While running the GCC test suite against 4.0.0-rc0, Kito found a
regression introduced by the decodetree conversion that caused divuw and
remuw to sign-extend their inputs. The ISA manual says they are
supposed to be zero extended:
DIVW and DIVUW instructions are only valid for RV64, and divide the
lower 32 bits of rs1 by the lower 32 bits of rs2, treating them as
signed and unsigned integers respectively, placing the 32-bit
quotient in rd, sign-extended to 64 bits. REMW and REMUW
instructions are only valid for RV64, and provide the corresponding
signed and unsigned remainder operations respectively. Both REMW
and REMUW always sign-extend the 32-bit result to 64 bits, including
on a divide by zero.
Here's Kito's reduced test case from the GCC test suite
unsigned calc_mp(unsigned mod)
{
unsigned a,b,c;
c=-1;
a=c/mod;
b=0-a*mod;
if (b > mod) { a += 1; b-=mod; }
return b;
}
int main(int argc, char *argv[])
{
unsigned x = 1234;
unsigned y = calc_mp(x);
if ((sizeof (y) == 4 && y != 680)
|| (sizeof (y) == 2 && y != 134))
abort ();
exit (0);
}
I haven't done any other testing on this, but it does fix the test case.
Backports commit f17e02cd3731bdfe2942d1d0b2a92f26da02408c from qemu
If vectored interrupts are enabled (bits[1:0]
of mtvec/stvec == 1) then use the following
logic for trap entry address calculation:
pc = mtvec + cause * 4
In addition to adding support for vectored interrupts
this patch simplifies the interrupt delivery logic
by making sync/async cause decoding and encoding
steps distinct.
The cause code and the sign bit indicating sync/async
is split at the beginning of the function and fixed
cause is renamed to cause. The MSB setting for async
traps is delayed until setting mcause/scause to allow
redundant variables to be eliminated. Some variables
are renamed for conciseness and moved so that decls
are at the start of the block.
Backports commit acbbb94e5730c9808830938e869d243014e2923a from qemu
This effectively changes riscv_cpu_update_mip
from edge to level. i.e. cpu_interrupt or
cpu_reset_interrupt are called regardless of
the current interrupt level.
Fixes WFI doesn't return when a IPI is issued:
- https://github.com/riscv/riscv-qemu/issues/132
To test:
1) Apply RISC-V Linux CPU hotplug patch:
- http://lists.infradead.org/pipermail/linux-riscv/2018-May/000603.html
2) Enable CONFIG_CPU_HOTPLUG in linux .config
3) Try to offline and online cpus:
echo 1 > /sys/devices/system/cpu/cpu2/online
echo 0 > /sys/devices/system/cpu/cpu2/online
echo 1 > /sys/devices/system/cpu/cpu2/online
Backports commit d26f5a423438e579d3ff0ca35e44edb966a36233 from qemu
This change checks elf_flags for EF_RISCV_RVE and if
present uses the RVE linux syscall ABI which uses t0
for the syscall number instead of a7.
Warn and exit if a non-RVE ABI binary is run on a
cpu with the RVE extension as it is incompatible.
Backports relevant parts of 5836c3eccedb6dfab16b8f606f2de24b8938b69c
from qemu
We can't allow the supervisor to control SEIP as this would allow the
supervisor to clear a pending external interrupt which will result in
lost a interrupt in the case a PLIC is attached. The SEIP bit must be
hardware controlled when a PLIC is attached.
This logic was previously hard-coded so SEIP was always masked even
if no PLIC was attached. This patch adds riscv_cpu_claim_interrupts
so that the PLIC can register control of SEIP. In the case of models
without a PLIC (spike), the SEIP bit remains software controlled.
This interface allows for hardware control of supervisor timer and
software interrupts by other interrupt controller models.
Backports commit e3e7039cc24ecf47d81c091e8bb04552d6564ad8 from qemu
Add a debugger field to CPURISCVState. Add riscv_csrrw_debug function
to set it. Disable mode checks when debugger field true.
Backports commit 753e3fe207db08ce0ef0405e8452c3397c9b9308 from qemu
This adds some missing CSR_* register macros, and documents some as being
priv v1.9.1 specific.
Backports commit 8e73df6aa3f2f0e5c26c03a94a88406616291815 from qemu
during the refactor to decodetree we removed the manual decoding that is
necessary for c.jal/c.addiw and removed the translation of c.flw/c.ld
and c.fsw/c.sd. This reintroduces the manual parsing and the
omited implementation.
Backports commit f330433b3633647b047cfa418c2ca4d18fda69c7 from qemu
with all 16 bit insns moved to decodetree no path is falling back to
gen_system(), so we can remove it.
Backports commit 8f7bc273868939f0821e07fb23792db63d45bffb from qemu
manual decoding in gen_arith() is not necessary with decodetree. For now
the function is called trans_arith as the original gen_arith still
exists. The former will be renamed to gen_arith as soon as the old
gen_arith can be removed.
Backports commit f2ab1728675772cd475a33f4df3d2f68a22c188f from qemu
gen_arith_imm() does a lot of decoding manually, which was hard to read
in case of the shift instructions and is not necessary anymore with
decodetree.
Backports commit 7a50d3e2ae7f13b24fe55990ea0b8ddcbbb43130 from qemu
With decodetree we don't need to convert RISC-V opcodes into to MemOps
as the old gen_store() did.
Backports commit bce8a342a1f0919479d18ec812b100136daa746b from qemu
With decodetree we don't need to convert RISC-V opcodes into to MemOps
as the old gen_load() did.
Backports commit 98898b20e9cca462843c22ad952c216ffd57d654 from qemu
We now utilizes argument-sets of decodetree such that no manual
decoding is necessary.
Backports commit 090cc2c898a04e42350eabf1bcf7d245471603f9 from qemu
we cannot remove the call to gen_arith() in decode_RV32_64G() since it
is used to translate multiply instructions.
Backports commit b73a987b09ad5081123dc6b1e8e6c8305a1c8673 from qemu
this splits the 64-bit only instructions into its own decode file such
that we generate the decoder for these instructions only for the RISC-V
64 bit target.
Backports commit 7e45a682edc32ba90d6955215f062210531b835b from qemu
for now only LUI & AUIPC are decoded and translated. If decodetree fails, we
fall back to the old decoder.
Backports commit 2a53cff418335ccb4719e9a94fde55f6ebcc895d from qemu
This ports over the RISC-V architecture from Qemu. This is currently a
very barebones transition. No code hooking or any fancy stuff.
Currently, you can feed it instructions and query the CPU state itself.
This also allows choosing whether or not RISC-V 32-bit or RISC-V 64-bit
is desirable through Unicorn's interface as well.
Extremely basic examples of executing a single instruction have been
added to the samples directory to help demonstrate how to use the basic
functionality.
