Ensure the compiler respects the size and placement of encl_buffer as expected by the external tests manipulating page permissions: 1. Declare encl_buffer as global, in order to ensure that it is not optimized away by the compiler, even when not used entirely by the test enclave code. 2. Place encl_buffer in a separate section that is explicitly placed at the start of the .data segment in the linker script to avoid the compiler placing it somewhere else in .data. Link: https://lore.kernel.org/all/a2732938-f3db-a0af-3d68-a18060f66e79@xxxxxxxxxxxxxx/ Signed-off-by: Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx> --- tools/testing/selftests/sgx/test_encl.c | 9 +++++---- tools/testing/selftests/sgx/test_encl.lds | 1 + 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c index 5b758eaf808c..02a9e8c55e82 100644 --- a/tools/testing/selftests/sgx/test_encl.c +++ b/tools/testing/selftests/sgx/test_encl.c @@ -5,11 +5,12 @@ #include "defines.h" /* - * Data buffer spanning two pages that will be placed first in .data - * segment. Even if not used internally the second page is needed by - * external test manipulating page permissions. + * Data buffer spanning two pages that will be placed first in the .data + * segment via the linker script. Even if not used internally the second page + * is needed by external test manipulating page permissions, so do not declare + * encl_buffer as static to make sure it is entirely preserved by the compiler. */ -static uint8_t encl_buffer[8192] = { 1 }; +uint8_t __attribute__((section(".data.encl_buffer"))) encl_buffer[8192]; enum sgx_enclu_function { EACCEPT = 0x5, diff --git a/tools/testing/selftests/sgx/test_encl.lds b/tools/testing/selftests/sgx/test_encl.lds index 27c2527ecbc4..2ec29340ba94 100644 --- a/tools/testing/selftests/sgx/test_encl.lds +++ b/tools/testing/selftests/sgx/test_encl.lds @@ -24,6 +24,7 @@ SECTIONS } : text .data : { + *(.data.encl_buffer) *(.data*) } : data -- 2.34.1
