selftests/sgx: Remove incomplete ABI sanitization code in test enclave

As the selftest enclave is *not* intended for production, simplify the
code by not initializing CPU configuration registers as expected by the
ABI on enclave entry or cleansing caller-save registers on enclave exit.

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>
Link: https://lore.kernel.org/all/da0cfb1e-e347-f7f2-ac72-aec0ee0d867d@intel.com/
Link: https://lore.kernel.org/all/20231005153854.25566-14-jo.vanbulck%40cs.kuleuven.be

diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
index 28fe5d2..d8c4ac9 100644 (file)
--- a/tools/testing/selftests/sgx/test_encl_bootstrap.S
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -59,21 +59,11 @@ encl_entry_core:
 
        push    %rcx # push the address after EENTER
 
+       # NOTE: as the selftest enclave is *not* intended for production,
+       # simplify the code by not initializing ABI registers on entry or
+       # cleansing caller-save registers on exit.
        call    encl_body
 
-       /* Clear volatile GPRs, except RAX (EEXIT function). */
-       xor     %rcx, %rcx
-       xor     %rdx, %rdx
-       xor     %rdi, %rdi
-       xor     %rsi, %rsi
-       xor     %r8, %r8
-       xor     %r9, %r9
-       xor     %r10, %r10
-       xor     %r11, %r11
-
-       # Reset status flags.
-       add     %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1
-
        # Prepare EEXIT target by popping the address of the instruction after
        # EENTER to RBX.
        pop     %rbx