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[PW_SID:1076727] [v2] cmpxchg: allow const-qualified old value in cmpxchg()#1714

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[PW_SID:1076727] [v2] cmpxchg: allow const-qualified old value in cmpxchg()#1714
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@linux-riscv-bot linux-riscv-bot commented Apr 3, 2026

PR for series 1076727 applied to workflow__riscv__fixes

Name: [v2] cmpxchg: allow const-qualified old value in cmpxchg()
URL: https://patchwork.kernel.org/project/linux-riscv/list/?series=1076727
Version: 2

Sean Chang and others added 13 commits February 18, 2026 20:49
riscv: fix various typos in comments and code
5d9d634 
Fix various typos in RISC-V architecture code and comments.
The following changes are included:

- arch/riscv/errata/thead/errata.c: "futher" → "further"
- arch/riscv/include/asm/atomic.h: "therefor" → "therefore", "arithmatic" → "arithmetic"
- arch/riscv/include/asm/elf.h: "availiable" → "available", "coorespends" → "corresponds"
- arch/riscv/include/asm/processor.h: "requries" → "is required"
- arch/riscv/include/asm/thread_info.h: "returing" → "returning"
- arch/riscv/kernel/acpi.c: "compliancy" → "compliance"
- arch/riscv/kernel/ftrace.c: "therefor" → "therefore"
- arch/riscv/kernel/head.S: "intruction" → "instruction"
- arch/riscv/kernel/mcount-dyn.S: "localtion → "location"
- arch/riscv/kernel/module-sections.c: "maxinum" → "maximum"
- arch/riscv/kernel/probes/kprobes.c: "reenabled" → "re-enabled"
- arch/riscv/kernel/probes/uprobes.c: "probbed" → "probed"
- arch/riscv/kernel/soc.c: "extremly" → "extremely"
- arch/riscv/kernel/suspend.c: "incosistent" → "inconsistent"
- arch/riscv/kvm/tlb.c: "cahce" → "cache"
- arch/riscv/kvm/vcpu_pmu.c: "indicies" → "indices"
- arch/riscv/lib/csum.c: "implmentations" → "implementations"
- arch/riscv/lib/memmove.S: "ammount" → "amount"
- arch/riscv/mm/cacheflush.c: "visable" → "visible"
- arch/riscv/mm/physaddr.c: "aginst" → "against"

Signed-off-by: Sean Chang <seanwascoding@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://patch.msgid.link/20260212163325.60389-1-seanwascoding@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@dramforever
riscv: smp: Remove outdated comment about disabling preemption
37a14b6 
Commit f1a0a37 ("sched/core: Initialize the idle task with
preemption disabled") removed a call to preempt_disable(), but not the
associated comment. Remove the outdated comment.

Fixes: f1a0a37 ("sched/core: Initialize the idle task with preemption disabled")
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Link: https://patch.msgid.link/20260204-riscv-smp-comment-update-2026-01-v1-1-8b77aa181530@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@dramforever
riscv: smp: Clarify comment "cache" -> "instruction cache"
4dd1663 
local_flush_icache_all() only flushes and synchronizes the *instruction*
cache, not the data cache. Since RISC-V does have a cbo.flush
instruction for data cache flush, clarify the comment to avoid
confusion.

Fixes: 58661a3 ("riscv: Flush the instruction cache during SMP bringup")
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Link: https://patch.msgid.link/20260204-riscv-smp-comment-update-2026-01-v1-2-8b77aa181530@iscas.ac.cn
Signed-off-by: Paul Walmsley <pjw@kernel.org>
riscv: move kaslr_offset() to page.h as a static inline function
37f1490 
The kaslr_offset() function is a simple accessor that returns
kernel_map.virt_offset. This commit change also ensures that kaslr_offset()
is consistently available across various kernel configurations without
requiring explicit linkage to mm/init.c.

Signed-off-by: Austin Kim <austin.kim@lge.com>
Link: https://patch.msgid.link/aYwJ76yHaMbbQVJA@adminpc-PowerEdge-R7525
Signed-off-by: Paul Walmsley <pjw@kernel.org>
riscv: export kaslr offset and satp in VMCOREINFO ELF notes
097da80 
The following options are required by the kdump crash utility for RISC-V
based vmcore file:

- kaslr: If the vmcore is generated from a KASLR-enabled Linux kernel,
         the KASLR offset is required for the crash utility to load
         the vmcore. Without the proper kaslr option, the crash utility
         fails to load the vmcore file.
- satp: The exact root page table address helps determine the correct base
        PGD address.

With this patch, RISC-V VMCOREINFO ELF notes now include both kaslr
and satp information.

Signed-off-by: Austin Kim <austin.kim@lge.com>
Link: https://patch.msgid.link/aYwKUE3ZzN7/ZY/A@adminpc-PowerEdge-R7525
Signed-off-by: Paul Walmsley <pjw@kernel.org>
riscv: kgdb: fix several debug register assignment bugs
1121200 
Fix several bugs in the RISC-V kgdb implementation:

- The element of dbg_reg_def[] that is supposed to pertain to the S1
  register embeds instead the struct pt_regs offset of the A1
  register.  Fix this to use the S1 register offset in struct pt_regs.

- The sleeping_thread_to_gdb_regs() function copies the value of the
  S10 register into the gdb_regs[] array element meant for the S9
  register, and copies the value of the S11 register into the array
  element meant for the S10 register.  It also neglects to copy the
  value of the S11 register.  Fix all of these issues.

Fixes: fe89bd2 ("riscv: Add KGDB support")
Cc: Vincent Chen <vincent.chen@sifive.com>
Link: https://patch.msgid.link/fde376f8-bcfd-bfe4-e467-07d8f7608d05@kernel.org
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@dramforever
riscv: patch: Avoid early phys_to_page()
3a87650 
Similarly to commit 8d09e2d ("arm64: patching: avoid early
page_to_phys()"), avoid using phys_to_page() for the kernel address case
in patch_map().

Since this is called from apply_boot_alternatives() in setup_arch(), and
commit 4267739 ("arch, mm: consolidate initialization of SPARSE
memory model") has moved sparse_init() to after setup_arch(),
phys_to_page() is not available there yet, and it panics on boot with
SPARSEMEM on RV32, which does not use SPARSEMEM_VMEMMAP.

Reported-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Closes: https://lore.kernel.org/r/20260223144108-dcace0b9-02e8-4b67-a7ce-f263bed36f26@linutronix.de/
Fixes: 4267739 ("arch, mm: consolidate initialization of SPARSE memory model")
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20260310-riscv-sparsemem-alternatives-fix-v1-1-659d5dd257e2@iscas.ac.cn
[pjw@kernel.org: fix the subject line to align with the patch description]
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@ukleinek
riscv: Simplify assignment for UTS_MACHINE
1351ac7 
The BITS variable conveniently allows to simplify the assignment for
UTS_MACHINE.

Signed-off-by: Uwe Kleine-König (The Capable Hub) <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20260313164012.1153936-2-u.kleine-koenig@baylibre.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@thecharlesjenkins
selftests: riscv: Add definition of BIT() macro
e93c297 
The BIT() macros is used by the validate_v_ptrace() test case, but not
defined. Include linux/bits.h to pull in this definition. To ensure that
the header in the kernel source is used, add tools/include to the header
search path.

Fixes: 30eb191 ("selftests: riscv: verify ptrace rejects invalid vector csr inputs")
Signed-off-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Reviewed-and-tested-by: Sergey Matyukevich <geomatsi@gmail.com>
Link: https://patch.msgid.link/20260309-fix_selftests-v2-1-9d5a553a531e@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@thecharlesjenkins
riscv: ptrace: Fix BIT() compilation issues
b1b59c4 
BIT() is being used in ptrace.h without a definition, resulting in
compilation errors in tools/testing/selftests/riscv/cfi/cfitests.c:

cfitests.c:101:60: error: implicit declaration of function ‘BIT’ [-Wimplicit-function-declaration]
  101 |                      if ((cfi_reg.cfi_status.cfi_state & CFI_ENABLE_MASK) != CFI_ENABLE_MASK)

Include linux/bits.h to resolve this issue.

Fixes: 2af7c9c ("riscv/ptrace: expose riscv CFI status and state via ptrace and in core files")
Signed-off-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Link: https://patch.msgid.link/20260309-fix_selftests-v2-3-9d5a553a531e@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
@thecharlesjenkins
selftests: riscv: Add license to cfi selftest
5ccc568 
The cfi selftest was missing a license so add it.

Signed-off-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Link: https://patch.msgid.link/20260309-fix_selftests-v2-4-9d5a553a531e@gmail.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>
Adding CI files
c315cbf
@liuhangbin
cmpxchg: allow const-qualified old value in cmpxchg()
39009d0 
The old value passed to cmpxchg() is semantically read-only: it is
only loaded into a register as a comparand and is never written back.
However, the macro currently assigns it implicitly to a local variable
of type __typeof__(*(ptr)), which triggers -Werror=discarded-qualifiers
when old is a const-qualified pointer and ptr points to a non-const type.

Fix this by using __auto_type with the conditional expression trick:

  __auto_type _o_ = 1 ? (o) : *(ptr);

The __auto_type deduces the type from the expression, so _o_ naturally
takes the const-qualified type when o is const-qualified, avoiding the
discarded-qualifiers warning. The conditional expression forces the
compiler to verify that o and *(ptr) have compatible types, preserving
the type-safety check that a bare __auto_type _o_ = (o) would lose.
Since the condition is the constant 1, the compiler optimizes away the
*(ptr) branch entirely with no runtime cost.

For macros where ptr is already captured in a local variable (arc's
_p_, hexagon's __ptr, riscv's __ptr), the captured variable is used
in the conditional expression to avoid re-evaluating ptr.

The new value is intentionally left without this treatment: new will
be stored into *ptr, so silently accepting a const-qualified new would
allow callers to store a pointer-to-const into a non-const location
without any compiler warning.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Linux RISC-V bot <linux.riscv.bot@gmail.com>
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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
build-rv32-defconfig
Desc: Builds riscv32 defconfig
Duration: 136.36 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
build-rv64-clang-allmodconfig
Desc: Builds riscv64 allmodconfig with Clang, and checks for errors and added warnings
Duration: 2159.72 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
build-rv64-gcc-allmodconfig
Desc: Builds riscv64 allmodconfig with GCC, and checks for errors and added warnings
Duration: 2908.65 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
build-rv64-nommu-k210-defconfig
Desc: Builds riscv64 defconfig with NOMMU for K210
Duration: 26.04 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
build-rv64-nommu-k210-virt
Desc: Builds riscv64 defconfig with NOMMU for the virt platform
Duration: 27.53 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
checkpatch
Desc: Runs checkpatch.pl on the patch
Duration: 3.84 seconds
Result: WARNING
Output:

WARNING: please, no spaces at the start of a line
#130: FILE: arch/powerpc/include/asm/cmpxchg.h:701:
+     __auto_type _o_ = 1 ? (o) : *(ptr);^I^I^I^I \$

WARNING: please, no spaces at the start of a line
#139: FILE: arch/powerpc/include/asm/cmpxchg.h:710:
+     __auto_type _o_ = 1 ? (o) : *(ptr);^I^I^I^I \$

WARNING: please, no spaces at the start of a line
#192: FILE: arch/sh/include/asm/cmpxchg.h:71:
+     __auto_type _o_ = 1 ? (o) : *(ptr);^I^I^I^I \$

WARNING: please, no spaces at the start of a line
#218: FILE: arch/sparc/include/asm/cmpxchg_64.h:173:
+     __auto_type _o_ = 1 ? (o) : *(ptr);^I^I^I^I \$

total: 0 errors, 4 warnings, 0 checks, 144 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

Commit 39009d05d33a ("cmpxchg: allow const-qualified old value in cmpxchg()") has style problems, please review.

NOTE: Ignored message types: ALLOC_SIZEOF_STRUCT CAMELCASE COMMIT_LOG_LONG_LINE GIT_COMMIT_ID MACRO_ARG_REUSE NO_AUTHOR_SIGN_OFF

NOTE: If any of the errors are false positives, please report
      them to the maintainer, see CHECKPATCH in MAINTAINERS.
total: 0 errors, 4 warnings, 0 checks, 144 lines checked
WARNING: please, no spaces at the start of a line

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
dtb-warn-rv64
Desc: Checks for Device Tree warnings/errors
Duration: 83.75 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
header-inline
Desc: Detects static functions without inline keyword in header files
Duration: 0.27 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
kdoc
Desc: Detects for kdoc errors
Duration: 0.89 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
module-param
Desc: Detect module_param changes
Duration: 0.29 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
verify-fixes
Desc: Verifies that the Fixes: tags exist
Duration: 0.25 seconds
Result: PASS

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linux-riscv-bot commented Apr 3, 2026

Patch 1: "[v2] cmpxchg: allow const-qualified old value in cmpxchg()"
verify-signedoff
Desc: Verifies that Signed-off-by: tags are correct
Duration: 0.31 seconds
Result: PASS

@linux-riscv-bot linux-riscv-bot force-pushed the workflow__riscv__fixes branch 4 times, most recently from 2830afe to 506e7f6 Compare April 5, 2026 01:35
@linux-riscv-bot linux-riscv-bot deleted the pw1076727 branch April 11, 2026 02:03
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5 participants

@linux-riscv-bot @dramforever @ukleinek @thecharlesjenkins @liuhangbin