
Objtool doesn't currently much like per-cpu usage in alternatives: arch/x86/entry/entry_64.o: warning: objtool: .altinstr_replacement+0xf: unsupported relocation in alternatives section f: 65 c7 04 25 00 00 00 00 00 00 00 80 movl $0x80000000,%gs:0x0 13: R_X86_64_32S __x86_call_depth Since the R_X86_64_32S relocation is location invariant (it's computation doesn't include P - the address of the location itself), it can be trivially allowed. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20220915111145.806607235@infradead.org
2022-09-15objtool,x86: Teach decode about LOOP* instructionsPeter Zijlstra1-0/+6
When 'discussing' control flow Masami mentioned the LOOP* instructions and I realized objtool doesn't decode them properly. As it turns out, these instructions are somewhat inefficient and as such unlikely to be emitted by the compiler (a few vmlinux.o checks can't find a single one) so this isn't critical, but still, best to decode them properly. Reported-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/Yxhd4EMKyoFoH9y4@hirez.programming.kicks-ass.net
2022-06-27x86,objtool: Create .return_sitesPeter Zijlstra1-0/+5
Find all the return-thunk sites and record them in a .return_sites section such that the kernel can undo this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
2022-04-22objtool: Reorganize cmdline optionsJosh Poimboeuf1-1/+1
Split the existing options into two groups: actions, which actually do something; and options, which modify the actions in some way. Also there's no need to have short flags for all the non-action options. Reserve short flags for the more important actions. While at it: - change a few of the short flags to be more intuitive - make option descriptions more consistently descriptive - sort options in the source like they are when printed - move options to a global struct Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/9dcaa752f83aca24b1b21f0b0eeb28a0c181c0b0.1650300597.git.jpoimboe@redhat.com
2022-03-15objtool: Add IBT/ENDBR decodingPeter Zijlstra1-5/+29
Intel IBT requires the target of any indirect CALL or JMP instruction to be the ENDBR instruction; optionally it allows those two instructions to have a NOTRACK prefix in order to avoid this requirement. The kernel will not enable the use of NOTRACK, as such any occurence of it in compiler generated code should be flagged. Teach objtool to Decode ENDBR instructions and WARN about NOTRACK prefixes. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220308154319.645963517@infradead.org
2022-03-15tools/objtool: Check for use of the ENQCMD instruction in the kernelFenghua Yu1-1/+10
The ENQCMD instruction implicitly accesses the PASID_MSR to fill in the pasid field of the descriptor being submitted to an accelerator. But there is no precise (and stable across kernel changes) point at which the PASID_MSR is updated from the value for one task to the next. Kernel code that uses accelerators must always use the ENQCMDS instruction which does not access the PASID_MSR. Check for use of the ENQCMD instruction in the kernel and warn on its usage. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20220207230254.3342514-11-fenghua.yu@intel.com Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2021-12-08objtool: Add straight-line-speculation validationPeter Zijlstra1-4/+9
Teach objtool to validate the straight-line-speculation constraints: - speculation trap after indirect calls - speculation trap after RET Notable: when an instruction is annotated RETPOLINE_SAFE, indicating speculation isn't a problem, also don't care about sls for that instruction. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211204134908.023037659@infradead.org
2021-10-29objtool,x86: Replace alternatives with .retpoline_sitesPeter Zijlstra1-120/+0
Instead of writing complete alternatives, simply provide a list of all the retpoline thunk calls. Then the kernel is free to do with them as it pleases. Simpler code all-round. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Borislav Petkov <bp@suse.de> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/r/20211026120309.850007165@infradead.org
2021-10-07Merge branch 'objtool/urgent'Peter Zijlstra1-1/+1
Fixup conflicts. # Conflicts: # tools/objtool/check.c
2021-10-05objtool: Make .altinstructions section entry size consistentJoe Lawrence1-1/+1
Commit e31694e0a7a7 ("objtool: Don't make .altinstructions writable") aligned objtool-created and kernel-created .altinstructions section flags, but there remains a minor discrepency in their use of a section entry size: objtool sets one while the kernel build does not. While sh_entsize of sizeof(struct alt_instr) seems intuitive, this small deviation can cause failures with external tooling (kpatch-build). Fix this by creating new .altinstructions sections with sh_entsize of 0 and then later updating sec->sh_size as alternatives are added to the section. An added benefit is avoiding the data descriptor and buffer created by elf_create_section(), but previously unused by elf_add_alternative(). Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/20210822225037.54620-2-joe.lawrence@redhat.com Cc: Andy Lavr <andy.lavr@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org
2021-09-17objtool: Support pv_opsindirect calls for noinstrPeter Zijlstra1-1/+33
Normally objtool will now follow indirect calls; there is no need. However, this becomes a problem with noinstr validation; if there's an indirect call from noinstr code, we very much need to know it is to another noinstr function. Luckily there aren't many indirect calls in entry code with the obvious exception of paravirt. As such, noinstr validation didn't work with paravirt kernels. In order to track pv_ops[] call targets, objtool reads the static pv_ops[] tables as well as direct assignments to the pv_ops[] array, provided the compiler makes them a single instruction like: bf87: 48 c7 05 00 00 00 00 00 00 00 00 movq $0x0,0x0(%rip) bf92 <xen_init_spinlocks+0x5f> bf8a: R_X86_64_PC32 pv_ops+0x268 There are, as of yet, no warnings for when this goes wrong :/ Using the functions found with the above means, all pv_ops[] calls are now subject to noinstr validation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210624095149.118815755@infradead.org
2021-09-15objtool: Handle __sanitize_cov*() tail callsPeter Zijlstra1-0/+20
Turns out the compilers also generate tail calls to __sanitize_cov*(), make sure to also patch those out in noinstr code. Fixes: 0f1441b44e82 ("objtool: Fix noinstr vs KCOV") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Marco Elver <elver@google.com> Link: https://lore.kernel.org/r/20210624095147.818783799@infradead.org
2021-09-15objtool: Introduce CFI hashPeter Zijlstra1-11/+9
Andi reported that objtool on vmlinux.o consumes more memory than his system has, leading to horrific performance. This is in part because we keep a struct instruction for every instruction in the file in-memory. Shrink struct instruction by removing the CFI state (which includes full register state) from it and demand allocating it. Given most instructions don't actually change CFI state, there's lots of repetition there, so add a hash table to find previous CFI instances. Reduces memory consumption (and runtime) for processing an x86_64-allyesconfig: pre: 4:40.84 real, 143.99 user, 44.18 sys, 30624988 mem post: 2:14.61 real, 108.58 user, 25.04 sys, 16396184 mem Suggested-by: Andi Kleen <andi@firstfloor.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210624095147.756759107@infradead.org
2021-06-24objtool: Don't make .altinstructions writableJosh Poimboeuf1-1/+1
When objtool creates the .altinstructions section, it sets the SHF_WRITE flag to make the section writable -- unless the section had already been previously created by the kernel. The mismatch between kernel-created and objtool-created section flags can cause failures with external tooling (kpatch-build). And the section doesn't need to be writable anyway. Make the section flags consistent with the kernel's. Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Reported-by: Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/6c284ae89717889ea136f9f0064d914cd8329d31.1624462939.git.jpoimboe@redhat.com
2021-06-11objtool: Only rewrite unconditional retpoline thunk callsPeter Zijlstra1-0/+4
It turns out that the compilers generate conditional branches to the retpoline thunks like: 5d5: 0f 85 00 00 00 00 jne 5db <cpuidle_reflect+0x22> 5d7: R_X86_64_PLT32 __x86_indirect_thunk_r11-0x4 while the rewrite can only handle JMP/CALL to the thunks. The result is the alternative wrecking the code. Make sure to skip writing the alternatives for conditional branches. Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Reported-by: Lukasz Majczak <lma@semihalf.com> Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Nathan Chancellor <nathan@kernel.org>
2021-05-12objtool/x86: Fix elf_add_alternative() endiannessVasily Gorbik1-1/+2
Currently x86 kernel cross-compiled on big endian system fails at boot with: kernel BUG at arch/x86/kernel/alternative.c:258! Corresponding bug condition look like the following: BUG_ON(feature >= (NCAPINTS + NBUGINTS) * 32); Fix that by converting alternative feature/cpuid to target endianness. Fixes: 9bc0bb50727c ("objtool/x86: Rewrite retpoline thunk calls") Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: https://lore.kernel.org/r/patch-2.thread-6c9df9.git-6c9df9a8098d.your-ad-here.call-01620841104-ext-2554@work.hours
2021-04-28Merge tag 'objtool-core-2021-04-28' of ↵Linus Torvalds1-119/+163
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull objtool updates from Ingo Molnar: - Standardize the crypto asm code so that it looks like compiler- generated code to objtool - so that it can understand it. This enables unwinding from crypto asm code - and also fixes the last known remaining objtool warnings for LTO and more. - x86 decoder fixes: clean up and fix the decoder, and also extend it a bit - Misc fixes and cleanups * tag 'objtool-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) x86/crypto: Enable objtool in crypto code x86/crypto/sha512-ssse3: Standardize stack alignment prologue x86/crypto/sha512-avx2: Standardize stack alignment prologue x86/crypto/sha512-avx: Standardize stack alignment prologue x86/crypto/sha256-avx2: Standardize stack alignment prologue x86/crypto/sha1_avx2: Standardize stack alignment prologue x86/crypto/sha_ni: Standardize stack alignment prologue x86/crypto/crc32c-pcl-intel: Standardize jump table x86/crypto/camellia-aesni-avx2: Unconditionally allocate stack buffer x86/crypto/aesni-intel_avx: Standardize stack alignment prologue x86/crypto/aesni-intel_avx: Fix register usage comments x86/crypto/aesni-intel_avx: Remove unused macros objtool: Support asm jump tables objtool: Parse options from OBJTOOL_ARGS objtool: Collate parse_options() users objtool: Add --backup objtool,x86: More ModRM sugar objtool,x86: Rewrite ADD/SUB/AND objtool,x86: Support %riz encodings objtool,x86: Simplify register decode ...
2021-04-02objtool/x86: Rewrite retpoline thunk callsPeter Zijlstra1-0/+117
When the compiler emits: "CALL __x86_indirect_thunk_\reg" for an indirect call, have objtool rewrite it to: ALTERNATIVE "call __x86_indirect_thunk_\reg", "call *%reg", ALT_NOT(X86_FEATURE_RETPOLINE) Additionally, in order to not emit endless identical .altinst_replacement chunks, use a global symbol for them, see __x86_indirect_alt_*. This also avoids objtool from having to do code generation. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/20210326151300.320177914@infradead.org
2021-04-02objtool: Handle per arch retpoline namingPeter Zijlstra1-0/+5
The __x86_indirect_ naming is obviously not generic. Shorten to allow matching some additional magic names later. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/20210326151259.630296706@infradead.org
2021-04-02Merge branch 'x86/cpu' into WIP.x86/core, to merge the NOP changes & resolve ↵Ingo Molnar1-5/+8
a semantic conflict Conflict-merge this main commit in essence: a89dfde3dc3c: ("x86: Remove dynamic NOP selection") With this upstream commit: b90829704780: ("bpf: Use NOP_ATOMIC5 instead of emit_nops(&prog, 5) for BPF_TRAMP_F_CALL_ORIG") Semantic merge conflict: arch/x86/net/bpf_jit_comp.c - memcpy(prog, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE); + memcpy(prog, x86_nops[5], X86_PATCH_SIZE); Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-03-15objtool/x86: Use asm/nops.hPeter Zijlstra1-5/+8
Since the kernel will rely on a single canonical set of NOPs, make sure objtool uses the exact same ones. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210312115749.136357911@infradead.org
2021-03-15tools/objtool: Convert to insn_decode()Borislav Petkov1-5/+4
Simplify code, no functional changes. Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210304174237.31945-18-bp@alien8.de
2021-03-06objtool,x86: More ModRM sugarPeter Zijlstra1-11/+17
Better helpers to decode ModRM. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/YCZB/ljatFXqQbm8@hirez.programming.kicks-ass.net
2021-03-06objtool,x86: Rewrite ADD/SUB/ANDPeter Zijlstra1-19/+51
Support sign extending and imm8 forms. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20210211173627.588366777@infradead.org
2021-03-06objtool,x86: Support %riz encodingsPeter Zijlstra1-19/+48
When there's a SIB byte, the register otherwise denoted by r/m will then be denoted by SIB.base REX.b will now extend this. SIB.index == SP is magic and notes an index value zero. This means that there's a bunch of alternative (longer) encodings for the same thing. Eg. 'ModRM.mod != 3, ModRM.r/m = AX' can be encoded as 'ModRM.mod != 3, ModRM.r/m = SP, SIB.base = AX, SIB.index = SP' which is actually 4 different encodings because the value of SIB.scale is irrelevant, giving rise to 5 different but equal encodings. Support these encodings and clean up the SIB handling in general. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20210211173627.472967498@infradead.org
2021-03-06objtool,x86: Simplify register decodePeter Zijlstra1-40/+39
Since the CFI_reg number now matches the instruction encoding order do away with the op_to_cfi_reg[] and use direct assignment. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20210211173627.362004522@infradead.org
2021-03-06objtool,x86: Rewrite LEAVEPeter Zijlstra1-3/+11
Since we can now have multiple stack-ops per instruction, we don't need to special case LEAVE and can simply emit the composite operations. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20210211173627.253273977@infradead.org
2021-03-06objtool,x86: Rewrite LEA decodePeter Zijlstra1-58/+28
Current LEA decoding is a bunch of special cases, properly decode the instruction, with exception of full SIB and RIP-relative modes. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20210211173627.143250641@infradead.org
2021-02-10objtool,x86: Additionally decode: mov %rsp, (%reg)Peter Zijlstra1-8/+34
Where we already decode: mov %rsp, %reg, also decode mov %rsp, (%reg). Nothing should match for this new stack-op. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
2021-01-26objtool: Combine UNWIND_HINT_RET_OFFSET and UNWIND_HINT_FUNCJosh Poimboeuf1-2/+2
The ORC metadata generated for UNWIND_HINT_FUNC isn't actually very func-like. With certain usages it can cause stack state mismatches because it doesn't set the return address (CFI_RA). Also, users of UNWIND_HINT_RET_OFFSET no longer need to set a custom return stack offset. Instead they just need to specify a func-like situation, so the current ret_offset code is hacky for no good reason. Solve both problems by simplifying the RET_OFFSET handling and converting it into a more useful UNWIND_HINT_FUNC. If we end up needing the old 'ret_offset' functionality again in the future, we should be able to support it pretty easily with the addition of a custom 'sp_offset' in UNWIND_HINT_FUNC. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lore.kernel.org/r/db9d1f5d79dddfbb3725ef6d8ec3477ad199948d.1611263462.git.jpoimboe@redhat.com
2021-01-14objtool: Rework header include pathsVasily Gorbik1-4/+4
Currently objtool headers are being included either by their base name or included via ../ from a parent directory. In case of a base name usage: #include "warn.h" #include "arch_elf.h" it does not make it apparent from which directory the file comes from. To make it slightly better, and actually to avoid name clashes some arch specific files have "arch_" suffix. And files from an arch folder have to revert to including via ../ e.g: #include "../../elf.h" With additional architectures support and the code base growth there is a need for clearer headers naming scheme for multiple reasons: 1. to make it instantly obvious where these files come from (objtool itself / objtool arch|generic folders / some other external files), 2. to avoid name clashes of objtool arch specific headers, potential obtool arch generic headers and the system header files (there is /usr/include/elf.h already), 3. to avoid ../ includes and improve code readability. 4. to give a warm fuzzy feeling to developers who are mostly kernel developers and are accustomed to linux kernel headers arranging scheme. Doesn't this make it instantly obvious where are these files come from? #include <objtool/warn.h> #include <arch/elf.h> And doesn't it look nicer to avoid ugly ../ includes? Which also guarantees this is elf.h from the objtool and not /usr/include/elf.h. #include <objtool/elf.h> This patch defines and implements new objtool headers arranging scheme. Which is: - all generic headers go to include/objtool (similar to include/linux) - all arch headers go to arch/$(SRCARCH)/include/arch (to get arch prefix). This is similar to linux arch specific "asm/*" headers but we are not abusing "asm" name and calling it what it is. This also helps to prevent name clashes (arch is not used in system headers or kernel exports). To bring objtool to this state the following things are done: 1. current top level tools/objtool/ headers are moved into include/objtool/ subdirectory, 2. arch specific headers, currently only arch/x86/include/ are moved into arch/x86/include/arch/ and were stripped of "arch_" suffix, 3. new -I$(srctree)/tools/objtool/include include path to make includes like <objtool/warn.h> possible, 4. rewriting file includes, 5. make git not to ignore include/objtool/ subdirectory. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-09-10objtool: Decode unwind hint register depending on architectureJulien Thierry1-0/+37
The set of registers that can be included in an unwind hint and their encoding will depend on the architecture. Have arch specific code to decode that register. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-06-18Merge branch 'objtool/urgent' into objtool/corePeter Zijlstra1-0/+18
Conflicts: tools/objtool/elf.c tools/objtool/elf.h tools/objtool/orc_gen.c tools/objtool/check.c Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-06-18objtool: Fix noinstr vs KCOVPeter Zijlstra1-0/+18
Since many compilers cannot disable KCOV with a function attribute, help it to NOP out any __sanitizer_cov_*() calls injected in noinstr code. This turns: 12: e8 00 00 00 00 callq 17 <lockdep_hardirqs_on+0x17> 13: R_X86_64_PLT32 __sanitizer_cov_trace_pc-0x4 into: 12: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 13: R_X86_64_NONE __sanitizer_cov_trace_pc-0x4 Just like recordmcount does. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Dmitry Vyukov <dvyukov@google.com>
2020-06-01objtool: Rename rela to relocMatt Helsley1-1/+1
Before supporting additional relocation types rename the relevant types and functions from "rela" to "reloc". This work be done with the following regex: sed -e 's/struct rela/struct reloc/g' \ -e 's/\([_\*]\)rela\(s\{0,1\}\)/\1reloc\2/g' \ -e 's/tmprela\(s\{0,1\}\)/tmpreloc\1/g' \ -e 's/relasec/relocsec/g' \ -e 's/rela_list/reloc_list/g' \ -e 's/rela_hash/reloc_hash/g' \ -e 's/add_rela/add_reloc/g' \ -e 's/rela->/reloc->/g' \ -e '/rela[,\.]/{ s/\([^\.>]\)rela\([\.,]\)/\1reloc\2/g ; }' \ -e 's/rela =/reloc =/g' \ -e 's/relas =/relocs =/g' \ -e 's/relas\[/relocs[/g' \ -e 's/relaname =/relocname =/g' \ -e 's/= rela\;/= reloc\;/g' \ -e 's/= relas\;/= relocs\;/g' \ -e 's/= relaname\;/= relocname\;/g' \ -e 's/, rela)/, reloc)/g' \ -e 's/\([ @]\)rela\([ "]\)/\1reloc\2/g' \ -e 's/ rela$/ reloc/g' \ -e 's/, relaname/, relocname/g' \ -e 's/sec->rela/sec->reloc/g' \ -e 's/(\(!\{0,1\}\)rela/(\1reloc/g' \ -i \ arch.h \ arch/x86/decode.c \ check.c \ check.h \ elf.c \ elf.h \ orc_gen.c \ special.c Notable exceptions which complicate the regex include gelf_* library calls and standard/expected section names which still use "rela" because they encode the type of relocation expected. Also, keep "rela" in the struct because it encodes a specific type of relocation we currently expect. It will eventually turn into a member of an anonymous union when a susequent patch adds implicit addend, or "rel", relocation support. Signed-off-by: Matt Helsley <mhelsley@vmware.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-04-30objtool: Add support for intra-function callsAlexandre Chartre1-0/+8
Change objtool to support intra-function calls. On x86, an intra-function call is represented in objtool as a push onto the stack (of the return address), and a jump to the destination address. That way the stack information is correctly updated and the call flow is still accurate. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200414103618.12657-4-alexandre.chartre@oracle.com
2020-04-30objtool: Move the IRET hack into the arch decoderMiroslav Benes1-10/+18
Quoting Julien: "And the other suggestion is my other email was that you don't even need to add INSN_EXCEPTION_RETURN. You can keep IRET as INSN_CONTEXT_SWITCH by default and x86 decoder lookups the symbol conaining an iret. If it's a function symbol, it can just set the type to INSN_OTHER so that it caries on to the next instruction after having handled the stack_op." Suggested-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200428191659.913283807@infradead.org
2020-04-30objtool: Remove INSN_STACKPeter Zijlstra1-23/+0
With the unconditional use of handle_insn_ops(), INSN_STACK has lost its purpose. Remove it. Suggested-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200428191659.854203028@infradead.org
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