[LLD][ELF][RISCV][Zicfilp] Handle .note.gnu.property sections for Zicfilp/Zicfiss features

lld/ELF/Config.h

@@ -235,6 +235,9 @@ struct Config {
   ReportPolicy zGcsReport = ReportPolicy::None;
   ReportPolicy zGcsReportDynamic = ReportPolicy::None;
   ReportPolicy zExecuteOnlyReport = ReportPolicy::None;
+  ReportPolicy zZicfilpUnlabeledReport = ReportPolicy::None;
+  ReportPolicy zZicfilpFuncSigReport = ReportPolicy::None;
+  ReportPolicy zZicfissReport = ReportPolicy::None;
   bool ltoBBAddrMap;
   llvm::StringRef ltoBasicBlockSections;
   std::pair<llvm::StringRef, llvm::StringRef> thinLTOObjectSuffixReplace;

lld/ELF/Driver.cpp

@@ -421,8 +421,18 @@ static void checkOptions(Ctx &ctx) {
           << "--pcrel-optimize is only supported on PowerPC64 targets";
   }
 
-  if (ctx.arg.relaxGP && ctx.arg.emachine != EM_RISCV)
-    ErrAlways(ctx) << "--relax-gp is only supported on RISC-V targets";
+  if (ctx.arg.emachine != EM_RISCV) {
+    if (ctx.arg.relaxGP)
+      ErrAlways(ctx) << "--relax-gp is only supported on RISC-V targets";
+    if (ctx.arg.zZicfilpUnlabeledReport != ReportPolicy::None)
+      ErrAlways(ctx) << "-z zicfilip-unlabeled-report is only supported on "
+                        "RISC-V targets";
+    if (ctx.arg.zZicfilpFuncSigReport != ReportPolicy::None)
+      ErrAlways(ctx) << "-z zicfilip-func-sig-report is only supported on "
+                        "RISC-V targets";
+    if (ctx.arg.zZicfissReport != ReportPolicy::None)
+      ErrAlways(ctx) << "-z zicfiss-report is only supported on RISC-V targets";
+  }
 
   if (ctx.arg.emachine != EM_386 && ctx.arg.emachine != EM_X86_64 &&
       ctx.arg.zCetReport != ReportPolicy::None)
@@ -1637,7 +1647,11 @@ static void readConfigs(Ctx &ctx, opt::InputArgList &args) {
       std::make_pair("execute-only-report", &ctx.arg.zExecuteOnlyReport),
       std::make_pair("gcs-report", &ctx.arg.zGcsReport),
       std::make_pair("gcs-report-dynamic", &ctx.arg.zGcsReportDynamic),
-      std::make_pair("pauth-report", &ctx.arg.zPauthReport)};
+      std::make_pair("pauth-report", &ctx.arg.zPauthReport),
+      std::make_pair("zicfilp-unlabeled-report",
+                     &ctx.arg.zZicfilpUnlabeledReport),
+      std::make_pair("zicfilp-func-sig-report", &ctx.arg.zZicfilpFuncSigReport),
+      std::make_pair("zicfiss-report", &ctx.arg.zZicfissReport)};
   bool hasGcsReportDynamic = false;
   for (opt::Arg *arg : args.filtered(OPT_z)) {
     std::pair<StringRef, StringRef> option =
@@ -2831,9 +2845,12 @@ static void redirectSymbols(Ctx &ctx, ArrayRef<WrappedSymbol> wrapped) {
 // For AArch64 PAuth-enabled object files, the core info of all of them must
 // match. Missing info for some object files with matching info for remaining
 // ones can be allowed (see -z pauth-report).
+//
+// RISC-V Zicfilp/Zicfiss extension also use the same mechanism to record
+// enabled features in the GNU_PROPERTY_RISCV_FEATURE_1_AND bit mask.
 static void readSecurityNotes(Ctx &ctx) {
   if (ctx.arg.emachine != EM_386 && ctx.arg.emachine != EM_X86_64 &&
-      ctx.arg.emachine != EM_AARCH64)
+      ctx.arg.emachine != EM_AARCH64 && ctx.arg.emachine != EM_RISCV)
     return;
 
   ctx.arg.andFeatures = -1;
@@ -2885,6 +2902,33 @@ static void readSecurityNotes(Ctx &ctx) {
         << ": -z cet-report: file does not have "
            "GNU_PROPERTY_X86_FEATURE_1_SHSTK property";
 
+    if (ctx.arg.emachine == EM_RISCV) {
+      reportUnless(ctx.arg.zZicfilpUnlabeledReport,
+                   features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED)
+          << f
+          << ": -z zicfilp-unlabeled-report: file does not have "
+             "GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED property";
+
+      reportUnless(ctx.arg.zZicfilpFuncSigReport,
+                   features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG)
+          << f
+          << ": -z zicfilp-func-sig-report: file does not have "
+             "GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG property";
+
+      if ((features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED) &&
+          (features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG))
+        Err(ctx) << f
+                 << ": file has conflicting properties: "
+                    "GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_UNLABELED and "
+                    "GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG";
+
+      reportUnless(ctx.arg.zZicfissReport,
+                   features & GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS)
+          << f
+          << ": -z zicfiss-report: file does not have "
+             "GNU_PROPERTY_RISCV_FEATURE_1_CFI_SS property";
+    }
+
     if (ctx.arg.zForceBti && !(features & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)) {
       features |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
       if (ctx.arg.zBtiReport == ReportPolicy::None)

lld/ELF/InputFiles.cpp

@@ -970,7 +970,7 @@ static void parseGnuPropertyNote(Ctx &ctx, ELFFileBase &f,
 }
 // Read the following info from the .note.gnu.property section and write it to
 // the corresponding fields in `ObjFile`:
-// - Feature flags (32 bits) representing x86 or AArch64 features for
+// - Feature flags (32 bits) representing x86, AArch64 or RISC-V features for
 //   hardware-assisted call flow control;
 // - AArch64 PAuth ABI core info (16 bytes).
 template <class ELFT>
@@ -979,6 +979,22 @@ static void readGnuProperty(Ctx &ctx, const InputSection &sec,
   using Elf_Nhdr = typename ELFT::Nhdr;
   using Elf_Note = typename ELFT::Note;
 
+  uint32_t featureAndType;
+  switch (ctx.arg.emachine) {
+  case EM_386:
+  case EM_X86_64:
+    featureAndType = GNU_PROPERTY_X86_FEATURE_1_AND;
+    break;
+  case EM_AARCH64:
+    featureAndType = GNU_PROPERTY_AARCH64_FEATURE_1_AND;
+    break;
+  case EM_RISCV:
+    featureAndType = GNU_PROPERTY_RISCV_FEATURE_1_AND;
+    break;
+  default:
+    return;
+  }
+
   ArrayRef<uint8_t> data = sec.content();
   auto err = [&](const uint8_t *place) -> ELFSyncStream {
     auto diag = Err(ctx);
@@ -999,10 +1015,6 @@ static void readGnuProperty(Ctx &ctx, const InputSection &sec,
       continue;
     }
 
-    uint32_t featureAndType = ctx.arg.emachine == EM_AARCH64
-                                  ? GNU_PROPERTY_AARCH64_FEATURE_1_AND
-                                  : GNU_PROPERTY_X86_FEATURE_1_AND;
-
     // Read a body of a NOTE record, which consists of type-length-value fields.
     ArrayRef<uint8_t> desc = note.getDesc(sec.addralign);
     const uint8_t *base = sec.content().data();
@@ -1066,9 +1078,9 @@ InputSectionBase *ObjFile<ELFT>::createInputSection(uint32_t idx,
     }
 
     // Object files that use processor features such as Intel Control-Flow
-    // Enforcement (CET) or AArch64 Branch Target Identification BTI, use a
-    // .note.gnu.property section containing a bitfield of feature bits like the
-    // GNU_PROPERTY_X86_FEATURE_1_IBT flag. Read a bitmap containing the flag.
+    // Enforcement (CET), AArch64 Branch Target Identification BTI or RISC-V
+    // Zicfilp/Zicfiss extensions, use a .note.gnu.property section containing
+    // a bitfield of feature bits like the GNU_PROPERTY_X86_FEATURE_1_IBT flag.
     //
     // Since we merge bitmaps from multiple object files to create a new
     // .note.gnu.property containing a single AND'ed bitmap, we discard an input

lld/ELF/SyntheticSections.cpp

@@ -325,15 +325,28 @@ GnuPropertySection::GnuPropertySection(Ctx &ctx)
                        ctx.arg.wordsize) {}
 
 void GnuPropertySection::writeTo(uint8_t *buf) {
+  uint32_t featureAndType;
+  switch (ctx.arg.emachine) {
+  case EM_386:
+  case EM_X86_64:
+    featureAndType = GNU_PROPERTY_X86_FEATURE_1_AND;
+    break;
+  case EM_AARCH64:
+    featureAndType = GNU_PROPERTY_AARCH64_FEATURE_1_AND;
+    break;
+  case EM_RISCV:
+    featureAndType = GNU_PROPERTY_RISCV_FEATURE_1_AND;
+    break;
+  default:
+    llvm_unreachable(
+        "target machine does not support .note.gnu.property section");
+  }
+
   write32(ctx, buf, 4);                          // Name size
   write32(ctx, buf + 4, getSize() - 16);         // Content size
   write32(ctx, buf + 8, NT_GNU_PROPERTY_TYPE_0); // Type
   memcpy(buf + 12, "GNU", 4);               // Name string
 
-  uint32_t featureAndType = ctx.arg.emachine == EM_AARCH64
-                                ? GNU_PROPERTY_AARCH64_FEATURE_1_AND
-                                : GNU_PROPERTY_X86_FEATURE_1_AND;
-
   unsigned offset = 16;
   if (ctx.arg.andFeatures != 0) {
     write32(ctx, buf + offset + 0, featureAndType);      // Feature type

lld/test/ELF/riscv-feature-zicfilp-func-sig.s

@@ -0,0 +1,193 @@
+# REQUIRES: riscv
+## Test the ZICFILP func-sig feature.
+## To lift maintenance burden, most tests are conducted only with 64-bit RISC-V
+## Naming convention: *-s.s files enables ZICFILP func-sig.
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc --filetype=obj --triple=riscv32 rv32-f1-s.s -o rv32-f1-s.o
+# RUN: llvm-mc --filetype=obj --triple=riscv32 rv32-f2-s.s -o rv32-f2-s.o
+# RUN: llvm-mc --filetype=obj --triple=riscv32 rv32-f3-s.s -o rv32-f3-s.o
+
+# RUN: llvm-mc --filetype=obj --triple=riscv64 f1-s.s -o f1-s.o
+# RUN: llvm-mc --filetype=obj --triple=riscv64 f2.s   -o f2.o
+# RUN: llvm-mc --filetype=obj --triple=riscv64 f2-s.s -o f2-s.o
+# RUN: llvm-mc --filetype=obj --triple=riscv64 f3.s   -o f3.o
+# RUN: llvm-mc --filetype=obj --triple=riscv64 f3-s.s -o f3-s.o
+
+## ZICFILP-func-sig should be enabled when it's enabled in all inputs
+# RUN: ld.lld rv32-f1-s.o rv32-f2-s.o rv32-f3-s.o -o out.rv32 --fatal-warnings
+# RUN: llvm-readelf -n out.rv32 | FileCheck --check-prefix=ZICFILP %s
+# RUN: ld.lld f1-s.o f2-s.o f3-s.o -o out --fatal-warnings
+# RUN: llvm-readelf -n out | FileCheck --check-prefix=ZICFILP %s
+# RUN: ld.lld f1-s.o f3-s.o --shared -o out.so --fatal-warnings
+# RUN: llvm-readelf -n out.so | FileCheck --check-prefix=ZICFILP %s
+# ZICFILP: Properties: RISC-V feature: ZICFILP-func-sig
+
+## ZICFILP-func-sig should not be enabled if it's not enabled in at least one
+## input
+# RUN: ld.lld f1-s.o f2.o f3-s.o -o out.no --fatal-warnings
+# RUN: llvm-readelf -n out.no | count 0
+# RUN: ld.lld f2-s.o f3.o --shared -o out.no.so --fatal-warnings
+# RUN: llvm-readelf -n out.no.so | count 0
+
+## zicfilp-func-sig-report should report any input files that don't have the
+## ZICFILP-func-sig property
+# RUN: ld.lld f1-s.o f2.o f3-s.o -z zicfilp-func-sig-report=warning 2>&1 | FileCheck --check-prefix=REPORT-WARN %s
+# RUN: not ld.lld f2-s.o f3.o --shared -z zicfilp-func-sig-report=error 2>&1 | FileCheck --check-prefix=REPORT-ERROR %s
+# RUN: ld.lld f1-s.o f2-s.o f3-s.o -z zicfilp-func-sig-report=warning 2>&1 | count 0
+# REPORT-WARN: warning: f2.o: -z zicfilp-func-sig-report: file does not have GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG property
+# REPORT-ERROR: error: f3.o: -z zicfilp-func-sig-report: file does not have GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG property
+
+## An invalid -z zicfilp-func-sig-report option should give an error
+# RUN: not ld.lld f2-s.o -z zicfilp-func-sig-report=x 2>&1 | FileCheck --check-prefix=INVALID %s
+# INVALID: error: unknown -z zicfilp-func-sig-report= value: x
+
+#--- rv32-f1-s.s
+.section ".note.gnu.property", "a"
+.balign 4
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 4
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 4
+ndesc_end:
+
+.text
+.globl _start
+.type f1,%function
+f1:
+  call f2
+  ret
+
+#--- f1-s.s
+.section ".note.gnu.property", "a"
+.balign 8
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 8
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 8
+ndesc_end:
+
+.text
+.globl _start
+.type f1,%function
+f1:
+  call f2
+  ret
+
+#--- f2.s
+.text
+.globl f2
+.type f2,@function
+f2:
+  .globl f3
+  .type f3, @function
+  call f3
+  ret
+
+#--- rv32-f2-s.s
+.section ".note.gnu.property", "a"
+.balign 4
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 4
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 4
+ndesc_end:
+
+.text
+.globl f2
+.type f2,@function
+f2:
+  .globl f3
+  .type f3, @function
+  call f3
+  ret
+
+#--- f2-s.s
+.section ".note.gnu.property", "a"
+.balign 8
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 8
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 8
+ndesc_end:
+
+.text
+.globl f2
+.type f2,@function
+f2:
+  .globl f3
+  .type f3, @function
+  call f3
+  ret
+
+#--- f3.s
+.text
+.globl f3
+.type f3,@function
+f3:
+  ret
+
+#--- rv32-f3-s.s
+.section ".note.gnu.property", "a"
+.balign 4
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 4
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 4
+ndesc_end:
+
+.text
+.globl f3
+.type f3,@function
+f3:
+  ret
+
+#--- f3-s.s
+.section ".note.gnu.property", "a"
+.balign 8
+.4byte 4
+.4byte (ndesc_end - ndesc_begin)
+.4byte 0x5        // NT_GNU_PROPERTY_TYPE_0
+.asciz "GNU"
+ndesc_begin:
+.balign 8
+.4byte 0xc0000000 // GNU_PROPERTY_RISCV_FEATURE_1_AND
+.4byte 4
+.4byte 4          // GNU_PROPERTY_RISCV_FEATURE_1_CFI_LP_FUNC_SIG
+.balign 8
+ndesc_end:
+
+.text
+.globl f3
+.type f3,@function
+f3:
+  ret