selftests/sgx: Include memory clobber for inline asm in test enclave

[ Upstream commit 853a57a43ebdb8c024160c1a0990bae85f4bcc2f ]

Add the "memory" clobber to the EMODPE and EACCEPT asm blocks to tell the
compiler the assembly code accesses to the secinfo struct. This ensures
the compiler treats the asm block as a memory barrier and the write to
secinfo will be visible to ENCLU.

Fixes: 20404a808593 ("selftests/sgx: Add test for EPCM permission changes")
Signed-off-by: Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/all/20231005153854.25566-4-jo.vanbulck%40cs.kuleuven.be
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/tools/testing/selftests/sgx/test_encl.c b/tools/testing/selftests/sgx/test_encl.c
index c0d6397..ae791df 100644 (file)
--- a/tools/testing/selftests/sgx/test_encl.c
+++ b/tools/testing/selftests/sgx/test_encl.c
@@ -24,10 +24,11 @@ static void do_encl_emodpe(void *_op)
        secinfo.flags = op->flags;
 
        asm volatile(".byte 0x0f, 0x01, 0xd7"
-                               :
+                               : /* no outputs */
                                : "a" (EMODPE),
                                  "b" (&secinfo),
-                                 "c" (op->epc_addr));
+                                 "c" (op->epc_addr)
+                               : "memory" /* read from secinfo pointer */);
 }
 
 static void do_encl_eaccept(void *_op)
@@ -42,7 +43,8 @@ static void do_encl_eaccept(void *_op)
                                : "=a" (rax)
                                : "a" (EACCEPT),
                                  "b" (&secinfo),
-                                 "c" (op->epc_addr));
+                                 "c" (op->epc_addr)
+                               : "memory" /* read from secinfo pointer */);
 
        op->ret = rax;
 }