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Date:   Mon, 15 Jun 2020 23:17:54 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To:     Sean Christopherson <sean.j.christopherson@intel.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-sgx@vger.kernel.org, linux-kselftest@vger.kernel.org,
        akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
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        rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com
Subject: Re: [PATCH v32 19/21] selftests/x86: Add a selftest for SGX
Message-ID: <20200615201754.GD5416@linux.intel.com>
References: <20200601075218.65618-1-jarkko.sakkinen@linux.intel.com>
 <20200601075218.65618-20-jarkko.sakkinen@linux.intel.com>
 <20200603220634.GB25606@linux.intel.com>
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On Wed, Jun 03, 2020 at 03:06:34PM -0700, Sean Christopherson wrote:
> On Mon, Jun 01, 2020 at 10:52:16AM +0300, Jarkko Sakkinen wrote:
> > Add a selftest for SGX. It is a trivial test where a simple enclave
> > copies one 64-bit word of memory between two memory locations.
> 
> ...
> 
> > --- /dev/null
> > +++ b/tools/testing/selftests/sgx/Makefile
> > @@ -0,0 +1,53 @@
> > +top_srcdir = ../../../..
> > +
> > +include ../lib.mk
> > +
> > +.PHONY: all clean
> > +
> > +CAN_BUILD_X86_64 := $(shell ../x86/check_cc.sh $(CC) \
> > +			    ../x86/trivial_64bit_program.c)
> > +
> > +ifndef OBJCOPY
> > +OBJCOPY := $(CROSS_COMPILE)objcopy
> > +endif
> > +
> > +INCLUDES := -I$(top_srcdir)/tools/include
> > +HOST_CFLAGS := -Wall -Werror -g $(INCLUDES) -fPIC -z noexecstack
> 
> There's a pending pull request for 5.8[1] that includes a patch that turns
> off automatic READ_IMPLIES_EXEC for x86_64[2].  Assuming that gets pulled
> for 5.8, we should drop noexecstack to verify/ensure that the workaround is
> no longer needed to avoid conflicts with the EPCM permissions.
> 
> [1] https://lkml.kernel.org/r/20200603213452.GG19667@zn.tnic
> [2] https://lkml.kernel.org/r/20200327064820.12602-4-keescook@chromium.org

If the check is removed from encl.c, then this needs to be taken into
account in backporting.

/Jarkko