[PATCHv2 2/7, GCC, ARM, V8M] Handling ARMv8-M Security Extension's cmse_nonsecure_entry attribute
Andre Vieira (lists)
Andre.SimoesDiasVieira@arm.com
Wed Aug 24 11:01:00 GMT 2016
On 25/07/16 14:21, Andre Vieira (lists) wrote:
> This patch adds support for the ARMv8-M Security Extensions
> 'cmse_nonsecure_entry' attribute. In this patch we implement the
> attribute handling and diagnosis around the attribute. See Section 5.4
> of ARM®v8-M Security Extensions
> (http://infocenter.arm.com/help/topic/com.arm.doc.ecm0359818/index.html).
>
> *** gcc/ChangeLog ***
> 2016-07-25 Andre Vieira <andre.simoesdiasvieira@arm.com>
> Thomas Preud'homme <thomas.preudhomme@arm.com>
>
> * config/arm/arm.c (arm_handle_cmse_nonsecure_entry): New.
> (arm_attribute_table): Added cmse_nonsecure_entry
> (arm_compute_func_type): Handle cmse_nonsecure_entry.
> (cmse_func_args_or_return_in_stack): New.
> (arm_handle_cmse_nonsecure_entry): New.
> * config/arm/arm.h (ARM_FT_CMSE_ENTRY): New macro define.
> (IS_CMSE_ENTRY): Likewise.
>
> *** gcc/testsuite/ChangeLog ***
> 2016-07-25 Andre Vieira <andre.simoesdiasvieira@arm.com>
> Thomas Preud'homme <thomas.preudhomme@arm.com>
>
> * gcc.target/arm/cmse/cmse-3.c: New.
>
Added more documentation as requested.
----
This patch adds support for the ARMv8-M Security Extensions
'cmse_nonsecure_entry' attribute. In this patch we implement the
attribute handling and diagnosis around the attribute. See Section 5.4
of ARM®v8-M Security Extensions
(http://infocenter.arm.com/help/topic/com.arm.doc.ecm0359818/index.html).
*** gcc/ChangeLog ***
2016-07-xx Andre Vieira <andre.simoesdiasvieira@arm.com>
Thomas Preud'homme <thomas.preudhomme@arm.com>
* config/arm/arm.c (arm_handle_cmse_nonsecure_entry): New.
(arm_attribute_table): Added cmse_nonsecure_entry
(arm_compute_func_type): Handle cmse_nonsecure_entry.
(cmse_func_args_or_return_in_stack): New.
(arm_handle_cmse_nonsecure_entry): New.
* config/arm/arm.h (ARM_FT_CMSE_ENTRY): New macro define.
(IS_CMSE_ENTRY): Likewise.
* doc/extend.texi (ARM ARMv8-M Security Extensions): New attribute.
*** gcc/testsuite/ChangeLog ***
2016-07-xx Andre Vieira <andre.simoesdiasvieira@arm.com>
Thomas Preud'homme <thomas.preudhomme@arm.com>
* gcc.target/arm/cmse/cmse-3.c: New.
-------------- next part --------------
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index e3697bbcb425999db31ac2b4f47e14bb3f2ffa89..5307ec8f904230db5ea44150ef471d928926ab6d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1373,6 +1373,7 @@ enum reg_class
#define ARM_FT_VOLATILE (1 << 4) /* Does not return. */
#define ARM_FT_NESTED (1 << 5) /* Embedded inside another func. */
#define ARM_FT_STACKALIGN (1 << 6) /* Called with misaligned stack. */
+#define ARM_FT_CMSE_ENTRY (1 << 7) /* ARMv8-M non-secure entry function. */
/* Some macros to test these flags. */
#define ARM_FUNC_TYPE(t) (t & ARM_FT_TYPE_MASK)
@@ -1381,6 +1382,7 @@ enum reg_class
#define IS_NAKED(t) (t & ARM_FT_NAKED)
#define IS_NESTED(t) (t & ARM_FT_NESTED)
#define IS_STACKALIGN(t) (t & ARM_FT_STACKALIGN)
+#define IS_CMSE_ENTRY(t) (t & ARM_FT_CMSE_ENTRY)
/* Structure used to hold the function stack frame layout. Offsets are
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 9903d9cd8c5ff68a2318a643bdf31cf48016eba4..11417ab3c2f7101866ee5d6b100913480e5c336e 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -134,6 +134,7 @@ static tree arm_handle_isr_attribute (tree *, tree, tree, int, bool *);
#if TARGET_DLLIMPORT_DECL_ATTRIBUTES
static tree arm_handle_notshared_attribute (tree *, tree, tree, int, bool *);
#endif
+static tree arm_handle_cmse_nonsecure_entry (tree *, tree, tree, int, bool *);
static void arm_output_function_epilogue (FILE *, HOST_WIDE_INT);
static void arm_output_function_prologue (FILE *, HOST_WIDE_INT);
static int arm_comp_type_attributes (const_tree, const_tree);
@@ -343,6 +344,9 @@ static const struct attribute_spec arm_attribute_table[] =
{ "notshared", 0, 0, false, true, false, arm_handle_notshared_attribute,
false },
#endif
+ /* ARMv8-M Security Extensions support. */
+ { "cmse_nonsecure_entry", 0, 0, true, false, false,
+ arm_handle_cmse_nonsecure_entry, false },
{ NULL, 0, 0, false, false, false, NULL, false }
};
@@ -3633,6 +3637,9 @@ arm_compute_func_type (void)
else
type |= arm_isr_value (TREE_VALUE (a));
+ if (lookup_attribute ("cmse_nonsecure_entry", attr))
+ type |= ARM_FT_CMSE_ENTRY;
+
return type;
}
@@ -6634,6 +6641,110 @@ arm_handle_notshared_attribute (tree *node,
}
#endif
+/* This function returns true if a function with declaration FNDECL, name
+ NAME and type FNTYPE uses the stack to pass arguments or return variables
+ and false otherwise. This is used for functions with the attributes
+ 'cmse_nonsecure_call' or 'cmse_nonsecure_entry' and this function will issue
+ diagnostic messages if the stack is used. */
+
+static bool
+cmse_func_args_or_return_in_stack (tree fndecl, tree name, tree fntype)
+{
+ function_args_iterator args_iter;
+ CUMULATIVE_ARGS args_so_far_v;
+ cumulative_args_t args_so_far;
+ bool first_param = true;
+ tree arg_type, prev_arg_type = NULL_TREE, ret_type;
+
+ /* Error out if any argument is passed on the stack. */
+ arm_init_cumulative_args (&args_so_far_v, fntype, NULL_RTX, fndecl);
+ args_so_far = pack_cumulative_args (&args_so_far_v);
+ FOREACH_FUNCTION_ARGS (fntype, arg_type, args_iter)
+ {
+ rtx arg_rtx;
+ machine_mode arg_mode = TYPE_MODE (arg_type);
+
+ prev_arg_type = arg_type;
+ if (VOID_TYPE_P (arg_type))
+ continue;
+
+ if (!first_param)
+ arm_function_arg_advance (args_so_far, arg_mode, arg_type, true);
+ arg_rtx = arm_function_arg (args_so_far, arg_mode, arg_type, true);
+ if (!arg_rtx
+ || arm_arg_partial_bytes (args_so_far, arg_mode, arg_type, true))
+ {
+ error ("%qE attribute not available to functions with arguments "
+ "passed on the stack", name);
+ return true;
+ }
+ first_param = false;
+ }
+
+ /* Error out for variadic functions since we cannot control how many
+ arguments will be passed and thus stack could be used. stdarg_p () is not
+ used for the checking to avoid browsing arguments twice. */
+ if (prev_arg_type != NULL_TREE && !VOID_TYPE_P (prev_arg_type))
+ {
+ error ("%qE attribute not available to functions with variable number "
+ "of arguments", name);
+ return true;
+ }
+
+ /* Error out if return value is passed on the stack. */
+ ret_type = TREE_TYPE (fntype);
+ if (arm_return_in_memory (ret_type, fntype))
+ {
+ error ("%qE attribute not available to functions that return value on "
+ "the stack", name);
+ return true;
+ }
+ return false;
+}
+
+/* Called upon detection of the use of the cmse_nonsecure_entry attribute, this
+ function will check whether the attribute is allowed here and will add the
+ attribute to the function declaration tree or otherwise issue a warning. */
+
+static tree
+arm_handle_cmse_nonsecure_entry (tree *node, tree name,
+ tree /* args */,
+ int /* flags */,
+ bool *no_add_attrs)
+{
+ tree fndecl;
+
+ if (!use_cmse)
+ {
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ /* Ignore attribute for function types. */
+ if (TREE_CODE (*node) != FUNCTION_DECL)
+ {
+ warning (OPT_Wattributes, "%qE attribute only applies to functions",
+ name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ fndecl = *node;
+
+ /* Warn for static linkage functions. */
+ if (!TREE_PUBLIC (fndecl))
+ {
+ warning (OPT_Wattributes, "%qE attribute has no effect on functions "
+ "with static linkage", name);
+ *no_add_attrs = true;
+ return NULL_TREE;
+ }
+
+ *no_add_attrs |= cmse_func_args_or_return_in_stack (fndecl, name,
+ TREE_TYPE (fndecl));
+ return NULL_TREE;
+}
+
/* Return 0 if the attributes for two types are incompatible, 1 if they
are compatible, and 2 if they are nearly compatible (which causes a
warning to be generated). */
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 85efef29b99c26350a67079c0fbcae02b036ac20..1531ed66bdd0b51c268c2a666c2e078b4f0d7ea6 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -12421,6 +12421,9 @@ Security Extensions: Requiremenets on Development Tools Engineering
Specification, which can be found at
@uref{http://infocenter.arm.com/help/topic/com.arm.doc.ecm0359818/ECM0359818_armv8m_security_extensions_reqs_on_dev_tools_1_0.pdf}.
+As part of the Security Extensions GCC implements a new function attribute
+@code{cmse_nonsecure_entry}.
+
As part of the Security Extensions GCC implements the intrinsics below. FPTR
is used here to mean any function pointer type.
diff --git a/gcc/testsuite/gcc.target/arm/cmse/cmse-3.c b/gcc/testsuite/gcc.target/arm/cmse/cmse-3.c
new file mode 100644
index 0000000000000000000000000000000000000000..2c2920e1dc310106d83203eb51e1a68a275d0152
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cmse/cmse-3.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-options "-mcmse" } */
+
+struct span {
+ int a, b;
+};
+struct span2 {
+ float a, b, c, d;
+};
+
+union test_union
+{
+ long long a;
+ int b;
+ struct span2 c;
+} test_union;
+
+void __attribute__ ((cmse_nonsecure_entry))
+foo (long long a, int b, long long c) {} /* { dg-error "not available to functions with arguments passed on the stack" } */
+
+void __attribute__ ((cmse_nonsecure_entry))
+bar (long long a, int b, struct span c) {} /* { dg-error "not available to functions with arguments passed on the stack" } */
+
+void __attribute__ ((cmse_nonsecure_entry))
+baz (int a, ...) {} /* { dg-error "not available to functions with variable number of arguments" } */
+
+struct span __attribute__ ((cmse_nonsecure_entry))
+qux (void) { /* { dg-error "not available to functions that return value on the stack" } */
+ struct span ret = {0, 0};
+ return ret;
+}
+
+void __attribute__ ((cmse_nonsecure_entry))
+norf (struct span2 a) {}
+
+void __attribute__ ((cmse_nonsecure_entry))
+foo2 (long long a, int b, union test_union c) {} /* { dg-error "not available to functions with arguments passed on the stack" } */
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