Commit Graph

45 Commits

Author SHA1 Message Date
LIU Zhiwei
83b519b8a4 target/riscv: Adjust csr write mask with XLEN
Write mask is representing the bits we care about.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220120122050.41546-11-zhiwei_liu@c-sky.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-01-21 15:52:57 +10:00
LIU Zhiwei
b655dc7cd9 target/riscv: Don't save pc when exception return
As pc will be written by the xepc in exception return, just ignore
pc in translation.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220120122050.41546-3-zhiwei_liu@c-sky.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-01-21 15:52:57 +10:00
Frédéric Pétrot
961738ffea target/riscv: helper functions to wrap calls to 128-bit csr insns
Given the side effects they have, the csr instructions are realized as
helpers. We extend this existing infrastructure for 128-bit sized csr.
We return 128-bit values using the same approach as for div/rem.
Theses helpers all call a unique function that is currently a fallback
on the 64-bit version.
The trans_csrxx functions supporting 128-bit are yet to be implemented.

Signed-off-by: Frédéric Pétrot <frederic.petrot@univ-grenoble-alpes.fr>
Co-authored-by: Fabien Portas <fabien.portas@grenoble-inp.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220106210108.138226-17-frederic.petrot@univ-grenoble-alpes.fr
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-01-08 15:46:10 +10:00
Nikita Shubin
0fbb5d2d3c target/riscv/pmp: fix no pmp illegal intrs
As per the privilege specification, any access from S/U mode should fail
if no pmp region is configured and pmp is present, othwerwise access
should succeed.

Fixes: d102f19a20 (target/riscv/pmp: Raise exception if no PMP entry is configured)
Signed-off-by: Nikita Shubin <n.shubin@yadro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20211214092659.15709-1-nikita.shubin@maquefel.me
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2022-01-08 15:46:09 +10:00
Richard Henderson
a974879b45 target/riscv: Reorg csr instructions
Introduce csrr and csrw helpers, for read-only and write-only insns.

Note that we do not properly implement this in riscv_csrrw, in that
we cannot distinguish true read-only (rs1 == 0) from any other zero
write_mask another source register -- this should still raise an
exception for read-only registers.

Only issue gen_io_start for CF_USE_ICOUNT.
Use ctx->zero for csrrc.
Use get_gpr and dest_gpr.

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210823195529.560295-19-richard.henderson@linaro.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2021-09-01 11:59:12 +10:00
Jose Martins
719f0f603c target/riscv: fix wfi exception behavior
The wfi exception trigger behavior should take into account user mode,
hstatus.vtw, and the fact the an wfi might raise different types of
exceptions depending on various factors:

If supervisor mode is not present:

- an illegal instruction exception should be generated if user mode
executes and wfi instruction and mstatus.tw = 1.

If supervisor mode is present:

- when a wfi instruction is executed, an illegal exception should be triggered
if either the current mode is user or the mode is supervisor and mstatus.tw is
set.

Plus, if the hypervisor extensions are enabled:

- a virtual instruction exception should be raised when a wfi is executed from
virtual-user or virtual-supervisor and hstatus.vtw is set.

Signed-off-by: Jose Martins <josemartins90@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20210420213656.85148-1-josemartins90@gmail.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2021-06-08 09:59:42 +10:00
Alistair Francis
533c91e8f2 target/riscv: Use RISCVException enum for CSR access
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-id: 302b208f40373557fa11b351b5c9f43039ca8ea3.1617290165.git.alistair.francis@wdc.com
2021-05-11 20:02:06 +10:00
Thomas Huth
19f4ed3652 hw: Do not include qemu/log.h if it is not necessary
Many files include qemu/log.h without needing it. Remove the superfluous
include statements.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20210328054833.2351597-1-thuth@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-02 17:24:50 +02:00
Atish Patra
d102f19a20 target/riscv/pmp: Raise exception if no PMP entry is configured
As per the privilege specification, any access from S/U mode should fail
if no pmp region is configured.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20201223192553.332508-1-atish.patra@wdc.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2021-01-16 10:57:21 -08:00
Alistair Francis
7687537ab0 target/riscv: Split the Hypervisor execute load helpers
Split the hypervisor execute load functions into two seperate functions.
This avoids us having to pass the memop to the C helper functions.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 5b1550f0faa3c435cc77f3c1ae811dea98ab9e36.1604464950.git.alistair.francis@wdc.com
2020-11-09 15:09:00 -08:00
Alistair Francis
743077b35b target/riscv: Remove the hyp load and store functions
Remove the special Virtulisation load and store functions and just use
the standard tcg tcg_gen_qemu_ld_tl() and tcg_gen_qemu_st_tl() functions
instead.

As part of this change we ensure we still run an access check to make
sure we can perform the operations.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 189ac3e53ef2854824d18aad7074c6649f17de2c.1604464950.git.alistair.francis@wdc.com
2020-11-09 15:08:57 -08:00
Alistair Francis
1c1c060aa8 target/riscv: Remove the HS_TWO_STAGE flag
The HS_TWO_STAGE flag is no longer required as the MMU index contains
the information if we are performing a two stage access.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: f514b128b1ff0fb41c85f914cee18f905007a922.1604464950.git.alistair.francis@wdc.com
2020-11-09 15:08:53 -08:00
Alistair Francis
3e5979046f target/riscv: Set the virtualised MMU mode when doing hyp accesses
When performing the hypervisor load/store operations set the MMU mode to
indicate that we are virtualised.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: e411c61a1452cad16853f13cac2fb86dc91ebee8.1604464950.git.alistair.francis@wdc.com
2020-11-09 15:08:50 -08:00
Yifei Jiang
284d697c74 target/riscv: Merge m/vsstatus and m/vsstatush into one uint64_t unit
mstatus/mstatush and vsstatus/vsstatush are two halved for RISCV32.
This patch expands mstatus and vsstatus to uint64_t instead of
target_ulong so that it can be saved as one unit and reduce some
ifdefs in the code.

Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
Signed-off-by: Yipeng Yin <yinyipeng1@huawei.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20201026115530.304-2-jiangyifei@huawei.com
2020-11-03 07:17:23 -08:00
Georg Kotheimer
1da46012ea target/riscv: Fix implementation of HLVX.WU instruction
The HLVX.WU instruction is supposed to read a machine word,
but prior to this change it read a byte instead.

Fixes: 8c5362acb5 ("target/riscv: Allow generating hlv/hlvx/hsv instructions")
Signed-off-by: Georg Kotheimer <georg.kotheimer@kernkonzept.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20201013172223.443645-1-georg.kotheimer@kernkonzept.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
2020-10-22 12:00:22 -07:00
Alistair Francis
69430111ab riscv: Convert interrupt logs to use qemu_log_mask()
Currently we log interrupts and exceptions using the trace backend in
riscv_cpu_do_interrupt(). We also log exceptions using the interrupt log
mask (-d int) in riscv_raise_exception().

This patch converts riscv_cpu_do_interrupt() to log both interrupts and
exceptions with the interrupt log mask, so that both are printed when a
user runs QEMU with -d int.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 29a8c766c7c4748d0f2711c3a0abb81208138c5e.1601652179.git.alistair.francis@wdc.com
2020-10-22 12:00:22 -07:00
Alistair Francis
e39a8320b0 target/riscv: Support the Virtual Instruction fault
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 4c744dce9b0b057cbb5cc0f4d4ac75cda682a8af.1597259519.git.alistair.francis@wdc.com
Message-Id: <4c744dce9b0b057cbb5cc0f4d4ac75cda682a8af.1597259519.git.alistair.francis@wdc.com>
2020-08-25 09:11:36 -07:00
Alistair Francis
57cb2083e6 target/riscv: Return the exception from invalid CSR accesses
When performing a CSR access let's return a negative exception value on
an error instead of -1. This will allow us to specify the exception in
future patches.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: a487dad60c9b8fe7a2b992c5e0dcc2504a9000a7.1597259519.git.alistair.francis@wdc.com
Message-Id: <a487dad60c9b8fe7a2b992c5e0dcc2504a9000a7.1597259519.git.alistair.francis@wdc.com>
2020-08-25 09:11:36 -07:00
Alistair Francis
f2d5850f71 target/riscv: Update the Hypervisor trap return/entry
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: e7e4e801234f2934306e734f65860f601a5745bd.1597259519.git.alistair.francis@wdc.com
Message-Id: <e7e4e801234f2934306e734f65860f601a5745bd.1597259519.git.alistair.francis@wdc.com>
2020-08-25 09:11:36 -07:00
Alistair Francis
8c5362acb5 target/riscv: Allow generating hlv/hlvx/hsv instructions
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 477c864312280ea55a98dc84cb01d826751b6c14.1597259519.git.alistair.francis@wdc.com
Message-Id: <477c864312280ea55a98dc84cb01d826751b6c14.1597259519.git.alistair.francis@wdc.com>
2020-08-25 09:11:35 -07:00
Alistair Francis
2761db5fc2 target/riscv: Implement checks for hfence
Call the helper_hyp_tlb_flush() function on hfence instructions which
will generate an illegal insruction execption if we don't have
permission to flush the Hypervisor level TLBs.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2020-06-19 08:24:07 -07:00
Alistair Francis
1a9540d1f1 target/riscv: Drop support for ISA spec version 1.09.1
The RISC-V ISA spec version 1.09.1 has been deprecated in QEMU since
4.1. It's not commonly used so let's remove support for it.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
2020-06-03 09:11:51 -07:00
Alistair Francis
ed5abf46b3
target/riscv: Correctly implement TSR trap
As reported in: https://bugs.launchpad.net/qemu/+bug/1851939 we weren't
correctly handling illegal instructions based on the value of MSTATUS_TSR
and the current privledge level.

This patch fixes the issue raised in the bug by raising an illegal
instruction if TSR is set and we are in S-Mode.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Jonathan Behrens <jonathan@fintelia.io
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-03-16 17:03:13 -07:00
Alistair Francis
e44b50b5b2
target/riscv: Add the MSTATUS_MPV_ISSET helper macro
Add a helper macro MSTATUS_MPV_ISSET() which will determine if the
MSTATUS_MPV bit is set for both 32-bit and 64-bit RISC-V.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-02-27 13:46:33 -08:00
Alistair Francis
551fa7e8a6
target/riscv: Add support for the 32-bit MSTATUSH CSR
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-02-27 13:46:32 -08:00
Alistair Francis
e3fba4bab6
target/riscv: Add Hypervisor trap return support
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-02-27 13:45:43 -08:00
Alistair Francis
9d0d112696
target/riscv: Generate illegal instruction on WFI when V=1
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-02-27 13:45:41 -08:00
Yiting Wang
a37f21c27d
riscv: Set xPIE to 1 after xRET
When executing an xRET instruction, supposing xPP holds the
value y, xIE is set to xPIE; the privilege mode is changed to y;
xPIE is set to 1. But QEMU sets xPIE to 0 incorrectly.

Signed-off-by: Yiting Wang <yiting.wang@windriver.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-01-16 10:02:41 -08:00
Richard Henderson
3109cd98a6 target/riscv: Use env_cpu, env_archcpu
Cleanup in the boilerplate that each target must define.
Replace riscv_env_get_cpu with env_archcpu.  The combination
CPU(riscv_env_get_cpu) should have used ENV_GET_CPU to begin;
use env_cpu now.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-06-10 07:03:42 -07:00
Jonathan Behrens
b86f416763
target/riscv: Do not allow sfence.vma from user mode
The 'sfence.vma' instruction is privileged, and should only ever be allowed
when executing in supervisor mode or higher.

Signed-off-by: Jonathan Behrens <fintelia@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-05-24 12:09:19 -07:00
Michael Clark
fb73883964
RISC-V: Use riscv prefix consistently on cpu helpers
* 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>
2019-02-11 15:56:21 -08:00
Michael Clark
7f2b5ff125
RISC-V: Implement mstatus.TSR/TW/TVM
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>
2019-02-11 15:56:21 -08:00
Michael Clark
c7b9517188
RISC-V: Implement modular CSR helper interface
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>
2019-01-08 13:59:09 -08:00
Michael Clark
426f03482c
RISC-V: Update CSR and interrupt definitions
* Add user-mode CSR defininitions.
* Reorder CSR definitions to match the specification.
* Change H mode interrupt comment to 'reserved'.
* Remove unused X_COP interrupt.
* Add user-mode interrupts.
* Remove erroneous until comments on machine mode interrupts.
* Move together paging mode and page table bit definitions.
* Move together interrupt and exception cause definitions.

Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 13:02:19 -07:00
Michael Clark
df354dd410
RISC-V: Move non-ops from op_helper to cpu_helper
This patch makes op_helper.c contain only instruction
operation helpers used by translate.c and moves any
unrelated cpu helpers into cpu_helper.c. No logic is
changed by this patch.

Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 13:02:14 -07:00
Michael Clark
85ba724fd6
RISC-V: Allow setting and clearing multiple irqs
Change the API of riscv_set_local_interrupt to take a
write mask and value to allow setting and clearing of
multiple local interrupts atomically in a single call.
Rename the new function to riscv_cpu_update_mip.

Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-17 13:02:09 -07:00
Philippe Mathieu-Daudé
0cd3f644fe RISC-V: Add trailing '\n' to qemu_log() calls
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-id: 20180606152128.449-11-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-06-08 13:15:33 +01:00
Michael Clark
b8643bd608
RISC-V: No traps on writes to misa,minstret,mcycle
These fields are marked WARL (Write Any Values, Reads
Legal Values) in the RISC-V Privileged Architecture
Specification so instead of raising exceptions,
illegal writes are silently dropped.

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
2018-05-06 10:39:38 +12:00
Michael Clark
1d1ee55274
RISC-V: Make mtvec/stvec ignore vectored traps
Vectored traps for asynchrounous interrupts are optional.
The mtvec/stvec mode field is WARL and hence does not trap
if an illegal value is written. Illegal values are ignored.

Later we can add RISCV_FEATURE_VECTORED_TRAPS however
until then the correct behavior for WARL (Write Any, Read
Legal) fields is to drop writes to unsupported bits.

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
2018-05-06 10:39:38 +12:00
Michael Clark
6fce529c4b
RISC-V: Add mcycle/minstret support for -icount auto
Previously the mycycle/minstret CSRs and rdcycle/rdinstret
psuedo instructions would return the time as a proxy for an
increasing instruction counter in the absence of having a
precise instruction count. If QEMU is invoked with -icount,
the mcycle/minstret CSRs and rdcycle/rdinstret psuedo
instructions will return the instruction count.

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2018-05-06 10:39:38 +12:00
Michael Clark
8c59f5c1b5
RISC-V: Use [ms]counteren CSRs when priv ISA >= v1.10
Privileged ISA v1.9.1 defines mscounteren and mucounteren:

* mscounteren contains a mask of counters available to S-mode
* mucounteren contains a mask of counters available to U-mode

Privileged ISA v1.10 defines mcounteren and scounteren:

* mcounteren contains a mask of counters available to S-mode
* scounteren contains a mask of counters available to U-mode

mcounteren and scounteren CSR registers were implemented
however they were not honoured for counter accesses when
the privilege ISA was >= v1.10. This fix solves the issue
by coalescing the counter enable registers. In addition
the code now  generates illegal instruction exceptions
for accesses to the counter enabled registers depending
on the privileged ISA version.

- Coalesce mscounteren and mcounteren into one variable
- Coalesce mucounteren and scounteren into one variable
- Makes mcounteren and scounteren CSR accesses generate
  illegal instructions when the privileged ISA <= v1.9.1
- Makes mscounteren and mucounteren CSR accesses generate
  illegal instructions when the privileged ISA >= v1.10

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
2018-05-06 10:39:38 +12:00
Michael Clark
e216590570
RISC-V: Allow S-mode mxr access when priv ISA >= v1.10
The mstatus.MXR alias in sstatus should only be writable
by S-mode if the privileged ISA version >= v1.10. Also MXR
was masked in sstatus CSR read but not sstatus CSR writes.
Now we correctly mask sstatus.mxr in both read and write.

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2018-05-06 10:39:38 +12:00
Michael Clark
33e3bc8d77
RISC-V: Hardwire satp to 0 for no-mmu case
satp is WARL so it should not trap on illegal writes, rather
it can be hardwired to zero and silently ignore illegal writes.

It seems the RISC-V WARL behaviour is preferred to having to
trap overhead versus simply reading back the value and checking
if the write took (saves hundreds of cycles and more complex
trap handling code).

Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Alistair Francis <Alistair.Francis@wdc.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
2018-05-06 10:39:38 +12:00
Michael Clark
b02403363f
RISC-V: Workaround for critical mstatus.FS bug
This change is a workaround for a bug where mstatus.FS
is not correctly reporting dirty after operations that
modify floating point registers. This a critical bug
or RISC-V in QEMU as it results in floating point
register file corruption when running SMP Linux due to
task migration and possibly uniprocessor Linux if
more than one process is using the FPU.

This workaround will return dirty if mstatus.FS is
switched from off to initial or clean. According to
the specification it is legal for an implementation
to return only off, or dirty.

Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Sagar Karandikar <sagark@eecs.berkeley.edu>
Cc: Bastian Koppelmann <kbastian@mail.uni-paderborn.de>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Alex Bennée <alex.bennee@linaro.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Michael Clark <mjc@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2018-03-29 10:22:26 -07:00
Michael Clark
0c3e702aca
RISC-V CPU Helpers
Privileged control and status register helpers and page fault handling.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Sagar Karandikar <sagark@eecs.berkeley.edu>
Signed-off-by: Michael Clark <mjc@sifive.com>
2018-03-07 08:30:28 +13:00