Access to a counter in U-mode is permitted only if the corresponding
bit is set in both mcounteren and scounteren. The current code
ignores mcounteren and checks scounteren only for U-mode access.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This patch adds support for writing misa. misa is validated based
on rules in the ISA specification. 'E' is mutually exclusive with
all other extensions. 'D' depends on 'F' so 'D' bit is dropped
if 'F' is not present. A conservative approach to consistency is
taken by flushing the translation cache on misa writes. misa_mask
is added to the CPU struct to store the original set of extensions.
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
* Add riscv prefix to raise_exception function
* Add riscv prefix to CSR read/write functions
* Add riscv prefix to signal handler function
* Add riscv prefix to get fflags function
* Remove redundant declaration of riscv_cpu_init
and rename cpu_riscv_init to riscv_cpu_init
* rename riscv_set_mode to riscv_cpu_set_mode
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This adds the necessary minimum to support S-mode
virtualization for priv ISA >= v1.10
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Co-authored-by: Matthew Suozzo <msuozzo@google.com>
Co-authored-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Modifed from Richard Henderson's patch [1] to integrate
with the new control and status register implementation.
[1] https://lists.nongnu.org/archive/html/qemu-devel/2018-03/msg07034.html
Note: the f* CSRs already mark mstatus.FS dirty using
env->mstatus |= mstatus.FS so the bug in the first
spin of this patch has been fixed in a prior commit.
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Co-authored-by: Richard Henderson <richard.henderson@linaro.org>
Co-authored-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
CSR predicate functions are added to the CSR table.
mstatus.FS and counter enable checks are moved
to predicate functions and two new predicates are
added to check misa.S for s* CSRs and a new PMP
CPU feature for pmp* CSRs.
Processors that don't implement S-mode will trap
on access to s* CSRs and processors that don't
implement PMP will trap on accesses to pmp* CSRs.
PMP checks are disabled in riscv_cpu_handle_mmu_fault
when the PMP CPU feature is not present.
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Use the new CSR read/modify/write interface to implement
atomic updates to mip/sip.
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Previous CSR code uses csr_read_helper and csr_write_helper
to update CSR registers however this interface prevents
atomic read/modify/write CSR operations; in addition
there is no trap-free method to access to CSRs due
to the monolithic CSR functions call longjmp.
The current iCSR interface is not safe to be called by
target/riscv/gdbstub.c as privilege checks or missing CSRs
may call longjmp to generate exceptions. It needs to
indicate existence so traps can be generated in the
CSR instruction helpers.
This commit moves CSR access from the monolithic switch
statements in target/riscv/op_helper.c into modular
read/write functions in target/riscv/csr.c using a new
function pointer table for dispatch (which can later
be used to allow CPUs to hook up model specific CSRs).
A read/modify/write interface is added to support atomic
CSR operations and a non-trapping interface is added
to allow exception-free access to CSRs by the debugger.
The CSR functions and CSR dispatch table are ordered
to match The RISC-V Instruction Set Manual, Volume II:
Privileged Architecture Version 1.10, 2.2 CSR Listing.
An API is added to allow derived cpu instances to modify
or implement new CSR operations.
Signed-off-by: Michael Clark <mjc@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
