RISC-V doesn't support floating-point exceptions.
RISC-V Instruction Set Manual: Volume I: User-Level ISA, 11.2 Floating-Point
Control and Status Register: "As allowed by the standard, we do not support
traps on floating-point exceptions in the base ISA, but instead require
explicit checks of the flags in software. We considered adding branches
controlled directly by the contents of the floating-point accrued exception
flags, but ultimately chose to omit these instructions to keep the ISA simple."
We still need these functions, because some applications (notably Perl) call
them, but we cannot provide a meaningful implementation.
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D25740
This avoids passing garbage to sigprocmask() if the jump buffer is
invalid.
Reviewed by: mhorne
Obtained from: CheriBSD
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24483
- Use a constant for the offset instead of a magic number.
- Use an addi instruction that writes to tp directly instead of a mv
that writes the result of a compiler-generated addi.
Reviewed by: mhorne
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D23521
Conditional branch and jump instructions do not always call via PLT
stubs and thus will not honor LD_PRELOAD, etc. lld warns about using
non-preemptible relocations for preemptible or unknown symbols whereas
bfd does not (at least for RISC-V).
Reviewed by: br, James Clarke
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22658
This saves an instruction in each case as well as an extra memory
indirection via the GOT for PIC code.
Reviewed by: br, James Clarke
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22656
o The correct value for _JB_SIGMASK is 27.
o The storage size for double-precision floating
point register is 8 bytes.
Submitted by: "James Clarke" <jrtc4@cam.ac.uk>
Reviewed by: markj@
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D16344
With SOFTFLOAT, libc and libm were built correctly, but any program
including fenv.h itself assumed it was on a hardfloat systen and emitted
inline fpu instructions for fedisableexcept() and friends.
Unlike r315424 which did this for MIPS, I've used riscv_float_abi_soft
and riscv_float_abi_double macros as appropriate rather than using
__riscv_float_abi_soft exclusively. This ensures that attempts to use an
unsupported hardfloat ABI will fail.
Reviewed by: br
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D10039
New version is not compatible on supervisor mode with v1.9.1
(previous version).
Highlights:
o BBL (Berkeley Boot Loader) provides no initial page tables
anymore allowing us to choose VM, to build page tables manually
and enable MMU in S-mode.
o SBI interface changed.
o GENERIC kernel.
FDT is now chosen standard for RISC-V hardware description.
DTB is now provided by Spike (golden model simulator). This
allows us to introduce GENERIC kernel. However, description
for console and timer devices is not provided in DTB, so move
these devices temporary to nexus bus.
o Supervisor can't access userspace by default. Solution is to
set SUM (permit Supervisor User Memory access) bit in sstatus
register.
o Compressed extension is now turned on by default.
o External GCC 7.1 compiler used.
o _gp renamed to __global_pointer$
o Compiler -march= string is now in use allowing us to choose
required extensions (compressed, FPU, atomic, etc).
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D11800
Hardfloat is now default (use riscv64sf as TARGET_ARCH
for softfloat).
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D8529
