[tip: x86/sgx] selftests/sgx: Specify freestanding environment for enclave compilation

[tip-bot2 for Jo Van Bulck]

The following commit has been merged into the x86/sgx branch of tip:

Commit-ID:     304b259e63b94c4f825e0648b33b15f8962955c7
Gitweb:        https://git.kernel.org/tip/304b259e63b94c4f825e0648b33b15f8962955c7
Author:        Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
AuthorDate:    Thu, 05 Oct 2023 17:38:46 +02:00
Committer:     Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Fri, 08 Dec 2023 10:05:27 -08:00

selftests/sgx: Specify freestanding environment for enclave compilation

Use -ffreestanding to assert the enclave compilation targets a
freestanding environment (i.e., without "main" or standard libraries).
This fixes clang reporting "undefined reference to `memset'" after
erroneously optimizing away the provided memset/memcpy implementations.

Still need to instruct the linker from using standard system startup
functions, but drop -nostartfiles as it is implied by -nostdlib.

Signed-off-by: Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Acked-by: Kai Huang <kai.huang@xxxxxxxxx>
Link: https://lore.kernel.org/all/20231005153854.25566-6-jo.vanbulck%40cs.kuleuven.be
---
 tools/testing/selftests/sgx/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/sgx/Makefile b/tools/testing/selftests/sgx/Makefile
index dcdd04b..7eb890b 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 -nostartfiles -fPIC \
+ENCL_CFLAGS += -Wall -Werror -static -nostdlib -ffreestanding -fPIC \
 	       -fno-stack-protector -mrdrnd $(INCLUDES)
 ENCL_LDFLAGS := -Wl,-T,test_encl.lds,--build-id=none