RISC-V glibc port, v7

[Palmer Dabbelt]

On Fri, 26 Jan 2018 19:57:27 PST (-0800), Palmer Dabbelt wrote:
> This v7 patch set contains what I think should be an acceptable glibc port for
> 64-bit RISC-V systems.  We've gotten some tenative approval for the v6 with
> changes, but I wanted to send another patch set out just to make sure everyone
> is on the same page.  The test suite is in roughly the same shape as it was
> last night, with the only expected difference being a handful of fixed test
> cases resulting from adding ipc_priv.h.  I've added Darius, Andrew, DJ, and
> myself as maintainers on the wiki and have updated most of the relevant pages.
>
> Darius has wiki access and will post the full test suite results as they come
> in.  Some preliminary results are on the wiki now.  This passes
> build-many-glibcs.py (with the listed modifications in the patch to add our
> targets) and doesn't regress on the test suite (for my admittedly limited
> qemu-user testing) for any of the targets.
>
> The one wrinkle here is that our Linux port doesn't land in a tarball until
> 4.15.  I'd be OK holding off until 4.15 is released (which will ideally be this
> Sunday), or submiting a follow-on patch to bump the Linux headers to 4.15 after
> merging this.  I ran a full build-many-glibcs.py with an Linux headers from an
> earlier 4.15 RC (I think maybe rc3), but I haven't run one since then.  I've
> kicked off the build but it'll take a while.
>
> Thanks, again, to everyone who has helped review our port!
>
> The full log of changes since the v6 port is:
>
> * We now have an ipc_priv.h
> * System call errors negate a0.
> * There's a soft-float libm-test-ulps file.
> * The __riscv_flen #ifs around EXCEPTION_TESTS and ROUNDING_TESTS go the right
>   way.
> * The comment in flush-icache.c has been corrected.
> * We use '.section .init_array,"a",%init_array' in crti.S.
> * crti.S no longer includes sys/asm.h.
> * The last remaining (as far as I know) ilp32/ilp32d references have been removed .
> * I've added mechanical ChangeLog entries to all the commits that just add new
>   files (the other commits already had entries).
>
> [v6] This v6 patch set is largely the same as the v5 patch set I submitted
> yesterday, but with the following changes:
>
> * We're now more explicit about the targets we support, which are
>   rv64imac/lp64, rv64imafdc/lp64, and rv64imafdc/lp64d (rv64gc is an alias for
>   rv64imafdc, and while I've tried to be consistent in the commits I might have
>   confused them a handful of times on the mailing list in conversation).
> * All mentions of the rv32i-based port have been removed, including removing
>   all the rv32 folders.
> * The ABI lists are listed as rv64 specific, we'll be targeting glibc-2.28 for
>   rv32 support.
> * build-many-glibcs.py now builds three non-multilib GCCs for RISC-V, each of
>   which builds one of the supported targets.
> * Our crti.S has been merged into sysdeps/init_array.
> * The soft float test support macros has been fixed.
> * The check for RVC has been removed, which I forgot about some how.
> * sysdep-cancel.h has been removed as it's obselete.
> * Some whitespace changes.
>
> [v5] A short log of the changes since our v4 includes
>
> * A proper implementation of lroundf on rv64.
> * Moving back to a nofpu directory, which got eaten by a previous patch set.
> * Support for dl-cache.
> * Many comment and whitespace fixes.
> * Better documentation of __riscv_flush_icache, along with some namespace
>   cleanups.
> * We now call the exit system call instead of _exit after a thread terminates.
> * Correct handling of S1 and S2 in ucontext-related code.
> * Correct SP handling when arguments are on the stack in ucontext-related code.
> * Correctly saving sigmask on setcontext.
> * We now test for floating-point exceptions.
>
> [v4] A highlight of the changes since our v3 includes:
>
> * Some ABI list cleanups, to match a few changes between when we last rebased
>   and now.
> * ucontext.h namespace fixes.
> * Copyright year has been updated to 2018, and "contributed by" lines have been
>   removed.
> * int in specified in all places were optional.
> * The floating-point support no longer uses ABI types, but uses explicit bit
>   widths.
> * Some floating point test macros have been defined to inform the test suite
>   how our ISA operates.
> * We now examine the ELF flags.
> * I've added ChangeLog entries for all the commits except those that just add
>   new files.
>
> [v3] Here's a summary of the changes since the previous patch set:
>
> * We now have 4 ABI/ISA pairs in build-many-glibcs.py, which is clean (with the
>   newest linux headers, see the patch for details).
> * Support for ilp32f and lp64f have been removed.
> * Support for systems without the A extension has been removed.
> * There are now ABI lists.
> * Many whitespace fixes to meet glibc's standards.
> * Included C and ASM files from other ports have been copied into ours.
> * with_fp_cond is now set, but I don't have a soft-fp directory yet.
> * We no longer maintain a -mno-plt list in our port, that existed to work
>   around a linker bug and is now defunct.
> * A handful of header files (mostly ucontext.h) have been cleaned up to be
>   namespace clean.
>
> [v2] A (very brief, as it's been 6 months) summary of the changes since the v1
> patch set includes:
>
> * Many copyright cleanups.
> * We're using the generic versions of a handful of functions and headers,
>   including ieee754.h, mathdef.h mathinline.h, fabs{,f}, and
>   fe{disable,enable,get}except.
> * Removal of lots of head code, including pthread_lock, atomic_fast.
> * A handful of ABI fixes to match our upstreamed Linux port, including
>   sigcontext, instruction-cache flushing, and some syscall sanitization.
> * We've changed to use libm_alias_{float,double}, like upstream
> * Compiler builtins are used for atomics where possible.
> * We now mandate the A extension in Linux, support for non-A systems has been
>   removed from glibc.
>
> [PATCH v7 01/17] sysdeps/init_array: Add PREINIT_FUNCTION to crti.S
> [PATCH v7 02/17] Skeleton documentation for the RISC-V port
> [PATCH v7 03/17] Add RISC-V entries to config.h.in
> [PATCH v7 04/17] Add documentation for __riscv_flush_icache
> [PATCH v7 05/17] RISC-V: ABI Implementation
> [PATCH v7 06/17] RISC-V: Startup and Dynamic Loading Code
> [PATCH v7 07/17] RISC-V: Thread-Local Storage Support
> [PATCH v7 08/17] RISC-V: Generic <math.h> and soft-fp Routines
> [PATCH v7 09/17] RISC-V: Hard Float Support
> [PATCH v7 10/17] RISC-V: Atomic and Locking Routines
> [PATCH v7 11/17] RISC-V: Linux Syscall Interface
> [PATCH v7 12/17] RISC-V: Linux ABI
> [PATCH v7 13/17] RISC-V: Linux Startup and Dynamic Loading Code
> [PATCH v7 14/17] RISC-V: Add ABI Lists
> [PATCH v7 15/17] RISC-V: Build Infastructure
> [PATCH v7 16/17] Add RISC-V to build-many-glibcs.py
> [PATCH v7 17/17] RISC-V: Add ipc_priv.h

Committed, with a handful of small changes.