Compiling for RISC-V

[John Baldwin]

FreeBSD ships OpenSSL 1.1.1 for FreeBSD/riscv (which is RV64 only).  I
don't recall having to do anything unusual to get OpenSSL to build or
run on RISC-V for that.

On 3/9/20 12:23 PM, Kristin Barber wrote:
> I did also try configuring for "no-asm", but there still seemed to be
> architecture-specific issues based on which files the errors were coming
> from.  I should probably also mention that I am attempting to cross-compile
> for RV64 from an x86 machine.
> 
> On Mon, Mar 9, 2020 at 3:12 PM Scott Neugroschl <scott_n at xypro.com> wrote:
> 
>>
>>
>> Is the “no-asm” configuration option still supported?
>>
>>
>>
>> *From:* openssl-users <openssl-users-bounces at openssl.org> *On Behalf Of *Kristin
>> Barber
>> *Sent:* Monday, March 9, 2020 12:03 PM
>> *To:* Richard Levitte <levitte at openssl.org>
>> *Cc:* openssl-users at openssl.org
>> *Subject:* Re: Compiling for RISC-V
>>
>>
>>
>> Hi Richard, thanks for the reply. It was helpful.
>>
>>
>>
>> You are correct, I was able to find a configuration that worked by passing
>> the RISC-V compiler via "make variable" assignment, along with some
>> relevant options.  Things start compiling, but the build fails on what
>> seems to be architecture-specific assembly files which are selected based
>> on which "platform" has been configured.  It did not seem to me that there
>> were RISC-V assembly-specific files as an option here, and based on your
>> reply, I think that is indeed the issue.  Am I understanding this correctly?
>>
>>
>>
>> Thanks,
>>
>>
>>
>> Kristin
>>
>>
>>
>> On Mon, Mar 9, 2020 at 3:03 AM Richard Levitte <levitte at openssl.org>
>> wrote:
>>
>> On Mon, 09 Mar 2020 05:18:17 +0100,
>> Kristin Barber wrote:
>>> I've looked at the INSTALL docs, and it doesn't seem that RISC-V
>> processors are supported
>>> currently as a platform. Is this correct?
>>
>> That is correct.  No one has implemented that support yet.
>>
>>> Is there a branch which enables configuring for a RISC-V machine that
>> hasn't yet made it into a
>>> stable release?
>>
>> Not that I know of.  Although, this same question has also been raised
>> on github (I forget the issue number).
>>
>>> Any advice on where to look for information or changes to the build
>> process in order to compile
>>> for RISC-V?
>>
>> The first thing to attempt is a generic build with no assembler.
>> There are some really simply config targets that could be a first
>> step, one of:
>>
>>     ./Configure cc
>>
>>     ./Configure gcc
>>
>> A (pretty big) step up from that, at least if Linux is your target,
>> would be one of these:
>>
>>     ./Configure linux-generic32
>>
>>     ./Configure linux-generic64
>>
>> Note that in either case, you may have to add C flags and ld flags,
>> which you can do in one of two ways:
>>
>> 1)  directly on the configuration command line, like this (Configure
>>     makes an educated guess on what flags go where):
>>
>>     ./Configure linux-generic64 -m64 -DWHATEVER=value -Wl,-something
>>
>> 2)  via "make variable" assignment:
>>
>>     ./Configure linux-generic64 \
>>                 CPPFLAGS='-DWHATEVER=value' \
>>                 CFLAGS='-m64' \
>>                 LDFLAGS='-Wl,-something'
>>
>> At some point, you might find a combination that works for you.  We
>> would definitely like to know what you figure out, and it may be that
>> the result makes it into our database of config targets (which, if
>> you're curious, are the files Configurations/*.conf).
>>
>> Now, configuration is the easy bit when it comes to new CPUs,
>> relatively speaking.  I assume that part of your question is whether
>> there is assembler support.  This is the hard part in terms of
>> effort.  We currently have no such thing at all for RISC-V, and I
>> haven't seen any attempts to start such an effort...  PRs would
>> certainly be welcome, but anyone who tries this will have to be
>> prepared for it to take a while to get into the main source.
>>
>> Cheers,
>> Richard
>>
>> --
>> Richard Levitte         levitte at openssl.org
>> OpenSSL Project         http://www.openssl.org/~levitte/
>> <https://linkprotect.cudasvc.com/url?a=http%3a%2f%2fwww.openssl.org%2f~levitte%2f&c=E,1,X0wuSd-kz2nVhT_NOTOEEEyCfRQ3PVlEpzPg7qMVOE18vBdtM4EJjJ0PDdArARBsvQZdWJpbcy94bbUgzuKmj9jsBIiAzT87yPNJQ_aU-tOjP9VR4huaxBYl6g,,&typo=1>
>>
>>
> 


-- 
John Baldwin