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Author SHA1 Message Date
Torsten Duwe
49af7a2cd5
riscv/kexec: load initrd high in available memory
When initrd is loaded low, the secondary kernel fails like this:

 INITRD: 0xdc581000+0x00eef000 overlaps in-use memory region

This initrd load address corresponds to the _end symbol, but the
reservation is aligned on PMD_SIZE, as explained by a comment in
setup_bootmem().

It is technically possible to align the initrd load address accordingly,
leaving a hole between the end of kernel and the initrd, but it is much
simpler to allocate the initrd top-down.

Fixes: 838b3e2848 ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: stable@vger.kernel.org
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/67c8eb9eea25717c2c8208d9bfbfaa39e6e2a1c6.1690365011.git.petr.tesarik.ext@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-04 10:27:44 -07:00
Torsten Duwe
d0b4f95a51
riscv/kexec: handle R_RISCV_CALL_PLT relocation type
R_RISCV_CALL has been deprecated and replaced by R_RISCV_CALL_PLT. See Enum
18-19 in Table 3. Relocation types here:

https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc

It was deprecated in ("Deprecated R_RISCV_CALL, prefer R_RISCV_CALL_PLT"):

a0dced8501

Recent tools (at least GNU binutils-2.40) already use R_RISCV_CALL_PLT.
Kernels built with such binutils fail kexec_load_file(2) with:

 kexec_image: Unknown rela relocation: 19
 kexec_image: Error loading purgatory ret=-8

The binary code at the call site remains the same, so tell
arch_kexec_apply_relocations_add() to handle _PLT alike.

Fixes: 838b3e2848 ("RISC-V: Load purgatory in kexec_file")
Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: Li Zhengyu <lizhengyu3@huawei.com>
Cc: stable@vger.kernel.org
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/b046b164af8efd33bbdb7d4003273bdf9196a5b0.1690365011.git.petr.tesarik.ext@huawei.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-04 10:27:11 -07:00
Song Shuai
fbe7d19d2b
riscv: Export va_kernel_pa_offset in vmcoreinfo
Since RISC-V Linux v6.4, the commit 3335068f87 ("riscv: Use
PUD/P4D/PGD pages for the linear mapping") changes phys_ram_base
from the physical start of the kernel to the actual start of the DRAM.

The Crash-utility's VTOP() still uses phys_ram_base and kernel_map.virt_addr
to translate kernel virtual address, that failed the Crash with Linux v6.4 [1].

Export kernel_map.va_kernel_pa_offset in vmcoreinfo to help Crash translate
the kernel virtual address correctly.

Fixes: 3335068f87 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
Link: https://lore.kernel.org/linux-riscv/20230724040649.220279-1-suagrfillet@gmail.com/ [1]
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Reviewed-by: Xianting Tian  <xianting.tian@linux.alibaba.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230724100917.309061-1-suagrfillet@gmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-02 13:50:31 -07:00
Sunil V L
568701fee3
RISC-V: ACPI: Fix acpi_os_ioremap to return iomem address
acpi_os_ioremap() currently is a wrapper to memremap() on
RISC-V. But the callers of acpi_os_ioremap() expect it to
return __iomem address and hence sparse tool reports a new
warning. Fix this issue by type casting to  __iomem type.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307230357.egcTAefj-lkp@intel.com/
Fixes: a91a9ffbd3 ("RISC-V: Add support to build the ACPI core")
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230724100346.1302937-1-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-02 13:49:43 -07:00
Justin Stitt
12d61a1bc2
RISC-V: cpu: refactor deprecated strncpy
`strncpy` is deprecated for use on NUL-terminated destination strings [1].

Favor not copying strings onto stack and instead use strings directly.
This avoids hard-coding sizes and buffer lengths all together.

Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Suggested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230802-arch-riscv-kernel-v2-1-24266e85bc96@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-02 13:45:28 -07:00
Conor Dooley
496ea826d1
RISC-V: provide Kconfig & commandline options to control parsing "riscv,isa"
As it says on the tin, provide Kconfig option to control parsing the
"riscv,isa" devicetree property. If either option is used, the kernel
will fall back to parsing "riscv,isa", where "riscv,isa-base" and
"riscv,isa-extensions" are not present.
The Kconfig options are set up so that the default kernel configuration
will enable the fallback path, without needing the commandline option.

Suggested-by: Andrew Jones <ajones@ventanamicro.com>
Suggested-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-aviator-plausibly-a35662485c2c@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:25 -07:00
Conor Dooley
c98f136aed
RISC-V: try new extension properties in of_early_processor_hartid()
To fully deprecate the kernel's use of "riscv,isa",
of_early_processor_hartid() needs to first try using the new properties,
before falling back to "riscv,isa".

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-tablet-jimmy-987fea0eb2e1@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:24 -07:00
Conor Dooley
90700a4fbf
RISC-V: enable extension detection from dedicated properties
Add support for parsing the new riscv,isa-extensions property in
riscv_fill_hwcap(), by means of a new "property" member of the
riscv_isa_ext_data struct. For now, this shadows the name of the
extension for all users, however this may not be the case for all
extensions, based on how the dt-binding is written.
For the sake of backwards compatibility, fall back to the old scheme
if the new properties are not detected. For now, just inform, rather
than warn, when that happens.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-vocation-profane-39a74b3c2649@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:23 -07:00
Conor Dooley
4265b0ec5e
RISC-V: split riscv_fill_hwcap() in 3
Before adding more complexity to it, split riscv_fill_hwcap() into 3
distinct sections:
- riscv_fill_hwcap() still is the top level function, into which the
  additional complexity will be added.
- riscv_fill_hwcap_from_isa_string() handles getting the information
  from the riscv,isa/ACPI equivalent across harts & the various quirks
  there
- riscv_parse_isa_string() does what it says on the tin.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-daylight-puritan-37aeb41a4d9b@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:22 -07:00
Conor Dooley
effc122ad1
RISC-V: add single letter extensions to riscv_isa_ext
So that riscv_fill_hwcap() can use riscv_isa_ext to probe for single
letter extensions, add them to it.
As a result, what gets spat out in /proc/cpuinfo will become borked, as
single letter extensions will be printed as part of the base extensions
and while printing from riscv_isa_arr. Take the opportunity to unify the
printing of the isa string, using the new member of riscv_isa_ext_data
in the process.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-despite-bright-de00ac888cc7@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:21 -07:00
Conor Dooley
37f988dcec
RISC-V: repurpose riscv_isa_ext array in riscv_fill_hwcap()
In riscv_fill_hwcap() riscv_isa_ext array can be looped over, rather
than duplicating the list of extensions with individual
SET_ISA_EXT_MAP() usage. While at it, drop the statement-of-the-obvious
comments from the struct, rename uprop to something more suitable for
its new use & constify the members.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-dastardly-affiliate-4cf819dccde2@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:19 -07:00
Conor Dooley
8135ade32c
RISC-V: shunt isa_ext_arr to cpufeature.c
To facilitate using one struct to define extensions, rather than having
several, shunt isa_ext_arr to cpufeature.c, where it will be used for
probing extension presence also.
As that scope of the array as widened, prefix it with riscv & drop the
type from the variable name.

Since the new array is const, print_isa() needs a wee bit of cleanup to
avoid complaints about losing the const qualifier.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-spirits-upside-a2c61c65fd5a@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:18 -07:00
Conor Dooley
131033689d
RISC-V: drop a needless check in print_isa_ext()
isa_ext_arr cannot be empty, as some of the extensions within it are
always built into the kernel. When this code was first added, back in
commit a9b202606c ("RISC-V: Improve /proc/cpuinfo output for ISA
extensions"), the array was empty and needed a dummy item & thus there
could be no extensions present. When the first multi-letter ones did
get added, it was Sscofpmf - which didn't have a Kconfig symbol to
disable it.

Remove this check, as it has been redundant since Sscofpmf was added.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-veggie-mug-3d3bf6787ae2@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:17 -07:00
Heiko Stuebner
67270fb388
RISC-V: don't parse dt/acpi isa string to get rv32/rv64
When filling hwcap the kernel already expects the isa string to start with
rv32 if CONFIG_32BIT and rv64 if CONFIG_64BIT.

So when recreating the runtime isa-string we can also just go the other way
to get the correct starting point for it.

Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Co-developed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-masculine-saddlebag-67a94966b091@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:16 -07:00
Palmer Dabbelt
2305989396
RISC-V: Provide a more helpful error message on invalid ISA strings
Right now we provide a somewhat unhelpful error message on systems with
invalid error messages, something along the lines of

	CPU with hartid=0 is not available
	------------[ cut here ]------------
	kernel BUG at arch/riscv/kernel/smpboot.c:174!
	Kernel BUG [#1]
	Modules linked in:
	CPU: 0 PID: 0 Comm: swapper Not tainted 6.4.0-rc1-00096-ge0097d2c62d5-dirty #1
	Hardware name: Microchip PolarFire-SoC Icicle Kit (DT)
	epc : of_parse_and_init_cpus+0x16c/0x16e
	 ra : of_parse_and_init_cpus+0x9a/0x16e
	epc : ffffffff80c04e0a ra : ffffffff80c04d38 sp : ffffffff81603e20
	 gp : ffffffff8182d658 tp : ffffffff81613f80 t0 : 000000000000006e
	 t1 : 0000000000000064 t2 : 0000000000000000 s0 : ffffffff81603e80
	 s1 : 0000000000000000 a0 : 0000000000000000 a1 : 0000000000000000
	 a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
	 a5 : 0000000000001fff a6 : 0000000000001fff a7 : ffffffff816148b0
	 s2 : 0000000000000001 s3 : ffffffff81492a4c s4 : ffffffff81a4b090
	 s5 : ffffffff81506030 s6 : 0000000000000040 s7 : 0000000000000000
	 s8 : 00000000bfb6f046 s9 : 0000000000000001 s10: 0000000000000000
	 s11: 00000000bf389700 t3 : 0000000000000000 t4 : 0000000000000000
	 t5 : ffffffff824dd188 t6 : ffffffff824dd187
	status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
	[<ffffffff80c04e0a>] of_parse_and_init_cpus+0x16c/0x16e
	[<ffffffff80c04c96>] setup_smp+0x1e/0x26
	[<ffffffff80c03ffe>] setup_arch+0x6e/0xb2
	[<ffffffff80c00384>] start_kernel+0x72/0x400
	Code: 80e7 4a00 a603 0009 b795 1097 ffe5 80e7 92c0 9002 (9002) 715d
	---[ end trace 0000000000000000 ]---
	Kernel panic - not syncing: Fatal exception in interrupt

Add a warning for the cases where the ISA string isn't valid.  It's still
above the BUG_ON cut, but hopefully it's at least a bit easier for users.

Reviewed-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230713-endless-spearhead-62a5a4b149bd@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-25 16:26:15 -07:00
Palmer Dabbelt
ab2dbc7acc
RISC-V: Don't include Zicsr or Zifencei in I from ACPI
ACPI ISA strings are based on a specification after Zicsr and Zifencei
were split out of I, so we shouldn't be treating them as part of I.  We
haven't release an ACPI-based kernel yet, so we don't need to worry
about compatibility with the old ISA strings.

Fixes: 07edc32779 ("RISC-V: always report presence of extensions formerly part of the base ISA")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230711224600.10879-1-palmer@rivosinc.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-12 10:04:40 -07:00
Linus Torvalds
4f6b6c2b2f RISC-V Patches for the 6.5 Merge Window, Part 2
* A bunch of fixes/cleanups from the first part of the merge window,
   mostly related to ACPI and vector as those were large.
 * Some documentation improvements, mostly related to the new code.
 * The "riscv,isa" DT key is deprecated.
 * Support for link-time dead code elimination.
 * Support for minor fault registration in userfaultd.
 * A handful of cleanups around CMO alternatives.
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Merge tag 'riscv-for-linus-6.5-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Palmer Dabbelt:

 - A bunch of fixes/cleanups from the first part of the merge window,
   mostly related to ACPI and vector as those were large

 - Some documentation improvements, mostly related to the new code

 - The "riscv,isa" DT key is deprecated

 - Support for link-time dead code elimination

 - Support for minor fault registration in userfaultd

 - A handful of cleanups around CMO alternatives

* tag 'riscv-for-linus-6.5-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (23 commits)
  riscv: mm: mark noncoherent_supported as __ro_after_init
  riscv: mm: mark CBO relate initialization funcs as __init
  riscv: errata: thead: only set cbom size & noncoherent during boot
  riscv: Select HAVE_ARCH_USERFAULTFD_MINOR
  RISC-V: Document the ISA string parsing rules for ACPI
  risc-v: Fix order of IPI enablement vs RCU startup
  mm: riscv: fix an unsafe pte read in huge_pte_alloc()
  dt-bindings: riscv: deprecate riscv,isa
  RISC-V: drop error print from riscv_hartid_to_cpuid()
  riscv: Discard vector state on syscalls
  riscv: move memblock_allow_resize() after linear mapping is ready
  riscv: Enable ARCH_SUSPEND_POSSIBLE for s2idle
  riscv: vdso: include vdso/vsyscall.h for vdso_data
  selftests: Test RISC-V Vector's first-use handler
  riscv: vector: clear V-reg in the first-use trap
  riscv: vector: only enable interrupts in the first-use trap
  RISC-V: Fix up some vector state related build failures
  RISC-V: Document that V registers are clobbered on syscalls
  riscv: disable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for LLD
  riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
  ...
2023-07-07 10:07:19 -07:00
Marc Zyngier
6259f3443c
risc-v: Fix order of IPI enablement vs RCU startup
Conor reports that risc-v tries to enable IPIs before telling the
core code to enable RCU. With the introduction of the mapple tree
as a backing store for the irq descriptors, this results in
a very shouty boot sequence, as RCU is legitimately upset.

Restore some sanity by moving the risc_ipi_enable() call after
notify_cpu_starting(), which explicitly enables RCU on the calling
CPU.

Fixes: 832f15f426 ("RISC-V: Treat IPIs as normal Linux IRQs")
Reported-by: Conor Dooley <conor@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230703-dupe-frying-79ae2ccf94eb@spud
Cc: Anup Patel <apatel@ventanamicro.com>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230703183126.1567625-1-maz@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-05 07:24:38 -07:00
Conor Dooley
52909f1768
RISC-V: drop error print from riscv_hartid_to_cpuid()
As of commit 2ac8743437 ("RISC-V: split early & late of_node to
hartid mapping") my CI complains about newly added pr_err() messages
during boot, for example:
[    0.000000] Couldn't find cpu id for hartid [0]
[    0.000000] riscv-intc: unable to find hart id for /cpus/cpu@0/interrupt-controller

Before the split, riscv_of_processor_hartid() contained a check for
whether the cpu was "available", before calling riscv_hartid_to_cpuid(),
but after the split riscv_of_processor_hartid() can be called for cpus
that are disabled.

Most callers of riscv_hartid_to_cpuid() already report custom errors
where it falls, making this print superfluous in those case. In other
places, the print adds nothing - see riscv_intc_init() for example.

Fixes: 2ac8743437 ("RISC-V: split early & late of_node to hartid mapping")
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230629-paternity-grafted-b901b76d04a0@wendy
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-04 09:04:12 -07:00
Björn Töpel
9657e9b7d2
riscv: Discard vector state on syscalls
The RISC-V vector specification states:
  Executing a system call causes all caller-saved vector registers
  (v0-v31, vl, vtype) and vstart to become unspecified.

The vector registers are set to all 1s, vill is set (invalid), and the
vector status is set to Dirty.

That way we can prevent userspace from accidentally relying on the
stated save.

Rémi pointed out [1] that writing to the registers might be
superfluous, and setting vill is sufficient.

Link: https://lore.kernel.org/linux-riscv/12784326.9UPPK3MAeB@basile.remlab.net/ # [1]
Suggested-by: Darius Rad <darius@bluespec.com>
Suggested-by: Palmer Dabbelt <palmer@rivosinc.com>
Suggested-by: Rémi Denis-Courmont <remi@remlab.net>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230629142228.1125715-1-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-04 08:59:24 -07:00
Ben Dooks
54cdede08f
riscv: vdso: include vdso/vsyscall.h for vdso_data
Add include of <vdso/vsyscall.h> to pull in the defition of vdso_data
to remove the following sparse warning:

arch/riscv/kernel/vdso.c:39:18: warning: symbol 'vdso_data' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Link: https://lore.kernel.org/r/20230616114357.159601-1-ben.dooks@codethink.co.uk
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-04 07:54:41 -07:00
Andy Chiu
75b59f2a90
riscv: vector: clear V-reg in the first-use trap
If there is no context switch happens after we enable V for a process,
then we return to user space with whatever left on the CPU's V registers
accessible to the process. The leaked data could belong to another
process's V-context saved from last context switch, impacting process's
confidentiality on the system.

To prevent this from happening, we clear V registers by restoring
zero'd V context after turining on V.

Fixes: cd05483724 ("riscv: Allocate user's vector context in the first-use trap")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230627015556.12329-2-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-01 07:38:21 -07:00
Andy Chiu
26c38cd802
riscv: vector: only enable interrupts in the first-use trap
The function irqentry_exit_to_user_mode() must be called with interrupt
disabled. The caller of do_trap_insn_illegal() also assumes running
without interrupts. So, we should turn off interrupts after
riscv_v_first_use_handler() returns.

Fixes: cd05483724 ("riscv: Allocate user's vector context in the first-use trap")
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Link: https://lore.kernel.org/r/20230625155416.18629-1-andy.chiu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-01 07:38:20 -07:00
Palmer Dabbelt
782aefb177
Merge patch series "riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION"
Jisheng Zhang <jszhang@kernel.org> says:

When trying to run linux with various opensource riscv core on
resource limited FPGA platforms, for example, those FPGAs with less
than 16MB SDRAM, I want to save mem as much as possible. One of the
major technologies is kernel size optimizations, I found that riscv
does not currently support HAVE_LD_DEAD_CODE_DATA_ELIMINATION, which
passes -fdata-sections, -ffunction-sections to CFLAGS and passes the
--gc-sections flag to the linker.

This not only benefits my case on FPGA but also benefits defconfigs.
Here are some notable improvements from enabling this with defconfigs:

nommu_k210_defconfig:
   text    data     bss     dec     hex
1112009  410288   59837 1582134  182436     before
 962838  376656   51285 1390779  1538bb     after

rv32_defconfig:
   text    data     bss     dec     hex
8804455 2816544  290577 11911576 b5c198     before
8692295 2779872  288977 11761144 b375f8     after

defconfig:
   text    data     bss     dec     hex
9438267 3391332  485333 13314932 cb2b74     before
9285914 3350052  483349 13119315 c82f53     after

patch1 and patch2 are clean ups.
patch3 fixes a typo.
patch4 finally enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for riscv.

* b4-shazam-merge:
  riscv: disable HAVE_LD_DEAD_CODE_DATA_ELIMINATION for LLD
  riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
  vmlinux.lds.h: use correct .init.data.* section name
  riscv: vmlinux-xip.lds.S: remove .alternative section
  riscv: move options to keep entries sorted
  riscv: Fix orphan section warnings caused by kernel/pi

Link: https://lore.kernel.org/r/20230523165502.2592-1-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-07-01 07:38:19 -07:00
Linus Torvalds
cccf0c2ee5 Tracing updates for 6.5:
- Add new feature to have function graph tracer record the return value.
   Adds a new option: funcgraph-retval ; when set, will show the return
   value of a function in the function graph tracer.
 
 - Also add the option: funcgraph-retval-hex where if it is not set, and
   the return value is an error code, then it will return the decimal of
   the error code, otherwise it still reports the hex value.
 
 - Add the file /sys/kernel/tracing/osnoise/per_cpu/cpu<cpu>/timerlat_fd
   That when a application opens it, it becomes the task that the timer lat
   tracer traces. The application can also read this file to find out how
   it's being interrupted.
 
 - Add the file /sys/kernel/tracing/available_filter_functions_addrs
   that works just the same as available_filter_functions but also shows
   the addresses of the functions like kallsyms, except that it gives the
   address of where the fentry/mcount jump/nop is. This is used by BPF to
   make it easier to attach BPF programs to ftrace hooks.
 
 - Replace strlcpy with strscpy in the tracing boot code.
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Merge tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing updates from Steven Rostedt:

 - Add new feature to have function graph tracer record the return
   value. Adds a new option: funcgraph-retval ; when set, will show the
   return value of a function in the function graph tracer.

 - Also add the option: funcgraph-retval-hex where if it is not set, and
   the return value is an error code, then it will return the decimal of
   the error code, otherwise it still reports the hex value.

 - Add the file /sys/kernel/tracing/osnoise/per_cpu/cpu<cpu>/timerlat_fd
   That when a application opens it, it becomes the task that the timer
   lat tracer traces. The application can also read this file to find
   out how it's being interrupted.

 - Add the file /sys/kernel/tracing/available_filter_functions_addrs
   that works just the same as available_filter_functions but also shows
   the addresses of the functions like kallsyms, except that it gives
   the address of where the fentry/mcount jump/nop is. This is used by
   BPF to make it easier to attach BPF programs to ftrace hooks.

 - Replace strlcpy with strscpy in the tracing boot code.

* tag 'trace-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Fix warnings when building htmldocs for function graph retval
  riscv: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
  tracing/boot: Replace strlcpy with strscpy
  tracing/timerlat: Add user-space interface
  tracing/osnoise: Skip running osnoise if all instances are off
  tracing/osnoise: Switch from PF_NO_SETAFFINITY to migrate_disable
  ftrace: Show all functions with addresses in available_filter_functions_addrs
  selftests/ftrace: Add funcgraph-retval test case
  LoongArch: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
  x86/ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
  arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
  tracing: Add documentation for funcgraph-retval and funcgraph-retval-hex
  function_graph: Support recording and printing the return value of function
  fgraph: Add declaration of "struct fgraph_ret_regs"
2023-06-30 10:33:17 -07:00
Linus Torvalds
533925cb76 RISC-V Patches for the 6.5 Merge Window, Part 1
* Support for ACPI.
 * Various cleanups to the ISA string parsing, including making them
   case-insensitive
 * Support for the vector extension.
 * Support for independent irq/softirq stacks.
 * Our CPU DT binding now has "unevaluatedProperties: false"
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Merge tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for ACPI

 - Various cleanups to the ISA string parsing, including making them
   case-insensitive

 - Support for the vector extension

 - Support for independent irq/softirq stacks

 - Our CPU DT binding now has "unevaluatedProperties: false"

* tag 'riscv-for-linus-6.5-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (78 commits)
  riscv: hibernate: remove WARN_ON in save_processor_state
  dt-bindings: riscv: cpus: switch to unevaluatedProperties: false
  dt-bindings: riscv: cpus: add a ref the common cpu schema
  riscv: stack: Add config of thread stack size
  riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK
  riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
  RISC-V: always report presence of extensions formerly part of the base ISA
  dt-bindings: riscv: explicitly mention assumption of Zicntr & Zihpm support
  RISC-V: remove decrement/increment dance in ISA string parser
  RISC-V: rework comments in ISA string parser
  RISC-V: validate riscv,isa at boot, not during ISA string parsing
  RISC-V: split early & late of_node to hartid mapping
  RISC-V: simplify register width check in ISA string parsing
  perf: RISC-V: Limit the number of counters returned from SBI
  riscv: replace deprecated scall with ecall
  riscv: uprobes: Restore thread.bad_cause
  riscv: mm: try VMA lock-based page fault handling first
  riscv: mm: Pre-allocate PGD entries for vmalloc/modules area
  RISC-V: hwprobe: Expose Zba, Zbb, and Zbs
  RISC-V: Track ISA extensions per hart
  ...
2023-06-30 09:37:26 -07:00
Linus Torvalds
9244724fbf A large update for SMP management:
- Parallel CPU bringup
 
     The reason why people are interested in parallel bringup is to shorten
     the (kexec) reboot time of cloud servers to reduce the downtime of the
     VM tenants.
 
     The current fully serialized bringup does the following per AP:
 
       1) Prepare callbacks (allocate, intialize, create threads)
       2) Kick the AP alive (e.g. INIT/SIPI on x86)
       3) Wait for the AP to report alive state
       4) Let the AP continue through the atomic bringup
       5) Let the AP run the threaded bringup to full online state
 
     There are two significant delays:
 
       #3 The time for an AP to report alive state in start_secondary() on
          x86 has been measured in the range between 350us and 3.5ms
          depending on vendor and CPU type, BIOS microcode size etc.
 
       #4 The atomic bringup does the microcode update. This has been
          measured to take up to ~8ms on the primary threads depending on
          the microcode patch size to apply.
 
     On a two socket SKL server with 56 cores (112 threads) the boot CPU
     spends on current mainline about 800ms busy waiting for the APs to come
     up and apply microcode. That's more than 80% of the actual onlining
     procedure.
 
     This can be reduced significantly by splitting the bringup mechanism
     into two parts:
 
       1) Run the prepare callbacks and kick the AP alive for each AP which
       	 needs to be brought up.
 
 	 The APs wake up, do their firmware initialization and run the low
       	 level kernel startup code including microcode loading in parallel
       	 up to the first synchronization point. (#1 and #2 above)
 
       2) Run the rest of the bringup code strictly serialized per CPU
       	 (#3 - #5 above) as it's done today.
 
 	 Parallelizing that stage of the CPU bringup might be possible in
 	 theory, but it's questionable whether required surgery would be
 	 justified for a pretty small gain.
 
     If the system is large enough the first AP is already waiting at the
     first synchronization point when the boot CPU finished the wake-up of
     the last AP. That reduces the AP bringup time on that SKL from ~800ms
     to ~80ms, i.e. by a factor ~10x.
 
     The actual gain varies wildly depending on the system, CPU, microcode
     patch size and other factors. There are some opportunities to reduce
     the overhead further, but that needs some deep surgery in the x86 CPU
     bringup code.
 
     For now this is only enabled on x86, but the core functionality
     obviously works for all SMP capable architectures.
 
   - Enhancements for SMP function call tracing so it is possible to locate
     the scheduling and the actual execution points. That allows to measure
     IPI delivery time precisely.
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Merge tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull SMP updates from Thomas Gleixner:
 "A large update for SMP management:

   - Parallel CPU bringup

     The reason why people are interested in parallel bringup is to
     shorten the (kexec) reboot time of cloud servers to reduce the
     downtime of the VM tenants.

     The current fully serialized bringup does the following per AP:

       1) Prepare callbacks (allocate, intialize, create threads)
       2) Kick the AP alive (e.g. INIT/SIPI on x86)
       3) Wait for the AP to report alive state
       4) Let the AP continue through the atomic bringup
       5) Let the AP run the threaded bringup to full online state

     There are two significant delays:

       #3 The time for an AP to report alive state in start_secondary()
          on x86 has been measured in the range between 350us and 3.5ms
          depending on vendor and CPU type, BIOS microcode size etc.

       #4 The atomic bringup does the microcode update. This has been
          measured to take up to ~8ms on the primary threads depending
          on the microcode patch size to apply.

     On a two socket SKL server with 56 cores (112 threads) the boot CPU
     spends on current mainline about 800ms busy waiting for the APs to
     come up and apply microcode. That's more than 80% of the actual
     onlining procedure.

     This can be reduced significantly by splitting the bringup
     mechanism into two parts:

       1) Run the prepare callbacks and kick the AP alive for each AP
          which needs to be brought up.

          The APs wake up, do their firmware initialization and run the
          low level kernel startup code including microcode loading in
          parallel up to the first synchronization point. (#1 and #2
          above)

       2) Run the rest of the bringup code strictly serialized per CPU
          (#3 - #5 above) as it's done today.

          Parallelizing that stage of the CPU bringup might be possible
          in theory, but it's questionable whether required surgery
          would be justified for a pretty small gain.

     If the system is large enough the first AP is already waiting at
     the first synchronization point when the boot CPU finished the
     wake-up of the last AP. That reduces the AP bringup time on that
     SKL from ~800ms to ~80ms, i.e. by a factor ~10x.

     The actual gain varies wildly depending on the system, CPU,
     microcode patch size and other factors. There are some
     opportunities to reduce the overhead further, but that needs some
     deep surgery in the x86 CPU bringup code.

     For now this is only enabled on x86, but the core functionality
     obviously works for all SMP capable architectures.

   - Enhancements for SMP function call tracing so it is possible to
     locate the scheduling and the actual execution points. That allows
     to measure IPI delivery time precisely"

* tag 'smp-core-2023-06-26' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
  trace,smp: Add tracepoints for scheduling remotelly called functions
  trace,smp: Add tracepoints around remotelly called functions
  MAINTAINERS: Add CPU HOTPLUG entry
  x86/smpboot: Fix the parallel bringup decision
  x86/realmode: Make stack lock work in trampoline_compat()
  x86/smp: Initialize cpu_primary_thread_mask late
  cpu/hotplug: Fix off by one in cpuhp_bringup_mask()
  x86/apic: Fix use of X{,2}APIC_ENABLE in asm with older binutils
  x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it
  x86/smpboot: Support parallel startup of secondary CPUs
  x86/smpboot: Implement a bit spinlock to protect the realmode stack
  x86/apic: Save the APIC virtual base address
  cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE
  x86/apic: Provide cpu_primary_thread mask
  x86/smpboot: Enable split CPU startup
  cpu/hotplug: Provide a split up CPUHP_BRINGUP mechanism
  cpu/hotplug: Reset task stack state in _cpu_up()
  cpu/hotplug: Remove unused state functions
  riscv: Switch to hotplug core state synchronization
  parisc: Switch to hotplug core state synchronization
  ...
2023-06-26 13:59:56 -07:00
Zhangjin Wu
c828856b51
riscv: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION
Select CONFIG_HAVE_LD_DEAD_CODE_DATA_ELIMINATION for RISC-V, allowing
the user to enable dead code elimination. In order for this to work,
ensure that we keep the alternative table by annotating them with KEEP.

This boots well on qemu with both rv32_defconfig & rv64 defconfig, but
it only shrinks their builds by ~1%, a smaller config is thereforce
customized to test this feature:

          | rv32                   | rv64
  --------|------------------------|---------------------
   No DCE | 4460684                | 4893488
      DCE | 3986716                | 4376400
   Shrink |  473968 (~10.6%)       |  517088 (~10.5%)

The config used above only reserves necessary options to boot on qemu
with serial console, more like the size-critical embedded scenes:

  - rv64 config: https://pastebin.com/crz82T0s
  - rv32 config: rv64 config + 32-bit.config

Here is Jisheng's original commit-msg:
When trying to run linux with various opensource riscv core on
resource limited FPGA platforms, for example, those FPGAs with less
than 16MB SDRAM, I want to save mem as much as possible. One of the
major technologies is kernel size optimizations, I found that riscv
does not currently support HAVE_LD_DEAD_CODE_DATA_ELIMINATION, which
passes -fdata-sections, -ffunction-sections to CFLAGS and passes the
--gc-sections flag to the linker.

This not only benefits my case on FPGA but also benefits defconfigs.
Here are some notable improvements from enabling this with defconfigs:

nommu_k210_defconfig:
   text    data     bss     dec     hex
1112009  410288   59837 1582134  182436     before
 962838  376656   51285 1390779  1538bb     after

rv32_defconfig:
   text    data     bss     dec     hex
8804455 2816544  290577 11911576 b5c198     before
8692295 2779872  288977 11761144 b375f8     after

defconfig:
   text    data     bss     dec     hex
9438267 3391332  485333 13314932 cb2b74     before
9285914 3350052  483349 13119315 c82f53     after

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Co-developed-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Tested-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com> # build
Link: https://lore.kernel.org/r/20230523165502.2592-5-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-25 16:24:05 -07:00
Jisheng Zhang
cead443a30
riscv: vmlinux-xip.lds.S: remove .alternative section
ALTERNATIVE mechanism can't work on XIP, and this is also reflected by
below Kconfig dependency:

RISCV_ALTERNATIVE
	...
	depends on !XIP_KERNEL
	...

So there's no .alternative section at all for XIP case, remove it.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com> # build
Link: https://lore.kernel.org/r/20230523165502.2592-3-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-25 16:24:03 -07:00
Song Shuai
91afbaafd6
riscv: hibernate: remove WARN_ON in save_processor_state
During hibernation or restoration, freeze_secondary_cpus
checks num_online_cpus via BUG_ON, and the subsequent
save_processor_state also does the checking with WARN_ON.

In the case of CONFIG_PM_SLEEP_SMP=n, freeze_secondary_cpus
is not defined, but the sole possible condition to disable
CONFIG_PM_SLEEP_SMP is !SMP where num_online_cpus is always 1.
We also don't have to check it in save_processor_state.

So remove the unnecessary checking in save_processor_state.

Fixes: c031721001 ("RISC-V: Add arch functions to support hibernation/suspend-to-disk")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230609075049.2651723-4-songshuaishuai@tinylab.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-23 10:06:22 -07:00
Palmer Dabbelt
b5e13f3ace
Merge patch series "riscv: Add independent irq/softirq stacks support"
guoren@kernel.org <guoren@kernel.org> says:

From: Guo Ren <guoren@linux.alibaba.com>

This patch series adds independent irq/softirq stacks to decrease the
press of the thread stack. Also, add a thread STACK_SIZE config for
users to adjust the proper size during compile time.

* b4-shazam-merge:
  riscv: stack: Add config of thread stack size
  riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK
  riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK

Link: https://lore.kernel.org/r/20230614013018.2168426-1-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-23 10:06:21 -07:00
Palmer Dabbelt
42b89447b6
Merge patch series "ISA string parser cleanups"
Conor Dooley <conor@kernel.org> says:

From: Conor Dooley <conor.dooley@microchip.com>

Here are some bits that were discussed with Drew on the "should we
allow caps" threads that I have now created patches for:
- splitting of riscv_of_processor_hartid() into two distinct functions,
  one for use purely during early boot, prior to the establishment of
  the possible-cpus mask & another to fit the other current use-cases
- that then allows us to then completely skip some validation of the
  hartid in the parser
- the biggest diff in the series is a rework of the comments in the
  parser, as I have mostly found the existing (sparse) ones to not be
  all that helpful whenever I have to go back and look at it
- from writing the comments, I found a conditional doing a bit of a
  dance that I found counter-intuitive, so I've had a go at making that
  match what I would expect a little better
- `i` implies 4 other extensions, so add them as extensions and set
  them for the craic. Sure why not like...

* b4-shazam-merge:
  RISC-V: always report presence of extensions formerly part of the base ISA
  dt-bindings: riscv: explicitly mention assumption of Zicntr & Zihpm support
  RISC-V: remove decrement/increment dance in ISA string parser
  RISC-V: rework comments in ISA string parser
  RISC-V: validate riscv,isa at boot, not during ISA string parsing
  RISC-V: split early & late of_node to hartid mapping
  RISC-V: simplify register width check in ISA string parsing

Link: https://lore.kernel.org/r/20230607-audacity-overhaul-82bb867a825f@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-23 10:06:20 -07:00
Guo Ren
dd69d07a5a
riscv: stack: Support HAVE_SOFTIRQ_ON_OWN_STACK
Add the HAVE_SOFTIRQ_ON_OWN_STACK feature for the IRQ_STACKS config, and
the irq and softirq use the same irq_stack of percpu.

Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230614013018.2168426-3-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-22 10:38:36 -07:00
Guo Ren
163e76cc6e
riscv: stack: Support HAVE_IRQ_EXIT_ON_IRQ_STACK
Add independent irq stacks for percpu to prevent kernel stack overflows.
It is also compatible with VMAP_STACK by arch_alloc_vmap_stack.

Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Clément Léger <cleger@rivosinc.com>
Link: https://lore.kernel.org/r/20230614013018.2168426-2-guoren@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-22 10:38:35 -07:00
Donglin Peng
b97aec082b riscv: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL
The previous patch ("function_graph: Support recording and printing
the return value of function") has laid the groundwork for the for
the funcgraph-retval, and this modification makes it available on
the RISC-V platform.

We introduce a new structure called fgraph_ret_regs for the RISC-V
platform to hold return registers and the frame pointer. We then
fill its content in the return_to_handler and pass its address to
the function ftrace_return_to_handler to record the return value.

Link: https://lore.kernel.org/linux-trace-kernel/a8d71b12259f90e7e63d0ea654fcac95b0232bbc.1680954589.git.pengdonglin@sangfor.com.cn

Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-22 10:39:56 -04:00
Conor Dooley
07edc32779
RISC-V: always report presence of extensions formerly part of the base ISA
Of these four extensions, two were part of the base ISA when the port was
written and are required by the kernel. The other two are implied when
`i` is in riscv,isa on DT systems.
There's not much that userspace can do with this extra information, but
there is no harm in reporting an ISA string that closer resembles the
current versions of the specifications either.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230607-nest-collision-5796b6be8be6@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:19 -07:00
Conor Dooley
7816ebc1dd
RISC-V: remove decrement/increment dance in ISA string parser
While expanding on the comments in the ISA string parsing code, I
noticed that the conditional decrement of `isa` at the end of the loop
was a bit odd.
The parsing code expects that at the start of the for loop, `isa` will
point to the first character of the next unparsed extension.
However, depending on what the next extension is, this may not be true.
Unless the next extension is a multi-letter extension preceded by an
underscore, `isa` will either point to the string's null-terminator or
to the first character of the next extension, once the switch statement
has been evaluated.
Obviously incrementing `isa` at the end of the loop could cause it to
increment past the null terminator or miss a single letter extension, so
`isa` is conditionally decremented, just so that the loop can increment
it again.

It's easier to understand the code if, instead of this decrement +
increment dance, we instead use a while loop & rely on the handling of
individual extension types to leave `isa` pointing to the first
character of the next extension.
As already mentioned, this won't be the case where the following
extension is multi-letter & preceded by an underscore. To handle that,
invert the check and increment rather than decrement.
Hopefully this eliminates a "huh?!?" moment the next time somebody tries
to understand this code.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-estate-left-f20faabefb89@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:17 -07:00
Conor Dooley
6b913e3da8
RISC-V: rework comments in ISA string parser
I have found these comments to not be at all helpful whenever I look at
the parser. Further, the comments in the default case (single letter
parser) are not quite right either.
Group the comments into a larger one at the start of each case, that
attempts to explain things at a higher level.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230607-headpiece-tannery-83ed5cc4856a@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:16 -07:00
Conor Dooley
069b0d5170
RISC-V: validate riscv,isa at boot, not during ISA string parsing
Since riscv_fill_hwcap() now only iterates over possible cpus, the
basic validation of whether riscv,isa contains "rv<width>" can be moved
to riscv_early_of_processor_hartid().

Further, "ima" support is required by the kernel, so reject any CPU not
fitting the bill.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-guts-blurry-67e711acf328@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:15 -07:00
Conor Dooley
2ac8743437
RISC-V: split early & late of_node to hartid mapping
Some back and forth with Drew [1] about riscv_fill_hwcap() resulted in
the realisation that it is not very useful to parse the DT & perform
validation of riscv,isa every time we would like to get the id for a
hart.

Although it is no longer called in riscv_fill_hwcap(),
riscv_of_processor_hartid() is called in several other places.
Notably in setup_smp() it forms part of the logic for filling the mask
of possible CPUs. Since a possible CPU must have passed this basic
validation of riscv,isa, a repeat validation is not required.

Rename riscv_of_processor_id() to riscv_early_of_processor_id(),
which will be called from setup_smp() & introduce a new
riscv_of_processor_id() which makes use of the pre-populated mask of
possible cpus.

Link: https://lore.kernel.org/linux-riscv/xvdswl3iyikwvamny7ikrxo2ncuixshtg3f6uucjahpe3xpc5c@ud4cz4fkg5dj/ [1]
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-glade-pastel-d8cbd9d9f3c6@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:14 -07:00
Conor Dooley
fed14be476
RISC-V: simplify register width check in ISA string parsing
Saving off the `isa` pointer to a temp variable, followed by checking if
it has been incremented is a bit of an odd pattern. Perhaps it was done
to avoid a funky looking if statement mixed with the ifdeffery.

Now that we use IS_ENABLED() here just return from the parser as soon as
we detect a mismatch between the string and the currently running
kernel.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
Link: https://lore.kernel.org/r/20230607-splatter-bacterium-a75bb9f0d0b7@spud
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-21 07:45:13 -07:00
Fangrui Song
4681dacade
riscv: replace deprecated scall with ecall
scall is a deprecated alias for ecall. ecall is used in several places,
so there is no assembler compatibility concern.

Signed-off-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20230423223210.126948-1-maskray@google.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-20 09:02:09 -07:00
Tiezhu Yang
58b1294dd1
riscv: uprobes: Restore thread.bad_cause
thread.bad_cause is saved in arch_uprobe_pre_xol(), it should be restored
in arch_uprobe_{post,abort}_xol() accordingly, otherwise the save operation
is meaningless, this change is similar with x86 and powerpc.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Fixes: 74784081aa ("riscv: Add uprobes supported")
Link: https://lore.kernel.org/r/1682214146-3756-1-git-send-email-yangtiezhu@loongson.cn
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-20 08:20:23 -07:00
Palmer Dabbelt
16252e018a
Merge patch series "RISC-V: Export Zba, Zbb to usermode via hwprobe"
Evan Green <evan@rivosinc.com> says:

This change detects the presence of Zba, Zbb, and Zbs extensions and exports
them per-hart to userspace via the hwprobe mechanism. Glibc can then use
these in setting up hwcaps-based library search paths.

There's a little bit of extra housekeeping here: the first change adds
Zba and Zbs to the set of extensions the kernel recognizes, and the second
change starts tracking ISA features per-hart (in addition to the ANDed
mask of features across all harts which the kernel uses to make
decisions). Now that we track the ISA information per-hart, we could
even fix up /proc/cpuinfo to accurately report extension per-hart,
though I've left that out of this series for now.

* b4-shazam-merge:
  RISC-V: hwprobe: Expose Zba, Zbb, and Zbs
  RISC-V: Track ISA extensions per hart
  RISC-V: Add Zba, Zbs extension probing

Link: https://lore.kernel.org/r/20230509182504.2997252-1-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 14:34:40 -07:00
Evan Green
c0baf32103
RISC-V: hwprobe: Expose Zba, Zbb, and Zbs
Add two new bits to the IMA_EXT_0 key for ZBA, ZBB, and ZBS extensions.
These are accurately reported per CPU.

Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230509182504.2997252-4-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:53:10 -07:00
Evan Green
82e9c66e81
RISC-V: Track ISA extensions per hart
The kernel maintains a mask of ISA extensions ANDed together across all
harts. Let's also keep a bitmap of ISA extensions for each CPU. Although
the kernel is currently unlikely to enable a feature that exists only on
some CPUs, we want the ability to report asymmetric CPU extensions
accurately to usermode.

Note that riscv_fill_hwcaps() runs before the per_cpu_offsets are built,
which is why I've used a [NR_CPUS] array rather than per_cpu() data.

Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230509182504.2997252-3-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:51:22 -07:00
Evan Green
c6699baf10
RISC-V: Add Zba, Zbs extension probing
Add the Zba address bit manipulation extension and Zbs single bit
instructions extension into those the kernel is aware of and maintains
in its riscv_isa bitmap.

Signed-off-by: Evan Green <evan@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Link: https://lore.kernel.org/r/20230509182504.2997252-2-evan@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:51:16 -07:00
Sunil V L
3b426d4b5b
RISC-V: ACPI : Fix for usage of pointers in different address space
The arch specific __acpi_map_table can be wrapper around either
early_memremap or early_ioremap. But early_memremap
routine works with normal pointers whereas __acpi_map_table expects
pointers in iomem address space. This causes kernel test bot to fail
while using the sparse tool. Fix the issue by using early_ioremap and
similar fix done for __acpi_unmap_table.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202305201427.I7QhPjNW-lkp@intel.com/
Fixes: a91a9ffbd3 ("RISC-V: Add support to build the ACPI core")
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230607112417.782085-2-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:27:58 -07:00
Song Shuai
c6399b8930
riscv: hibernation: Remove duplicate call of suspend_restore_csrs
The suspend_restore_csrs is called in both __hibernate_cpu_resume
and the `else` of subsequent swsusp_arch_suspend.

Removing the first call makes both suspend_{save,restore}_csrs
left in swsusp_arch_suspend for clean code.

Fixes: c031721001 ("RISC-V: Add arch functions to support hibernation/suspend-to-disk")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: JeeHeng Sia <jeeheng.sia@starfivetech.com>
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Link: https://lore.kernel.org/r/20230522025020.285042-1-songshuaishuai@tinylab.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:27:57 -07:00
Song Shuai
650ea2a1dd
riscv: hibernation: Replace jalr with jr before suspend_restore_regs
No need to link the x1/ra reg via jalr before suspend_restore_regs
So it's better to replace jalr with jr.

Signed-off-by: Song Shuai <suagrfillet@gmail.com>
Reviewed-by: JeeHeng Sia <jeeheng.sia@starfivetech.com >
Link: https://lore.kernel.org/r/20230519060854.214138-1-suagrfillet@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-06-19 09:27:56 -07:00