Branching flow protection

Support for flow protected branches. More...

Macros
#define	MCUX_CSSL_FP_BRANCH_DECL(id)
	Declaration of a flow protected branch.
#define	MCUX_CSSL_FP_BRANCH_POSITIVE(...)
	Positive scenario for a branch is executed.
#define	MCUX_CSSL_FP_BRANCH_NEGATIVE(...)
	Negative scenario of a branch is executed.
#define	MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE(...)
	Expectation that positive branch has been taken.
#define	MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE(...)
	Expectation that negative branch has been taken.

Detailed Description

Support for flow protected branches.

This subset of Flow protection macros is used to protect positive/negative branches (if, else).

The mechanism allows to check that the expected case was taken, but not necessarily that the entire case was executed.

Important note:

For this protection to work, both if and else cases need to be present, even if empty besides the MCUX_CSSL_FP_BRANCH_POSITIVE or MCUX_CSSL_FP_BRANCH_NEGATIVE macro usage.

Both cases need either MCUX_CSSL_FP_BRANCH_POSITIVE or MCUX_CSSL_FP_BRANCH_NEGATIVE (not both, not none).

Every MCUX_CSSL_FP_BRANCH_POSITIVE macro use needs to be balanced with MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE, specifying a matching condition. (Same for MCUX_CSSL_FP_BRANCH_NEGATIVE with MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE).

See also

mcuxCsslFlowProtection_Branch_example.c

Declaration

MCUX_CSSL_FP_BRANCH_DECL

Events

MCUX_CSSL_FP_BRANCH_POSITIVE
MCUX_CSSL_FP_BRANCH_NEGATIVE

Expectations

MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE
MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE

Macro Definition Documentation

MCUX_CSSL_FP_BRANCH_DECL

#define MCUX_CSSL_FP_BRANCH_DECL

(

id

)

Declaration of a flow protected branch.

To inform the flow protection mechanism about a branch that needs to be protected, a branch identifier needs to be declared. This identifier can then be used in the events and expectation macros. For example:

MCUX_CSSL_FP_BRANCH_DECL(someBranchIdentifier);
if (condition)
{
  MCUX_CSSL_FP_BRANCH_POSITIVE(someBranchIdentifier);
}
else
{
  MCUX_CSSL_FP_BRANCH_NEGATIVE(someBranchIdentifier);
}
// ...
MCUX_CSSL_FP_FUNCTION_EXIT(someFunction, 0,
  MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE(someBranchIdentifier, condition),
  MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE(someBranchIdentifier, !condition)
);

Events

MCUX_CSSL_FP_BRANCH_POSITIVE
MCUX_CSSL_FP_BRANCH_NEGATIVE

Expectations

MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE
MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE

Parameters

id	Identifier for the branch that is flow protected.

Examples

mcuxCsslFlowProtection_Branch_example.c.

MCUX_CSSL_FP_BRANCH_POSITIVE

#define MCUX_CSSL_FP_BRANCH_POSITIVE

(

...

)

Positive scenario for a branch is executed.

This branch event macro informs the flow mechanism that the positive scenario of the branch is executed for the branch declared by MCUX_CSSL_FP_BRANCH_DECL with the given id. For example:

MCUX_CSSL_FP_BRANCH_DECL(someBranchIdentifier);
if (condition)
{
  MCUX_CSSL_FP_BRANCH_POSITIVE(someBranchIdentifier);
}
else
{
  MCUX_CSSL_FP_BRANCH_NEGATIVE(someBranchIdentifier);
}
// ...
MCUX_CSSL_FP_FUNCTION_EXIT(someFunction, 0,
  MCUX_CSSL_FP_CONDITIONAL_IMPL(condition,
    MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE(someBranchIdentifier)),
  MCUX_CSSL_FP_CONDITIONAL_IMPL(!condition,
    MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE(someBranchIdentifier))
);

Declaration

MCUX_CSSL_FP_BRANCH_DECL

Expectation

MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE

Parameters

...	The following parameters need to be passed (comma separated): id: Identifier for the branch for which the positive scenario is executed. expect: Zero or more (comma separated) declarations of expected code flow behavior related to this event.

Examples

mcuxCsslFlowProtection_Branch_example.c.

MCUX_CSSL_FP_BRANCH_NEGATIVE

#define MCUX_CSSL_FP_BRANCH_NEGATIVE

(

...

)

Negative scenario of a branch is executed.

This branch event macro informs the flow mechanism that the positive scenario of the branch is executed for the branch declared by MCUX_CSSL_FP_BRANCH_DECL with the given id.

For example usage see MCUX_CSSL_FP_BRANCH_POSITIVE.

Declaration

MCUX_CSSL_FP_BRANCH_DECL

Expectation

MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE

Parameters

...	The following parameters need to be passed (comma separated): id: Identifier for the branch for which the negative scenario is executed. expect: Zero or more (comma separated) declarations of expected code flow behavior related to this event.

Examples

mcuxCsslFlowProtection_Branch_example.c.

MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE

#define MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE

(

...

)

Expectation that positive branch has been taken.

This expectation macro indicates to the flow protection mechanism that the branch declared by MCUX_CSSL_FP_BRANCH_DECL with the given id has executed the positive scenario (under the given condition). For example:

MCUX_CSSL_FP_BRANCH_DECL(someBranchIdentifier);
if (condition)
{
  MCUX_CSSL_FP_BRANCH_POSITIVE(someBranchIdentifier);
}
else
{
  MCUX_CSSL_FP_BRANCH_NEGATIVE(someBranchIdentifier);
}
// ...
MCUX_CSSL_FP_FUNCTION_EXIT(someFunction, 0,
  // Providing the condition as part of the branch expectation.
  // Alternatively, the expectation can be placed in a conditional block.
  MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE(someBranchIdentifier, condition),
  MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE(someBranchIdentifier, !condition)
);

Declaration

MCUX_CSSL_FP_BRANCH_DECL

Event

MCUX_CSSL_FP_BRANCH_POSITIVE

See also

MCUX_CSSL_FP_FUNCTION_ENTRY

MCUX_CSSL_FP_FUNCTION_EXIT

MCUX_CSSL_FP_FUNCTION_EXIT_WITH_CHECK

MCUX_CSSL_FP_EXPECT

MCUX_CSSL_FP_CONDITIONAL

Parameters

...	The following parameters need to be passed (comma separated): id: Identifier of the flow protected branch. condition: Optional, condition under which this branch is taken.

Examples

mcuxCsslFlowProtection_Branch_example.c.

MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE

#define MCUX_CSSL_FP_BRANCH_TAKEN_NEGATIVE

(

...

)

Expectation that negative branch has been taken.

This expectation macro indicates to the flow protection mechanism that the branch declared by MCUX_CSSL_FP_BRANCH_DECL with the given id has executed the negative scenario (under the given condition).

For example usage see MCUX_CSSL_FP_BRANCH_TAKEN_POSITIVE.

Declaration

MCUX_CSSL_FP_BRANCH_DECL

Event

MCUX_CSSL_FP_BRANCH_NEGATIVE

See also

MCUX_CSSL_FP_FUNCTION_ENTRY

MCUX_CSSL_FP_FUNCTION_EXIT

MCUX_CSSL_FP_FUNCTION_EXIT_WITH_CHECK

MCUX_CSSL_FP_EXPECT

MCUX_CSSL_FP_CONDITIONAL

Parameters

...	The following parameters need to be passed (comma separated): id: Identifier of the flow protected branch. condition: Optional, condition under which this branch is taken.

Examples

mcuxCsslFlowProtection_Branch_example.c.