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authorLinus Torvalds <torvalds@linux-foundation.org>2018-02-26 09:34:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-26 09:34:21 -0800
commit85a2d939c05965ab9e849735436a3c8d3538dc75 (patch)
treeba5436dc3c687dc84b22536824b68ab413fc7c4a /arch/x86/lib
parentd4858aaf6bd8a90e2dacc0dfec2077e334dcedbf (diff)
parent946fbbc13dce68902f64515b610eeb2a6c3d7a64 (diff)
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Thomas Gleixner: "Yet another pile of melted spectrum related changes: - sanitize the array_index_nospec protection mechanism: Remove the overengineered array_index_nospec_mask_check() magic and allow const-qualified types as index to avoid temporary storage in a non-const local variable. - make the microcode loader more robust by properly propagating error codes. Provide information about new feature bits after micro code was updated so administrators can act upon. - optimizations of the entry ASM code which reduce code footprint and make the code simpler and faster. - fix the {pmd,pud}_{set,clear}_flags() implementations to work properly on paravirt kernels by removing the address translation operations. - revert the harmful vmexit_fill_RSB() optimization - use IBRS around firmware calls - teach objtool about retpolines and add annotations for indirect jumps and calls. - explicitly disable jumplabel patching in __init code and handle patching failures properly instead of silently ignoring them. - remove indirect paravirt calls for writing the speculation control MSR as these calls are obviously proving the same attack vector which is tried to be mitigated. - a few small fixes which address build issues with recent compiler and assembler versions" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) KVM/VMX: Optimize vmx_vcpu_run() and svm_vcpu_run() by marking the RDMSR path as unlikely() KVM/x86: Remove indirect MSR op calls from SPEC_CTRL objtool, retpolines: Integrate objtool with retpoline support more closely x86/entry/64: Simplify ENCODE_FRAME_POINTER extable: Make init_kernel_text() global jump_label: Warn on failed jump_label patching attempt jump_label: Explicitly disable jump labels in __init code x86/entry/64: Open-code switch_to_thread_stack() x86/entry/64: Move ASM_CLAC to interrupt_entry() x86/entry/64: Remove 'interrupt' macro x86/entry/64: Move the switch_to_thread_stack() call to interrupt_entry() x86/entry/64: Move ENTER_IRQ_STACK from interrupt macro to interrupt_entry x86/entry/64: Move PUSH_AND_CLEAR_REGS from interrupt macro to helper function x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP objtool: Add module specific retpoline rules objtool: Add retpoline validation objtool: Use existing global variables for options x86/mm/sme, objtool: Annotate indirect call in sme_encrypt_execute() x86/boot, objtool: Annotate indirect jump in secondary_startup_64() x86/paravirt, objtool: Annotate indirect calls ...
Diffstat (limited to 'arch/x86/lib')
-rw-r--r--arch/x86/lib/Makefile1
-rw-r--r--arch/x86/lib/retpoline.S56
2 files changed, 0 insertions, 57 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 91e9700cc6dc..25a972c61b0a 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -28,7 +28,6 @@ lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o insn-eval.o
lib-$(CONFIG_RANDOMIZE_BASE) += kaslr.o
lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
lib-$(CONFIG_RETPOLINE) += retpoline.o
-OBJECT_FILES_NON_STANDARD_retpoline.o :=y
obj-y += msr.o msr-reg.o msr-reg-export.o hweight.o
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 480edc3a5e03..c909961e678a 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -7,7 +7,6 @@
#include <asm/alternative-asm.h>
#include <asm/export.h>
#include <asm/nospec-branch.h>
-#include <asm/bitsperlong.h>
.macro THUNK reg
.section .text.__x86.indirect_thunk
@@ -47,58 +46,3 @@ GENERATE_THUNK(r13)
GENERATE_THUNK(r14)
GENERATE_THUNK(r15)
#endif
-
-/*
- * Fill the CPU return stack buffer.
- *
- * Each entry in the RSB, if used for a speculative 'ret', contains an
- * infinite 'pause; lfence; jmp' loop to capture speculative execution.
- *
- * This is required in various cases for retpoline and IBRS-based
- * mitigations for the Spectre variant 2 vulnerability. Sometimes to
- * eliminate potentially bogus entries from the RSB, and sometimes
- * purely to ensure that it doesn't get empty, which on some CPUs would
- * allow predictions from other (unwanted!) sources to be used.
- *
- * Google experimented with loop-unrolling and this turned out to be
- * the optimal version - two calls, each with their own speculation
- * trap should their return address end up getting used, in a loop.
- */
-.macro STUFF_RSB nr:req sp:req
- mov $(\nr / 2), %_ASM_BX
- .align 16
-771:
- call 772f
-773: /* speculation trap */
- pause
- lfence
- jmp 773b
- .align 16
-772:
- call 774f
-775: /* speculation trap */
- pause
- lfence
- jmp 775b
- .align 16
-774:
- dec %_ASM_BX
- jnz 771b
- add $((BITS_PER_LONG/8) * \nr), \sp
-.endm
-
-#define RSB_FILL_LOOPS 16 /* To avoid underflow */
-
-ENTRY(__fill_rsb)
- STUFF_RSB RSB_FILL_LOOPS, %_ASM_SP
- ret
-END(__fill_rsb)
-EXPORT_SYMBOL_GPL(__fill_rsb)
-
-#define RSB_CLEAR_LOOPS 32 /* To forcibly overwrite all entries */
-
-ENTRY(__clear_rsb)
- STUFF_RSB RSB_CLEAR_LOOPS, %_ASM_SP
- ret
-END(__clear_rsb)
-EXPORT_SYMBOL_GPL(__clear_rsb)