git: 973bbdab4703 - main - mk: Add a BTI-report linker feature

The branch main has been updated by andrew:

URL: https://cgit.FreeBSD.org/src/commit/?id=973bbdab47035ebd16200c63d095904924dc44d9

commit 973bbdab47035ebd16200c63d095904924dc44d9
Author:     Jose Luis Duran <jlduran@gmail.com>
AuthorDate: 2024-08-22 03:23:59 +0000
Commit:     Andrew Turner <andrew@FreeBSD.org>
CommitDate: 2024-08-30 16:03:17 +0000

    mk: Add a BTI-report linker feature
    
    Add support for specifying how to report the missing Branch Target
    Identification (BTI) linker feature on AArch64.
    
    For:
    
    Kernel:    bti-report on when the linker supports it
    Userspace: bti-report on when the linker supports it and
               BTI_REPORT_ERROR is defined
    
    Fixes:  43e8849bc294 ("conf: Enable BTI checking in the arm64 kernel")
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/1393
---
 share/mk/bsd.lib.mk    |  2 +-
 share/mk/bsd.linker.mk | 11 ++++++++---
 share/mk/bsd.prog.mk   |  2 +-
 sys/conf/kern.mk       |  2 +-
 4 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/share/mk/bsd.lib.mk b/share/mk/bsd.lib.mk
index 575b521bea55..6e288b9cd4ce 100644
--- a/share/mk/bsd.lib.mk
+++ b/share/mk/bsd.lib.mk
@@ -99,7 +99,7 @@ LDFLAGS+= -Wl,-zretpolineplt
 LDFLAGS.bfd+= -Wl,-znoexecstack
 .if ${MK_BRANCH_PROTECTION} != "no"
 CFLAGS+=  -mbranch-protection=standard
-.if ${MACHINE_ARCH} == "aarch64" && defined(BTI_REPORT_ERROR)
+.if ${LINKER_FEATURES:Mbti-report} && defined(BTI_REPORT_ERROR)
 LDFLAGS+= -Wl,-zbti-report=error
 .endif
 .endif
diff --git a/share/mk/bsd.linker.mk b/share/mk/bsd.linker.mk
index 0e9477284ea3..cceeadd05b94 100644
--- a/share/mk/bsd.linker.mk
+++ b/share/mk/bsd.linker.mk
@@ -11,9 +11,11 @@
 # LINKER_FEATURES may contain one or more of the following, based on
 # linker support for that feature:
 #
-# - build-id:  support for generating a Build-ID note
-# - retpoline: support for generating PLT with retpoline speculative
-#              execution vulnerability mitigation
+# - build-id:   support for generating a Build-ID note
+# - retpoline:  support for generating PLT with retpoline speculative
+#               execution vulnerability mitigation
+# - bti-report: support for specifying how to report the missing
+#               Branch Target Identification (BTI) property (AArch64)
 #
 # LINKER_FREEBSD_VERSION is the linker's internal source version.
 #
@@ -112,6 +114,9 @@ ${X_}LINKER_FEATURES+=	retpoline
 .if ${${X_}LINKER_TYPE} == "lld" && ${${X_}LINKER_VERSION} >= 90000
 ${X_}LINKER_FEATURES+=	ifunc-noplt
 .endif
+.if ${${X_}LINKER_TYPE} == "lld" && ${${X_}LINKER_VERSION} >= 140000
+${X_}LINKER_FEATURES+=	bti-report
+.endif
 .endif
 .else
 # Use LD's values
diff --git a/share/mk/bsd.prog.mk b/share/mk/bsd.prog.mk
index 74a653057bda..89534b21d0e7 100644
--- a/share/mk/bsd.prog.mk
+++ b/share/mk/bsd.prog.mk
@@ -71,7 +71,7 @@ LDFLAGS+= -Wl,-zretpolineplt
 LDFLAGS.bfd+= -Wl,-znoexecstack
 .if ${MK_BRANCH_PROTECTION} != "no"
 CFLAGS+=  -mbranch-protection=standard
-.if ${MACHINE_ARCH} == "aarch64" && defined(BTI_REPORT_ERROR)
+.if ${LINKER_FEATURES:Mbti-report} && defined(BTI_REPORT_ERROR)
 LDFLAGS+= -Wl,-zbti-report=error
 .endif
 .endif
diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 079bd1173fad..00492584921b 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -143,7 +143,7 @@ CFLAGS += -mgeneral-regs-only
 CFLAGS += -ffixed-x18
 # Build with BTI+PAC
 CFLAGS += -mbranch-protection=standard
-.if ${LINKER_TYPE} == "lld"
+.if ${LINKER_FEATURES:Mbti-report}
 LDFLAGS += -Wl,-zbti-report=error
 .endif
 # TODO: support outline atomics