Commit Graph

12 Commits

Author SHA1 Message Date
Conor Dooley 9493e6f3ce
RISC-V: take text_mutex during alternative patching
Guenter reported a splat during boot, that Samuel pointed out was the
lockdep assertion failing in patch_insn_write():

WARNING: CPU: 0 PID: 0 at arch/riscv/kernel/patch.c:63 patch_insn_write+0x222/0x2f6
epc : patch_insn_write+0x222/0x2f6
 ra : patch_insn_write+0x21e/0x2f6
epc : ffffffff800068c6 ra : ffffffff800068c2 sp : ffffffff81803df0
 gp : ffffffff81a1ab78 tp : ffffffff81814f80 t0 : ffffffffffffe000
 t1 : 0000000000000001 t2 : 4c45203a76637369 s0 : ffffffff81803e40
 s1 : 0000000000000004 a0 : 0000000000000000 a1 : ffffffffffffffff
 a2 : 0000000000000004 a3 : 0000000000000000 a4 : 0000000000000001
 a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000052464e43
 s2 : ffffffff80b4889c s3 : 000000000000082c s4 : ffffffff80b48828
 s5 : 0000000000000828 s6 : ffffffff8131a0a0 s7 : 0000000000000fff
 s8 : 0000000008000200 s9 : ffffffff8131a520 s10: 0000000000000018
 s11: 000000000000000b t3 : 0000000000000001 t4 : 000000000000000d
 t5 : ffffffffd8180000 t6 : ffffffff81803bc8
status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[<ffffffff800068c6>] patch_insn_write+0x222/0x2f6
[<ffffffff80006a36>] patch_text_nosync+0xc/0x2a
[<ffffffff80003b86>] riscv_cpufeature_patch_func+0x52/0x98
[<ffffffff80003348>] _apply_alternatives+0x46/0x86
[<ffffffff80c02d36>] apply_boot_alternatives+0x3c/0xfa
[<ffffffff80c03ad8>] setup_arch+0x584/0x5b8
[<ffffffff80c0075a>] start_kernel+0xa2/0x8f8

This issue was exposed by 702e64550b ("riscv: fpu: switch has_fpu() to
riscv_has_extension_likely()"), as it is the patching in has_fpu() that
triggers the splats in Guenter's report.

Take the text_mutex before doing any code patching to satisfy lockdep.

Fixes: ff689fd21c ("riscv: add RISC-V Svpbmt extension support")
Fixes: a35707c3d8 ("riscv: add memory-type errata for T-Head")
Fixes: 1a0e5dbd37 ("riscv: sifive: Add SiFive alternative ports")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/20230212154333.GA3760469@roeck-us.net/
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Samuel Holland <samuel@sholland.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230212194735.491785-1-conor@kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-21 17:21:33 -08:00
Samuel Holland bfd6fc5d80
riscv: Fix early alternative patching
Now that the text to patch is located using a relative offset from the
alternative entry, the text address should be computed without applying
the kernel mapping offset, both before and after VM setup.

Fixes: 8d23e94a44 ("riscv: switch to relative alternative entries")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230212021534.59121-2-samuel@sholland.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-02-14 16:10:35 -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 65e9fb0818
drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores
With the T-HEAD C9XX cores being designed before or during the ratification
to the SSCOFPMF extension, it implements functionality very similar but
not equal to it.

It implements overflow handling and also some privilege-mode filtering.
While SSCOFPMF supports this for all modes, the C9XX only implements the
filtering for M-mode and S-mode but not user-mode.

So add some adaptions to allow the C9XX to still handle
its PMU through the regular SBI PMU interface instead of defining new
interfaces or drivers.

To work properly, this requires a matching change in SBI, though the actual
interface between kernel and SBI does not change.

The main differences are a the overflow CSR and irq number.

As the reading of the overflow-csr is in the hot-path during irq handling,
use an errata and alternatives to not introduce new conditionals there.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/all/20221011231841.2951264-2-heiko@sntech.de/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-27 14:35:20 -07:00
Palmer Dabbelt 6224db7881
Merge patch series "Some style cleanups for recent extension additions"
Heiko Stuebner <heiko@sntech.de> says:

As noted by some people, some parts of the recently added extensions
(svpbmt, zicbom) + t-head errata could use some styling upgrades.

So this series provides these.

changes in v2:
- add patch also converting cpufeature probe to BIT()
- update commit message in patch1 (Conor)

Heiko Stuebner (5):
  riscv: cleanup svpbmt cpufeature probing
  riscv: drop some idefs from CMO initialization
  riscv: use BIT() macros in t-head errata init
  riscv: use BIT() marco for cpufeature probing
  riscv: check for kernel config option in t-head memory types errata

arch/riscv/errata/thead/errata.c    | 14 ++++++-----
 arch/riscv/include/asm/cacheflush.h |  2 ++
 arch/riscv/kernel/cpufeature.c      | 39 ++++++++++++-----------------
 3 files changed, 26 insertions(+), 29 deletions(-)

Link: https://lore.kernel.org/r/20220905111027.2463297-1-heiko@sntech.de

* b4-shazam-merge:
  riscv: check for kernel config option in t-head memory types errata
  riscv: use BIT() marco for cpufeature probing
  riscv: use BIT() macros in t-head errata init
  riscv: drop some idefs from CMO initialization
  riscv: cleanup svpbmt cpufeature probing

Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-13 08:46:31 -07:00
Heiko Stuebner 1405773310
riscv: check for kernel config option in t-head memory types errata
The t-head variant of page-based memory types should also check first
for the enabled kernel config option.

Fixes: a35707c3d8 ("riscv: add memory-type errata for T-Head")
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20220905111027.2463297-6-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-13 08:46:30 -07:00
Heiko Stuebner 499590c084
riscv: use BIT() macros in t-head errata init
Using the appropriate BIT macro makes the code better readable.

Suggested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20220905111027.2463297-4-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-13 08:46:28 -07:00
Heiko Stuebner f055268e39
riscv: drop some idefs from CMO initialization
Wrapping things in #ifdefs makes the code harder to read
while we also have IS_ENABLED() macros to do this in regular code
and the extension detection is not _that_ runtime critical.

So define a stub for riscv_noncoherent_supported() in the
non-CONFIG_RISCV_DMA_NONCOHERENT case and move the code to
us IS_ENABLED.

Suggested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20220905111027.2463297-3-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-10-13 08:46:27 -07:00
Palmer Dabbelt 8f7e001e03
RISC-V: Clean up the Zicbom block size probing
This fixes two issues: I truncated the warning's hart ID when porting to
the 64-bit hart ID code, and the original code's warning handling could
fire on an uninitialized hart ID.

The biggest change here is that riscv_cbom_block_size is no longer
initialized, as IMO the default isn't sane: there's nothing in the ISA
that mandates any specific cache block size, so falling back to one will
just silently produce the wrong answer on some systems.  This also
changes the probing order so the cache block size is known before
enabling Zicbom support.

CC: stable@vger.kernel.org
CC: Andrew Jones <ajones@ventanamicro.com>
CC: Heiko Stuebner <heiko@sntech.de>
CC: Atish Patra <atishp@rivosinc.com>
Fixes: 3aefb2ee5b ("riscv: implement Zicbom-based CMO instructions + the t-head variant")
Fixes: 1631ba1259 ("riscv: Add support for non-coherent devices using zicbom extension")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
[Conor: fixed the redefinition errors]
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220912224800.998121-1-mail@conchuod.ie
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-09-13 02:06:11 -07:00
Heiko Stuebner d20ec75292
riscv: implement cache-management errata for T-Head SoCs
The T-Head C906 and C910 implement a scheme for handling
cache operations different from the generic Zicbom extension.

Add an errata for it next to the generic dma coherency ops.

Reviewed-by: Samuel Holland <samuel@sholland.org>
Tested-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20220706231536.2041855-5-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-08-03 17:29:59 -07:00
Heiko Stuebner 1771c8c9e6
riscv: remove usage of function-pointers from cpufeatures and t-head errata
Having a list of alternatives to check with a per-entry function pointer
to a check function is nice style-wise. But in case of early-alternatives
it can clash with the non-relocated kernel and the function pointer in
the list pointing to a completely wrong location.

This isn't an issue with one or two list entries, as in that case the
compiler seems to unroll the loop and even usage of the list structure
and then only does relative jumps into the check functions based on this.

When adding a third entry to either list though, the issue that was
hiding there from the beginning is triggered resulting a jump to a
memory address that isn't part of the kernel at all.

The list of features/erratas only contained an unused name and the
pointer to the check function, so an easy solution for the problem
is to just unroll the loop in code, dismantle the whole list structure
and just call the relevant check functions one by one ourself.

For the T-Head errata this includes moving the stage-check inside
the check functions.

The issue is only relevant for things that might be called for early-
alternatives (T-Head and possible future main extensions), so the
SiFive erratas were not affected from the beginning, as they got
an early return for early-alternatives in the original patchset.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20220526205646.258337-6-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-06-16 15:47:41 -07:00
Heiko Stuebner a35707c3d8
riscv: add memory-type errata for T-Head
Some current cpus based on T-Head cores implement memory-types
way different than described in the svpbmt spec even going
so far as using PTE bits marked as reserved.

Add the T-Head vendor-id and necessary errata code to
replace the affected instructions.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20220511192921.2223629-13-heiko@sntech.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2022-05-11 21:36:33 -07:00