Commit Graph

566 Commits

Author SHA1 Message Date
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
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
Ivan Orlov
5c992a115a lib: tests: Move tests to a separate directory
Move all of the SBIUnit-related code into the lib/sbi/tests directory.
Update 'Makefile' to index objects from the tests subdirectory.

I don't think creating the full separate list of Makefile variables
(libsbitests-objs-path-y, libsbitests-object-mks, etc. as it is done for
libsbiutils) is necessary for the tests because:

1) `lib/sbi/tests/objects.mk` is already indexed into
'libsbi-objects-mks' since the find expression for the libsbi-object-mks
variable looks for objects.mk files in the nested directories as well).

2) Tests are tightly coupled with the `lib/sbi/` sources, therefore it
may be reasonable to store the list of lib/sbi and lib/sbi/tests object
files together in the libsbi-objs-path-y variable.

Additionally, update relative paths in the tests where necessary.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-19 11:20:40 +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
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
Bo Gan
9221fe58d1 lib: sbi: change prototype of sbi_misaligned_load/store_handler
This simplifies both handlers such that when the handler needs to
redirect the original trap, it's readily available.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:48:00 +05:30
Bo Gan
a17600c186 lib: sbi: change prototype of sbi_trap_redirect
sbi_trap_redirect now uses const pointer to `trap`.
This ensures the caller that we never change `trap` in sbi_trap_redirect.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:36:39 +05:30
Bo Gan
2471cf2e6c include: sbi: rename sbi_misaligned_ldst.h to sbi_trap_ldst.h
Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:36:35 +05:30
Bo Gan
c0a63205f8 lib: sbi: rename sbi_misaligned_ldst.c to sbi_trap_ldst.c
Signed-off-by: Bo Gan <ganboing@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-11 10:36:29 +05:30
Qingyu Shang
e11025c52d lib: sbi: Add initial domain context management support
The domain context management component in OpenSBI provides basic CPU
context management routines for existing OpenSBI domain. As domain
extension, it was initially designed to facilitate the suspension
and resumption of domains, enabling secure domains to efficiently
share CPU resources.

The patch also provides an addition to the OpenSBI domain to provide
updates on hart-domain assignment and declarations of contexts within
the domain.

Signed-off-by: Qingyu Shang <2931013282@sjtu.edu.cn>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Tested-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-10 10:26:42 +05:30
Ivan Orlov
87d8fe7865 lib: tests: Add sbi_console test
Add the test suite covering some of the functions from
lib/sbi/sbi_console.c: putc, puts and printf. The test covers a variety
of format specifiers for printf and different strings and characters for
putc and puts.

In order to do that, the test "mocks" the sbi_console_device structure
by setting the 'console_dev' variable to the virtual console.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
2024-03-10 10:12:52 +05:30
Ivan Orlov
e5f53fdea3 lib: tests: Add a test for sbi_bitmap
Add test suite covering all of the functions from lib/sbi/sbi_bitmap.c:
__bitmap_and, __bitmap_or and __bitmap_xor.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
2024-03-10 10:12:39 +05:30
Ivan Orlov
874fcefdf5 lib: Add SBIUnit testing macros and functions
This patch introduces all of the SBIUnit macros and functions which
can be used during the test development process. Also, it defines
the 'run_all_tests' function, which is being called during the
'init_coldboot' right after printing the boot hart information.

Also, add the CONFIG_SBIUNIT Kconfig entry in order to be able to
turn the tests on and off. When the CONFIG_SBIUNIT is disabled,
the tests and all related code is excluded completely on the
compilation stage.

Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
2024-03-10 10:05:28 +05:30
Nylon Chen
748bef1f9d lib: sbi_misaligned_ldst: Add handling of C.LHU/C.LH and C.SH
Added exception handling for compressed instructions C.LHU, C.LH, and
C.SH from the zcb extension to the sbi_misaligned_ldst library.

Signed-off-by: Nylon Chen <nylon.chen@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-05 09:31:52 +05:30
Atish Patra
6bb6b61c27 lib: sbi: Add support for smcsrind and smcdeleg
Smcsrind allows generic indirect CSR access mechanism while
Smcdeleg allows delegating hpmcounters in Supervisor mode.

Enable both extensions and set the appropriate bits in mstateen
and menvcfg.

Co-developed-by: Kaiwen Xue <kaiwenxue1@gmail.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-04 10:20:41 +05:30
Joshua Yeong
322b598475 lib: sbi_hsm: Restor hart state to stop when fails to start
Hart state should change back to hart stop when hsm_device_hart_start()
or sbi_ipi_raw_send() fails to perform hart start.

Signed-off-by: Joshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-02-24 18:18:34 +05:30
yang.zhang
88273fe19e lib: sbi_pmu: Before using we should ensure PMU init done
If trap earlier before sbi_pmu_init done, some path would call
sbi_pmu_ctr_incr_fw, then it would go wrong:
1. if phs_ptr_offset is zero, then it get a wrong pmu state ptr
2. if phs_ptr_offset is ok, but we didn't call pmu_set_hart_state_ptr
it would be NULL POINT

Of course, the above situation will not occur at present, but it is
reasonable to check before using.

Signed-off-by: yang.zhang <yang.zhang@hexintek.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-02-20 16:24:06 +05:30
Himanshu Chauhan
1ec353d504 lib: sbi: Use mask to check the free bit during trigger allocation
The trigger allocation function uses bit shift instead of mask to check the
mapped status of the triggers. This causes index 0 to be return always. As a
result, the older triggers are overwritten.

Use the mask for MAPPED field in state word to check if the trigger is mapped.

Fixes: 97f234f15 ("lib: sbi: Introduce the SBI debug triggers extension support")
Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-02-05 10:23:01 +05:30
Himanshu Chauhan
bb90a9ebf6 lib: sbi: Print number of debug triggers found
Print the total number of triggers found on the boot hart.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-01-10 10:55:52 +05:30
Himanshu Chauhan
76a2a15c40 lib: sbi: Implement SBI debug trigger extension
This patch adds functions to register ecalls for debug triggers
and handler to handle the debug trigger function IDs.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-01-10 10:55:50 +05:30
Himanshu Chauhan
97f234f15c lib: sbi: Introduce the SBI debug triggers extension support
RISC-V Debug specification includes Sdtrig ISA extension
which describes Trigger Module. Triggers can cause
a breakpoint exception or trace action without execution
of a special instruction. They can be used to implement
hardware breakpoints and watchpoints for native debugging.

The SBI Debut Trigger extension (Draft v6) can be found at:
https://lists.riscv.org/g/tech-debug/topic/99825362#1302

This patch is an initial implementation of SBI Debug
Trigger Extension (Draft v6) in OpenSBI.

The following features are supported:
 * mcontrol, mcontrol6 triggers
 * Breakpoint and trace actions

NOTE: Chained triggers are not supported

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-01-10 10:55:42 +05:30
Himanshu Chauhan
40dac6bcfe lib: sbi: Detect support of debug triggers
Detect if debug triggers, sdtrig extension, is supported
by the CPU. The support is detected by access traps and
ISA string parsing.

Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-01-10 09:43:37 +05:30
Anup Patel
bbd065d903 lib: sbi: Detect Zicntr extension only based on traps
OpenSBI uses time CSR if Zicntr extension present which causes
it to crash on an older QEMU because QEMU generates Zicntr in
the ISA string for unleashed machine which only has CYCLE and
INSTRET counters.

Fixes: 776770d2ad ("lib: sbi: Using one array to define the
name of extensions")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
2023-12-27 12:25:09 +05:30
Xiang W
63e09ad3f7 lib: sbi: Fix shift bug in sbi_system_reset
There is a problem with judging whether the current hart belongs to
hmask. If cur_hartid minus hbase is greater than BITS_PER_LONG, the
previous hmask will also have a bit cleared incorrectly, which will
cause some harts to lose ipi.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-26 21:28:34 +05:30
Anup Patel
2b80b92f02 lib: sbi: Do not enter OpenSBI with mseccfg.MML == 1
On platforms with Smepmp, the previous booting stage must enter
OpenSBI with mseccfg.MML == 0. This allows OpenSBI to configure
it's own M-mode only regions without depending on the previous
booting stage.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
2023-12-19 15:56:37 +05:30
Anup Patel
5a57e8cd41 lib: sbi: Remove the SBI_ETRAP error code
The SBI_ETRAP error code was introduced only for doing trap
redirection in generic sbi_ecall_handler(). Now the trap
redirection is moved into sbi_ecall_legacy.c and SBI_ETRAP
error code is only used in this source file so let us remove
it.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
2023-12-19 15:56:37 +05:30
Anup Patel
3284bea833 lib: sbi: Allow ecall handlers to directly update register state
Some of the upcoming SBI extensions (such as SSE) will directly
update register state so improve the prototype of ecall handler
to accommodate this. Further, this flexibility allows us to
push the trap redirection from sbi_ecall_handler() to the
sbi_ecall_legacy_handler().

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
2023-12-19 15:56:37 +05:30
Anup Patel
416ceb3cd7 lib: sbi_tlb: Reduce size of struct sbi_tlb_info
Let us reduce the size of struct sbi_tlb_info by doing the
following:
1) Change the data type of asid and vmid fields to uint16_t
2) Replace local_fn() function pointer with an enum

Based on the above, the size of struct sbi_tlb_info is reduced
by 16 bytes on RV64 and 4 bytes on RV32.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
2023-12-19 15:56:37 +05:30
Yong-Xuan Wang
3daac8fb87 lib: sbi: Detect extensions from the ISA string in DT
Enable access to some extensions through menvcfg and show them in "Boot
HART ISA Extensions" if they are present in the device tree.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-19 15:39:17 +05:30
Yong-Xuan Wang
776770d2ad lib: sbi: Using one array to define the name of extensions
Define an array sbi_hart_ext to map extension ID and name , and use it
for ISA parsing and printing out the supported extensions.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-19 14:14:22 +05:30
Yong-Xuan Wang
056fe6f85d lib: sbi: Refactor the code for enable extensions in menvfg CSR
Use 1 variable to store the value of menvcfg.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-19 13:54:33 +05:30
Yong-Xuan Wang
2c8be566f3 lib: sbi: Improve the code of privilege mode and extensions detection
We can enhance the code by creating 2 unified interface with macro  for
privilege mode and extensions detection, which relies on supported
privilege modes and CSRs.

Signed-off-by: Yong-Xuan Wang <yongxuan.wang@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-19 13:46:02 +05:30
Xiang W
925ce14622 lib: sbi: Simplify the initialization of root_hmask in sbi_domain_init
The original code has multiple conversions between hartid and
hartindex. Can call sbi_hartmask_set_hartindex directly to
avoid conversion.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-18 19:51:45 +05:30
Samuel Holland
2707250495 lib: sbi_ipi: Drop unnecessary ipi_process check
sbi_ipi_event_create() disallows registering an IPI event with a NULL
.process callback, so the function pointer will never be NULL here.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Xiang W <wxjstz@126.com>
2023-12-18 19:26:35 +05:30
Samuel Holland
446fa65eb5 lib: sbi_ipi: Process self-IPIs in sbi_ipi_send()
An IPI sent to the local hart can be processed directly instead of
triggering the IPI device. This is more efficient, and it avoids a
deadlock when the .sync callback is defined. Since interrupts are
disabled while handling an ecall, the IPI would not get delivered
until the next mret, but sbi_ipi_sync() is called before then.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Xiang W <wxjstz@126.com>
2023-12-18 19:26:33 +05:30
Samuel Holland
a894187e28 lib: sbi_ipi: Do not ignore errors from sbi_ipi_send()
Currently, failures in sbi_ipi_send() are silently ignored, which makes
them difficult to debug. Instead, abort sending the IPI and pass back
the error, but still synchronize any IPIs already sent.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
2023-12-18 19:26:11 +05:30
Samuel Holland
35cba92655 lib: sbi_tlb: Check tlb_range_flush_limit only once per request
The tlb_update() callback is called for each destination hart.
Move the size check earlier, so it is executed only once.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-11 10:41:48 +05:30
Xiang W
a2e254e881 lib: sbi: skip wait_for_coldboot when coolboot done
When warmboot via HSM, coolboot has been completed and
wait_for_coldboot can be skipped to speed up.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-11 09:36:57 +05:30
Inochi Amaoto
87aa3069d1 platform: recalculate heap size to support new tlb entry number
Previous patch introduced a change that using hart count as the default
number of tlb entries in the fifo. This makes the default tlb fifo size
grow in square with the number of harts. So the default heap size is
not enough to allocate tlb fifo when the hart count is big.

Fixes: 52fd64b ("platform: Uses hart count as the default size of tlb info")
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-11 09:23:24 +05:30
Nick Hu
a25fc74699 lib: sbi_hsm: Put the resume_pending hart in the interruptible hart mask
Current interruptible hart mask doesn't include the hart which HSM state
is SBI_HSM_STATE_RESUME_PENDING. So when there is a request to send an
IPI to the hart which is in the resume process, this hart would miss the
IPI forever. Put the SBI_HSM_STATE_RESUME_PENDING hart in the
interruptible hart mask to fix the issue.

Signed-off-by: Nick Hu <nick.hu@sifive.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-10 13:24:13 +05:30
Atish Patra
11a0ba5d4b lib: sbi_pmu: Fix the counter info function
The counter info should only return valid hardware counters for the ones
set in the counter mask. Otherwise, it will report incorrect number of
hardware counters to the supervisor if the platform has discontiguous
counters.

Fixes: c744ed77b1 ("lib: sbi_pmu: Enable noncontigous hpm event and counters")
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 22:50:23 +05:30
Atish Patra
ee725174ba lib: sbi_pmu: Add PMU snapshot definitions
OpenSBI doesn't support SBI PMU snapshot yet as there is not much benefit
unless the multiple counters overflow at the same time.

Just add the definition and return not supported error at this moment. The
default returned error is also not supported. Thus, no functional change
intended.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
2023-12-08 22:50:21 +05:30
Samuel Holland
93da66b7d4 lib: sbi_hart: Store PMP granularity as log base 2
This minimizes the need to call log2roundup() to recover the log value.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 22:43:12 +05:30
Xiang W
07419ec84b lib: sbi: Prevent redundant sbi_ipi_process
Multiple harts may try to send IPI to a particular target hart A
in which case the send_ipi() should be called only when the old
value of the hart A ipi_type is zero.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 17:07:03 +05:30
Anup Patel
88398696c8 lib: sbi: Replace __atomic_op_bit_ord with __atomic intrinsics
Simplify atomic-related bit operations through __atomic intrinsics.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 14:06:40 +05:30
Xiang W
11bf49b444 lib: sbi: Fix __atomic_op_bit_ord and comments
The original code returns the value of the word before modification.
When modifying the upper 32 bits under RV64, the value returned via
int return will have no meaning. Corrected to return the value of the
bit. And modify the function description.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 13:47:31 +05:30
Xiang W
6b9a849482 lib: sbi: Remove xchg/cmpxchg implemented via lr/sc
lr/sc is part of the A extension. If the A extension is not supported,
lr/sc cannot be used. So remove xchg/cmpxchg.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 10:54:35 +05:30
Yu Chien Peter Lin
a48f2cfd94 sbi: sbi_pmu: Add hw_counter_filter_mode() to pmu device
Add support for custom PMU extensions to set inhibit bits
on custom CSRs by introducing the PMU device callback
hw_counter_filter_mode(). This allows the perf tool to
restrict event counting under a specified privileged
mode by appending a modifier, e.g. perf record -e event:k
to count events only happening in kernel mode.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-06 17:30:01 +05:30