[PATCH 00/35] jump_label, objtool, IBRS and IBPB

From: Peter Zijlstra <peterz@infradead.org>
From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <ak@linux.intel.com>,
	Arjan Van De Ven <arjan.van.de.ven@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Jason Baron <jbaron@akamai.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 00/35] jump_label, objtool, IBRS and IBPB
Date: Thu, 18 Jan 2018 14:48:00 +0100	[thread overview]
Message-ID: <20180118134800.711245485@infradead.org> (raw)

Lots of patches..

They include:

 - objtool validation of jump_label/static_cpu_has

   Allows asserting that the code block following a jump_label/static_cpu_has
   is indeed unconditional. Ensures GCC doesn't generate particularly stupid
   code which would re-insert a dynamic test.

 - objtool validation of retpoline

   Looks for indirect JMP/CALL sites when build with a retpoline enabled
   compiler. Has already spotted a bunch of sites that need fixing, see
   below.

 - makes x86 hard rely on asm-goto to ensure we can indeed use static_cpu_has
   to avoid dynamic branches (and thus speculation).

 - The IBRS/IBPB patches from Thomas that use static_cpu_has()

   These hard rely on the above; we must not speculate across the IBRS/IBPB
   MSR writes otherwise that would totally defeat the point. Prior patches had
   LFENCE crud in the else-clause, which then makes the primitives
   unconditionally expensive.

 - Rebased the IBRS/IBPB-KVM patches from Ashok on top

 - Random odd fixes for various things encountered while doing the above.

Please have a look and sorry for this many patches.

---

Output of a x86_64-allmodconfig -KCOV -KASAN build:

arch/x86/entry/.tmp_entry_64.o: warning: objtool: .entry.text+0x1cb2: indirect call found in RETPOLINE build
arch/x86/entry/.tmp_entry_64.o: warning: objtool: .entry.text+0x1cc7: indirect call found in RETPOLINE build
arch/x86/hyperv/.tmp_mmu.o: warning: objtool: hyperv_flush_tlb_others()+0x30c: indirect call found in RETPOLINE build
arch/x86/hyperv/.tmp_mmu.o: warning: objtool: hyperv_flush_tlb_others()+0x3b0: indirect call found in RETPOLINE build
arch/x86/hyperv/.tmp_mmu.o: warning: objtool: hyperv_flush_tlb_others_ex()+0x3a1: indirect call found in RETPOLINE build
arch/x86/hyperv/.tmp_mmu.o: warning: objtool: hyperv_flush_tlb_others_ex()+0x45c: indirect call found in RETPOLINE build
arch/x86/xen/.tmp_multicalls.o: warning: objtool: xen_mc_flush()+0x1da: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_emulate.o: warning: objtool: fastop()+0x54: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_emulate.o: warning: objtool: em_loop()+0xcc: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_emulate.o: warning: objtool: x86_emulate_insn()+0xbd6: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_emulate.o: warning: objtool: x86_emulate_insn()+0xc1a: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_emulate.o: warning: objtool: x86_emulate_insn()+0xc66: indirect call found in RETPOLINE build
arch/x86/kvm/.tmp_vmx.o: warning: objtool: vmx_handle_external_intr()+0x50: indirect call found in RETPOLINE build
arch/x86/mm/.tmp_mem_encrypt_boot.o: warning: objtool: sme_encrypt_execute()+0x48: indirect call found in RETPOLINE build
drivers/hv/.tmp_hv.o: warning: objtool: hv_post_message()+0x72: indirect call found in RETPOLINE build
drivers/hv/.tmp_connection.o: warning: objtool: vmbus_set_event()+0x33: indirect call found in RETPOLINE build
drivers/pci/host/.tmp_pci-hyperv.o: warning: objtool: hv_irq_unmask()+0x22b: indirect call found in RETPOLINE build
drivers/xen/.tmp_privcmd.o: warning: objtool: privcmd_ioctl()+0xcf: indirect call found in RETPOLINE build
drivers/watchdog/.tmp_hpwdt.o: warning: objtool: .text+0x24: indirect call found in RETPOLINE build