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From: "Huang, Kai" <kai.huang@intel.com>
To: "linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
	"jarkko@kernel.org" <jarkko@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Van Bulck, Jo" <jo.vanbulck@cs.kuleuven.be>
Cc: "dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>
Subject: Re: [PATCH v5 08/13] selftests/sgx: Handle relocations in test enclave
Date: Fri, 1 Sep 2023 00:16:04 +0000	[thread overview]
Message-ID: <78a775310efdd4c0f3505d6b18788408b3a2ea4f.camel@intel.com> (raw)
In-Reply-To: <55ef3859-774e-1bd3-0e2a-5105cbf0d33a@cs.kuleuven.be>

On Fri, 2023-09-01 at 01:26 +0200, Jo Van Bulck wrote:
> On 01.09.23 01:13, Huang, Kai wrote:
> > > encl_body:
> > >      /* snipped */
> > >      lea    encl_op_array(%rip), %rcx
> > >      lea    __encl_base(%rip), %rax
> > >      add    (%rcx,%rdx,8),%rax
> > >      jmp    *%rax
> > 
> > call *%rax
> > 
> > ?
> > 
> > >      ret
> 
> Good catch, but this is indeed the code as generated with gcc -Os (for 
> readability). It seems the compiler choose a JMP over a CALL (as the 
> stack is untouched and the callee can immediately return to the caller).

Ah, OK.

I thought it's a typo, but obviously the compiler is smarter. :-)

> 
> Somehow, the compiler still emits a RET after the JMP (which is not 
> supposed to return here) though. I agree this is unnecessarily confusing 
> and can simply remove the RET from the commit message.

The RET is for encl_body itself I suppose.

> 
> Best,
> Jo


  reply	other threads:[~2023-09-01  0:16 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-31 13:41 [PATCH v5 00/13] selftests/sgx: Fix compilation errors Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 01/13] selftests/sgx: Fix uninitialized pointer dereference in error path Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 02/13] selftests/sgx: Fix uninitialized pointer dereferences in encl_get_entry Jo Van Bulck
2023-09-04 20:27   ` Jarkko Sakkinen
2023-08-31 13:41 ` [PATCH v5 03/13] selftests/sgx: Include memory clobber for inline asm in test enclave Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 04/13] selftests/sgx: Separate linker options Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 05/13] selftests/sgx: Specify freestanding environment for enclave compilation Jo Van Bulck
2023-08-31 23:15   ` Huang, Kai
2023-08-31 13:41 ` [PATCH v5 06/13] selftests/sgx: Remove redundant enclave base address save/restore Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 07/13] selftests/sgx: Produce static-pie executable for test enclave Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 08/13] selftests/sgx: Handle relocations in " Jo Van Bulck
2023-08-31 23:13   ` Huang, Kai
2023-08-31 23:26     ` Jo Van Bulck
2023-09-01  0:16       ` Huang, Kai [this message]
2023-08-31 13:41 ` [PATCH v5 09/13] selftests/sgx: Fix linker script asserts Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 10/13] selftests/sgx: Ensure test enclave buffer is entirely preserved Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 11/13] selftests/sgx: Ensure expected location of test enclave buffer Jo Van Bulck
2023-08-31 13:41 ` [PATCH v5 12/13] selftests/sgx: Discard unsupported ELF sections Jo Van Bulck
2023-09-04 20:33   ` Jarkko Sakkinen
2023-08-31 13:41 ` [PATCH v5 13/13] selftests/sgx: Remove incomplete ABI sanitization code in test enclave Jo Van Bulck
2023-09-04 20:39   ` Jarkko Sakkinen

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