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Differential D112355

[X86] Don't add implicit REP prefix to VIA PadLock xstore
ClosedPublic

Authored by jrtc27 on Oct 22 2021, 5:22 PM.

Details

Reviewers
craig.topper
Commits
rG2d8c18fbbdd1: [X86] Don't add implicit REP prefix to VIA PadLock xstore
Summary

Commit 8fa3e8fa1492 added an implicit REP prefix to all VIA PadLock
instructions, but GNU as doesn't add one to xstore, only all the others.
This resulted in a kernel panic regression in FreeBSD upon updating to
LLVM 11 (https://bugs.freebsd.org/259218) which includes the commit in
question. This partially reverts that commit.

Diff Detail

Event Timeline

jrtc27 created this revision.Oct 22 2021, 5:22 PM
Herald added subscribers: pengfei, hiraditya, krytarowski and 2 others. · View Herald TranscriptOct 22 2021, 5:22 PM
jrtc27 requested review of this revision.Oct 22 2021, 5:22 PM
Herald added a project: Restricted Project. · View Herald TranscriptOct 22 2021, 5:22 PM
Herald added a subscriber: llvm-commits. · View Herald Transcript
Harbormaster completed remote builds in B130231: Diff 381686.Oct 22 2021, 5:23 PM
jrtc27 added a parent revision: D112354: [NFC][X86] Add MC tests for all untested VIA PadLock instructions.Oct 22 2021, 5:24 PM
craig.topper accepted this revision.Oct 22 2021, 5:32 PM

LGTM

This revision is now accepted and ready to land.Oct 22 2021, 5:32 PM
This revision was landed with ongoing or failed builds.Oct 22 2021, 5:58 PM
Closed by commit rG2d8c18fbbdd1: [X86] Don't add implicit REP prefix to VIA PadLock xstore (authored by jrtc27). · Explain Why
This revision was automatically updated to reflect the committed changes.
jrtc27 added a commit: rG2d8c18fbbdd1: [X86] Don't add implicit REP prefix to VIA PadLock xstore.

Revision Contents

PathSize
llvm/
lib/
Target/
X86/
2 lines
test/
MC/
X86/
5 lines

Diff 381686

llvm/lib/Target/X86/X86InstrSystem.td

Show First 20 Lines • Show All 578 Lines • ▼ Show 20 Linesdef XRSTORS64 : RI<0xC7, MRM3m, (outs), (ins opaquemem:$dst),
"xrstors64\t$dst", "xrstors64\t$dst",
[(int_x86_xrstors64 addr:$dst, EDX, EAX)]>, PS, Requires<[HasXSAVES, In64BitMode]>; [(int_x86_xrstors64 addr:$dst, EDX, EAX)]>, PS, Requires<[HasXSAVES, In64BitMode]>;
} // Uses } // Uses
} // SchedRW } // SchedRW
//===----------------------------------------------------------------------===// //===----------------------------------------------------------------------===//
// VIA PadLock crypto instructions // VIA PadLock crypto instructions
let Defs = [RAX, RDI], Uses = [RDX, RDI], SchedRW = [WriteSystem] in let Defs = [RAX, RDI], Uses = [RDX, RDI], SchedRW = [WriteSystem] in
def XSTORE : I<0xa7, MRM_C0, (outs), (ins), "xstore", []>, TB, REP; def XSTORE : I<0xa7, MRM_C0, (outs), (ins), "xstore", []>, TB;
def : InstAlias<"xstorerng", (XSTORE)>; def : InstAlias<"xstorerng", (XSTORE)>;
let SchedRW = [WriteSystem] in { let SchedRW = [WriteSystem] in {
let Defs = [RSI, RDI], Uses = [RBX, RDX, RSI, RDI] in { let Defs = [RSI, RDI], Uses = [RBX, RDX, RSI, RDI] in {
def XCRYPTECB : I<0xa7, MRM_C8, (outs), (ins), "xcryptecb", []>, TB, REP; def XCRYPTECB : I<0xa7, MRM_C8, (outs), (ins), "xcryptecb", []>, TB, REP;
def XCRYPTCBC : I<0xa7, MRM_D0, (outs), (ins), "xcryptcbc", []>, TB, REP; def XCRYPTCBC : I<0xa7, MRM_D0, (outs), (ins), "xcryptcbc", []>, TB, REP;
def XCRYPTCTR : I<0xa7, MRM_D8, (outs), (ins), "xcryptctr", []>, TB, REP; def XCRYPTCTR : I<0xa7, MRM_D8, (outs), (ins), "xcryptctr", []>, TB, REP;
▲ Show 20 Lines • Show All 159 Lines • Show Last 20 Lines

llvm/test/MC/X86/padlock.s

// RUN: llvm-mc -triple i386-unknown-unknown --show-encoding %s | FileCheck %s // RUN: llvm-mc -triple i386-unknown-unknown --show-encoding %s | FileCheck %s
/// Check xstore does not get an implicit REP prefix but all other PadLock
/// instructions do.
xstore xstore
// CHECK: xstore // CHECK: xstore
// CHECK: encoding: [0xf3,0x0f,0xa7,0xc0] // CHECK: encoding: [0x0f,0xa7,0xc0]
xcryptecb xcryptecb
// CHECK: xcryptecb // CHECK: xcryptecb
// CHECK: encoding: [0xf3,0x0f,0xa7,0xc8] // CHECK: encoding: [0xf3,0x0f,0xa7,0xc8]
xcryptcbc xcryptcbc
// CHECK: xcryptcbc // CHECK: xcryptcbc
// CHECK: encoding: [0xf3,0x0f,0xa7,0xd0] // CHECK: encoding: [0xf3,0x0f,0xa7,0xd0]
xcryptctr xcryptctr
// CHECK: xcryptctr // CHECK: xcryptctr
Show All 16 Lines