Commit Graph

722 Commits

Author SHA1 Message Date
Zong Li
570b9ae89a include: sbi_bitops: add ULL version for BIT and GENMASK
Add BIT_ULL and GENMASK_ULL for dealing with 64-bits data on
32-bits CPU, then we don't need to separate the operation to
low part and high part. For instance, the MMIO register is
64 bits wide.

Signed-off-by: Zong Li <zong.li@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-23 18:33:02 +05:30
Samuel Holland
040fcf49ab lib: sbi_domain_context: Fix file permissions
These C source files should not be marked as executable.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-23 18:26:47 +05:30
Samuel Holland
1cb234b1c9 lib: sbi: fwft: add support for SBI_FWFT_POINTER_MASKING_PMLEN
Add support for controlling the pointer masking mode on harts which
support the Smnpm extension. This extension can only exist on harts
where XLEN >= 64 bits. This implementation selects the mode with the
smallest PMLEN that satisfies the caller's requested lower bound.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-23 17:50:40 +05:30
Samuel Holland
ebfaf1974e lib: sbi: Fix writes to emulated 32-bit htimedelta CSR
Writes to the low half CSR should not affect the high half of the value.
Make this separation explicit by writing to the delta in memory as two
adjacent XLEN-sized values.

Fixes: 1e9f88889f ("lib: Emulate HTIMEDELTA CSR for platforms not having TIME CSR")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-20 21:52:06 +05:30
Samuel Holland
65f04badf7 lib: sbi: Use a linked list to track domains
This removes the compile-time limit on the number of domains. It also
reduces firmware size by about 200 bytes by removing the lookup table.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-20 21:40:32 +05:30
Samuel Holland
792715e4f3 include: sbi_domain: Fix incorrect comments
These comments are inaccurate as of commit db56341dfa ("lib: sbi:
Allow platforms to provide root domain memory regions"), which modified
root domain registration to go through sbi_domain_register() like other
domains.

Fixes: db56341dfa ("lib: sbi: Allow platforms to provide root domain memory regions")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-20 21:16:41 +05:30
Samuel Holland
8cb7f89d7c lib: utils/fdt: Add fdt_get_address_rw() helper
Help tracking the lifecycle of the FDT blob by indicating which parts of
the firmware modify it, and thus invalidate any previously-obtained
offsets or pointers to data inside the blob.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:03:04 +05:30
Samuel Holland
c36801841e lib: utils/serial: Pass the FDT to fdt_serial_init()
Indicate that this function does not modify the FDT blob, and
deduplicate the call to fdt_get_address().

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:03:01 +05:30
Samuel Holland
fa6dfce017 lib: utils/reset: Pass the FDT to fdt_reset_init()
Indicate that this function does not modify the FDT blob, and
deduplicate the call to fdt_get_address().

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:58 +05:30
Samuel Holland
b15cc7715a lib: utils/timer: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:48 +05:30
Samuel Holland
bd76eb4950 lib: utils/serial: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:46 +05:30
Samuel Holland
57a0479302 lib: utils/reset: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:42 +05:30
Samuel Holland
1bbda9b26f lib: utils/regmap: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:39 +05:30
Samuel Holland
7df1c8126f lib: utils/irqchip: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:36 +05:30
Samuel Holland
d561418f22 lib: utils/ipi: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:33 +05:30
Samuel Holland
039e810437 lib: utils/i2c: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:28 +05:30
Samuel Holland
c585354380 lib: utils/gpio: Constify FDT pointers in parsing functions
Indicate that none of these functions modify the devicetree by
constifying the parameter type.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:27 +05:30
Samuel Holland
33ba4e0567 lib: utils/fdt: Constify FDT parsing functions
Distinguish between functions which modify the devicetree and those
which only extract information from it. Other than the iterators in
fdt_domain.c, this is a mechanical conversion.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:25 +05:30
Samuel Holland
f229a32828 lib: utils/regmap: Fix typo in comment
Balance the quotation marks; double quotes are idiomatic here.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:23 +05:30
Samuel Holland
bcb81f0cbe lib: utils/fdt: Fix fdt_add_cpu_idle_states() prototype
The function prototype should use the same parameter name as the
documentation and the function definition.

Fixes: 33bf917460 ("lib: utils: Add fdt_add_cpu_idle_states() helper function")
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-24 13:02:21 +05:30
Dongdong Zhang
d4322eebd0 lib: sbi: Enhance CSR Handling in system_opcode_insn
- Completed TODO in `system_opcode_insn` to ensure CSR read/write
  instruction handling.
- Refactored to use new macros `GET_RS1_NUM` and `GET_CSR_NUM`.
- Updated `GET_RM` macro and replaced hardcoded funct3 values with
  constants (`CSRRW`, `CSRRS`, `CSRRC`, etc.).
- Removed redundant `GET_RM` from `riscv_fp.h`.
- Improved validation and error handling for CSR instructions.

This patch enhances the clarity and correctness of CSR handling
in `system_opcode_insn`.

Signed-off-by: Dongdong Zhang <zhangdongdong@eswincomputing.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-23 13:36:49 +05:30
Gregor Haas
b9c091ed89 lib: sbi: Implement aligned memory allocators
This change adds a simple implementation of sbi_aligned_alloc(), for future use
in allocating aligned memory for SMMTT tables.

Signed-off-by: Gregor Haas <gregorhaas1997@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-09 08:51:27 +05:30
Gregor Haas
8b898c4e50 lib: sbi: Support multiple heaps
The upcoming SMMTT implementation will require some larger contiguous memory
regions for the memory tracking tables. We plan to specify the memory region
for these tables as a reserved-memory node in the device tree, and then
dynamically allocate individual tables out of this region. These changes to the
SBI heap allocator will allow us to explicitly create and allocate from a
dedicated heap tied to the table memory region.

Signed-off-by: Gregor Haas <gregorhaas1997@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-09 08:51:24 +05:30
Eric Lin
df997c6e55 include: Adjust Sscofpmf mhpmevent mask for upper 8 bits
Currently, OpenSBI reserves the upper 16 bits in mhpmevent for
the Sscofpmf extension.

However, according to the Sscofpmf extension specification[1],
it only defines the upper 8 bits in mhpmevent for privilege mode
inhibit and counter overflow disable. Other bits are defined by
the platform for event selection.

Since vendors might define raw event encoding exceeding 48 bits in
mhpmevent, we should adjust the MHPMEVENT_SSCOF_MASK to support it.

Link: https://github.com/riscvarchive/riscv-count-overflow [1]
Signed-off-by: Eric Lin <eric.lin@sifive.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-08-02 08:43:27 +05:30
Anup Patel
d35c76a766 include: sbi: Add macros to create FIFO as local or global variable
The FIFO data structure is quite handy of variety of use-case so add
SBI_FIFO_INITIALIZER() and SBI_FIFO_DEFINE() helper macros to create
FIFO as local or global variable.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-By: Himanshu Chauhan <hchauhan@ventanamicro.com>
2024-07-24 12:18:39 +05:30
Anup Patel
94c3c53a56 lib: sbi: Allow forceful queueing of data in sbi_fifo_enqueue()
Extend sbi_fifo_enqueue() to allow forceful queueing by droping
data from the tail.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-By: Himanshu Chauhan <hchauhan@ventanamicro.com>
2024-07-24 12:18:36 +05:30
Anup Patel
119b15a553 lib: sbi: Remove sbi_console_init() and console_init() platform callback
Now that all platforms have been updated to initialize serial console
device in early_init(), the sbi_console_init() and console_init()
platform callback are redundant hence remove them.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-By: Himanshu Chauhan <hchauhan@ventanamicro.com>
2024-07-24 12:18:33 +05:30
Anup Patel
455de672dd include: Bump-up version to 1.5
This patch updates OpenSBI version to 1.5 as part of
release preparation.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
2024-06-30 14:03:26 +05:30
Clément Léger
aa5a859369 lib: sbi: add support for firmware features extension
This extension allows the software running in supervisor mode to control
the behavior of various features of the SBI [1]. Implement the support
for such extension.

Link: https://lists.riscv.org/g/tech-prs/message/924 [1]
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-06-19 18:09:22 +05:30
Yong-Xuan Wang
53844c98d0 lib: sbi: Add support for Svade and Svadu extensions
Add support for Svade and Svadu extensions. When both are present in the
device tree, the M-mode firmware should select the Svade extension
to comply with the RVA23 profile, which mandates Svade and lists Svadu as
an optional extension.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-06-18 16:41:32 +05:30
Yu Chien Peter Lin
3a94a32580 sbi: sbi_domain_context: Fix trap context for domain context switching
Save/restore sbi_trap_context during domain context switching to
ensure proper trap handling and isolation. This maintains correct
domain-specific state, avoiding context corruption.

Fixes: abea949721 ("lib: sbi: Introduce trap context")
Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Alvin Chang <alvinga@andestech.com>
Tested-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Yong Li <yong.li@intel.com>
Tested-by: Yong Li <yong.li@intel.com>
2024-06-13 19:21:27 +05:30
Alvin Chang
17e829129d sbi: sbi_domain_context: Add spinlock for updating domain assigned_harts
Add spinlock protection to avoid race condition on assigned_harts
during domain context switching. Also, rename/add variables for
accessing the corresponding domain of target/current context.

Signed-off-by: Alvin Chang <alvinga@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-05-07 20:11:30 +05:30
Clément Léger
c21c99db6a lib: sbi: sse: fix typos, comments and spacing errors
Fix some errors spotted by Samuel while reviewing the SSE implementation.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reported-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-05-07 17:24:11 +05:30
Ivan Orlov
f6243d9ce5 lib: tests: Add test suite init function
Allow to define an init function for the test suite. It could help us
to initialize global variable once, and use them in multiple test cases
after the initialization.

For instance, if multiple test cases use the same atomic_t var, it
could be helpful to call ATOMIC_INIT once during the suite
initialization.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-05-07 11:27:13 +05:30
Anup Patel
beb0cd177f lib: sbi: Simplify wait_for_coldboot() implementation
On QEMU virt machine with large number of HARTs, some of the HARTs
randomly fail to come out of wait_for_coldboot() due to one of the
following race-conditions:

1) Failing HARTs are not able to acquire the coldboot_lock and
   update the coldboot_hartmask in wait_for_coldboot() before
   the coldboot HART acquires the coldboot_lock and sends IPI
   in wake_coldboot_harts() hence the failing HARTs never
   receive IPI from the coldboot HART.

2) Failing HARTs acquire the coldbood_lock and update the
   coldboot_hartmask before coldboot HART does sbi_scratch_init()
   so the sbi_hartmask_set_hartid() does not update the
   coldboot_hartmask on the failing HARTs hence they never
   receive IPI from the coldboot HART.

To address this, use a simple busy-loop in wait_for_coldboot() for
polling on coldboot_done flag.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
2024-04-05 17:48:23 +05:30
Vivian Wang
5c9a73565f include: sbi: Support byteorder macros in assembly
Avoid using C types and casts if sbi/sbi_byteorder.h is included in
assembly code

Signed-off-by: Vivian Wang <dramforever@live.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-04-05 17:23:51 +05:30
Clément Léger
06fc453ec1 lib: sbi: Add SSE support for PMU events
Add SSE callbacks registration to PMU driver in order to disable
interrupt delegation for PMU interrupts. When interrupts are
undelegated send the PMU SSE event upon LCOFIP IRQ.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-04-05 17:09:39 +05:30
Clément Léger
c8cdf01d8f lib: sbi: Add support for Supervisor Software Events extension
This extension [1] allows to deliver events from SBI to supervisor via
a software mechanism. This extension defines events (either local or
global) which are signaled by the SBI on specific signal sources (IRQ,
exceptions, etc) and are injected to be executed in supervisor mode.

[1] https://lists.riscv.org/g/tech-prs/message/798

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-04-05 15:47:30 +05:30
Anup Patel
5b11f16c3c lib: sbi: Pass trap context pointer to sbi_ecall_handler()
To be consistent with other trap handlers, pass trap context pointer
to sbi_ecall_handler().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
2024-03-19 11:31:39 +05:30
Anup Patel
43d346c0c1 lib: sbi: Remove regs parameter from trap irq handling functions
The trap irq handling functions no longer require regs parameter
so remove it.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
2024-03-19 11:31:35 +05:30
Anup Patel
d84e7eb7f0 lib: sbi: Remove regs paramter of sbi_irqchip_process()
The irqchip handlers will typically not need pointer to trap registers
so remove regs parameter of sbi_irqchip_process().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
2024-03-19 11:31:33 +05:30
Anup Patel
f414cf931e lib: sbi: Simplify parameters of sbi_illegal_insn_handler()
The struct sbi_trap_context already has the information needed by
sbi_illegal_insn_handler() so directly pass struct sbi_trap_context
pointer to this function.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
2024-03-19 11:31:31 +05:30
Anup Patel
fea33a9334 lib: sbi: Simplify parameters of misaligned and access fault handlers
The struct sbi_trap_context already has the information needed by
misaligned load/store and access fault load/store handlers so directly
pass struct sbi_trap_context pointer to these functions.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
2024-03-19 11:31:28 +05:30
Anup Patel
abea949721 lib: sbi: Introduce trap context
Club the struct sbi_trap_regs and struct sbi_trap_info a new
struct sbi_trap_context (aka trap context) which must be saved
by low-level trap handler before calling sbi_trap_handler().

To track nested traps, the struct sbi_scratch points to the current
trap context and the trap context has pointer to pervious context
of previous trap.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
2024-03-19 11:31:22 +05:30
Anup Patel
60ffc154c8 include: sbi: Add trap_context pointer in struct sbi_scratch
To track nested traps, the struct sbi_scratch needs a pointer the
current trap context so add trap_context pointer in struct sbi_context.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
2024-03-19 11:31:20 +05:30
Anup Patel
ebb697ad8c lib: sbi: Remove sbi_trap_exit() and related code
Over the years, no uses of sbi_trap_exit() have been found so remove
it and also remove related code from fw_base.S and sbi_scratch.h.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Tested-by: Samuel Holland <samuel.holland@sifive.com>
2024-03-19 11:31:18 +05:30
Samuel Holland
2e8517865a lib: sbi: Remove epc from struct sbi_trap_info
In the only places this value is used, it duplicates mepc from
struct sbi_trap_regs.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-19 11:31:16 +05:30
Bo Gan
81e3ba77a6 lib: sbi: call platform load/store emulators
sbi_load/store_access_handler now tries to call platform emulators
if defined. Otherwise, redirects the fault. If the platform code
returns failure, this means the H/S/U has accessed the emulated
devices in an unexpected manner, which is very likely caused by
buggy code in H/S/U. We redirect the fault, so lower privileged
level can get notified, and act accordingly. (E.g., oops in Linux)

We let the handler truly fail if the trap was originated from M mode.
In this case, something must be very wrong and we should just fail.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:56:02 +05:30
Bo Gan
ddf3b649f1 include: sbi: add emulate_load/store handler to platform ops
This patch allows the platform to define load/store emulators. This
enables a platform to trap-and-emulate special devices or filter
access to existing physical devices.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:54:14 +05:30
Bo Gan
4c112650bb lib: sbi: abstract out insn decoding to unify mem fault handlers
This patch abstracts out the instruction decoding part of misaligned ld/st
fault handlers, so it can be reused by ld/st access fault handlers.
Also Added lb/lbu/sb decoding. (previously unreachable by misaligned fault)

sbi_trap_emulate_load/store is now the common handler which takes a `emu`
parameter that is responsible for emulating the misaligned or access fault.
The `emu` callback is expected to fixup the fault, and based on the return
code of `emu`, sbi_trap_emulate_load/store will:

  r/wlen => the fixup is successful and regs/mepc needs to be updated.
  0      => the fixup is successful, but regs/mepc should be left untouched
            (this is usually used if `emu` does `sbi_trap_redirect`)
  -err   => failed, sbi_trap_error will be called

For now, load/store access faults are blindly redirected. It will be
enhanced in the following patches.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:50:39 +05:30