[PATCH v7 09/14] x86/vdso: Insert endbr32/endbr64 to vDSO - Yu-cheng Yu

From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-mm@kvack.org, linux-arch@vger.kernel.org,
	linux-api@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Andy Lutomirski <luto@amacapital.net>,
	Balbir Singh <bsingharora@gmail.com>,
	Borislav Petkov <bp@alien8.de>,
	Cyrill Gorcunov <gorcunov@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Eugene Syromiatnikov <esyr@redhat.com>,
	Florian Weimer <fweimer@redhat.com>,
	"H.J. Lu" <hjl.tools@gmail.com>, Jann Horn <jannh@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Kees Cook <keescook@chromium.org>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Nadav Amit <nadav.amit@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, Pavel Machek <pavel@ucw.cz>,
	Peter Zijlstra <peterz@infradead.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
	Vedvyas Shanbhogue <vedvyas.shanbhogue@intel.com>,
	Dave Martin <Dave.Martin@arm.com>
Subject: [PATCH v7 09/14] x86/vdso: Insert endbr32/endbr64 to vDSO
Date: Thu,  6 Jun 2019 13:09:21 -0700	[thread overview]
Message-ID: <20190606200926.4029-10-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20190606200926.4029-1-yu-cheng.yu@intel.com>

From: "H.J. Lu" <hjl.tools@gmail.com>

When Intel indirect branch tracking is enabled, functions in vDSO which
may be called indirectly must have endbr32 or endbr64 as the first
instruction.  Compiler must support -fcf-protection=branch so that it
can be used to compile vDSO.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
---
 arch/x86/entry/vdso/Makefile          | 12 +++++++++++-
 arch/x86/entry/vdso/vdso-layout.lds.S |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 42fe42e82baf..718fc17b0d67 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -108,13 +108,17 @@ vobjx32s := $(foreach F,$(vobjx32s-y),$(obj)/$F)
 
 # Convert 64bit object file to x32 for x32 vDSO.
 quiet_cmd_x32 = X32     $@
-      cmd_x32 = $(OBJCOPY) -O elf32-x86-64 $< $@
+      cmd_x32 = $(OBJCOPY) -R .note.gnu.property -O elf32-x86-64 $< $@
 
 $(obj)/%-x32.o: $(obj)/%.o FORCE
 	$(call if_changed,x32)
 
 targets += vdsox32.lds $(vobjx32s-y)
 
+ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER
+    $(obj)/vclock_gettime.o $(obj)/vgetcpu.o $(obj)/vdso32/vclock_gettime.o: KBUILD_CFLAGS += -fcf-protection=branch
+endif
+
 $(obj)/%.so: OBJCOPYFLAGS := -S
 $(obj)/%.so: $(obj)/%.so.dbg FORCE
 	$(call if_changed,objcopy)
@@ -173,6 +177,12 @@ quiet_cmd_vdso = VDSO    $@
 VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
 	$(call ld-option, --build-id) $(call ld-option, --eh-frame-hdr) \
 	-Bsymbolic
+ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER
+  VDSO_LDFLAGS += $(call ldoption, -z$(comma)ibt)
+endif
+ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER
+  VDSO_LDFLAGS += $(call ldoption, -z$(comma)shstk)
+endif
 GCOV_PROFILE := n
 
 #
diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S b/arch/x86/entry/vdso/vdso-layout.lds.S
index 93c6dc7812d0..3fea2ce318bc 100644
--- a/arch/x86/entry/vdso/vdso-layout.lds.S
+++ b/arch/x86/entry/vdso/vdso-layout.lds.S
@@ -52,6 +52,7 @@ SECTIONS
 		*(.gnu.linkonce.b.*)
 	}						:text
 
+	.note.gnu.property : { *(.note.gnu.property) }	:text	:note
 	.note		: { *(.note.*) }		:text	:note
 
 	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
-- 
2.17.1

