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author | Jo Van Bulck <jo.vanbulck@cs.kuleuven.be> | 2023-10-05 18:38:48 +0300 |
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committer | Dave Hansen <dave.hansen@linux.intel.com> | 2023-12-08 21:05:27 +0300 |
commit | f7884e732841450de36c2b1ed49b91e8e854a7d1 (patch) | |
tree | e41714c0f2a3be207b58c301fe019b8f23289185 | |
parent | 4f812df8f37463767c2a74c2bd77de94acdb2be6 (diff) | |
download | linux-f7884e732841450de36c2b1ed49b91e8e854a7d1.tar.xz |
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.
When building the original "lea (encl_stack)(%rbx), %rax" assembly code
with -static-pie -fPIE, the linker complains about a relocation it cannot
resolve:
/usr/local/bin/ld: /tmp/cchIWyfG.o: relocation R_X86_64_32S against
`.data' can not be used when making a PIE object; recompile with -fPIE
collect2: error: ld returned 1 exit status
Thus, since only RIP-relative addressing is legit for local symbols, use
"encl_stack(%rip)" and declare an explicit "__encl_base" symbol at the
start of the linker script to be able to calculate the stack address
relative to the current TCS in the enclave assembly entry code.
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/all/f9c24d89-ed72-7d9e-c650-050d722c6b04@cs.kuleuven.be/
Link: https://lore.kernel.org/all/20231005153854.25566-8-jo.vanbulck%40cs.kuleuven.be
-rw-r--r-- | tools/testing/selftests/sgx/Makefile | 2 | ||||
-rw-r--r-- | tools/testing/selftests/sgx/test_encl.lds | 1 | ||||
-rw-r--r-- | tools/testing/selftests/sgx/test_encl_bootstrap.S | 9 |
3 files changed, 8 insertions, 4 deletions
diff --git a/tools/testing/selftests/sgx/Makefile b/tools/testing/selftests/sgx/Makefile index 7eb890bdd3f0..8d2ba6adc92b 100644 --- a/tools/testing/selftests/sgx/Makefile +++ b/tools/testing/selftests/sgx/Makefile @@ -14,7 +14,7 @@ endif INCLUDES := -I$(top_srcdir)/tools/include HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC HOST_LDFLAGS := -z noexecstack -lcrypto -ENCL_CFLAGS += -Wall -Werror -static -nostdlib -ffreestanding -fPIC \ +ENCL_CFLAGS += -Wall -Werror -static-pie -nostdlib -ffreestanding -fPIE \ -fno-stack-protector -mrdrnd $(INCLUDES) ENCL_LDFLAGS := -Wl,-T,test_encl.lds,--build-id=none diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds index a1ec64f7d91f..62d37160f59b 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 e0ce993d3f2c..28fe5d2ac0af 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 |