[PATCH v6 13/13] selftests/sgx: Remove incomplete ABI sanitization code in test enclave

From: Jo Van Bulck
Date: Thu Sep 21 2023 - 16:26:53 EST


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.

Link: https://lore.kernel.org/all/da0cfb1e-e347-f7f2-ac72-aec0ee0d867d@xxxxxxxxx/
Signed-off-by: Jo Van Bulck <jo.vanbulck@xxxxxxxxxxxxxx>
Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
---
.../testing/selftests/sgx/test_encl_bootstrap.S | 16 +++-------------
1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
index 28fe5d2ac0af..d8c4ac94e032 100644
--- 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
--
2.25.1