Add patch for arm64 BTI hints in Boost.Context asm

Resolves: RHEL-50164 The patch had to be modified to remove the .hidden directives added upstream by 245904742b8a15f94fd5fe963fac746239f8900c (which is included in boost-1.87.0).
2026-04-22 10:38:53 +01:00 · 2026-04-22 10:38:53 +01:00 · af5d757e7a
commit af5d757e7a
parent 02695ebc08
2 changed files with 125 additions and 1 deletions
--- a/boost-1.83-context-arm64-bti-hint.patch
+++ b/boost-1.83-context-arm64-bti-hint.patch
@ -0,0 +1,117 @@
+commit 1be6822473b78278af1779fc6f642128996473d8
+Author: Zayd Rajab <zaydr@amazon.com>
+Date:   Fri Aug 15 22:13:10 2025 +0000
+
+    [AArch64][BTI] Add BTI hint + GNU property to fcontext trampolines (ELF/GAS)
+    
+    The AArch64 fcontext trampolines (jump_fcontext, make_fcontext, ontop_fcontext)
+    are indirect-entry-points. On BTI-enforcing systems they must begin with a BTI
+    or the first resume can trap with SIGILL.
+    
+    Insert `bti c` (hint #34) at each entry under `__ARM_FEATURE_BTI_DEFAULT`, and
+    emit `GNU_PROPERTY_AARCH64_FEATURE_1_BTI` from each AArch64 assembly file so
+    linkers map the DSO with PROT_BTI without requiring -z force-bti.
+    
+    Scope: ELF/GAS AArch64 trampolines only; +4 bytes per entry
+    
+    Fixes #308
+
+diff --git a/src/asm/jump_arm64_aapcs_elf_gas.S b/src/asm/jump_arm64_aapcs_elf_gas.S
+index 7c1f075..b8abb2e 100644
+--- a/libs/context/src/asm/jump_arm64_aapcs_elf_gas.S
+++ b/libs/context/src/asm/jump_arm64_aapcs_elf_gas.S
+@@ -53,10 +53,28 @@
+ 
+ .file "jump_arm64_aapcs_elf_gas.S"
+ .text
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+/* Mark this object as requiring BTI, enabling the linker to set BTI on the output */
+    .pushsection .note.gnu.property, "a", %note
+    .p2align 3
+    .long 4                      /* namesz */
+    .long 16                     /* descsz (16 bytes) */
+    .long 5                      /* type = NT_GNU_PROPERTY_TYPE_0 */
+    .asciz "GNU"
+    .p2align 3
+    .long 0xc0000000             /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */
+    .long 4                      /* datasz = 4 */
+    .long 1                      /* GNU_PROPERTY_AARCH64_FEATURE_1_BTI */
+    .long 0                      /* pad to 8-byte alignment */
+    .popsection
+#endif
+ .align  2
+ .global jump_fcontext
+ .type   jump_fcontext, %function
+ jump_fcontext:
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+    hint    #34                    /* bti c: valid indirect-entry target */
+#endif
+     # prepare stack for GP + FPU
+     sub  sp, sp, #0xb0
+ 
+diff --git a/src/asm/make_arm64_aapcs_elf_gas.S b/src/asm/make_arm64_aapcs_elf_gas.S
+index 8ac825b..2465254 100644
+--- a/libs/context/src/asm/make_arm64_aapcs_elf_gas.S
+++ b/libs/context/src/asm/make_arm64_aapcs_elf_gas.S
+@@ -53,10 +53,28 @@
+ 
+ .file "make_arm64_aapcs_elf_gas.S"
+ .text
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+/* Mark this object as requiring BTI, enabling the linker to set BTI on the output */
+    .pushsection .note.gnu.property, "a", %note
+    .p2align 3
+    .long 4                      /* namesz */
+    .long 16                     /* descsz (16 bytes) */
+    .long 5                      /* type = NT_GNU_PROPERTY_TYPE_0 */
+    .asciz "GNU"
+    .p2align 3
+    .long 0xc0000000             /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */
+    .long 4                      /* datasz = 4 */
+    .long 1                      /* GNU_PROPERTY_AARCH64_FEATURE_1_BTI */
+    .long 0                      /* pad to 8-byte alignment */
+    .popsection
+#endif
+ .align  2
+ .global make_fcontext
+ .type   make_fcontext, %function
+ make_fcontext:
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+    hint    #34    /* bti c */
+#endif
+     # shift address in x0 (allocated stack) to lower 16 byte boundary
+     and x0, x0, ~0xF
+ 
+diff --git a/src/asm/ontop_arm64_aapcs_elf_gas.S b/src/asm/ontop_arm64_aapcs_elf_gas.S
+index 8e40fc7..1e6b466 100644
+--- a/libs/context/src/asm/ontop_arm64_aapcs_elf_gas.S
+++ b/libs/context/src/asm/ontop_arm64_aapcs_elf_gas.S
+@@ -53,10 +53,28 @@
+ 
+ .file "ontop_arm64_aapcs_elf_gas.S"
+ .text
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+/* Mark this object as requiring BTI, enabling the linker to set BTI on the output */
+    .pushsection .note.gnu.property, "a", %note
+    .p2align 3
+    .long 4                      /* namesz */
+    .long 16                     /* descsz (16 bytes) */
+    .long 5                      /* type = NT_GNU_PROPERTY_TYPE_0 */
+    .asciz "GNU"
+    .p2align 3
+    .long 0xc0000000             /* GNU_PROPERTY_AARCH64_FEATURE_1_AND */
+    .long 4                      /* datasz = 4 */
+    .long 1                      /* GNU_PROPERTY_AARCH64_FEATURE_1_BTI */
+    .long 0                      /* pad to 8-byte alignment */
+    .popsection
+#endif
+ .align  2
+ .global ontop_fcontext
+ .type   ontop_fcontext, %function
+ ontop_fcontext:
+#if defined(__ARM_FEATURE_BTI_DEFAULT) && (__ARM_FEATURE_BTI_DEFAULT == 1)
+    hint    #34    /* bti c */
+#endif
+     # prepare stack for GP + FPU
+     sub  sp, sp, #0xb0
+ 
--- a/boost.spec
+++ b/boost.spec
@ -46,7 +46,7 @@ Name: boost
 %global real_name boost
 Summary: The free peer-reviewed portable C++ source libraries
 Version: 1.83.0
-Release: 7%{?dist}
+Release: 8%{?dist}
 License: BSL-1.0 AND MIT AND Python-2.0.1

 # Replace each . with _ in %%{version}
@ -166,6 +166,9 @@ Patch8: boost-1.83-regex-test-fixes.patch
 # https://github.com/boostorg/thread/pull/408
 Patch9: boost-1.83-fix-no-member-named_that_error.patch

+# https://github.com/boostorg/context/pull/312
+Patch10: boost-1.83-context-arm64-bti-hint.patch
+
 %bcond_with tests
 %bcond_with docs_generated

@ -1295,6 +1298,10 @@ fi
 %{_mandir}/man1/b2.1*

 %changelog
+* Wed Apr 22 2026 Jonathan Wakely <jwakely@redhat.com> - 1.83.0-8
+- Add patch for arm64 BTI hints in Boost.Context asm
+  Resolves: RHEL-50164
+
 * Tue Jan 27 2026 Patrick Palka <ppalka@redhat.com> - 1.83.0-7
 - Add boost-url dependency to metapackage
  Resolves: RHEL-124169