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Subject[PATCH v2] selftests/sgx: Use rip relative addressing for encl_stack
Date
Simplify the test_encl_bootstrap.S flow by using RIP-relative addressing.
The compiler automatically puts relative addresses for RIP index addresses.

In order to get a clean and tweakless solution, define separate entry point
for each TCS.

Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v2:
* Based on Reinette's example, make proper structuring with separate
entry points for each TCS.
---
.../selftests/sgx/test_encl_bootstrap.S | 30 +++++++++++--------
1 file changed, 18 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/sgx/test_encl_bootstrap.S b/tools/testing/selftests/sgx/test_encl_bootstrap.S
index 82fb0dfcbd23..cc2353f38bcc 100644
--- a/tools/testing/selftests/sgx/test_encl_bootstrap.S
+++ b/tools/testing/selftests/sgx/test_encl_bootstrap.S
@@ -10,12 +10,13 @@
.section ".tcs", "aw"
.balign 4096

+encl_tcs1:
.fill 1, 8, 0 # STATE (set by CPU)
.fill 1, 8, 0 # FLAGS
.quad encl_ssa_tcs1 # OSSA
.fill 1, 4, 0 # CSSA (set by CPU)
.fill 1, 4, 1 # NSSA
- .quad encl_entry # OENTRY
+ .quad encl_entry1 # OENTRY
.fill 1, 8, 0 # AEP (set by EENTER and ERESUME)
.fill 1, 8, 0 # OFSBASE
.fill 1, 8, 0 # OGSBASE
@@ -23,13 +24,13 @@
.fill 1, 4, 0xFFFFFFFF # GSLIMIT
.fill 4024, 1, 0 # Reserved

- # TCS2
+encl_tcs2:
.fill 1, 8, 0 # STATE (set by CPU)
.fill 1, 8, 0 # FLAGS
.quad encl_ssa_tcs2 # OSSA
.fill 1, 4, 0 # CSSA (set by CPU)
.fill 1, 4, 1 # NSSA
- .quad encl_entry # OENTRY
+ .quad encl_entry2 # OENTRY
.fill 1, 8, 0 # AEP (set by EENTER and ERESUME)
.fill 1, 8, 0 # OFSBASE
.fill 1, 8, 0 # OGSBASE
@@ -39,15 +40,19 @@

.text

-encl_entry:
- # RBX contains the base address for TCS, which is the first address
- # inside the enclave for TCS #1 and one page into the enclave for
- # TCS #2. By adding the value of encl_stack to it, we get
- # the absolute address for the stack.
- lea (encl_stack)(%rbx), %rax
+encl_entry1:
+ lea (encl_stack1)(%rip), %rax
xchg %rsp, %rax
push %rax
+ jmp encl_continue

+encl_entry2:
+ lea (encl_stack2)(%rip), %rax
+ xchg %rsp, %rax
+ push %rax
+ jmp encl_continue
+
+encl_continue:
push %rcx # push the address after EENTER
push %rbx # push the enclave base address

@@ -84,13 +89,14 @@ encl_entry:

encl_ssa_tcs1:
.space 4096
+
encl_ssa_tcs2:
.space 4096

+encl_stack1:
.balign 4096
- # Stack of TCS #1
.space 4096
-encl_stack:
+
+encl_stack2:
.balign 4096
- # Stack of TCS #2
.space 4096
--
2.35.1
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