From: Michael Clark <michaeljclark@mac.com>
To: musl@lists.openwall.com,
Dean Michael Ancajas <dbancajas@gmail.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Rich Felker <dalias@libc.org>
Subject: Re: Porting to RISC-V
Date: Thu, 03 May 2018 08:37:13 +1200 [thread overview]
Message-ID: <BF67221A-08E1-4578-9268-B46D4F4289CF@mac.com> (raw)
In-Reply-To: <20180502194533.GB1392@brightrain.aerifal.cx>
> On 3/05/2018, at 7:45 AM, Rich Felker <dalias@libc.org> wrote:
>
> On Wed, May 02, 2018 at 03:40:04PM -0400, Dean Michael Ancajas wrote:
>> Can you send a link of the wiki?
>
> https://wiki.musl-libc.org/
> https://wiki.musl-libc.org/porting.html
Here’s a pointer to my fork of Aric Belsito’s tree, including several fixes to get threads and atomics passing libc-tests.
- https://github.com/michaeljclark/musl-riscv
This is the list of contributors as far as I know, but I might have to do a deeper inspection of the git history:
Aric Belsito <lluixhi@gmail.com>
Alex Suykov <alex.suykov@gmail.com>
Michael Clark <michaeljclark@mac.com>
I’ve talked to Palmer Dabbelt about moving the port to the riscv github organisation retaining all of the contributor history. Typically riscv repos are prefixed with riscv- versus suffixed however that is a minor detail. We’ll need to squash the port into some more logical commits as there is quite a bit of churn in the history, however we’ll tag the repo in its current state to keep the contributor history.
Threads and mutexes are working. I need to sync with latest musl and run libc-tests again and we need to run the tests in RISC-V Linux versus RISC-V QEMU linux-user. Running against linux-kernel will give more accurate results compared to QEMU’s linux-user emulation which may not be 100% accurate. This is easier to do now as there are several glibc based full Linux distros that can be run in QEMU RISC-V and on real hardware with networking and block storage. i.e. we can rsync binaries in over ssh in the QEMU virt machine. Indeed folk have been running self-hosted GCC bootstraps in the Fedora RISC-V port which has toolchain packages. Now there is a Debian port, and iirc there may even be a SUSE port (Palmer?)
Here is some recent info on QEMU for RISC-V, which might help with the porting effort:
- https://github.com/riscv/riscv-qemu/wiki
- https://www.sifive.com/blog/2018/04/25/risc-v-qemu-part-2-the-risc-v-qemu-port-is-upstream/
Here is the last update I sent regarding the RISC-V musl port…
Issues fixed since picking up GSoC musl-riscv branch:
• gcc patch to set the musl dynamic linker name (ELF interp) is upstream
• /lib/ld-musl-riscv32.so.1 (-mabi=ilp32d, default, hard float)
• /lib/ld-musl-riscv64.so.1 (-mabi=lp64d, default, hard float)
• /lib/ld-musl-riscv32-sf.so.1 (-mabi=ilp32, soft float)
• /lib/ld-musl-riscv64-sf.so.1 (-mabi=lp64, soft float)
• /lib/ld-musl-riscv32-sp.so.1 (-mabi=ilp32f, single precision)
• /lib/ld-musl-riscv64-sp.so.1 (-mabi=lp64f, single precision)
• fixed failing pthread tests.
• a_cas was deadlocking (updated a_cas in atomic_a.h, fixed missing inline asm constraint)
• defined the minimal set of atomics required by the musl library
• fixed failing sigaltstack tests (update sigaltstack and ucontext in signal.h)
• fixed failing ipc_sem tests (added struct semid_ds in sem.h)
• fixed failing stat tests (defined blksize_t and nlink_t in alltypes.h.in)
• rename sigcontext __regs to gregs so that gcc would compile
• rename _gp to __global_pointer$ in the crt to work with current binutils
• change definition of long double to quadruple precision
• update syscalls.h.in to use asm-generic syscall definitions
• update stat.h to use asm-generic stat definition
Remaining issues:
• rebase to current musl-libc
• audit arch/riscv32 and arch/riscv64 headers to make sure they match linux-4.16
• check results of tests that are expected to fail (compare with other architectures)
• ELF thread local variables are not being initialised
• tls_init test is failing
Note: riscv32 glibc is not yet upstream so the 32-bit ABI is not yet frozen.
Rich, BTW It seems the TLS offset is directly above the thread pointer (tp).
$ cat foo.c
__thread int i = 42;
void foo()
{
i++;
}
0000000000010226 <foo>:
10226: 00022703 lw a4,0(tp) # 0 <i>
1022a: 2705 addiw a4,a4,1
1022c: 00e22023 sw a4,0(tp) # 0 <i>
10230: 8082 ret
0000000000010a7a <__set_thread_area>:
10a7a: 822a mv tp,a0
10a7c: 4501 li a0,0
10a7e: 8082 ret
Michael.
next prev parent reply other threads:[~2018-05-02 20:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-02 19:28 Dean Michael Ancajas
2018-05-02 19:37 ` Rich Felker
2018-05-02 19:40 ` Dean Michael Ancajas
2018-05-02 19:45 ` Rich Felker
2018-05-02 20:37 ` Michael Clark [this message]
2018-05-02 20:45 ` Palmer Dabbelt
2018-09-23 0:55 ` Khem Raj
2018-09-23 0:45 ` Rich Felker
2018-09-23 2:40 ` Michael Clark
2018-09-23 2:47 ` Rich Felker
2018-09-23 4:41 ` Michael Clark
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