arch-riscv: Fix implementation of CMO extension instructions
This change introduces a template for store instruction's mem access.
The new template is called CacheBlockBasedStore.
The reasons for not reusing the current Store's mem access template
are as follows,
- The CMO extension instructions operate on cache block size
granularity,
while regular load/store instructions operate on data of size 64 bits or
fewer.
- The writeMemAtomicLE/writeMemTimingLE interfaces do not allow passing
nullptr as data. However, CPUs in gem5 rely on (data == NULL) to detect
CACHE_BLOCK_ZERO instructions. Setting `Mem = 0;` to `uint64_t Mem;`
does not solve the problem as the reference is allocated and thus,
it's always true that `&Mem != NULL`. This change uses the
writeMemAtomic/writeMemTiming interfaces instead.
- Per CMO v1.0.1, the instructions in the spec do not generate
address misaligned faults.
- The CMO extension instructions do not use IMM.
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arch-riscv: Fix generateDisassembly for Store with 1 source reg
Currently, store instructions are assumed to have two source registers.
However, since we are supporting the RISC-V CMO instructions, which
are Store instructions in gem5 but they only have one source register.
This change allows printing disassembly of Store instructions with
one source register.
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arch-riscv: Make Zicbom/Zicboz extensions optional in FS mode
Currently, we're enable Zicbom/Zicboz by default. Since those
extensions might be buggy as they are not well-tested, making
those entensions optional allows running simulation where
the performance implication of the instructions do not matter.
Effectively, by turning off the extensions, we simply remove
those extensions from the device tree, so the OS would not
use them. It doesn't prohibit the userspace application to
use those instructions, however.
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arch-riscv: Add all supporting Z extensions to RISC-V isa string
52354662aa