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* x86/speculation: Fill RSB on vmexit for IBRSJosh Poimboeuf2022-06-273-9/+62
| | | | | | | | | | Prevent RSB underflow/poisoning attacks with RSB. While at it, add a bunch of comments to attempt to document the current state of tribal knowledge about RSB attacks and what exactly is being mitigated. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* KVM: VMX: Fix IBRS handling after vmexitJosh Poimboeuf2022-06-271-1/+6
| | | | | | | | | For legacy IBRS to work, the IBRS bit needs to be always re-written after vmexit, even if it's already on. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* KVM: VMX: Prevent guest RSB poisoning attacks with eIBRSJosh Poimboeuf2022-06-276-31/+73
| | | | | | | | | | | | On eIBRS systems, the returns in the vmexit return path from __vmx_vcpu_run() to vmx_vcpu_run() are exposed to RSB poisoning attacks. Fix that by moving the post-vmexit spec_ctrl handling to immediately after the vmexit. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* KVM: VMX: Convert launched argument to flagsJosh Poimboeuf2022-06-275-9/+31
| | | | | | | | | | | | | | | | | | Convert __vmx_vcpu_run()'s 'launched' argument to 'flags', in preparation for doing SPEC_CTRL handling immediately after vmexit, which will need another flag. This is much easier than adding a fourth argument, because this code supports both 32-bit and 64-bit, and the fourth argument on 32-bit would have to be pushed on the stack. Note that __vmx_vcpu_run_flags() is called outside of the noinstr critical section because it will soon start calling potentially traceable functions. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* KVM: VMX: Flatten __vmx_vcpu_run()Josh Poimboeuf2022-06-271-73/+46
| | | | | | | | | Move the vmx_vm{enter,exit}() functionality into __vmx_vcpu_run(). This will make it easier to do the spec_ctrl handling before the first RET. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* objtool: Re-add UNWIND_HINT_{SAVE_RESTORE}Josh Poimboeuf2022-06-271-2/+10
| | | | | | | | | | | | | Commit c536ed2fffd5 ("objtool: Remove SAVE/RESTORE hints") removed the save/restore unwind hints because they were no longer needed. Now they're going to be needed again so re-add them. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/speculation: Remove x86_spec_ctrl_maskJosh Poimboeuf2022-06-271-30/+1
| | | | | | | | | | | This mask has been made redundant by kvm_spec_ctrl_test_value(). And it doesn't even work when MSR interception is disabled, as the guest can just write to SPEC_CTRL directly. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/speculation: Use cached host SPEC_CTRL value for guest entry/exitJosh Poimboeuf2022-06-271-11/+1
| | | | | | | | | There's no need to recalculate the host value for every entry/exit. Just use the cached value in spec_ctrl_current(). Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/speculation: Fix SPEC_CTRL write on SMT state changeJosh Poimboeuf2022-06-271-1/+2
| | | | | | | | | If the SMT state changes, SSBD might get accidentally disabled. Fix that. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/speculation: Fix firmware entry SPEC_CTRL handlingJosh Poimboeuf2022-06-271-6/+4
| | | | | | | | The firmware entry code may accidentally clear STIBP or SSBD. Fix that. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/speculation: Fix RSB filling with CONFIG_RETPOLINE=nJosh Poimboeuf2022-06-273-6/+0
| | | | | | | | | | | | | If a kernel is built with CONFIG_RETPOLINE=n, but the user still wants to mitigate Spectre v2 using IBRS or eIBRS, the RSB filling will be silently disabled. There's nothing retpoline-specific about RSB buffer filling. Remove the CONFIG_RETPOLINE guards around it. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/cpu/amd: Add Spectral ChickenPeter Zijlstra2022-06-274-1/+33
| | | | | | | | | | | | | | | Zen2 uarchs have an undocumented, unnamed, MSR that contains a chicken bit for some speculation behaviour. It needs setting. Note: very belatedly AMD released naming; it's now officially called MSR_AMD64_DE_CFG2 and MSR_AMD64_DE_CFG2_SUPPRESS_NOBR_PRED_BIT but shall remain the SPECTRAL CHICKEN. Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com> 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>
* objtool: Add entry UNRET validationPeter Zijlstra2022-06-276-9/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Since entry asm is tricky, add a validation pass that ensures the retbleed mitigation has been done before the first actual RET instruction. Entry points are those that either have UNWIND_HINT_ENTRY, which acts as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or those that have UWIND_HINT_IRET_REGS at +0. This is basically a variant of validate_branch() that is intra-function and it will simply follow all branches from marked entry points and ensures that all paths lead to ANNOTATE_UNRET_END. If a path hits RET or an indirection the path is a fail and will be reported. There are 3 ANNOTATE_UNRET_END instances: - UNTRAIN_RET itself - exception from-kernel; this path doesn't need UNTRAIN_RET - all early exceptions; these also don't need UNTRAIN_RET 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>
* x86/bugs: Do IBPB fallback check only onceJosh Poimboeuf2022-06-271-10/+5
| | | | | | | | | | When booting with retbleed=auto, if the kernel wasn't built with CONFIG_CC_HAS_RETURN_THUNK, the mitigation falls back to IBPB. Make sure a warning is printed in that case. The IBPB fallback check is done twice, but it really only needs to be done once. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/bugs: Add retbleed=ibpbPeter Zijlstra2022-06-275-13/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | jmp2ret mitigates the easy-to-attack case at relatively low overhead. It mitigates the long speculation windows after a mispredicted RET, but it does not mitigate the short speculation window from arbitrary instruction boundaries. On Zen2, there is a chicken bit which needs setting, which mitigates "arbitrary instruction boundaries" down to just "basic block boundaries". But there is no fix for the short speculation window on basic block boundaries, other than to flush the entire BTB to evict all attacker predictions. On the spectrum of "fast & blurry" -> "safe", there is (on top of STIBP or no-SMT): 1) Nothing System wide open 2) jmp2ret May stop a script kiddy 3) jmp2ret+chickenbit Raises the bar rather further 4) IBPB Only thing which can count as "safe". Tentative numbers put IBPB-on-entry at a 2.5x hit on Zen2, and a 10x hit on Zen1 according to lmbench. [ bp: Fixup feature bit comments, document option, 32-bit build fix. ] Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com> 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>
* x86/xen: Add UNTRAIN_RETPeter Zijlstra2022-06-271-1/+7
| | | | | | | | | Ensure the Xen entry also passes through UNTRAIN_RET. 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>
* x86/xen: Rename SYS* entry pointsPeter Zijlstra2022-06-273-16/+16
| | | | | | | | | | | Native SYS{CALL,ENTER} entry points are called entry_SYS{CALL,ENTER}_{64,compat}, make sure the Xen versions are named consistently. 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>
* objtool: Update Retpoline validationPeter Zijlstra2022-06-273-0/+9
| | | | | | | | | | Update retpoline validation with the new CONFIG_RETPOLINE requirement of not having bare naked RET instructions. 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>
* intel_idle: Disable IBRS during long idlePeter Zijlstra2022-06-272-0/+7
| | | | | | | | | | | | | | | | | | | | | | Having IBRS enabled while the SMT sibling is idle unnecessarily slows down the running sibling. OTOH, disabling IBRS around idle takes two MSR writes, which will increase the idle latency. Therefore, only disable IBRS around deeper idle states. Shallow idle states are bounded by the tick in duration, since NOHZ is not allowed for them by virtue of their short target residency. Only do this for mwait-driven idle, since that keeps interrupts disabled across idle, which makes disabling IBRS vs IRQ-entry a non-issue. Note: C6 is a random threshold, most importantly C1 probably shouldn't disable IBRS, benchmarking needed. Suggested-by: Tim Chen <tim.c.chen@linux.intel.com> 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>
* x86/bugs: Report Intel retbleed vulnerabilityPeter Zijlstra2022-06-273-18/+46
| | | | | | | | | | | | Skylake suffers from RSB underflow speculation issues; report this vulnerability and it's mitigation (spectre_v2=ibrs). [jpoimboe: cleanups, eibrs] 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>
* x86/bugs: Split spectre_v2_select_mitigation() and ↵Peter Zijlstra2022-06-271-8/+17
| | | | | | | | | | | | spectre_v2_user_select_mitigation() retbleed will depend on spectre_v2, while spectre_v2_user depends on retbleed. Break this cycle. 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>
* x86/speculation: Add spectre_v2=ibrs option to support Kernel IBRSPawan Gupta2022-06-272-14/+53
| | | | | | | | | | | | Extend spectre_v2= boot option with Kernel IBRS. [jpoimboe: no STIBP with IBRS] Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> 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>
* x86/bugs: Optimize SPEC_CTRL MSR writesPeter Zijlstra2022-06-273-8/+14
| | | | | | | | | | | | When changing SPEC_CTRL for user control, the WRMSR can be delayed until return-to-user when KERNEL_IBRS has been enabled. This avoids an MSR write during context switch. 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>
* x86/entry: Add kernel IBRS implementationPeter Zijlstra2022-06-274-10/+111
| | | | | | | | | | | | | | | | | Implement Kernel IBRS - currently the only known option to mitigate RSB underflow speculation issues on Skylake hardware. Note: since IBRS_ENTER requires fuller context established than UNTRAIN_RET, it must be placed after it. However, since UNTRAIN_RET itself implies a RET, it must come after IBRS_ENTER. This means IBRS_ENTER needs to also move UNTRAIN_RET. Note 2: KERNEL_IBRS is sub-optimal for XenPV. 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>
* x86/bugs: Keep a per-CPU IA32_SPEC_CTRL valuePeter Zijlstra2022-06-273-6/+25
| | | | | | | | | | | | | Due to TIF_SSBD and TIF_SPEC_IB the actual IA32_SPEC_CTRL value can differ from x86_spec_ctrl_base. As such, keep a per-CPU value reflecting the current task's MSR content. [jpoimboe: rename] 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>
* x86/bugs: Enable STIBP for JMP2RETKim Phillips2022-06-271-12/+46
| | | | | | | | | | | For untrained return thunks to be fully effective, STIBP must be enabled or SMT disabled. Co-developed-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/bugs: Add AMD retbleed= boot parameterAlexandre Chartre2022-06-272-1/+110
| | | | | | | | | | | | | | | | | | | Add the "retbleed=<value>" boot parameter to select a mitigation for RETBleed. Possible values are "off", "auto" and "unret" (JMP2RET mitigation). The default value is "auto". Currently, "retbleed=auto" will select the unret mitigation on AMD and Hygon and no mitigation on Intel (JMP2RET is not effective on Intel). [peterz: rebase; add hygon] [jpoimboe: cleanups] Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> 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>
* x86/bugs: Report AMD retbleed vulnerabilityAlexandre Chartre2022-06-273-0/+33
| | | | | | | | | | | | | | | | Report that AMD x86 CPUs are vulnerable to the RETBleed (Arbitrary Speculative Code Execution with Return Instructions) attack. [peterz: add hygon] [kim: invert parity; fam15h] Co-developed-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Kim Phillips <kim.phillips@amd.com> Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> 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>
* x86: Add magic AMD return-thunkPeter Zijlstra2022-06-278-6/+109
| | | | | | | | | | | | | | | | | | | | | | | Note: needs to be in a section distinct from Retpolines such that the Retpoline RET substitution cannot possibly use immediate jumps. ORC unwinding for zen_untrain_ret() and __x86_return_thunk() is a little tricky but works due to the fact that zen_untrain_ret() doesn't have any stack ops and as such will emit a single ORC entry at the start (+0x3f). Meanwhile, unwinding an IP, including the __x86_return_thunk() one (+0x40) will search for the largest ORC entry smaller or equal to the IP, these will find the one ORC entry (+0x3f) and all works. [ Alexandre: SVM part. ] [ bp: Build fix, massages. ] Suggested-by: Andrew Cooper <Andrew.Cooper3@citrix.com> 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>
* x86/entry: Avoid very early RETPeter Zijlstra2022-06-271-10/+2
| | | | | | | | | | | | | | | | | | | | | | | Commit ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()") manages to introduce a CALL/RET pair that is before SWITCH_TO_KERNEL_CR3, which means it is before RETBleed can be mitigated. Revert to an earlier version of the commit in Fixes. Down side is that this will bloat .text size somewhat. The alternative is fully reverting it. The purpose of this patch was to allow migrating error_entry() to C, including the whole of kPTI. Much care needs to be taken moving that forward to not re-introduce this problem of early RETs. Fixes: ee774dac0da1 ("x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry()") 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>
* x86: Use return-thunk in asm codePeter Zijlstra2022-06-273-1/+15
| | | | | | | | | | | | | | | Use the return thunk in asm code. If the thunk isn't needed, it will get patched into a RET instruction during boot by apply_returns(). Since alternatives can't handle relocations outside of the first instruction, putting a 'jmp __x86_return_thunk' in one is not valid, therefore carve out the memmove ERMS path into a separate label and jump to it. 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>
* x86/sev: Avoid using __x86_return_thunkKim Phillips2022-06-271-2/+6
| | | | | | | | | | | | Specifically, it's because __enc_copy() encrypts the kernel after being relocated outside the kernel in sme_encrypt_execute(), and the RET macro's jmp offset isn't amended prior to execution. Signed-off-by: Kim Phillips <kim.phillips@amd.com> 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>
* x86/vsyscall_emu/64: Don't use RET in vsyscall emulationPeter Zijlstra2022-06-271-3/+6
| | | | | | | | | This is userspace code and doesn't play by the normal kernel rules. 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>
* x86/kvm: Fix SETcc emulation for return thunksPeter Zijlstra2022-06-271-13/+15
| | | | | | | | | | | | | | | | | | | | | | | Prepare the SETcc fastop stuff for when RET can be larger still. The tricky bit here is that the expressions should not only be constant C expressions, but also absolute GAS expressions. This means no ?: and 'true' is ~0. Also ensure em_setcc() has the same alignment as the actual FOP_SETCC() ops, this ensures there cannot be an alignment hole between em_setcc() and the first op. Additionally, add a .skip directive to the FOP_SETCC() macro to fill any remaining space with INT3 traps; however the primary purpose of this directive is to generate AS warnings when the remaining space goes negative. Which is a very good indication the alignment magic went side-ways. 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>
* x86/bpf: Use alternative RET encodingPeter Zijlstra2022-06-271-2/+17
| | | | | | | | | Use the return thunk in eBPF generated code, if needed. 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>
* x86/ftrace: Use alternative RET encodingPeter Zijlstra2022-06-271-2/+5
| | | | | | | | | Use the return thunk in ftrace trampolines, if needed. 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>
* x86,static_call: Use alternative RET encodingPeter Zijlstra2022-06-273-7/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In addition to teaching static_call about the new way to spell 'RET', there is an added complication in that static_call() is allowed to rewrite text before it is known which particular spelling is required. In order to deal with this; have a static_call specific fixup in the apply_return() 'alternative' patching routine that will rewrite the static_call trampoline to match the definite sequence. This in turn creates the problem of uniquely identifying static call trampolines. Currently trampolines are 8 bytes, the first 5 being the jmp.d32/ret sequence and the final 3 a byte sequence that spells out 'SCT'. This sequence is used in __static_call_validate() to ensure it is patching a trampoline and not a random other jmp.d32. That is, false-positives shouldn't be plenty, but aren't a big concern. OTOH the new __static_call_fixup() must not have false-positives, and 'SCT' decodes to the somewhat weird but semi plausible sequence: push %rbx rex.XB push %r12 Additionally, there are SLS concerns with immediate jumps. Combined it seems like a good moment to change the signature to a single 3 byte trap instruction that is unique to this usage and will not ever get generated by accident. As such, change the signature to: '0x0f, 0xb9, 0xcc', which decodes to: ud1 %esp, %ecx 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>
* x86: Undo return-thunk damagePeter Zijlstra2022-06-276-2/+78
| | | | | | | | | | | Introduce X86_FEATURE_RETHUNK for those afflicted with needing this. [ bp: Do only INT3 padding - simpler. ] 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>
* x86/retpoline: Use -mfunction-returnPeter Zijlstra2022-06-273-0/+17
| | | | | | | | | | | | | | | | | Utilize -mfunction-return=thunk-extern when available to have the compiler replace RET instructions with direct JMPs to the symbol __x86_return_thunk. This does not affect assembler (.S) sources, only C sources. -mfunction-return=thunk-extern has been available since gcc 7.3 and clang 15. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/retpoline: Swizzle retpoline thunkPeter Zijlstra2022-06-271-3/+3
| | | | | | | | | | | | | Put the actual retpoline thunk as the original code so that it can become more complicated. Specifically, it allows RET to be a JMP, which can't be .altinstr_replacement since that doesn't do relocations (except for the very first instruction). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/retpoline: Cleanup some #ifdeferyPeter Zijlstra2022-06-273-9/+14
| | | | | | | | | | | On it's own not much of a cleanup but it prepares for more/similar code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* x86/cpufeatures: Move RETPOLINE flags to word 11Peter Zijlstra2022-06-271-2/+6
| | | | | | | | | | | In order to extend the RETPOLINE features to 4, move them to word 11 where there is still room. This mostly keeps DISABLE_RETPOLINE simple. 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>
* x86/kvm/vmx: Make noinstr cleanPeter Zijlstra2022-06-272-5/+5
| | | | | | | | | | | | The recent mmio_stale_data fixes broke the noinstr constraints: vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x15b: call to wrmsrl.constprop.0() leaves .noinstr.text section vmlinux.o: warning: objtool: vmx_vcpu_enter_exit+0x1bf: call to kvm_arch_has_assigned_device() leaves .noinstr.text section make it all happy again. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de>
* Merge tag 'soc-fixes-5.19' of ↵Linus Torvalds2022-06-2620-110/+78
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc Pull ARM SoC fixes from Arnd Bergmann: "A number of fixes have accumulated, but they are largely for harmless issues: - Several OF node leak fixes - A fix to the Exynos7885 UART clock description - DTS fixes to prevent boot failures on TI AM64 and J721s2 - Bus probe error handling fixes for Baikal-T1 - A fixup to the way STM32 SoCs use separate dts files for different firmware stacks - Multiple code fixes for Arm SCMI firmware, all dealing with robustness of the implementation - Multiple NXP i.MX devicetree fixes, addressing incorrect data in DT nodes - Three updates to the MAINTAINERS file, including Florian Fainelli taking over BCM283x/BCM2711 (Raspberry Pi) from Nicolas Saenz Julienne" * tag 'soc-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (29 commits) ARM: dts: aspeed: nuvia: rename vendor nuvia to qcom arm: mach-spear: Add missing of_node_put() in time.c ARM: cns3xxx: Fix refcount leak in cns3xxx_init MAINTAINERS: Update email address arm64: dts: ti: k3-am64-main: Remove support for HS400 speed mode arm64: dts: ti: k3-j721s2: Fix overlapping GICD memory region ARM: dts: bcm2711-rpi-400: Fix GPIO line names bus: bt1-axi: Don't print error on -EPROBE_DEFER bus: bt1-apb: Don't print error on -EPROBE_DEFER ARM: Fix refcount leak in axxia_boot_secondary ARM: dts: stm32: move SCMI related nodes in a dedicated file for stm32mp15 soc: imx: imx8m-blk-ctrl: fix display clock for LCDIF2 power domain ARM: dts: imx6qdl-colibri: Fix capacitive touch reset polarity ARM: dts: imx6qdl: correct PU regulator ramp delay firmware: arm_scmi: Fix incorrect error propagation in scmi_voltage_descriptors_get firmware: arm_scmi: Avoid using extended string-buffers sizes if not necessary firmware: arm_scmi: Fix SENSOR_AXIS_NAME_GET behaviour when unsupported ARM: dts: imx7: Move hsic_phy power domain to HSIC PHY node soc: bcm: brcmstb: pm: pm-arm: Fix refcount leak in brcmstb_pm_probe MAINTAINERS: Update BCM2711/BCM2835 maintainer ...
| * ARM: dts: aspeed: nuvia: rename vendor nuvia to qcomJae Hyun Yoo2022-06-242-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Nuvia has been acquired by Qualcomm and the vendor name 'nuvia' will not be used anymore so rename aspeed-bmc-nuvia-dc-scm.dts to aspeed-bmc-qcom-dc-scm-v1.dts and change 'nuvia' to 'qcom' as its vendor name in the file. Fixes: 7b46aa7c008d ("ARM: dts: aspeed: Add Nuvia DC-SCM BMC") Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com> Signed-off-by: Joel Stanley <joel@jms.id.au> Link: https://lore.kernel.org/r/20220523175640.60155-1-quic_jaehyoo@quicinc.com Link: https://lore.kernel.org/r/20220624070511.4070659-1-joel@jms.id.au' Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| * Merge tag 'samsung-fixes-5.19' of ↵Arnd Bergmann2022-06-242-6/+7
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux into arm/fixes Samsung fixes for v5.19 Both fixes are for issues present before v5.19 merge window: 1. Correct UART clocks on Exynos7885. Although the initial, fixed DTS commit is from v5.18, the issue will be exposed with a upcoming fix to Exynos7885 clock driver, so we need to correct the DTS earlier. 2. Fix theoretical OF node leak in Exynos machine code. * tag 'samsung-fixes-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux: ARM: exynos: Fix refcount leak in exynos_map_pmu arm64: dts: exynos: Correct UART clocks on Exynos7885 Link: https://lore.kernel.org/r/20220624080423.31427-1-krzysztof.kozlowski@linaro.org Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| | * ARM: exynos: Fix refcount leak in exynos_map_pmuMiaoqian Lin2022-06-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | of_find_matching_node() returns a node pointer with refcount incremented, we should use of_node_put() on it when not need anymore. Add missing of_node_put() to avoid refcount leak. of_node_put() checks null pointer. Fixes: fce9e5bb2526 ("ARM: EXYNOS: Add support for mapping PMU base address via DT") Signed-off-by: Miaoqian Lin <linmq006@gmail.com> Link: https://lore.kernel.org/r/20220523145513.12341-1-linmq006@gmail.com Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
| | * arm64: dts: exynos: Correct UART clocks on Exynos7885David Virag2022-06-061-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The clocks in the serial UART nodes were swapped by mistake on Exynos7885. This only worked correctly because of a mistake in the clock driver which has been fixed. With the fixed clock driver in place, the baudrate of the UARTs get miscalculated. Fix this by correcting the clocks in the dtsi. Fixes: 06874015327b ("arm64: dts: exynos: Add initial device tree support for Exynos7885 SoC") Signed-off-by: David Virag <virag.david003@gmail.com> Link: https://lore.kernel.org/r/20220526055840.45209-3-virag.david003@gmail.com Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
| * | Merge tag 'arm-soc/for-5.19/devicetree-fixes' of ↵Arnd Bergmann2022-06-241-3/+3
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://github.com/Broadcom/stblinux into arm/fixes This pull request contains Broadcom ARM-SoC Device Tree fixes for 5.19, please pull the following: - Stefan fixes the Raspberry Pi 400 GPIO expander line names to match that of the downstream Raspberry Pi Linux tree * tag 'arm-soc/for-5.19/devicetree-fixes' of https://github.com/Broadcom/stblinux: ARM: dts: bcm2711-rpi-400: Fix GPIO line names Link: https://lore.kernel.org/r/20220620170745.2485199-1-f.fainelli@gmail.com Signed-off-by: Arnd Bergmann <arnd@arndb.de>
| | * | ARM: dts: bcm2711-rpi-400: Fix GPIO line namesStefan Wahren2022-06-171-3/+3
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | The GPIO expander line names has been fixed in the vendor tree last year, so upstream these changes. Fixes: 1c701accecf2 ("ARM: dts: Add Raspberry Pi 400 support") Reported-by: Ivan T. Ivanov <iivanov@suse.de> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
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