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_v37 1/6] x86/vdso: x86/sgx: Explicitly force 8-byte CMP for detecting user handler
Date: Fri, 4 Sep 2020 03:44:32 -0700 [thread overview]
Message-ID: <20200904104437.29555-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200904104437.29555-1-sean.j.christopherson@intel.com>
Use 'cmpq' to force an 8-byte CMP when checking for a user provided exit
handler. The handler is a pointer, which is guaranteed to be an 8-byte
value since SGX is 64-bit mode only, and gcc defaults to 'cmpl' given a
bare 'cmp', i.e. is only checking the lower 32 bits. This could cause
a false negative when detecting a user exit handler.
Acked-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Acked-by: Jethro Beekman <jethro@fortanix.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/entry/vdso/vsgx_enter_enclave.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/entry/vdso/vsgx_enter_enclave.S b/arch/x86/entry/vdso/vsgx_enter_enclave.S
index be7e467e1efb3..2d88acd408d4e 100644
--- a/arch/x86/entry/vdso/vsgx_enter_enclave.S
+++ b/arch/x86/entry/vdso/vsgx_enter_enclave.S
@@ -48,7 +48,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave)
/* Invoke userspace's exit handler if one was provided. */
.Lhandle_exit:
- cmp $0, 0x20(%rbp)
+ cmpq $0, 0x20(%rbp)
jne .Linvoke_userspace_handler
.Lout:
--
2.28.0
next prev parent reply other threads:[~2020-09-04 10:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 10:44 [PATCH for_v37 0/6] x86/vdso: x86/sgx: Rework SGX vDSO API Sean Christopherson
2020-09-04 10:44 ` Sean Christopherson [this message]
2020-09-04 10:44 ` [PATCH for_v37 2/6] x86/vdso: x86/sgx: Rework __vdso_sgx_enter_enclave() API Sean Christopherson
2020-09-04 13:46 ` Jarkko Sakkinen
2020-09-04 10:44 ` [PATCH for_v37 3/6] x86/vdso: x86/sgx: Introduce dedicated SGX exit reasons for vDSO Sean Christopherson
2020-09-04 14:06 ` Jarkko Sakkinen
2020-09-04 10:44 ` [PATCH for_v37 4/6] selftests/sgx: Update the SGX selftest to match the reworked vDSO API Sean Christopherson
2020-09-04 14:07 ` Jarkko Sakkinen
2020-09-04 10:44 ` [PATCH for_v37 5/6] selftests/sgx: Sanity check the return value of the vDSO call Sean Christopherson
2020-09-04 14:07 ` Jarkko Sakkinen
2020-09-04 10:44 ` [PATCH for_v37 6/6] selftests/sgx: Add a smoke test to ensure the user handler is invoked Sean Christopherson
2020-09-04 14:10 ` Jarkko Sakkinen
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