aboutsummaryrefslogtreecommitdiff
path: root/target/riscv/csr.c
AgeCommit message (Collapse)AuthorFilesLines
2019-03-19RISC-V: Add support for vectored interruptsMichael Clark1-6/+6
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. Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Alistair Francis <Alistair.Francis@wdc.com> Signed-off-by: Michael Clark <mjc@sifive.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-03-19RISC-V: Allow interrupt controllers to claim interruptsMichael Clark1-8/+2
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. Cc: Palmer Dabbelt <palmer@sifive.com> Cc: Sagar Karandikar <sagark@eecs.berkeley.edu> Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de> Cc: Alistair Francis <Alistair.Francis@wdc.com> Signed-off-by: Michael Clark <mjc@sifive.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-03-19RISC-V: Add debug support for accessing CSRs.Jim Wilson1-7/+25
Add a debugger field to CPURISCVState. Add riscv_csrrw_debug function to set it. Disable mode checks when debugger field true. Signed-off-by: Jim Wilson <jimw@sifive.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20190212230903.9215-1-jimw@sifive.com> Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-02-11target/riscv: fix counter-enable checks in ctr()Xi Wang1-3/+9
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>
2019-02-11RISC-V: Add misa runtime write supportMichael Clark1-1/+53
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>
2019-02-11RISC-V: Use riscv prefix consistently on cpu helpersMichael Clark1-4/+4
* 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>
2019-02-11RISC-V: Implement mstatus.TSR/TW/TVMMichael Clark1-4/+13
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>
2019-02-11RISC-V: Mark mstatus.fs dirtyRichard Henderson1-12/+0
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>
2019-01-09RISC-V: Implement existential predicates for CSRsMichael Clark1-76/+93
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>
2019-01-09RISC-V: Implement atomic mip/sip CSR updatesMichael Clark1-28/+28
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>
2019-01-08RISC-V: Implement modular CSR helper interfaceMichael Clark1-0/+846
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>
generated by cgit v1.1 at 2024-11-03 09:53:23 +0000