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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Nathaniel McCallum <npmccallum@redhat.com>,
	Cedric Xing <cedric.xing@intel.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Andy Lutomirski <luto@amacapital.net>,
	linux-sgx@vger.kernel.org
Subject: [PATCH for_v29 7/8] selftests/x86: sgx: Stop clobbering non-volatile registers
Date: Wed, 18 Mar 2020 18:11:29 -0700
Message-ID: <20200319011130.8556-8-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200319011130.8556-1-sean.j.christopherson@intel.com>

Stop clearing non-volatile registers in the enclave's trampoline code,
there are no secrets to preserve, and not clobbering the registers makes
the enclave compatible with calling the vDSO from C.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 tools/testing/selftests/x86/sgx/encl_bootstrap.S | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/tools/testing/selftests/x86/sgx/encl_bootstrap.S b/tools/testing/selftests/x86/sgx/encl_bootstrap.S
index 3a1479f1cdcf..173e76fa6da6 100644
--- a/tools/testing/selftests/x86/sgx/encl_bootstrap.S
+++ b/tools/testing/selftests/x86/sgx/encl_bootstrap.S
@@ -40,7 +40,7 @@ encl_entry:
 
 	pop	%rbx # pop the enclave base address
 
-	# Clear GPRs.
+	/* Clear volatile GPRs, except RAX (EEXIT leaf). */
 	xor     %rcx, %rcx
 	xor     %rdx, %rdx
 	xor     %rdi, %rdi
@@ -49,10 +49,6 @@ encl_entry:
 	xor     %r9, %r9
 	xor     %r10, %r10
 	xor     %r11, %r11
-	xor     %r12, %r12
-	xor     %r13, %r13
-	xor     %r14, %r14
-	xor     %r15, %r15
 
 	# Reset status flags.
 	add     %rdx, %rdx # OF = SF = AF = CF = 0; ZF = PF = 1
-- 
2.24.1


  parent reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19  1:11 [PATCH for_v29 0/8] x86/sgx: Make vDSO callable from C Sean Christopherson
2020-03-19  1:11 ` [PATCH for_v29 1/8] x86/sgx: vdso: Remove an incorrect statement the enter enclave comment Sean Christopherson
2020-03-19 20:49   ` Jarkko Sakkinen
2020-03-19  1:11 ` [PATCH for_v29 2/8] x86/sgx: vdso: Make the %rsp fixup on return from handler relative Sean Christopherson
2020-03-20  2:39   ` Jarkko Sakkinen
2020-03-20  2:42     ` Jarkko Sakkinen
2020-03-19  1:11 ` [PATCH for_v29 3/8] x86/sgx: vdso: Make __vdso_sgx_enter_enclave() callable from C code Sean Christopherson
2020-03-19 20:03   ` Xing, Cedric
2020-03-19 20:11     ` Sean Christopherson
2020-03-20  3:07       ` Jarkko Sakkinen
2020-03-20 23:26         ` Sean Christopherson
2020-03-21  0:57           ` Jarkko Sakkinen
2020-03-19  1:11 ` [PATCH for_v29 4/8] x86/sgx: vdso: Define a typedef for __vdso_sgx_enter_enclave Sean Christopherson
2020-03-19  1:11 ` [PATCH for_v29 5/8] selftests/x86: sgx: Zero out @result before invoking vDSO sub-test Sean Christopherson
2020-03-19  1:11 ` [PATCH for_v29 6/8] selftests/x86: sgx: Pass EENTER to vDSO wrapper instead of hardcoding Sean Christopherson
2020-03-19  1:11 ` Sean Christopherson [this message]
2020-03-19  1:11 ` [PATCH for_v29 8/8] selftests/x86: Add selftest to invoke __vsgx_enter_enclave() from C Sean Christopherson
2020-03-20  0:57 ` [PATCH for_v29 0/8] x86/sgx: Make vDSO callable " Jarkko Sakkinen
2020-03-20 23:25   ` Sean Christopherson
2020-03-21  0:55     ` Jarkko Sakkinen
2020-03-21 20:11       ` Sean Christopherson

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