From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Xing, Cedric" <cedric.xing@intel.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Nathaniel McCallum <npmccallum@redhat.com>,
Jethro Beekman <jethro@fortanix.com>,
Andy Lutomirski <luto@amacapital.net>,
linux-sgx@vger.kernel.org
Subject: Re: [PATCH for_v29 3/8] x86/sgx: vdso: Make __vdso_sgx_enter_enclave() callable from C code
Date: Thu, 19 Mar 2020 13:11:45 -0700 [thread overview]
Message-ID: <20200319201144.GF11305@linux.intel.com> (raw)
In-Reply-To: <9a4878b9-bcad-b279-acd5-2eef03b13af8@intel.com>
On Thu, Mar 19, 2020 at 01:03:41PM -0700, Xing, Cedric wrote:
> On 3/18/2020 6:11 PM, Sean Christopherson wrote:
> > #endif
> > SYM_FUNC_START(__vdso_sgx_enter_enclave)
> > /* Prolog */
> >@@ -82,7 +84,9 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave)
> > .cfi_rel_offset %rbp, 0
> > mov %rsp, %rbp
> > .cfi_def_cfa_register %rbp
> >+ push %rbx
> A CFI directive is needed here:
>
> .cfi_rel_offset %rbx, -8
Darn, I suspected as much, but wasn't 100% positive. Shouldn't have
hedged. :-)
Is the rule of thumb for adding directives that one is needed any time
there is a new saved value of a register, or if the relative address of
the last saved value changes? Are CFI directives only used for
non-volatile registers?
> >+ mov %ecx, %eax
> > .Lenter_enclave:
> > /* EENTER <= leaf <= ERESUME */
> > cmp $0x2, %eax
> >@@ -108,6 +112,7 @@ SYM_FUNC_START(__vdso_sgx_enter_enclave)
> > jne .Linvoke_userspace_handler
> > .Lout:
> >+ pop %rbx
> > leave
> > .cfi_def_cfa %rsp, 8
> > ret
> >
next prev parent reply other threads:[~2020-03-19 20:11 UTC|newest]
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 [this message]
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 ` [PATCH for_v29 7/8] selftests/x86: sgx: Stop clobbering non-volatile registers Sean Christopherson
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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