Version 0.2 of the SBI specification [1] marked the existing SBI
functions as "legacy" in order to move to a newer calling convention. It
also introduced a set of replacement extensions for some of the legacy
functionality. In particular, the TIME, IPI, and RFENCE extensions
implement and extend the semantics of their legacy counterparts, while
conforming to the newer version of the spec.
Update our SBI code to use the new replacement extensions when
available, and fall back to the legacy ones. These will eventually be
dropped, when support for version 0.2 is ubiquitous.
[1] https://github.com/riscv/riscv-sbi-doc/blob/master/riscv-sbi.adoc
Submitted by: Danjel Q. <danq1222@gmail.com>
Reviewed by: kp
Differential Revision: https://reviews.freebsd.org/D26953
S-mode software has write access to the SIP.SSIP bit, so instead of
making a second round-trip through the SBI we can clear it ourselves.
The SBI spec has deprecated this function for this exactly this reason.
Submitted by: Danjel Q. <danq1222@gmail.com
Reviewed by: kp
Differential Revision: https://reviews.freebsd.org/D26952
The existing names were inherited from arm64, but we should prefer
RISC-V terminology. Change the prefix to SCAUSE, and further change the
names to better match the RISC-V spec and be more consistent with one
another. Also, remove two codes that are not defined for S-mode (machine
and hypervisor ecall).
While here, apply style(9) to some condition checks.
Reviewed by: kp
Discussed with: jrtc27
Differential Revision: https://reviews.freebsd.org/D26918
Every other architecture defines this and this is required for
interrupts to work when using QEMU's PCI VirtIO devices (which all
report an interrupt line of 0) for two reasons.
Firstly, interrupt line 0 is wrong; they use one of 0x20-0x23 with the
lines being cycled across devices like normal. Moreover, RISC-V uses
INTRNG, whose IRQs are virtual as indices into its irq_map, so even if
we have the right interrupt line we still need to try and route the
interrupt in order to ultimately call into intr_map_irq and get back a
unique index into the map for the given line, otherwise we will use
whatever happens to be in irq_map[line] (which for QEMU where the line
is initialised to 0 results in using the first allocated interrupt,
namely the RTC on IRQ 11 at time of commit).
Note that pci_assign_interrupt will still do the wrong thing for INTRNG
when using a tunable, as it will bypass INTRNG entirely and use the
tunable's value as the index into irq_map, when it should instead
(indirectly) call intr_map_irq to allocate a new entry for the given
IRQ and treat the tunable as stating the physical line in use, which is
what one would expect. This, however, is a problem shared by all INTRNG
architectures, and not exclusive to RISC-V.
Reviewed by: kib
Approved by: kib
Differential Revision: https://reviews.freebsd.org/D26564
On Ampere Altra systems, the sparse population of RAM within the
physical address space causes the vm_page_dump bitmap to be much
larger than necessary, increasing the size from ~8 Mib to > 2 Gib
(and overflowing `int` for the size).
Changing the page dump bitmap also changes the minidump file
format, so changes are also necessary in libkvm.
Reviewed by: jhb
Approved by: scottl (implicit)
MFC after: 1 week
Sponsored by: Ampere Computing, Inc.
Differential Revision: https://reviews.freebsd.org/D26131
These definitions were repeated by all architectures, with small
variations. Consolidate the common definitons in machine
independent code and use bitset(9) macros for manipulation. Many
opportunities for deduplication remain in the machine dependent
minidump logic. The only intended functional change is increasing
the bit index type to vm_pindex_t, allowing the indexing of pages
with address of 8 TiB and greater.
Reviewed by: kib, markj
Approved by: scottl (implicit)
MFC after: 1 week
Sponsored by: Ampere Computing, Inc.
Differential Revision: https://reviews.freebsd.org/D26129
One problem with the bus_space_read_N() and bus_space_write_N() family of
functions is that they provide no protection against exceptions which can
occur when no physical hardware or device responds to the read or write
cycles. In such a situation, the system typically would panic due to a
kernel-mode bus error. The bus_space_peek_N() and bus_space_poke_N() family
of functions provide a mechanism to handle these exceptions gracefully
without the risk of crashing the system.
Typical example is access to PCI(e) configuration space in bus enumeration
function on badly implemented PCI(e) root complexes (RK3399 or Neoverse
N1 N1SDP and/or access to PCI(e) register when device is in deep sleep state.
This commit adds a real implementation for arm64 only. The remaining
architectures have bus_space_peek()/bus_space_poke() emulated by using
bus_space_read()/bus_space_write() (without exception handling).
MFC after: 1 month
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D25371
This allows privileged userspace processes to find information about the
physical page backing a given mapping. It is useful in applications
such as DPDK which perform some of their own memory management.
Reviewed by: kib, jhb (previous version)
MFC after: 2 weeks
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara Inc.
Differential Revision: https://reviews.freebsd.org/D26237
There was an additional 7 bytes of compiler-inserted padding at the
end of the structure visible via 'ptype /o' in gdb.
Reviewed by: mhorne
Obtained from: CheriBSD
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D25867
RISC-V doesn't support floating-point exceptions.
RISC-V Instruction Set Manual: Volume I: User-Level ISA, 11.2 Floating-Point
Control and Status Register: "As allowed by the standard, we do not support
traps on floating-point exceptions in the base ISA, but instead require
explicit checks of the flags in software. We considered adding branches
controlled directly by the contents of the floating-point accrued exception
flags, but ultimately chose to omit these instructions to keep the ISA simple."
We still need these functions, because some applications (notably Perl) call
them, but we cannot provide a meaningful implementation.
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D25740
This implementation doesn't have any major deviations from the other EFI
ports. I've copied the boilerplate from arm and arm64.
I've tested this with the following boot flows:
OpenSBI (M-mode) -> u-boot (S-mode) -> loader.efi -> FreeBSD
OpenSBI (M-mode) -> u-boot (S-mode) -> boot1.efi -> loader.efi -> FreeBSD
Due to the way that u-boot handles secondary CPUs, OpenSBI >= v0.7 is required,
as the HSM extension is needed to bring them up explicitly. Because of this,
using BBL as the SBI implementation will not be possible. Additionally, there
are a few recent u-boot changes that are required as well, all of which will be
present in the upcoming v2020.07 release.
Looks good: emaste
Differential Revision: https://reviews.freebsd.org/D25135
The top 10 bits of a pte are reserved by specification[1] and are not part of
the PPN.
[1] 'Volume II: RISC-V Privileged Architectures V20190608-Priv-MSU-Ratified',
'4.4.1 Addressing and Memory Protection', page 72: "The PTE format for Sv39 is
shown in Figure 4.18. ... Bits 63–54 are reserved for future use and must be
zeroed by software for forward compatibility."
Submitted by: Nathaniel Filardo <nwf20@cl.cam.ac.uk>
Reviewed by: kp, mhorne
Differential Revision: https://reviews.freebsd.org/D25523
In locore, we must detect and handle different arguments passed by
loader(8) compared to what we recieve when booting directly via SBI
firmware. Currently we receive the hart ID in a0 and a pointer to the
device tree blob in a1. loader(8) provides only a pointer to its
metadata in a0.
The solution to this is to add an additional entry point, _alt_start.
This will be placed first in the .text section, so SBI firmware will
enter here, and jump to the common pagetable setup shortly after. Since
loader(8) understands our ELF kernel, it will enter at the ELF's entry
address, which points to _start. This approach leads to very little
guesswork as to which way we booted.
Fix-up initriscv() to parse the loader's metadata, continuing to use
fake_preload_metadata() in the SBI direct boot case.
Reviewed by: markj, jrtc27 (asm portion)
Differential Revision: https://reviews.freebsd.org/D24912
This can happen with very large kernels (e.g. ones embedding a root
filesystem). The DTB written by OpenSBI/BBL is quite small so this is
unlikely to hit important data, but if it does this can result in very
confusing and hard-to-debug crashes. Add a KASSERT() and a verbose print
to catch this problem with debug kernels.
While this will not print any output by default if it fails (that would
depend on EARLY_PRINTF), at least the kernel now halts reliably instead
of randomly crashing.
Reviewed By: mhorne
Differential Revision: https://reviews.freebsd.org/D25153
This is in preparation for booting via loader(8). Lift these macros from arm64
so we don't need to worry about the size when inserting new elements. This
could have been done in r359673, but I didn't think I would be returning to
this function so soon.
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D24910
For userland, MACHINE_ARCH reflects the current ABI via preprocessor
directives. For the kernel, the hw.machine_arch sysctl uses the ELF
header flags of the current process to select the correct MACHINE_ARCH
value.
Reviewed by: imp, kp
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D24543
Replace our hand-rolled functions with the generic ones provided by
kern/subr_physmem.c. This greatly simplifies the initialization of
physical memory regions and kernel globals.
Tested by: nick
Differential Revision: https://reviews.freebsd.org/D24154
The location of the device-tree blob is passed to the kernel by the
previous booting stage (i.e. BBL or OpenSBI). Currently, we leave it
untouched and mark the 1MB of memory holding it as unavailable.
Instead, do what is done by other fake_preload_metadata() routines and
copy to the DTB to KVA space. This is more in line with what loader(8)
will provide us in the future, and it allows us to reclaim the hole in
physical memory.
Reviewed by: markj, kp (earlier version)
Differential Revision: https://reviews.freebsd.org/D24152
Use __riscv_flen instead of __riscv_float_abi_soft. While the latter works for
userland (and one could argue it's more correct), it fails for the kernel. We
compile the kernel with -mabi=lp64 (eg soft float abi) to avoid floating point
instructions in the kernel. We also compile the kernel -march=rv64imafdc for
hard float kernels (eg those with options FPE), but with -march=rv64imac for
softfloat kernels (eg those with FPE). Since we do this, in the kernel (as in
userland) __riscv_flen will be defined for 'riscv64' and not for 'riscv64sf'.
This also removes the -DMACHINE_ARCH hack now that it's no longer needed.
Longer term, we should return the ABI from the sysctl hw.machine_arch like on
amd64 for i386 binaries.
Suggested by: mhorne@
Differential Revision: https://reviews.freebsd.org/D23813
MACHINE_ARCH sets the hw.machine_arch sysctl in the kernel. In userspace
it sets MACHINE_ARCH in bmake, which bsd.cpu.mk uses to configure the
target ABI for ports.
For riscv64sf builds (i.e. soft-float) that needs to be riscv64sf, but
the sysctl didn't reflect that. It is static.
Set the define from the riscv makefile so that we correctly reflect our
actual build (i.e. riscv64 or riscv64sf), depending on what TARGET_ARCH
we were built with.
That still doesn't satisfy userspace builds (e.g. bmake), so check if
we're building with a software-floating point toolchain there. That
check doesn't work in the kernel, because it never uses floating point.
Reviewed by: philip (previous version), mhorne
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D23741
While cause codes higher than 16 are reserved, the exception code
field of the register is defined to be all bits but the upper-most
bit.
Reviewed by: mhorne
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D23510
This fixes continuing from debug.kdb.enter=1 after enabling the use of
compressed instructions since the compiler can emit the two byte
c.ebreak instead of the 4 byte ebreak.
Reviewed by: br
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D23507
This reverts r177661. The change is no longer very useful since
out-of-tree KLDs will be built to target SMP kernels anyway. Moveover
it breaks the KBI in !SMP builds since cpuset_t's layout depends on the
value of MAXCPU, and several kernel interfaces, notably
smp_rendezvous_cpus(), take a cpuset_t as a parameter.
PR: 243711
Reviewed by: jhb, kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23512
cpu_switch/throw() and savectx() do not save or restore any values in
these fields which mostly held non-callee-save registers.
makectx() copied these fields from kdb_frame, but they weren't used
except for PC_REGS using pcb_sepc. Change PC_REGS to use
kdb_frame->tf_sepc directly instead.
Reviewed by: br
MFC after: 2 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D23395
The SD bit is defined as the MSB of the sstatus register, meaning its
position will vary depending on the CSR's length. Previously, there were
two (unused) defines for this, for the 32 and 64-bit cases, but their
definitions were swapped.
Consolidate these into one define: SSTATUS_SD, and make the definition
dependent on the value of __riscv_xlen.
Reviewed by: br
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D23402
This is a 32-bit structure embedded in each vm_page, consisting mostly
of page queue state. The use of a structure makes it easy to store a
snapshot of a page's queue state in a stack variable and use cmpset
loops to update that state without requiring the page lock.
This change merely adds the structure and updates references to atomic
state fields. No functional change intended.
Reviewed by: alc, jeff, kib
Sponsored by: Netflix, Intel
Differential Revision: https://reviews.freebsd.org/D22650
o Remove All Rights Reserved from my notices
o imp@FreeBSD.org everywhere
o regularize punctiation, eliminate date ranges
o Make sure that it's clear that I don't claim All Rights reserved by listing
All Rights Reserved on same line as other copyright holders (but not
me). Other such holders are also listed last where it's clear.
SBI version 0.2 introduces functions for obtaining the details of the
SBI implementation, such as version and implemntation ID. Print this
info at startup when it is available.
Reviewed by: jhb, kp
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22327
Allow for an additional argument to sbi_call which will be passed in a6.
This is required for SBI spec 0.2 support, as a6 will indicate the SBI
function ID.
While here, introduce some macros to clean up the calls.
Reviewed by: kp, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22325
The lr.w instruction used to read the value from memory sign-extends
the value read from memory. GCC sign-extends the 32-bit comparison
value passed in whereas clang currently does not. As a result, if the
value being compared has the MSB set, the comparison fails for
matching 32-bit values when compiled with clang.
Use a cast to explicitly sign-extend the unsigned comparison value.
This works with both GCC and clang.
There is commentary in the RISC-V spec that suggests that GCC's
approach is more correct, but it is not clear if the commentary in the
RISC-V spec is binding.
Reviewed by: mhorne
Obtained from: Axiado
MFC after: 2 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22084
We must also check for large mappings. pmap_page_is_mapped() is
mostly used in assertions, so the problem was not very noticeable.
Reviewed by: alc
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21824
Many extern struct pcpu <something>__pcpu declarations were
copied/pasted in sources. The issue is that the definition is MD, but
it cannot be provided by machine/pcpu.h due to actual struct pcpu
defined in sys/pcpu.h later than the inclusion of machine/pcpu.h.
This forced the copying when other code needed direct access to
__pcpu. There is no way around it, due to machine/pcpu.h supplying
part of struct pcpu fields.
To work around the problem, add a new machine/pcpu_aux.h header, which
should fill any needed MD definitions after struct pcpu definition is
completed. This allows to remove copies of __pcpu spread around the
source. Also on x86 it makes it possible to remove work arounds like
OFFSETOF_CURTHREAD or clang specific warnings supressions.
Reported and tested by: lwhsu, bcran
Reviewed by: imp, markj (previous version)
Discussed with: jhb
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21418
doing so adds more flexibility with less redundant code.
Reviewed by: jhb, markj, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21250
AT_HWCAP is a field in the elf auxiliary vector meant to describe
cpu-specific hardware features. For RISC-V we want to use this to
indicate the presence of any standard extensions supported by the CPU.
This allows userland applications to query the system for supported
extensions using elf_aux_info(3).
Support for an extension is indicated by the presence of its
corresponding bit in AT_HWCAP -- e.g. systems supporting the 'c'
extension (compressed instructions) will have the second bit set.
Extensions advertised through AT_HWCAP are only those that are supported
by all harts in the system.
Reviewed by: jhb, markj
Approved by: markj (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D20493
The gp register is intended to used by the linker as another means of
performing relaxations, and should point to the small data section (.sdata).
Currently gp is being used as the pcpu pointer within the kernel, but the more
appropriate choice for this is the tp register, which is unused.
Swap existing usage of gp with tp within the kernel, and set up gp properly
at boot with the value of __global_pointer$ for all harts.
Additionally, remove some cases of accessing tp from the PCB, as it is not
part of the per-thread state. The user's tp and gp should be tracked only
through the trapframe.
Reviewed by: markj, jhb
Approved by: markj (mentor)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19893
from SiFive, Inc.
The first core on this SoC (hart 0) is a 64-bit microcontroller.
o Pick a hart to run boot process using hart lottery.
This allows to exclude hart 0 from running the boot process.
(BBL releases hart 0 after the main harts, so it never wins the lottery).
o Renumber CPUs early on boot.
Exclude non-MMU cores. Store the original hart ID in struct pcpu. This
allows to find out the correct destination for IPIs and remote sfence
calls.
Thanks to SiFive, Inc for the board provided.
Reviewed by: markj
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D20225
