Updating encrypted security context in stack pointers for exception handling and tight bounding of on-stack arguments

At least one non-transitory machine-readable storage medium comprising instructions, wherein the instructions when executed by one or more processors perform operations comprising:

• performing a simulated return in a program from a callee function to a caller function based on a first input stack pointer that includes a first security context of a callee stack frame associated with the callee function, wherein the simulated return is to simulate a normal return from the callee function that is cryptographically protected, wherein performing the simulated return is to include generating a first simulated stack pointer to a caller stack frame associated with the caller function;
• and
• in response to identifying an exception handler in the caller function, performing a simulated call based on a second input stack pointer, wherein the simulated call is to simulate a normal call from the caller function that is cryptographically protected, wherein performing the simulated call is to include generating a second simulated stack pointer that includes a new security context of a new stack frame containing an encrypted instruction pointer associated with the exception handler, the second input stack pointer to include a second security context of the caller stack frame.

An apparatus comprising:

• decoder circuitry to decode a first instruction, the first instruction to include a first field for an identifier of an operand and a second field for an opcode, the opcode to indicate that execution circuitry is to perform a simulated call using the operand to simulate a normal call from a caller function that is cryptographically protected, wherein to perform the simulated call is to include generating an output stack pointer encoded with a new security context for a new stack frame in stack memory;
• and
• execution circuitry to execute the decoded first instruction according to the opcode to perform a simulated call using the operand to simulate a normal call from a caller function that is cryptographically protected, wherein to perform the simulated call is to include generating an output stack pointer encoded with a new security context of a new stack frame in a stack memory, the operand comprising an input stack pointer encoded with a caller security context of a caller stack frame in the stack memory.