17 Commits

Author SHA1 Message Date
Yuan Tan
174e8ac027
riscv: alternatives: fix a typo in comment
In the usage of ALTERNATIVE, "always" is misspelled as "alwyas".

Signed-off-by: Yuan Tan <tanyuan@tinylab.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230723165155.4896-1-tanyuan@tinylab.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-08-02 13:49:07 -07:00
Andrew Jones
0b2f658f53
RISC-V: alternatives: Support patching multiple insns in assembly
As pointed out in commit d374a16539b1 ("RISC-V: fix compile error
from deduplicated __ALTERNATIVE_CFG_2"), we need quotes around
parameters passed to macros within macros to avoid spaces being
interpreted as separators. ALT_NEW_CONTENT was trying to handle
this by defining new_c has a vararg, but this isn't sufficient
for calling ALTERNATIVE() from assembly with multiple instructions
in the new/old sequences. Remove the vararg "hack" and use quotes.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230224162631.405473-2-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 21:26:01 -07:00
Andrew Jones
ff19a8dee1
riscv: alternatives: Rename errata_id to patch_id
Alternatives are used for both errata and cpufeatures. Use a more
generic name, 'patch_id', as in "ID of code patching site", to
avoid confusion when alternatives are used for cpufeatures.

Signed-off-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/20230224154601.88163-5-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-03-14 20:51:23 -07:00
Palmer Dabbelt
3863f2a431
Merge patch series "dt-bindings: Add a cpu-capacity property for RISC-V"
Conor Dooley <conor@kernel.org> says:

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

Ever since RISC-V starting using generic arch topology code, the code
paths for cpu-capacity have been there but there's no binding defined to
actually convey the information. Defining the same property as used on
arm seems to be the only logical thing to do, so do it.

[Palmer: This is on top of the fix required to make it work, which
itself wasn't merged until late in the 6.2 cycle and thus pulls in
various other fixes.]

* b4-shazam-merge:
  dt-bindings: riscv: add a capacity-dmips-mhz cpu property
  dt-bindings: arm: move cpu-capacity to a shared loation
  riscv: Move call to init_cpu_topology() to later initialization stage
  riscv/kprobe: Fix instruction simulation of JALR
  riscv: fix -Wundef warning for CONFIG_RISCV_BOOT_SPINWAIT
  MAINTAINERS: add an IRC entry for RISC-V
  RISC-V: fix compile error from deduplicated __ALTERNATIVE_CFG_2
  dt-bindings: riscv: fix single letter canonical order
  dt-bindings: riscv: fix underscore requirement for multi-letter extensions
  riscv: uaccess: fix type of 0 variable on error in get_user()
  riscv, kprobes: Stricter c.jr/c.jalr decoding

Link: https://lore.kernel.org/r/20230104180513.1379453-1-conor@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-14 19:29:46 -08:00
Jisheng Zhang
8d23e94a44
riscv: switch to relative alternative entries
Instead of using absolute addresses for both the old instrucions and
the alternative instructions, use offsets relative to the alt_entry
values. So this not only cuts the size of the alternative entry, but
also meets the prerequisite for patching alternatives in the vDSO,
since absolute alternative entries are subject to dynamic relocation,
which is incompatible with the vDSO building.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230128172856.3814-10-jszhang@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-01-31 23:29:41 -08:00
Heiko Stuebner
d374a16539
RISC-V: fix compile error from deduplicated __ALTERNATIVE_CFG_2
On the non-assembler-side wrapping alternative-macros inside other macros
to prevent duplication of code works, as the end result will just be a
string that gets fed to the asm instruction.

In real assembler code, wrapping .macro blocks inside other .macro blocks
brings more restrictions on usage it seems and the optimization done by
commit 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
results in a compile error like:

../arch/riscv/lib/strcmp.S: Assembler messages:
../arch/riscv/lib/strcmp.S:15: Error: too many positional arguments
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "887:"
../arch/riscv/lib/strcmp.S:15: Error: backward ref to unknown label "886:"
../arch/riscv/lib/strcmp.S:15: Error: attempt to move .org backwards

Wrapping the variables containing assembler code in quotes solves this issue,
compilation and the code in question still works and objdump also shows sane
decompiled results of the affected code.

Fixes: 2ba8c7dc71c0 ("riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2")
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230105192610.1940841-1-heiko@sntech.de
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-01-19 16:37:05 -08:00
Andrew Jones
26fb4b90b7
riscv: Don't duplicate _ALTERNATIVE_CFG* macros
Reduce clutter by only defining the _ALTERNATIVE_CFG* macros once,
rather than once for assembly and once for C. To do that, we need to
add __ALTERNATIVE_CFG* macros to the assembly side, but those are
one-liners. Also take the opportunity to do a bit of reformatting,
taking full advantage of the fact checkpatch gives us 100 char lines.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221129150053.50464-5-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-09 18:14:24 -08:00
Andrew Jones
bb2efcde59
riscv: alternatives: Drop the underscores from the assembly macro names
The underscores aren't needed because there isn't anything already
named without them and the _CFG extension. This is a bit of a cleanup
by itself, but the real motivation is for a coming patch which would
otherwise need to add two more underscores to these macro names,
i.e. ____ALTERNATIVE_CFG, and that'd be gross.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221129150053.50464-4-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-09 18:14:23 -08:00
Andrew Jones
7d52eace1b
riscv: alternatives: Don't name unused macro parameters
Without CONFIG_RISCV_ALTERNATIVE only the first parameter of the
ALTERNATIVE macros is needed. Use ... for the rest to cut down on
clutter. While there, fix a couple space vs. tab issues.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221129150053.50464-3-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-09 18:14:22 -08:00
Andrew Jones
2ba8c7dc71
riscv: Don't duplicate __ALTERNATIVE_CFG in __ALTERNATIVE_CFG_2
Build __ALTERNATIVE_CFG_2 by adding on to __ALTERNATIVE_CFG rather
than duplicating it.

Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221129150053.50464-2-ajones@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-12-09 18:14:21 -08:00
Nathan Chancellor
61114e734c
riscv: Move alternative length validation into subsection
After commit 49b290e430d3 ("riscv: prevent compressed instructions in
alternatives"), builds with LLVM's integrated assembler fail:

  In file included from arch/riscv/mm/init.c:10:
  In file included from ./include/linux/mm.h:29:
  In file included from ./include/linux/pgtable.h:6:
  In file included from ./arch/riscv/include/asm/pgtable.h:108:
  ./arch/riscv/include/asm/tlbflush.h:23:2: error: expected assembly-time absolute expression
          ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
          ^
  ./arch/riscv/include/asm/errata_list.h:33:5: note: expanded from macro 'ALT_FLUSH_TLB_PAGE'
  asm(ALTERNATIVE("sfence.vma %0", "sfence.vma", SIFIVE_VENDOR_ID,        \
      ^
  ./arch/riscv/include/asm/alternative-macros.h:187:2: note: expanded from macro 'ALTERNATIVE'
          _ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k)
          ^
  ./arch/riscv/include/asm/alternative-macros.h:113:2: note: expanded from macro '_ALTERNATIVE_CFG'
          __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k))
          ^
  ./arch/riscv/include/asm/alternative-macros.h:110:2: note: expanded from macro '__ALTERNATIVE_CFG'
          ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c)
          ^
  ./arch/riscv/include/asm/alternative-macros.h:99:3: note: expanded from macro 'ALT_NEW_CONTENT'
          ".org   . - (889b - 888b) + (887b - 886b)\n"                    \
           ^
  <inline asm>:26:6: note: instantiated into assembly here
  .org    . - (889b - 888b) + (887b - 886b)
          ^

This error happens because LLVM's integrated assembler has a one-pass
design, which means it cannot figure out the instruction lengths when
the .org directive is outside of the subsection that contains the
instructions, which was changed by the .option directives added by the
above change.

Move the .org directives before the .previous directive so that these
directives are always within the same subsection, which resolves the
failures and does not introduce any new issues with GNU as. This was
done for arm64 in commit 966a0acce2fc ("arm64/alternatives: move length
validation inside the subsection") and commit 22315a2296f4 ("arm64:
alternatives: Move length validation in alternative_{insn, endif}").

While there is no error from the assembly versions of the macro, they
appear to have the same problem so just make the same change there as
well so that there are no problems in the future.

Link: https://github.com/ClangBuiltLinux/linux/issues/1640
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220516214520.3252074-1-nathan@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-06-02 15:55:22 -07:00
Heiko Stuebner
49b290e430
riscv: prevent compressed instructions in alternatives
Instructions are opportunistically compressed by the RISC-V assembler
when possible, but in alternatives-blocks both the old and new content
need to be the same size, so having the toolchain do somewhat random
optimizations will cause strange side-effects like
"attempt to move .org backwards" compile-time errors.

Already a simple "and" used in alternatives assembly will cause these
mismatched code sizes.

So prevent compressed instructions to be generated in alternatives-
code and use option-push and -pop to only limit this to the relevant
code blocks

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-7-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-05-11 21:36:32 -07:00
Heiko Stuebner
e509204acb
riscv: extend concatenated alternatives-lines to the same length
ALT_NEW_CONTENT already uses same-length assembler lines, so
extend this to the other elements as well.

This makes it more readable when these elements need to be extended
in the future.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-6-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-05-11 21:36:32 -07:00
Heiko Stuebner
fbdba60b81
riscv: implement ALTERNATIVE_2 macro
When the alternatives were added the commit already provided a template
on how to implement 2 different alternatives for one piece of code.

Make this usable.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-5-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-05-11 21:36:32 -07:00
Heiko Stuebner
e64f737ad7
riscv: integrate alternatives better into the main architecture
Right now the alternatives need to be explicitly enabled and
erratas are limited to SiFive ones.

We want to use alternatives not only for patching soc erratas,
but in the future also for handling different behaviour depending
on the existence of future extensions.

So move the core alternatives over to the kernel subdirectory
and move the CONFIG_RISCV_ALTERNATIVE to be a hidden symbol
which we expect relevant erratas and extensions to just select
if needed.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Link: https://lore.kernel.org/r/20220511192921.2223629-2-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-05-11 21:36:31 -07:00
Vitaly Wool
858cf86049
riscv: alternative: fix typo in macro name
alternative-macros.h defines ALT_NEW_CONTENT in its assembly part
and ALT_NEW_CONSTENT in the C part. Most likely it is the latter
that is wrong.

Fixes: 6f4eea90465ad
	(riscv: Introduce alternative mechanism to apply errata solution)
Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-06-10 20:35:05 -07:00
Vincent Chen
6f4eea9046
riscv: Introduce alternative mechanism to apply errata solution
Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU
vendors' errata solution at runtime. The main purpose of this patch is
to provide a framework. Therefore, the implementation is quite basic for
now so that some scenarios could not use this schemei, such as patching
code to a module, relocating the patching code and heterogeneous CPU
topology.

Users could use the macro ALTERNATIVE to apply an errata to the existing
code flow. In the macro ALTERNATIVE, users need to specify the manufacturer
information(vendorid, archid, and impid) for this errata. Therefore, kernel
will know this errata is suitable for which CPU core. During the booting
procedure, kernel will select the errata required by the CPU core and then
patch it. It means that the kernel only applies the errata to the specified
CPU core. In this case, the vendor's errata does not affect each other at
runtime. The above patching procedure only occurs during the booting phase,
so we only take the overhead of the "alternative" mechanism once.

This "alternative" mechanism is enabled by default to ensure that all
required errata will be applied. However, users can disable this feature by
the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE".

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:55 -07:00