The test enclave (test_encl.elf) is built with two initialized Thread Control Structures (TCS) included in the binary. Both TCS are initialized with the same entry point, encl_entry, that correctly computes the absolute address of the stack based on the stack of each TCS that is also built into the binary.
A new TCS can be added dynamically to the enclave and requires to be initialized with an entry point used to enter the enclave. Since the existing entry point, encl_entry, assumes that the TCS and its stack exists at particular offsets within the binary it is not able to handle a dynamically added TCS and its stack.
Introduce a new entry point, encl_dyn_entry, that initializes the absolute address of that thread's stack to the address immediately preceding the TCS itself. It is now possible to dynamically add a contiguous memory region to the enclave with the new stack preceding the new TCS. With the new TCS initialized with encl_dyn_entry as entry point the absolute address of the stack is computed correctly on entry.
Acked-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Reinette Chatre reinette.chatre@intel.com --- Changes since V3: - Add Jarkko's Acked-by tag.
tools/testing/selftests/sgx/test_encl_bootstrap.S | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S index 82fb0dfcbd23..03ae0f57e29d 100644 --- a/tools/testing/selftests/sgx/test_encl_bootstrap.S +++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S @@ -45,6 +45,12 @@ encl_entry: # TCS #2. By adding the value of encl_stack to it, we get # the absolute address for the stack. lea (encl_stack)(%rbx), %rax + jmp encl_entry_core +encl_dyn_entry: + # Entry point for dynamically created TCS page expected to follow + # its stack directly. + lea -1(%rbx), %rax +encl_entry_core: xchg %rsp, %rax push %rax