Many CPUs implement return address branch prediction as a stack. The
RISCV architecture refers to this as a return address stack (RAS). If
this gets corrupted then the CPU will mispredict at least one but
potentally many function returns.
There are two issues with the current RISCV exception code:
- We are using the alternate link stack (x5/t0) for the indirect branch
which makes the hardware think this is a function return. This will
corrupt the RAS.
- We modify the return address of handle_exception to point to
ret_from_exception. This will also corrupt the RAS.
Testing the null system call latency before and after the patch:
Visionfive2 (StarFive JH7110 / U74)
baseline: 189.87 ns
patched: 176.76 ns
Lichee pi 4a (T-Head TH1520 / C910)
baseline: 666.58 ns
patched: 636.90 ns
Just over 7% on the U74 and just over 4% on the C910.
Signed-off-by: Anton Blanchard <antonb@tenstorrent.com>
Signed-off-by: Cyril Bur <cyrilbur@tenstorrent.com>
Tested-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://lore.kernel.org/r/20240607061335.2197383-1-cyrilbur@tenstorrent.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Before cacheinfo can be built correctly, we need to initialize level
and type. Since RISC-V currently does not have a register group that
describes cache-related attributes like ARM64, we cannot obtain them
directly, so now we obtain cache leaves from the ACPI PPTT table
(acpi_get_cache_info()) and set the cache type through split_levels.
Suggested-by: Jeremy Linton <jeremy.linton@arm.com>
Suggested-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Link: https://lore.kernel.org/r/20240617131425.7526-2-cuiyunhui@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
ci_leaf_init() is a declared static function. The implementation of the
function body and the caller do not use the parameter (struct device_node
*node) input parameter, so remove it.
Fixes: 6a24915145 ("Revert "riscv: Set more data to cacheinfo"")
Signed-off-by: Yunhui Cui <cuiyunhui@bytedance.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20240617131425.7526-1-cuiyunhui@bytedance.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The ACPI SPCR code has been used to enable console output for ARM64 and
X86. The same code can be reused for RISC-V. Furthermore, SPCR table is
mandated for headless system as outlined in the RISC-V BRS
Specification, chapter 6.
Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20240502073751.102093-2-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Since commit 7caa976546 ("ftrace: riscv: move from REGS to ARGS"),
kprobe on ftrace is not supported by riscv, because riscv's support for
FTRACE_WITH_REGS has been replaced with support for FTRACE_WITH_ARGS, and
KPROBES_ON_FTRACE will be supplanted by FPROBES. So remove the deprecated
kprobe on ftrace support, which is misunderstood.
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240613111347.1745379-1-ruanjinjie@huawei.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Charlie Jenkins <charlie@rivosinc.com> says:
All extensions, both standard and vendor, live in one struct
"riscv_isa_ext". There is currently one vendor extension, xandespmu, but
it is likely that more vendor extensions will be added to the kernel in
the future. As more vendor extensions (and standard extensions) are
added, riscv_isa_ext will become more bloated with a mix of vendor and
standard extensions.
This also allows each vendor to be conditionally enabled through
Kconfig.
* b4-shazam-merge:
riscv: cpufeature: Extract common elements from extension checking
riscv: Introduce vendor variants of extension helpers
riscv: Add vendor extensions to /proc/cpuinfo
riscv: Extend cpufeature.c to detect vendor extensions
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-0-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
All of the supported vendor extensions that have been listed in
riscv_isa_vendor_ext_list can be exported through /proc/cpuinfo.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-2-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Instead of grouping all vendor extensions into the same riscv_isa_ext
that standard instructions use, create a struct
"riscv_isa_vendor_ext_data_list" that allows each vendor to maintain
their vendor extensions independently of the standard extensions.
xandespmu is currently the only vendor extension so that is the only
extension that is affected by this change.
An additional benefit of this is that the extensions of each vendor can
be conditionally enabled. A config RISCV_ISA_VENDOR_EXT_ANDES has been
added to allow for that.
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
Tested-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
Link: https://lore.kernel.org/r/20240719-support_vendor_extensions-v3-1-0af7587bbec0@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Currently the entries appear to be in a random order (although according
to Palmer he has tried to sort them by key value) which makes it harder
to find entries in a growing list, and more likely to have conflicts as
all patches are adding to the end of the list. Sort them alphabetically
instead.
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20240717-dedicate-squeamish-7e4ab54df58f@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Haibo Xu <haibo1.xu@intel.com> says:
This patch series enable RISC-V ACPI NUMA support which was based on
the recently approved ACPI ECR[1].
Patch 1/4 add RISC-V specific acpi_numa.c file to parse NUMA information
from SRAT and SLIT ACPI tables.
Patch 2/4 add the common SRAT RINTC affinity structure handler.
Patch 3/4 change the ACPI_NUMA to a hidden option since it would be selected
by default on all supported platform.
Patch 4/4 replace pr_info with pr_debug in arch_acpi_numa_init() to avoid
potential boot noise on ACPI platforms that are not NUMA.
Based-on: https://github.com/linux-riscv/linux-riscv/tree/for-next
[1] https://drive.google.com/file/d/1YTdDx2IPm5IeZjAW932EYU-tUtgS08tX/view?usp=sharing
Testing:
Since the ACPI AIA/PLIC support patch set is still under upstream review,
hence it is tested using the poll based HVC SBI console and RAM disk.
1) Build latest Qemu with the following patch backported
42bd4eeefd
2) Build latest EDK-II
https://github.com/tianocore/edk2/blob/master/OvmfPkg/RiscVVirt/README.md
3) Build Linux with the following configs enabled
CONFIG_RISCV_SBI_V01=y
CONFIG_SERIAL_EARLYCON_RISCV_SBI=y
CONFIG_NONPORTABLE=y
CONFIG_HVC_RISCV_SBI=y
CONFIG_NUMA=y
CONFIG_ACPI_NUMA=y
4) Build buildroot rootfs.cpio
5) Launch the Qemu machine
qemu-system-riscv64 -nographic \
-machine virt,pflash0=pflash0,pflash1=pflash1 -smp 4 -m 8G \
-blockdev node-name=pflash0,driver=file,read-only=on,filename=RISCV_VIRT_CODE.fd \
-blockdev node-name=pflash1,driver=file,filename=RISCV_VIRT_VARS.fd \
-object memory-backend-ram,size=4G,id=m0 \
-object memory-backend-ram,size=4G,id=m1 \
-numa node,memdev=m0,cpus=0-1,nodeid=0 \
-numa node,memdev=m1,cpus=2-3,nodeid=1 \
-numa dist,src=0,dst=1,val=30 \
-kernel linux/arch/riscv/boot/Image \
-initrd buildroot/output/images/rootfs.cpio \
-append "root=/dev/ram ro console=hvc0 earlycon=sbi"
[ 0.000000] ACPI: SRAT: Node 0 PXM 0 [mem 0x80000000-0x17fffffff]
[ 0.000000] ACPI: SRAT: Node 1 PXM 1 [mem 0x180000000-0x27fffffff]
[ 0.000000] NUMA: NODE_DATA [mem 0x17fe3bc40-0x17fe3cfff]
[ 0.000000] NUMA: NODE_DATA [mem 0x27fff4c40-0x27fff5fff]
...
[ 0.000000] ACPI: NUMA: SRAT: PXM 0 -> HARTID 0x0 -> Node 0
[ 0.000000] ACPI: NUMA: SRAT: PXM 0 -> HARTID 0x1 -> Node 0
[ 0.000000] ACPI: NUMA: SRAT: PXM 1 -> HARTID 0x2 -> Node 1
[ 0.000000] ACPI: NUMA: SRAT: PXM 1 -> HARTID 0x3 -> Node 1
* b4-shazam-merge:
ACPI: NUMA: replace pr_info with pr_debug in arch_acpi_numa_init
ACPI: NUMA: change the ACPI_NUMA to a hidden option
ACPI: NUMA: Add handler for SRAT RINTC affinity structure
ACPI: RISCV: Add NUMA support based on SRAT and SLIT
Link: https://lore.kernel.org/r/cover.1718268003.git.haibo1.xu@intel.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Add acpi_numa.c file to enable parse NUMA information from
ACPI SRAT and SLIT tables. SRAT table provide CPUs(Hart) and
memory nodes to proximity domain mapping, while SLIT table
provide the distance metrics between proximity domains.
Signed-off-by: Haibo Xu <haibo1.xu@intel.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Link: https://lore.kernel.org/r/65dbad1fda08a32922c44886e4581e49b4a2fecc.1718268003.git.haibo1.xu@intel.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
* Support for various new ISA extensions:
* The Zve32[xf] and Zve64[xfd] sub-extensios of the vector
extension.
* Zimop and Zcmop for may-be-operations.
* The Zca, Zcf, Zcd and Zcb sub-extensions of the C extension.
* Zawrs,
* riscv,cpu-intc is now dtschema.
* A handful of performance improvements and cleanups to text patching.
* Support for memory hot{,un}plug
* The highest user-allocatable virtual address is now visible in
hwprobe.
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Merge tag 'riscv-for-linus-6.11-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Palmer Dabbelt:
- Support for various new ISA extensions:
* The Zve32[xf] and Zve64[xfd] sub-extensios of the vector
extension
* Zimop and Zcmop for may-be-operations
* The Zca, Zcf, Zcd and Zcb sub-extensions of the C extension
* Zawrs
- riscv,cpu-intc is now dtschema
- A handful of performance improvements and cleanups to text patching
- Support for memory hot{,un}plug
- The highest user-allocatable virtual address is now visible in
hwprobe
* tag 'riscv-for-linus-6.11-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (58 commits)
riscv: lib: relax assembly constraints in hweight
riscv: set trap vector earlier
KVM: riscv: selftests: Add Zawrs extension to get-reg-list test
KVM: riscv: Support guest wrs.nto
riscv: hwprobe: export Zawrs ISA extension
riscv: Add Zawrs support for spinlocks
dt-bindings: riscv: Add Zawrs ISA extension description
riscv: Provide a definition for 'pause'
riscv: hwprobe: export highest virtual userspace address
riscv: Improve sbi_ecall() code generation by reordering arguments
riscv: Add tracepoints for SBI calls and returns
riscv: Optimize crc32 with Zbc extension
riscv: Enable DAX VMEMMAP optimization
riscv: mm: Add support for ZONE_DEVICE
virtio-mem: Enable virtio-mem for RISC-V
riscv: Enable memory hotplugging for RISC-V
riscv: mm: Take memory hotplug read-lock during kernel page table dump
riscv: mm: Add memory hotplugging support
riscv: mm: Add pfn_to_kaddr() implementation
riscv: mm: Refactor create_linear_mapping_range() for memory hot add
...
Most of this is part of my ongoing work to clean up the system call
tables. In this bit, all of the newer architectures are converted to
use the machine readable syscall.tbl format instead in place of complex
macros in include/uapi/asm-generic/unistd.h.
This follows an earlier series that fixed various API mismatches
and in turn is used as the base for planned simplifications.
The other two patches are dead code removal and a warning fix.
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Merge tag 'asm-generic-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"Most of this is part of my ongoing work to clean up the system call
tables. In this bit, all of the newer architectures are converted to
use the machine readable syscall.tbl format instead in place of
complex macros in include/uapi/asm-generic/unistd.h.
This follows an earlier series that fixed various API mismatches and
in turn is used as the base for planned simplifications.
The other two patches are dead code removal and a warning fix"
* tag 'asm-generic-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
vmlinux.lds.h: catch .bss..L* sections into BSS")
fixmap: Remove unused set_fixmap_offset_io()
riscv: convert to generic syscall table
openrisc: convert to generic syscall table
nios2: convert to generic syscall table
loongarch: convert to generic syscall table
hexagon: use new system call table
csky: convert to generic syscall table
arm64: rework compat syscall macros
arm64: generate 64-bit syscall.tbl
arm64: convert unistd_32.h to syscall.tbl format
arc: convert to generic syscall table
clone3: drop __ARCH_WANT_SYS_CLONE3 macro
kbuild: add syscall table generation to scripts/Makefile.asm-headers
kbuild: verify asm-generic header list
loongarch: avoid generating extra header files
um: don't generate asm/bpf_perf_event.h
csky: drop asm/gpio.h wrapper
syscalls: add generic scripts/syscall.tbl
The exception vector of the booting hart is not set before enabling
the mmu and then still points to the value of the previous firmware,
typically _start. That makes it hard to debug setup_vm() when bad
things happen. So fix that by setting the exception vector earlier.
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: yang.zhang <yang.zhang@hexintek.com>
Link: https://lore.kernel.org/r/20240508022445.6131-1-gaoshanliukou@163.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Andrew Jones <ajones@ventanamicro.com> says:
Zawrs provides two instructions (wrs.nto and wrs.sto), where both are
meant to allow the hart to enter a low-power state while waiting on a
store to a memory location. The instructions also both wait an
implementation-defined "short" duration (unless the implementation
terminates the stall for another reason). The difference is that while
wrs.sto will terminate when the duration elapses, wrs.nto, depending on
configuration, will either just keep waiting or an ILL exception will be
raised. Linux will use wrs.nto, so if platforms have an implementation
which falls in the "just keep waiting" category (which is not expected),
then it should _not_ advertise Zawrs in the hardware description.
Like wfi (and with the same {m,h}status bits to configure it), when
wrs.nto is configured to raise exceptions it's expected that the higher
privilege level will see the instruction was a wait instruction, do
something, and then resume execution following the instruction. For
example, KVM does configure exceptions for wfi (hstatus.VTW=1) and
therefore also for wrs.nto. KVM does this for wfi since it's better to
allow other tasks to be scheduled while a VCPU waits for an interrupt.
For waits such as those where wrs.nto/sto would be used, which are
typically locks, it is also a good idea for KVM to be involved, as it
can attempt to schedule the lock holding VCPU.
This series starts with Christoph's addition of the riscv
smp_cond_load_relaxed function which applies wrs.sto when available.
That patch has been reworked to use wrs.nto and to use the same approach
as Arm for the wait loop, since we can't have arbitrary C code between
the load-reserved and the wrs. Then, hwprobe support is added (since the
instructions are also usable from usermode), and finally KVM is
taught about wrs.nto, allowing guests to see and use the Zawrs
extension.
We still don't have test results from hardware, and it's not possible to
prove that using Zawrs is a win when testing on QEMU, not even when
oversubscribing VCPUs to guests. However, it is possible to use KVM
selftests to force a scenario where we can prove Zawrs does its job and
does it well. [4] is a test which does this and, on my machine, without
Zawrs it takes 16 seconds to complete and with Zawrs it takes 0.25
seconds.
This series is also available here [1]. In order to use QEMU for testing
a build with [2] is needed. In order to enable guests to use Zawrs with
KVM using kvmtool, the branch at [3] may be used.
[1] https://github.com/jones-drew/linux/commits/riscv/zawrs-v3/
[2] https://lore.kernel.org/all/20240312152901.512001-2-ajones@ventanamicro.com/
[3] https://github.com/jones-drew/kvmtool/commits/riscv/zawrs/
[4] cb2beccebc
Link: https://lore.kernel.org/r/20240426100820.14762-8-ajones@ventanamicro.com
* b4-shazam-merge:
KVM: riscv: selftests: Add Zawrs extension to get-reg-list test
KVM: riscv: Support guest wrs.nto
riscv: hwprobe: export Zawrs ISA extension
riscv: Add Zawrs support for spinlocks
dt-bindings: riscv: Add Zawrs ISA extension description
riscv: Provide a definition for 'pause'
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Export Zawrs ISA extension through hwprobe.
[Palmer: there's a gap in the numbers here as there will be a merge
conflict when this is picked up. To avoid confusion I just set the
hwprobe ID to match what it would be post-merge.]
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20240426100820.14762-12-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
RISC-V code uses the generic ticket lock implementation, which calls
the macros smp_cond_load_relaxed() and smp_cond_load_acquire().
Introduce a RISC-V specific implementation of smp_cond_load_relaxed()
which applies WRS.NTO of the Zawrs extension in order to reduce power
consumption while waiting and allows hypervisors to enable guests to
trap while waiting. smp_cond_load_acquire() doesn't need a RISC-V
specific implementation as the generic implementation is based on
smp_cond_load_relaxed() and smp_acquire__after_ctrl_dep() sufficiently
provides the acquire semantics.
This implementation is heavily based on Arm's approach which is the
approach Andrea Parri also suggested.
The Zawrs specification can be found here:
https://github.com/riscv/riscv-zawrs/blob/main/zawrs.adoc
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Co-developed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20240426100820.14762-11-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Some userspace applications (OpenJDK for instance) uses the free MSBs
in pointers to insert additional information for their own logic and
need to get this information from somewhere. Currently they rely on
parsing /proc/cpuinfo "mmu=svxx" string to obtain the current value of
virtual address usable bits [1]. Since this reflect the raw supported
MMU mode, it might differ from the logical one used internally which is
why arch_get_mmap_end() is used. Exporting the highest mmapable address
through hwprobe will allow a more stable interface to be used. For that
purpose, add a new hwprobe key named
RISCV_HWPROBE_KEY_HIGHEST_VIRT_ADDRESS which will export the highest
userspace virtual address.
Link: https://github.com/openjdk/jdk/blob/master/src/hotspot/os_cpu/linux_riscv/vm_version_linux_riscv.cpp#L171 [1]
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240410144558.1104006-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The sbi_ecall() function arguments are not in the same order as the
ecall arguments, so we end up re-ordering the registers before the
ecall which is useless and costly.
So simply reorder the arguments in the same way as expected by ecall.
Instead of reordering directly the arguments of sbi_ecall(), use a proxy
macro since the current ordering is more natural.
Before:
Dump of assembler code for function sbi_ecall:
0xffffffff800085e0 <+0>: add sp,sp,-32
0xffffffff800085e2 <+2>: sd s0,24(sp)
0xffffffff800085e4 <+4>: mv t1,a0
0xffffffff800085e6 <+6>: add s0,sp,32
0xffffffff800085e8 <+8>: mv t3,a1
0xffffffff800085ea <+10>: mv a0,a2
0xffffffff800085ec <+12>: mv a1,a3
0xffffffff800085ee <+14>: mv a2,a4
0xffffffff800085f0 <+16>: mv a3,a5
0xffffffff800085f2 <+18>: mv a4,a6
0xffffffff800085f4 <+20>: mv a5,a7
0xffffffff800085f6 <+22>: mv a6,t3
0xffffffff800085f8 <+24>: mv a7,t1
0xffffffff800085fa <+26>: ecall
0xffffffff800085fe <+30>: ld s0,24(sp)
0xffffffff80008600 <+32>: add sp,sp,32
0xffffffff80008602 <+34>: ret
After:
Dump of assembler code for function __sbi_ecall:
0xffffffff8000b6b2 <+0>: add sp,sp,-32
0xffffffff8000b6b4 <+2>: sd s0,24(sp)
0xffffffff8000b6b6 <+4>: add s0,sp,32
0xffffffff8000b6b8 <+6>: ecall
0xffffffff8000b6bc <+10>: ld s0,24(sp)
0xffffffff8000b6be <+12>: add sp,sp,32
0xffffffff8000b6c0 <+14>: ret
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Yunhui Cui <cuiyunhui@bytedance.com>
Link: https://lore.kernel.org/r/20240322112629.68170-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
These are useful for measuring the latency of SBI calls. The SBI HSM
extension is excluded because those functions are called from contexts
such as cpuidle where instrumentation is not allowed.
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240321230131.1838105-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The uapi/asm/unistd_{32,64}.h and asm/syscall_table_{32,64}.h headers can
now be generated from scripts/syscall.tbl, which makes this consistent
with the other architectures that have their own syscall.tbl.
riscv has two extra system call that gets added to scripts/syscall.tbl.
The newstat and rlimit entries in the syscall_abis_64 line are for system
calls that were part of the generic ABI when riscv64 got added but are
no longer enabled by default for new architectures. Both riscv32 and
riscv64 also implement memfd_secret, which is optional for all
architectures.
Unlike all the other 32-bit architectures, the time32 and stat64
sets of syscalls are not enabled on riscv32.
Both the user visible side of asm/unistd.h and the internal syscall
table in the kernel should have the same effective contents after this.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
If the kexec crash code is called in the interrupt context, the
machine_kexec_mask_interrupts() function will trigger a deadlock while
trying to acquire the irqdesc spinlock and then deactivate irqchip in
irq_set_irqchip_state() function.
Unlike arm64, riscv only requires irq_eoi handler to complete EOI and
keeping irq_set_irqchip_state() will only leave this possible deadlock
without any use. So we simply remove it.
Link: https://lore.kernel.org/linux-riscv/20231208111015.173237-1-songshuaishuai@tinylab.org/
Fixes: b17d19a531 ("riscv: kexec: Fixup irq controller broken in kexec crash path")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Ryo Takakura <takakura@valinux.co.jp>
Link: https://lore.kernel.org/r/20240626023316.539971-1-songshuaishuai@tinylab.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
ftrace_graph_ret_addr() takes an `idx` integer pointer that is used to
optimize the stack unwinding. Pass it a valid pointer to utilize the
optimizations that might be available in the future.
The commit is making riscv's usage of ftrace_graph_ret_addr() match
x86_64.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20240618145820.62112-1-puranjay@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
* A fix for vector load/store instruction decoding, which could result
in reserved vector element length encodings decoding as valid vector
instructions.
* Instruction patching now aggressively flushes the local instruction
cache, to avoid situations where patching functions on the flush path
results in torn instructions being fetched.
* A fix to prevent the stack walker from showing up as part of traces.
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Merge tag 'riscv-for-linus-6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- A fix for vector load/store instruction decoding, which could result
in reserved vector element length encodings decoding as valid vector
instructions.
- Instruction patching now aggressively flushes the local instruction
cache, to avoid situations where patching functions on the flush path
results in torn instructions being fetched.
- A fix to prevent the stack walker from showing up as part of traces.
* tag 'riscv-for-linus-6.10-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
riscv: stacktrace: convert arch_stack_walk() to noinstr
riscv: patch: Flush the icache right after patching to avoid illegal insns
RISC-V: fix vector insn load/store width mask
Clément Léger <cleger@rivosinc.com> says:
Add support for (yet again) more RVA23U64 missing extensions. Add
support for Zimop, Zcmop, Zca, Zcf, Zcd and Zcb extensions ISA string
parsing, hwprobe and kvm support. Zce, Zcmt and Zcmp extensions have
been left out since they target microcontrollers/embedded CPUs and are
not needed by RVA23U64.
Since Zc* extensions states that C implies Zca, Zcf (if F and RV32), Zcd
(if D), this series modifies the way ISA string is parsed and now does
it in two phases. First one parses the string and the second one
validates it for the final ISA description.
* b4-shazam-merge:
KVM: riscv: selftests: Add Zcmop extension to get-reg-list test
RISC-V: KVM: Allow Zcmop extension for Guest/VM
riscv: hwprobe: export Zcmop ISA extension
riscv: add ISA extension parsing for Zcmop
dt-bindings: riscv: add Zcmop ISA extension description
KVM: riscv: selftests: Add some Zc* extensions to get-reg-list test
RISC-V: KVM: Allow Zca, Zcf, Zcd and Zcb extensions for Guest/VM
riscv: hwprobe: export Zca, Zcf, Zcd and Zcb ISA extensions
riscv: add ISA parsing for Zca, Zcf, Zcd and Zcb
riscv: add ISA extensions validation callback
dt-bindings: riscv: add Zca, Zcf, Zcd and Zcb ISA extension description
KVM: riscv: selftests: Add Zimop extension to get-reg-list test
RISC-V: KVM: Allow Zimop extension for Guest/VM
riscv: hwprobe: export Zimop ISA extension
riscv: add ISA extension parsing for Zimop
dt-bindings: riscv: add Zimop ISA extension description
Link: https://lore.kernel.org/r/20240619113529.676940-1-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Add parsing for Zcmop ISA extension which was ratified in commit
c732a4f39a4c ("Zcmop is ratified/1.0") of the riscv-isa-manual.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240619113529.676940-14-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The Zc* standard extension for code reduction introduces new extensions.
This patch adds support for Zca, Zcf, Zcd and Zcb. Zce, Zcmt and Zcmp
are left out of this patch since they are targeting microcontrollers/
embedded CPUs instead of application processors.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619113529.676940-9-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Since a few extensions (Zicbom/Zicboz) already needs validation and
future ones will need it as well (Zc*) add a validate() callback to
struct riscv_isa_ext_data. This require to rework the way extensions are
parsed and split it in two phases. First phase is isa string or isa
extension list parsing and consists in enabling all the extensions in a
temporary bitmask (source isa) without any validation. The second step
"resolves" the final isa bitmap, handling potential missing dependencies.
The mechanism is quite simple and simply validate each extension
described in the source bitmap before enabling it in the resolved isa
bitmap. validate() callbacks can return either 0 for success,
-EPROBEDEFER if extension needs to be validated again at next loop. A
previous ISA bitmap is kept to avoid looping multiple times if an
extension dependencies are never satisfied until we reach a stable
state. In order to avoid any potential infinite looping, allow looping
a maximum of the number of extension we handle. Zicboz and Zicbom
extensions are modified to use this validation mechanism.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619113529.676940-8-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Add parsing for Zimop ISA extension which was ratified in commit
58220614a5f of the riscv-isa-manual.
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Link: https://lore.kernel.org/r/20240619113529.676940-3-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This first patch in the larger series is a fix, so I'm merging it into
fixes while the rest of the patch set is still under development.
* b4-shazam-merge:
riscv: stacktrace: convert arch_stack_walk() to noinstr
Link: https://lore.kernel.org/r/20240613-dev-andyc-dyn-ftrace-v4-v1-0-1a538e12c01e@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
arch_stack_walk() is called intensively in function_graph when the
kernel is compiled with CONFIG_TRACE_IRQFLAGS. As a result, the kernel
logs a lot of arch_stack_walk and its sub-functions into the ftrace
buffer. However, these functions should not appear on the trace log
because they are part of the ftrace itself. This patch references what
arm64 does for the smae function. So it further prevent the re-enter
kprobe issue, which is also possible on riscv.
Related-to: commit 0fbcd8abf3 ("arm64: Prohibit instrumentation on arch_stack_walk()")
Fixes: 680341382d ("riscv: add CALLER_ADDRx support")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240613-dev-andyc-dyn-ftrace-v4-v1-1-1a538e12c01e@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
We cannot delay the icache flush after patching some functions as we may
have patched a function that will get called before the icache flush.
The only way to completely avoid such scenario is by flushing the icache
as soon as we patch a function. This will probably be costly as we don't
batch the icache maintenance anymore.
Fixes: 6ca445d8af ("riscv: Fix early ftrace nop patching")
Reported-by: Conor Dooley <conor.dooley@microchip.com>
Closes: https://lore.kernel.org/linux-riscv/20240613-lubricant-breath-061192a9489a@wendy/
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andy Chiu <andy.chiu@sifive.com>
Link: https://lore.kernel.org/r/20240624082141.153871-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Samuel Holland <samuel.holland@sifive.com> says:
Here are a few changes to minimize calls to stop_machine() and
flush_icache_*() in the various text patching functions, as well as
to simplify the code.
* b4-shazam-merge:
riscv: Remove extra variable in patch_text_nosync()
riscv: Use offset_in_page() in text patching functions
riscv: Pass patch_text() the length in bytes
riscv: Simplify text patching loops
riscv: kprobes: Use patch_text_nosync() for insn slots
riscv: jump_label: Simplify assembly syntax
riscv: jump_label: Batch icache maintenance
Link: https://lore.kernel.org/r/20240327160520.791322-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This cast is superfluous, and is incorrect anyway if compressed
instructions may be present.
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240327160520.791322-8-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This is a bit easier to parse than the equivalent bit manipulation.
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240327160520.791322-7-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
patch_text_nosync() already handles an arbitrary length of code, so this
removes a superfluous loop and reduces the number of icache flushes.
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240327160520.791322-6-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This reduces the number of variables and makes the code easier to parse.
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240327160520.791322-5-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
These instructions are not yet visible to the rest of the system,
so there is no need to do the whole stop_machine() dance.
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240327160520.791322-4-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Switch to the batched version of the jump label update functions so
instruction cache maintenance is deferred until the end of the update.
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240327160520.791322-2-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Most architectures that implement the old-style mmap() with byte offset
use 'unsigned long' as the type for that offset, but microblaze and
riscv have the off_t type that is shared with userspace, matching the
prototype in include/asm-generic/syscalls.h.
Make this consistent by using an unsigned argument everywhere. This
changes the behavior slightly, as the argument is shifted to a page
number, and an user input with the top bit set would result in a
negative page offset rather than a large one as we use elsewhere.
For riscv, the 32-bit sys_mmap2() definition actually used a custom
type that is different from the global declaration, but this was
missed due to an incorrect type check.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Make has_vector() to check for ZVE32X. Every in-kernel usage of V that
requires a more complicate version of V must then call out explicitly.
Also, change riscv_v_first_use_handler(), and boot code that calls
riscv_v_setup_vsize() to accept ZVE32X.
Most kernel/user interfaces requires minimum of ZVE32X. Thus, programs
compiled and run with ZVE32X should be supported by the kernel on most
aspects. This includes context-switch, signal, ptrace, prctl, and
hwprobe.
One exception is that ELF_HWCAP returns 'V' only if full V is supported
on the platform. This means that the system without a full V must not
rely on ELF_HWCAP to tell whether it is allowable to execute Vector
without first invoking a prctl() check.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Joel Granados <j.granados@samsung.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-7-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The following Vector subextensions for "embedded" platforms are added
into RISCV_HWPROBE_KEY_IMA_EXT_0:
- ZVE32X
- ZVE32F
- ZVE64X
- ZVE64F
- ZVE64D
Extensions ending with an X indicates that the platform doesn't have a
vector FPU.
Extensions ending with F/D mean that whether single (F) or double (D)
precision vector operation is supported.
The number 32 or 64 follows from ZVE tells the maximum element length.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-6-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Multiple Vector subextensions are added. Also, the patch takes care of
the dependencies of Vector subextensions by macro expansions. So, if
some "embedded" platform only reports "zve64f" on the ISA string, the
parser is able to expand it to zve32x zve32f zve64x and zve64f.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-5-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Single-letter extensions may also imply multiple subextensions. For
example, Vector extension implies zve64d, and zve64d implies zve64f.
Extension parsing for "riscv,isa-extensions" has the ability to resolve
the dependency by calling match_isa_ext(). This patch makes deprecated
parser call the same function for single letter extensions.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-3-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Currently we only support Vector for SMP platforms, that is, all SMP
cores have the same vlenb. If we happen to detect a mismatching vlen, it
is better to just fail bootting it up to prevent further race/scheduling
issues.
Also, move .Lsecondary_park forward and chage `tail smp_callin` into a
regular call in the early assembly. So a core would be parked right
after a return from smp_callin. Note that a successful smp_callin
does not return.
Fixes: 7017858eb2 ("riscv: Introduce riscv_v_vsize to record size of Vector context")
Reported-by: Conor Dooley <conor.dooley@microchip.com>
Closes: https://lore.kernel.org/linux-riscv/20240228-vicinity-cornstalk-4b8eb5fe5730@spud/
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Yunhui Cui <cuiyunhui@bytedance.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-2-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
The function would fail when it detects the calling hart's vlen doesn't
match the first one's. The boot hart is the first hart calling this
function during riscv_fill_hwcap, so it is impossible to fail here. Add
a comment about this behavior.
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240510-zve-detection-v5-1-0711bdd26c12@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
