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From 4667ff92d36ebd3a891da823ccad82453860603d Mon Sep 17 00:00:00 2001
From: Reinette Chatre <reinette.chatre@intel.com>
Date: Mon, 7 Feb 2022 16:45:47 -0800
Subject: [PATCH 25/34] selftests/sgx: Introduce dynamic entry point
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.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
---
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
--
2.35.1
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