diff mbox series

x86: Disable sibcall if indirect_return attribute doesn't match

Message ID 20220714174244.295605-1-hjl.tools@gmail.com
State New
Headers show
Series x86: Disable sibcall if indirect_return attribute doesn't match | expand

Commit Message

H.J. Lu July 14, 2022, 5:42 p.m. UTC 
When shadow stack is enabled, function with indirect_return attribute
may return via indirect jump.  In this case, we need to disable sibcall
if caller doesn't have indirect_return attribute and indirect branch
tracking is enabled since compiler won't generate ENDBR when calling the
caller.

gcc/

	PR target/85620
	* config/i386/i386.cc (ix86_function_ok_for_sibcall): Return
	false if callee has indirect_return attribute and caller
	doesn't.

gcc/testsuite/

	PR target/85620
	* gcc.target/i386/pr85620-2.c: Updated.
	* gcc.target/i386/pr85620-5.c: New test.
	* gcc.target/i386/pr85620-6.c: Likewise.
	* gcc.target/i386/pr85620-7.c: Likewise.
---
 gcc/config/i386/i386.cc                   | 10 ++++++++++
 gcc/testsuite/gcc.target/i386/pr85620-2.c |  3 ++-
 gcc/testsuite/gcc.target/i386/pr85620-5.c | 13 +++++++++++++
 gcc/testsuite/gcc.target/i386/pr85620-6.c | 14 ++++++++++++++
 gcc/testsuite/gcc.target/i386/pr85620-7.c | 14 ++++++++++++++
 5 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-5.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-6.c
 create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-7.c

Comments

Hongtao Liu July 15, 2022, 3:45 a.m. UTC | #1 
On Fri, Jul 15, 2022 at 1:44 AM H.J. Lu via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> When shadow stack is enabled, function with indirect_return attribute
> may return via indirect jump.  In this case, we need to disable sibcall
> if caller doesn't have indirect_return attribute and indirect branch
> tracking is enabled since compiler won't generate ENDBR when calling the
> caller.
>
LGTM.
> gcc/
>
>         PR target/85620
>         * config/i386/i386.cc (ix86_function_ok_for_sibcall): Return
>         false if callee has indirect_return attribute and caller
>         doesn't.
>
> gcc/testsuite/
>
>         PR target/85620
>         * gcc.target/i386/pr85620-2.c: Updated.
>         * gcc.target/i386/pr85620-5.c: New test.
>         * gcc.target/i386/pr85620-6.c: Likewise.
>         * gcc.target/i386/pr85620-7.c: Likewise.
> ---
>  gcc/config/i386/i386.cc                   | 10 ++++++++++
>  gcc/testsuite/gcc.target/i386/pr85620-2.c |  3 ++-
>  gcc/testsuite/gcc.target/i386/pr85620-5.c | 13 +++++++++++++
>  gcc/testsuite/gcc.target/i386/pr85620-6.c | 14 ++++++++++++++
>  gcc/testsuite/gcc.target/i386/pr85620-7.c | 14 ++++++++++++++
>  5 files changed, 53 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-5.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-6.c
>  create mode 100644 gcc/testsuite/gcc.target/i386/pr85620-7.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index 3a3c7299eb4..e03f86d4a23 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -1024,6 +1024,16 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
>          return false;
>      }
>
> +  /* Disable sibcall if callee has indirect_return attribute and
> +     caller doesn't since callee will return to the caller's caller
> +     via an indirect jump.  */
> +  if (((flag_cf_protection & (CF_RETURN | CF_BRANCH))
> +       == (CF_RETURN | CF_BRANCH))
> +      && lookup_attribute ("indirect_return", TYPE_ATTRIBUTES (type))
> +      && !lookup_attribute ("indirect_return",
> +                           TYPE_ATTRIBUTES (TREE_TYPE (cfun->decl))))
> +    return false;
> +
>    /* Otherwise okay.  That also includes certain types of indirect calls.  */
>    return true;
>  }
> diff --git a/gcc/testsuite/gcc.target/i386/pr85620-2.c b/gcc/testsuite/gcc.target/i386/pr85620-2.c
> index b2e680fa1fe..14ce0ffd1e1 100644
> --- a/gcc/testsuite/gcc.target/i386/pr85620-2.c
> +++ b/gcc/testsuite/gcc.target/i386/pr85620-2.c
> @@ -1,6 +1,7 @@
>  /* { dg-do compile } */
>  /* { dg-options "-O2 -fcf-protection" } */
> -/* { dg-final { scan-assembler-times {\mendbr} 1 } } */
> +/* { dg-final { scan-assembler-times {\mendbr} 2 } } */
> +/* { dg-final { scan-assembler-not "jmp" } } */
>
>  struct ucontext;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr85620-5.c b/gcc/testsuite/gcc.target/i386/pr85620-5.c
> new file mode 100644
> index 00000000000..04537702d09
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr85620-5.c
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fcf-protection" } */
> +/* { dg-final { scan-assembler-not "jmp" } } */
> +
> +struct ucontext;
> +
> +extern int (*bar) (struct ucontext *) __attribute__((__indirect_return__));
> +
> +int
> +foo (struct ucontext *oucp)
> +{
> +  return bar (oucp);
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr85620-6.c b/gcc/testsuite/gcc.target/i386/pr85620-6.c
> new file mode 100644
> index 00000000000..0b6a64e8454
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr85620-6.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fcf-protection" } */
> +/* { dg-final { scan-assembler "jmp" } } */
> +
> +struct ucontext;
> +
> +extern int bar (struct ucontext *) __attribute__((__indirect_return__));
> +
> +__attribute__((__indirect_return__))
> +int
> +foo (struct ucontext *oucp)
> +{
> +  return bar (oucp);
> +}
> diff --git a/gcc/testsuite/gcc.target/i386/pr85620-7.c b/gcc/testsuite/gcc.target/i386/pr85620-7.c
> new file mode 100644
> index 00000000000..fa62d56decf
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr85620-7.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fcf-protection" } */
> +/* { dg-final { scan-assembler "jmp" } } */
> +
> +struct ucontext;
> +
> +extern int (*bar) (struct ucontext *) __attribute__((__indirect_return__));
> +extern int foo (struct ucontext *) __attribute__((__indirect_return__));
> +
> +int
> +foo (struct ucontext *oucp)
> +{
> +  return bar (oucp);
> +}
> --
> 2.36.1
>
diff mbox series

Patch

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 3a3c7299eb4..e03f86d4a23 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -1024,6 +1024,16 @@  ix86_function_ok_for_sibcall (tree decl, tree exp)
 	 return false;
     }
 
+  /* Disable sibcall if callee has indirect_return attribute and
+     caller doesn't since callee will return to the caller's caller
+     via an indirect jump.  */
+  if (((flag_cf_protection & (CF_RETURN | CF_BRANCH))
+       == (CF_RETURN | CF_BRANCH))
+      && lookup_attribute ("indirect_return", TYPE_ATTRIBUTES (type))
+      && !lookup_attribute ("indirect_return",
+			    TYPE_ATTRIBUTES (TREE_TYPE (cfun->decl))))
+    return false;
+
   /* Otherwise okay.  That also includes certain types of indirect calls.  */
   return true;
 }
diff --git a/gcc/testsuite/gcc.target/i386/pr85620-2.c b/gcc/testsuite/gcc.target/i386/pr85620-2.c
index b2e680fa1fe..14ce0ffd1e1 100644
--- a/gcc/testsuite/gcc.target/i386/pr85620-2.c
+++ b/gcc/testsuite/gcc.target/i386/pr85620-2.c
@@ -1,6 +1,7 @@ 
 /* { dg-do compile } */
 /* { dg-options "-O2 -fcf-protection" } */
-/* { dg-final { scan-assembler-times {\mendbr} 1 } } */
+/* { dg-final { scan-assembler-times {\mendbr} 2 } } */
+/* { dg-final { scan-assembler-not "jmp" } } */
 
 struct ucontext;
 
diff --git a/gcc/testsuite/gcc.target/i386/pr85620-5.c b/gcc/testsuite/gcc.target/i386/pr85620-5.c
new file mode 100644
index 00000000000..04537702d09
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr85620-5.c
@@ -0,0 +1,13 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* { dg-final { scan-assembler-not "jmp" } } */
+
+struct ucontext;
+
+extern int (*bar) (struct ucontext *) __attribute__((__indirect_return__));
+
+int
+foo (struct ucontext *oucp)
+{
+  return bar (oucp);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr85620-6.c b/gcc/testsuite/gcc.target/i386/pr85620-6.c
new file mode 100644
index 00000000000..0b6a64e8454
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr85620-6.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* { dg-final { scan-assembler "jmp" } } */
+
+struct ucontext;
+
+extern int bar (struct ucontext *) __attribute__((__indirect_return__));
+
+__attribute__((__indirect_return__))
+int
+foo (struct ucontext *oucp)
+{
+  return bar (oucp);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr85620-7.c b/gcc/testsuite/gcc.target/i386/pr85620-7.c
new file mode 100644
index 00000000000..fa62d56decf
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr85620-7.c
@@ -0,0 +1,14 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -fcf-protection" } */
+/* { dg-final { scan-assembler "jmp" } } */
+
+struct ucontext;
+
+extern int (*bar) (struct ucontext *) __attribute__((__indirect_return__));
+extern int foo (struct ucontext *) __attribute__((__indirect_return__));
+
+int
+foo (struct ucontext *oucp)
+{
+  return bar (oucp);
+}