Add ix86_check_ucontext_function_referencehjl/pr81842

9 files changed, 203 insertions, 3 deletions

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 35037434bf5..feeb533056e 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -2679,6 +2679,39 @@ rest_of_insert_endbranch (void)
   return 0;
 }
 
+/* Check if FNDECL is a ucontext function.  */
+
+void
+ix86_check_ucontext_function_reference (location_t loc,
+					tree fndecl)
+{
+  if (!ix86_check_ucontext_functions
+      || !TARGET_SHSTK
+      || !DECL_FILE_SCOPE_P (fndecl)
+      || !TREE_PUBLIC (fndecl))
+    return;
+
+  /* For instrumentation clones, we want to derive flags from the
+     original name.  */
+  cgraph_node *node = cgraph_node::get (fndecl);
+  if (node && node->instrumentation_clone)
+    fndecl = node->orig_decl;
+
+  tree name_decl = DECL_NAME (fndecl);
+  if (name_decl
+      && (IDENTIFIER_LENGTH (name_decl) == 10
+	  || IDENTIFIER_LENGTH (name_decl) == 11))
+    {
+      const char *name = IDENTIFIER_POINTER (name_decl);
+
+      if (! strcmp (name, "getcontext")
+	  || ! strcmp (name, "setcontext")
+	  || ! strcmp (name, "makecontext")
+	  || ! strcmp (name, "swapcontext"))
+	error_at (loc, "%qE cannot be used with -mshstk", fndecl);
+    }
+}
+
 namespace {
 
 const pass_data pass_data_insert_endbranch =
@@ -18117,10 +18150,18 @@ ix86_print_operand (FILE *file, rtx x, int code)
 	}
       if (CONST_INT_P (x))
 	fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x));
-      else if (flag_pic || MACHOPIC_INDIRECT)
-	output_pic_addr_const (file, x, code);
       else
-	output_addr_const (file, x);
+	{
+	  if (GET_CODE (x) == SYMBOL_REF
+	      && SYMBOL_REF_DECL (x)
+	      && TREE_CODE (SYMBOL_REF_DECL (x)) == FUNCTION_DECL)
+	    ix86_check_ucontext_function_reference (input_location,
+						    SYMBOL_REF_DECL (x));
+	  if (flag_pic || MACHOPIC_INDIRECT)
+	    output_pic_addr_const (file, x, code);
+	  else
+	    output_addr_const (file, x);
+	}
     }
 }
 
diff --git a/gcc/config/i386/i386.opt b/gcc/config/i386/i386.opt
index 04e391d311d..13b9697ba7e 100644
--- a/gcc/config/i386/i386.opt
+++ b/gcc/config/i386/i386.opt
@@ -1005,6 +1005,10 @@ Target Report Mask(ISA_SHSTK) Var(ix86_isa_flags2) Save
 Specifically enables an shadow stack support feature from Control-flow
 Enforcment Technology (CET).
 
+mcheck-ucontext-functions
+Target Report Var(ix86_check_ucontext_functions) Init(1)
+Check references to ucontext functions.
+
 mcet-switch
 Target Report Undocumented Var(flag_cet_switch) Init(0)
 Turn on CET instrumentation for switch statements, which use jump table and
diff --git a/gcc/config/i386/linux-common.h b/gcc/config/i386/linux-common.h
index 6613807180e..5dff543ab76 100644
--- a/gcc/config/i386/linux-common.h
+++ b/gcc/config/i386/linux-common.h
@@ -126,3 +126,20 @@ extern void file_end_indicate_exec_stack_and_cet (void);
 
 #undef TARGET_ASM_FILE_END
 #define TARGET_ASM_FILE_END file_end_indicate_exec_stack_and_cet
+
+#if !defined USED_FOR_TARGET && !defined GENERATOR_FILE
+#include "input.h"
+
+extern void ix86_check_ucontext_function_reference (location_t, tree);
+
+#undef  ASM_OUTPUT_EXTERNAL
+#define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME)			\
+  do								\
+    {								\
+      if (TREE_CODE (DECL) == FUNCTION_DECL)			\
+	ix86_check_ucontext_function_reference (UNKNOWN_LOCATION,\
+						DECL);	\
+      default_elf_asm_output_external (FILE, DECL, NAME);	\
+    }								\
+  while (0)
+#endif
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-1.c b/gcc/testsuite/gcc.target/i386/pr81842-1.c
new file mode 100644
index 00000000000..bd6bf775625
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-1.c
@@ -0,0 +1,28 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet" } */
+
+#include <ucontext.h>
+
+int
+func1 (ucontext_t *ucp)
+{
+  return getcontext (ucp); /* { dg-error "'getcontext' cannot be used with -mshstk" } */
+}
+
+int
+func2 (const ucontext_t *ucp)
+{
+  return setcontext (ucp); /* { dg-error "'setcontext' cannot be used with -mshstk" } */
+}
+
+int
+func3 (ucontext_t *oucp, const ucontext_t *ucp)
+{
+  return swapcontext (oucp, ucp); /* { dg-error "'swapcontext' cannot be used with -mshstk" } */
+}
+
+void
+func4 (ucontext_t *ucp, void (*func) (void))
+{
+  makecontext (ucp, func, 0); /* { dg-error "'makecontext' cannot be used with -mshstk" } */
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-2.c b/gcc/testsuite/gcc.target/i386/pr81842-2.c
new file mode 100644
index 00000000000..202b1aa1888
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-2.c
@@ -0,0 +1,28 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet -mno-check-ucontext-functions" } */
+
+#include <ucontext.h>
+
+int
+func1 (ucontext_t *ucp)
+{
+  return getcontext (ucp);
+}
+
+int
+func2 (const ucontext_t *ucp)
+{
+  return setcontext (ucp);
+}
+
+int
+func3 (ucontext_t *oucp, const ucontext_t *ucp)
+{
+  return swapcontext (oucp, ucp);
+}
+
+void
+func4 (ucontext_t *ucp, void (*func) (void))
+{
+  makecontext (ucp, func, 0);
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-3.c b/gcc/testsuite/gcc.target/i386/pr81842-3.c
new file mode 100644
index 00000000000..f98a8b56a71
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-3.c
@@ -0,0 +1,32 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet" } */
+
+#include <ucontext.h>
+
+void *
+func1 (void)
+{
+  return getcontext;
+}
+
+void *
+func2 (void)
+{
+  return setcontext;
+}
+
+void *
+func3 (void)
+{
+  return swapcontext;
+}
+
+void *
+func4 (void)
+{
+  return makecontext;
+}
+/* { dg-error "'getcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'setcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'swapcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'makecontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-4.c b/gcc/testsuite/gcc.target/i386/pr81842-4.c
new file mode 100644
index 00000000000..d4d1dce1311
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-4.c
@@ -0,0 +1,28 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet -mno-check-ucontext-functions" } */
+
+#include <ucontext.h>
+
+void *
+func1 (void)
+{
+  return getcontext;
+}
+
+void *
+func2 (void)
+{
+  return setcontext;
+}
+
+void *
+func3 (void)
+{
+  return swapcontext;
+}
+
+void *
+func4 (void)
+{
+  return makecontext;
+}
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-5.c b/gcc/testsuite/gcc.target/i386/pr81842-5.c
new file mode 100644
index 00000000000..b9acf7a2e07
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-5.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet" } */
+
+#include <ucontext.h>
+
+void *p1 = getcontext;
+void *p2 = setcontext;
+void *p3 = swapcontext;
+void *p4 = makecontext;
+/* { dg-error "'getcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'setcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'swapcontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
+/* { dg-error "'makecontext' cannot be used with -mshstk" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/gcc.target/i386/pr81842-6.c b/gcc/testsuite/gcc.target/i386/pr81842-6.c
new file mode 100644
index 00000000000..01d5a3ddf8f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81842-6.c
@@ -0,0 +1,9 @@
+/* { dg-do compile { target *-*-linux* } } */
+/* { dg-options "-fcf-protection -mcet -mno-check-ucontext-functions" } */
+
+#include <ucontext.h>
+
+void *p1 = getcontext;
+void *p2 = setcontext;
+void *p3 = swapcontext;
+void *p4 = makecontext;