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Message-Id: <20230819094332.8535-3-jo.vanbulck@cs.kuleuven.be>
Date: Sat, 19 Aug 2023 11:43:25 +0200
From: Jo Van Bulck <jo.vanbulck@...kuleuven.be>
To: jarkko@...nel.org, kai.huang@...el.com, linux-sgx@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: dave.hansen@...ux.intel.com,
Jo Van Bulck <jo.vanbulck@...kuleuven.be>
Subject: [PATCH v3 2/9] selftests/sgx: Produce static-pie executable for test enclave
The current combination of -static and -fPIC creates a static executable
with position-dependent addresses for global variables. Use -static-pie
and -fPIE to create a proper static position independent executable that
can be loaded at any address without a dynamic linker.
Link: https://lore.kernel.org/all/f9c24d89-ed72-7d9e-c650-050d722c6b04@cs.kuleuven.be/
Signed-off-by: Jo Van Bulck <jo.vanbulck@...kuleuven.be>
Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>
---
tools/testing/selftests/sgx/Makefile | 2 +-
tools/testing/selftests/sgx/test_encl.lds | 1 +
tools/testing/selftests/sgx/test_encl_bootstrap.S | 12 ++++++------
3 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/sgx/Makefile b/tools/testing/selftests/sgx/Makefile
index 50aab6b57..1d6315a2e 100644
--- a/tools/testing/selftests/sgx/Makefile
+++ b/tools/testing/selftests/sgx/Makefile
@@ -13,7 +13,7 @@ endif
INCLUDES := -I$(top_srcdir)/tools/include
HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack
-ENCL_CFLAGS := -Wall -Werror -static -nostdlib -nostartfiles -fPIC \
+ENCL_CFLAGS := -Wall -Werror -static-pie -nostdlib -nostartfiles -fPIE \
-fno-stack-protector -mrdrnd $(INCLUDES)
TEST_CUSTOM_PROGS := $(OUTPUT)/test_sgx
diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds
index a1ec64f7d..62d37160f 100644
--- a/tools/testing/selftests/sgx/test_encl.lds
+++ b/tools/testing/selftests/sgx/test_encl.lds
@@ -10,6 +10,7 @@ PHDRS
SECTIONS
{
. = 0;
+ __encl_base = .;
.tcs : {
*(.tcs*)
} : tcs
diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
index 03ae0f57e..28fe5d2ac 100644
--- a/tools/testing/selftests/sgx/test_encl_bootstrap.S
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -42,9 +42,12 @@
encl_entry:
# RBX contains the base address for TCS, which is the first address
# inside the enclave for TCS #1 and one page into the enclave for
- # TCS #2. By adding the value of encl_stack to it, we get
- # the absolute address for the stack.
- lea (encl_stack)(%rbx), %rax
+ # TCS #2. First make it relative by substracting __encl_base and
+ # then add the address of encl_stack to get the address for the stack.
+ lea __encl_base(%rip), %rax
+ sub %rax, %rbx
+ lea encl_stack(%rip), %rax
+ add %rbx, %rax
jmp encl_entry_core
encl_dyn_entry:
# Entry point for dynamically created TCS page expected to follow
@@ -55,12 +58,9 @@ encl_entry_core:
push %rax
push %rcx # push the address after EENTER
- push %rbx # push the enclave base address
call encl_body
- pop %rbx # pop the enclave base address
-
/* Clear volatile GPRs, except RAX (EEXIT function). */
xor %rcx, %rcx
xor %rdx, %rdx
--
2.25.1
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