diff mbox series

[v3,6/8] riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations

Message ID 20250919073714.83063-7-luxu.kernel@bytedance.com
State New
Headers show
Series riscv: Add Zalasr ISA extension support | expand

Commit Message

路旭 Sept. 19, 2025, 7:37 a.m. UTC
The existing arch_xchg/arch_cmpxchg operations are implemented by
inserting fence instructions before or after atomic instructions.
This commit replaces them with real acquire/release semantics.

|----------------------------------------------------------------|
|    |    arch_xchg_release       |     arch_cmpxchg_release     |
|    |-----------------------------------------------------------|
|    | zabha      | !zabha        | zabha+zacas | !(zabha+zacas) |
| rl |-----------------------------------------------------------|
|    |            | (fence rw, w) |             | (fence rw, w)  |
|    | amoswap.rl | lr.w          | amocas.rl   | lr.w           |
|    |            | sc.w.rl       |             | sc.w.rl        |
|----------------------------------------------------------------|
|    |    arch_xchg_acquire       |     arch_cmpxchg_acquire     |
|    |-----------------------------------------------------------|
|    | zabha      | !zabha        | zabha+zacas | !(zabha+zacas) |
| aq |-----------------------------------------------------------|
|    |            | lr.w.aq       |             | lr.w.aq        |
|    | amoswap.aq | sc.w          | amocas.aq   | sc.w           |
|    |            | (fence r, rw) |             | (fence r, rw)  |
|----------------------------------------------------------------|

(fence rw, w), (fence r, rw) here means such instructions will only
be inserted when zalasr is not implemented.

Signed-off-by: Xu Lu <luxu.kernel@bytedance.com>
---
 arch/riscv/include/asm/atomic.h  |   6 --
 arch/riscv/include/asm/cmpxchg.h | 136 ++++++++++++++-----------------
 2 files changed, 63 insertions(+), 79 deletions(-)

Comments

kernel test robot Sept. 20, 2025, 2:52 p.m. UTC | #1
Hi Xu,

kernel test robot noticed the following build errors:

[auto build test ERROR on robh/for-next]
[also build test ERROR on kvm/queue kvm/next linus/master v6.17-rc6]
[cannot apply to kvm/linux-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Xu-Lu/riscv-add-ISA-extension-parsing-for-Zalasr/20250919-154304
base:   https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next
patch link:    https://lore.kernel.org/r/20250919073714.83063-7-luxu.kernel%40bytedance.com
patch subject: [PATCH v3 6/8] riscv: Apply acquire/release semantics to arch_xchg/arch_cmpxchg operations
config: riscv-randconfig-002-20250920 (https://download.01.org/0day-ci/archive/20250920/202509202249.rOR3GJbT-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 7c861bcedf61607b6c087380ac711eb7ff918ca6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250920/202509202249.rOR3GJbT-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202509202249.rOR3GJbT-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from lib/objpool.c:3:
>> include/linux/objpool.h:156:7: error: invalid .org offset '1528' (at offset '1532')
     156 |                 if (try_cmpxchg_release(&slot->head, &head, head + 1))
         |                     ^
   include/linux/atomic/atomic-instrumented.h:4899:2: note: expanded from macro 'try_cmpxchg_release'
    4899 |         raw_try_cmpxchg_release(__ai_ptr, __ai_oldp, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:228:9: note: expanded from macro 'raw_try_cmpxchg_release'
     228 |         ___r = raw_cmpxchg_release((_ptr), ___o, (_new)); \
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   In file included from lib/objpool.c:3:
>> include/linux/objpool.h:156:7: error: invalid .org offset '1528' (at offset '1532')
     156 |                 if (try_cmpxchg_release(&slot->head, &head, head + 1))
         |                     ^
   include/linux/atomic/atomic-instrumented.h:4899:2: note: expanded from macro 'try_cmpxchg_release'
    4899 |         raw_try_cmpxchg_release(__ai_ptr, __ai_oldp, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:228:9: note: expanded from macro 'raw_try_cmpxchg_release'
     228 |         ___r = raw_cmpxchg_release((_ptr), ___o, (_new)); \
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   note: (skipping 4 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   2 errors generated.
--
>> lib/generic-radix-tree.c:53:12: error: invalid .org offset '1850' (at offset '1854')
      53 |                 if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
         |                          ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   lib/generic-radix-tree.c:74:14: error: invalid .org offset '1862' (at offset '1866')
      74 |                         if (!(n = cmpxchg_release(p, NULL, new_node)))
         |                                   ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
>> lib/generic-radix-tree.c:53:12: error: invalid .org offset '1850' (at offset '1854')
      53 |                 if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
         |                          ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   lib/generic-radix-tree.c:74:14: error: invalid .org offset '1862' (at offset '1866')
      74 |                         if (!(n = cmpxchg_release(p, NULL, new_node)))
         |                                   ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   4 errors generated.
--
   In file included from lib/refcount.c:6:
   In file included from include/linux/mutex.h:17:
   In file included from include/linux/lockdep.h:14:
   In file included from include/linux/smp.h:13:
   In file included from include/linux/cpumask.h:14:
   In file included from include/linux/atomic.h:80:
>> include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '528' (at offset '532')
    2083 |         return raw_cmpxchg_release(&v->counter, old, new);
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
     238 |                 __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx,  \
         |                 ^
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   In file included from lib/refcount.c:6:
   In file included from include/linux/mutex.h:17:
   In file included from include/linux/lockdep.h:14:
   In file included from include/linux/smp.h:13:
   In file included from include/linux/cpumask.h:14:
   In file included from include/linux/atomic.h:80:
   include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '540' (at offset '544')
    2083 |         return raw_cmpxchg_release(&v->counter, old, new);
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
     238 |                 __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx,  \
         |                 ^
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   In file included from lib/refcount.c:6:
   In file included from include/linux/mutex.h:17:
   In file included from include/linux/lockdep.h:14:
   In file included from include/linux/smp.h:13:
   In file included from include/linux/cpumask.h:14:
   In file included from include/linux/atomic.h:80:
>> include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '528' (at offset '532')
    2083 |         return raw_cmpxchg_release(&v->counter, old, new);
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
     238 |                 __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx,  \
         |                 ^
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   In file included from lib/refcount.c:6:
   In file included from include/linux/mutex.h:17:
   In file included from include/linux/lockdep.h:14:
   In file included from include/linux/smp.h:13:
   In file included from include/linux/cpumask.h:14:
   In file included from include/linux/atomic.h:80:
   include/linux/atomic/atomic-arch-fallback.h:2083:9: error: invalid .org offset '540' (at offset '544')
    2083 |         return raw_cmpxchg_release(&v->counter, old, new);
         |                ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   arch/riscv/include/asm/cmpxchg.h:238:3: note: expanded from macro '_arch_cmpxchg'
     238 |                 __arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx,  \
         |                 ^
   note: (skipping 2 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   4 errors generated.
--
>> fs/overlayfs/file.c:147:10: error: invalid .org offset '3640' (at offset '3644')
     147 |                         old = cmpxchg_release(&of->upperfile, NULL, upperfile);
         |                               ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
>> fs/overlayfs/file.c:147:10: error: invalid .org offset '3640' (at offset '3644')
     147 |                         old = cmpxchg_release(&of->upperfile, NULL, upperfile);
         |                               ^
   include/linux/atomic/atomic-instrumented.h:4803:2: note: expanded from macro 'cmpxchg_release'
    4803 |         raw_cmpxchg_release(__ai_ptr, __VA_ARGS__); \
         |         ^
   include/linux/atomic/atomic-arch-fallback.h:77:29: note: expanded from macro 'raw_cmpxchg_release'
      77 | #define raw_cmpxchg_release arch_cmpxchg_release
         |                             ^
   arch/riscv/include/asm/cmpxchg.h:265:2: note: expanded from macro 'arch_cmpxchg_release'
     265 |         _arch_cmpxchg((ptr), (o), (n),                                  \
         |         ^
   note: (skipping 3 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
   arch/riscv/include/asm/alternative-macros.h:104:2: note: expanded from macro '_ALTERNATIVE_CFG'
     104 |         __ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, IS_ENABLED(CONFIG_k))
         |         ^
   arch/riscv/include/asm/alternative-macros.h:94:2: note: expanded from macro '__ALTERNATIVE_CFG'
      94 |         ALT_NEW_CONTENT(vendor_id, patch_id, enable, new_c)
         |         ^
   arch/riscv/include/asm/alternative-macros.h:81:3: note: expanded from macro 'ALT_NEW_CONTENT'
      81 |         ".org   . - (887b - 886b) + (889b - 888b)\n"                    \
         |          ^
   <inline asm>:27:6: note: instantiated into assembly here
      27 | .org    . - (887b - 886b) + (889b - 888b)
         |         ^
   2 errors generated.
..


vim +156 include/linux/objpool.h

b4edb8d2d4647a wuqiang.matt    2023-10-17  100  
b4edb8d2d4647a wuqiang.matt    2023-10-17  101  /**
b4edb8d2d4647a wuqiang.matt    2023-10-17  102   * objpool_init() - initialize objpool and pre-allocated objects
b4edb8d2d4647a wuqiang.matt    2023-10-17  103   * @pool:    the object pool to be initialized, declared by caller
b4edb8d2d4647a wuqiang.matt    2023-10-17  104   * @nr_objs: total objects to be pre-allocated by this object pool
b4edb8d2d4647a wuqiang.matt    2023-10-17  105   * @object_size: size of an object (should be > 0)
b4edb8d2d4647a wuqiang.matt    2023-10-17  106   * @gfp:     flags for memory allocation (via kmalloc or vmalloc)
b4edb8d2d4647a wuqiang.matt    2023-10-17  107   * @context: user context for object initialization callback
b4edb8d2d4647a wuqiang.matt    2023-10-17  108   * @objinit: object initialization callback for extra setup
b4edb8d2d4647a wuqiang.matt    2023-10-17  109   * @release: cleanup callback for extra cleanup task
b4edb8d2d4647a wuqiang.matt    2023-10-17  110   *
b4edb8d2d4647a wuqiang.matt    2023-10-17  111   * return value: 0 for success, otherwise error code
b4edb8d2d4647a wuqiang.matt    2023-10-17  112   *
b4edb8d2d4647a wuqiang.matt    2023-10-17  113   * All pre-allocated objects are to be zeroed after memory allocation.
b4edb8d2d4647a wuqiang.matt    2023-10-17  114   * Caller could do extra initialization in objinit callback. objinit()
b4edb8d2d4647a wuqiang.matt    2023-10-17  115   * will be called just after slot allocation and called only once for
b4edb8d2d4647a wuqiang.matt    2023-10-17  116   * each object. After that the objpool won't touch any content of the
b4edb8d2d4647a wuqiang.matt    2023-10-17  117   * objects. It's caller's duty to perform reinitialization after each
b4edb8d2d4647a wuqiang.matt    2023-10-17  118   * pop (object allocation) or do clearance before each push (object
b4edb8d2d4647a wuqiang.matt    2023-10-17  119   * reclamation).
b4edb8d2d4647a wuqiang.matt    2023-10-17  120   */
b4edb8d2d4647a wuqiang.matt    2023-10-17  121  int objpool_init(struct objpool_head *pool, int nr_objs, int object_size,
b4edb8d2d4647a wuqiang.matt    2023-10-17  122  		 gfp_t gfp, void *context, objpool_init_obj_cb objinit,
b4edb8d2d4647a wuqiang.matt    2023-10-17  123  		 objpool_fini_cb release);
b4edb8d2d4647a wuqiang.matt    2023-10-17  124  
a3b00f10da808b Andrii Nakryiko 2024-04-24  125  /* try to retrieve object from slot */
a3b00f10da808b Andrii Nakryiko 2024-04-24  126  static inline void *__objpool_try_get_slot(struct objpool_head *pool, int cpu)
a3b00f10da808b Andrii Nakryiko 2024-04-24  127  {
a3b00f10da808b Andrii Nakryiko 2024-04-24  128  	struct objpool_slot *slot = pool->cpu_slots[cpu];
a3b00f10da808b Andrii Nakryiko 2024-04-24  129  	/* load head snapshot, other cpus may change it */
a3b00f10da808b Andrii Nakryiko 2024-04-24  130  	uint32_t head = smp_load_acquire(&slot->head);
a3b00f10da808b Andrii Nakryiko 2024-04-24  131  
a3b00f10da808b Andrii Nakryiko 2024-04-24  132  	while (head != READ_ONCE(slot->last)) {
a3b00f10da808b Andrii Nakryiko 2024-04-24  133  		void *obj;
a3b00f10da808b Andrii Nakryiko 2024-04-24  134  
a3b00f10da808b Andrii Nakryiko 2024-04-24  135  		/*
a3b00f10da808b Andrii Nakryiko 2024-04-24  136  		 * data visibility of 'last' and 'head' could be out of
a3b00f10da808b Andrii Nakryiko 2024-04-24  137  		 * order since memory updating of 'last' and 'head' are
a3b00f10da808b Andrii Nakryiko 2024-04-24  138  		 * performed in push() and pop() independently
a3b00f10da808b Andrii Nakryiko 2024-04-24  139  		 *
a3b00f10da808b Andrii Nakryiko 2024-04-24  140  		 * before any retrieving attempts, pop() must guarantee
a3b00f10da808b Andrii Nakryiko 2024-04-24  141  		 * 'last' is behind 'head', that is to say, there must
a3b00f10da808b Andrii Nakryiko 2024-04-24  142  		 * be available objects in slot, which could be ensured
a3b00f10da808b Andrii Nakryiko 2024-04-24  143  		 * by condition 'last != head && last - head <= nr_objs'
a3b00f10da808b Andrii Nakryiko 2024-04-24  144  		 * that is equivalent to 'last - head - 1 < nr_objs' as
a3b00f10da808b Andrii Nakryiko 2024-04-24  145  		 * 'last' and 'head' are both unsigned int32
a3b00f10da808b Andrii Nakryiko 2024-04-24  146  		 */
a3b00f10da808b Andrii Nakryiko 2024-04-24  147  		if (READ_ONCE(slot->last) - head - 1 >= pool->nr_objs) {
a3b00f10da808b Andrii Nakryiko 2024-04-24  148  			head = READ_ONCE(slot->head);
a3b00f10da808b Andrii Nakryiko 2024-04-24  149  			continue;
a3b00f10da808b Andrii Nakryiko 2024-04-24  150  		}
a3b00f10da808b Andrii Nakryiko 2024-04-24  151  
a3b00f10da808b Andrii Nakryiko 2024-04-24  152  		/* obj must be retrieved before moving forward head */
a3b00f10da808b Andrii Nakryiko 2024-04-24  153  		obj = READ_ONCE(slot->entries[head & slot->mask]);
a3b00f10da808b Andrii Nakryiko 2024-04-24  154  
a3b00f10da808b Andrii Nakryiko 2024-04-24  155  		/* move head forward to mark it's consumption */
a3b00f10da808b Andrii Nakryiko 2024-04-24 @156  		if (try_cmpxchg_release(&slot->head, &head, head + 1))
a3b00f10da808b Andrii Nakryiko 2024-04-24  157  			return obj;
a3b00f10da808b Andrii Nakryiko 2024-04-24  158  	}
a3b00f10da808b Andrii Nakryiko 2024-04-24  159  
a3b00f10da808b Andrii Nakryiko 2024-04-24  160  	return NULL;
a3b00f10da808b Andrii Nakryiko 2024-04-24  161  }
a3b00f10da808b Andrii Nakryiko 2024-04-24  162
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/atomic.h b/arch/riscv/include/asm/atomic.h
index 5b96c2f61adb5..b79a4f889f339 100644
--- a/arch/riscv/include/asm/atomic.h
+++ b/arch/riscv/include/asm/atomic.h
@@ -18,12 +18,6 @@ 
 
 #include <asm/cmpxchg.h>
 
-#define __atomic_acquire_fence()					\
-	__asm__ __volatile__(RISCV_ACQUIRE_BARRIER "" ::: "memory")
-
-#define __atomic_release_fence()					\
-	__asm__ __volatile__(RISCV_RELEASE_BARRIER "" ::: "memory");
-
 static __always_inline int arch_atomic_read(const atomic_t *v)
 {
 	return READ_ONCE(v->counter);
diff --git a/arch/riscv/include/asm/cmpxchg.h b/arch/riscv/include/asm/cmpxchg.h
index 0b749e7102162..207fdba38d1fc 100644
--- a/arch/riscv/include/asm/cmpxchg.h
+++ b/arch/riscv/include/asm/cmpxchg.h
@@ -15,15 +15,23 @@ 
 #include <asm/cpufeature-macros.h>
 #include <asm/processor.h>
 
-#define __arch_xchg_masked(sc_sfx, swap_sfx, prepend, sc_append,		\
-			   swap_append, r, p, n)				\
+/*
+ * These macros are here to improve the readability of the arch_xchg_XXX()
+ * and arch_cmpxchg_XXX() macros.
+ */
+#define LR_SFX(x)		x
+#define SC_SFX(x)		x
+#define CAS_SFX(x)		x
+#define SC_PREPEND(x)		x
+#define SC_APPEND(x)		x
+
+#define __arch_xchg_masked(lr_sfx, sc_sfx, swap_sfx, sc_prepend, sc_append,	\
+			   r, p, n)						\
 ({										\
 	if (IS_ENABLED(CONFIG_RISCV_ISA_ZABHA) &&				\
 	    riscv_has_extension_unlikely(RISCV_ISA_EXT_ZABHA)) {		\
 		__asm__ __volatile__ (						\
-			prepend							\
 			"	amoswap" swap_sfx " %0, %z2, %1\n"		\
-			swap_append						\
 			: "=&r" (r), "+A" (*(p))				\
 			: "rJ" (n)						\
 			: "memory");						\
@@ -37,14 +45,16 @@ 
 		ulong __rc;							\
 										\
 		__asm__ __volatile__ (						\
-		       prepend							\
 		       PREFETCHW_ASM(%5)					\
+		       ALTERNATIVE(__nops(1), sc_prepend,			\
+				   0, RISCV_ISA_EXT_ZALASR, 1)			\
 		       "0:	lr.w %0, %2\n"					\
 		       "	and  %1, %0, %z4\n"				\
 		       "	or   %1, %1, %z3\n"				\
 		       "	sc.w" sc_sfx " %1, %1, %2\n"			\
 		       "	bnez %1, 0b\n"					\
-		       sc_append						\
+		       ALTERNATIVE(__nops(1), sc_append,			\
+				   0, RISCV_ISA_EXT_ZALASR, 1)			\
 		       : "=&r" (__retx), "=&r" (__rc), "+A" (*(__ptr32b))	\
 		       : "rJ" (__newx), "rJ" (~__mask), "rJ" (__ptr32b)		\
 		       : "memory");						\
@@ -53,19 +63,17 @@ 
 	}									\
 })
 
-#define __arch_xchg(sfx, prepend, append, r, p, n)			\
+#define __arch_xchg(sfx, r, p, n)					\
 ({									\
 	__asm__ __volatile__ (						\
-		prepend							\
 		"	amoswap" sfx " %0, %2, %1\n"			\
-		append							\
 		: "=r" (r), "+A" (*(p))					\
 		: "r" (n)						\
 		: "memory");						\
 })
 
-#define _arch_xchg(ptr, new, sc_sfx, swap_sfx, prepend,			\
-		   sc_append, swap_append)				\
+#define _arch_xchg(ptr, new, lr_sfx, sc_sfx, swap_sfx,			\
+		   sc_prepend, sc_append)				\
 ({									\
 	__typeof__(ptr) __ptr = (ptr);					\
 	__typeof__(*(__ptr)) __new = (new);				\
@@ -73,22 +81,20 @@ 
 									\
 	switch (sizeof(*__ptr)) {					\
 	case 1:								\
-		__arch_xchg_masked(sc_sfx, ".b" swap_sfx,		\
-				   prepend, sc_append, swap_append,	\
+		__arch_xchg_masked(lr_sfx, sc_sfx, ".b" swap_sfx,	\
+				   sc_prepend, sc_append,		\
 				   __ret, __ptr, __new);		\
 		break;							\
 	case 2:								\
-		__arch_xchg_masked(sc_sfx, ".h" swap_sfx,		\
-				   prepend, sc_append, swap_append,	\
+		__arch_xchg_masked(lr_sfx, sc_sfx, ".h" swap_sfx,	\
+				   sc_prepend, sc_append,		\
 				   __ret, __ptr, __new);		\
 		break;							\
 	case 4:								\
-		__arch_xchg(".w" swap_sfx, prepend, swap_append,	\
-			      __ret, __ptr, __new);			\
+		__arch_xchg(".w" swap_sfx, __ret, __ptr, __new);	\
 		break;							\
 	case 8:								\
-		__arch_xchg(".d" swap_sfx, prepend, swap_append,	\
-			      __ret, __ptr, __new);			\
+		__arch_xchg(".d" swap_sfx, __ret, __ptr, __new);	\
 		break;							\
 	default:							\
 		BUILD_BUG();						\
@@ -97,17 +103,23 @@ 
 })
 
 #define arch_xchg_relaxed(ptr, x)					\
-	_arch_xchg(ptr, x, "", "", "", "", "")
+	_arch_xchg(ptr, x, LR_SFX(""), SC_SFX(""), CAS_SFX(""),		\
+		   SC_PREPEND(__nops(1)), SC_APPEND(__nops(1)))
 
 #define arch_xchg_acquire(ptr, x)					\
-	_arch_xchg(ptr, x, "", "", "",					\
-		   RISCV_ACQUIRE_BARRIER, RISCV_ACQUIRE_BARRIER)
+	_arch_xchg(ptr, x, LR_SFX(".aq"), SC_SFX(""), CAS_SFX(".aq"),	\
+		   SC_PREPEND(__nops(1)),				\
+		   SC_APPEND(RISCV_ACQUIRE_BARRIER))
 
 #define arch_xchg_release(ptr, x)					\
-	_arch_xchg(ptr, x, "", "", RISCV_RELEASE_BARRIER, "", "")
+	_arch_xchg(ptr, x, LR_SFX(""), SC_SFX(".rl"), CAS_SFX(".rl"),	\
+		   SC_PREPEND(RISCV_RELEASE_BARRIER),			\
+		   SC_APPEND(__nops(1)))
 
 #define arch_xchg(ptr, x)						\
-	_arch_xchg(ptr, x, ".rl", ".aqrl", "", RISCV_FULL_BARRIER, "")
+	_arch_xchg(ptr, x, LR_SFX(""), SC_SFX(".aqrl"),			\
+		   CAS_SFX(".aqrl"), SC_PREPEND(__nops(1)),		\
+		   SC_APPEND(__nops(1)))
 
 #define xchg32(ptr, x)							\
 ({									\
@@ -126,9 +138,7 @@ 
  * store NEW in MEM.  Return the initial value in MEM.  Success is
  * indicated by comparing RETURN with OLD.
  */
-#define __arch_cmpxchg_masked(sc_sfx, cas_sfx,					\
-			      sc_prepend, sc_append,				\
-			      cas_prepend, cas_append,				\
+#define __arch_cmpxchg_masked(lr_sfx, sc_sfx, cas_sfx, sc_prepend, sc_append,	\
 			      r, p, o, n)					\
 ({										\
 	if (IS_ENABLED(CONFIG_RISCV_ISA_ZABHA) &&				\
@@ -138,9 +148,7 @@ 
 		r = o;								\
 										\
 		__asm__ __volatile__ (						\
-			cas_prepend							\
 			"	amocas" cas_sfx " %0, %z2, %1\n"		\
-			cas_append							\
 			: "+&r" (r), "+A" (*(p))				\
 			: "rJ" (n)						\
 			: "memory");						\
@@ -155,15 +163,17 @@ 
 		ulong __rc;							\
 										\
 		__asm__ __volatile__ (						\
-			sc_prepend							\
-			"0:	lr.w %0, %2\n"					\
+			ALTERNATIVE(__nops(1), sc_prepend,			\
+				    0, RISCV_ISA_EXT_ZALASR, 1)			\
+			"0:	lr.w" lr_sfx " %0, %2\n"			\
 			"	and  %1, %0, %z5\n"				\
 			"	bne  %1, %z3, 1f\n"				\
 			"	and  %1, %0, %z6\n"				\
 			"	or   %1, %1, %z4\n"				\
 			"	sc.w" sc_sfx " %1, %1, %2\n"			\
 			"	bnez %1, 0b\n"					\
-			sc_append							\
+			ALTERNATIVE(__nops(1), sc_append,			\
+				    0, RISCV_ISA_EXT_ZALASR, 1)			\
 			"1:\n"							\
 			: "=&r" (__retx), "=&r" (__rc), "+A" (*(__ptr32b))	\
 			: "rJ" ((long)__oldx), "rJ" (__newx),			\
@@ -174,9 +184,7 @@ 
 	}									\
 })
 
-#define __arch_cmpxchg(lr_sfx, sc_sfx, cas_sfx,				\
-		       sc_prepend, sc_append,				\
-		       cas_prepend, cas_append,				\
+#define __arch_cmpxchg(lr_sfx, sc_sfx, cas_sfx,	sc_prepend, sc_append,	\
 		       r, p, co, o, n)					\
 ({									\
 	if (IS_ENABLED(CONFIG_RISCV_ISA_ZACAS) &&			\
@@ -184,9 +192,7 @@ 
 		r = o;							\
 									\
 		__asm__ __volatile__ (					\
-			cas_prepend					\
 			"	amocas" cas_sfx " %0, %z2, %1\n"	\
-			cas_append					\
 			: "+&r" (r), "+A" (*(p))			\
 			: "rJ" (n)					\
 			: "memory");					\
@@ -194,12 +200,14 @@ 
 		register unsigned int __rc;				\
 									\
 		__asm__ __volatile__ (					\
-			sc_prepend					\
+			ALTERNATIVE(__nops(1), sc_prepend,		\
+				    0, RISCV_ISA_EXT_ZALASR, 1)		\
 			"0:	lr" lr_sfx " %0, %2\n"			\
 			"	bne  %0, %z3, 1f\n"			\
 			"	sc" sc_sfx " %1, %z4, %2\n"		\
 			"	bnez %1, 0b\n"				\
-			sc_append					\
+			ALTERNATIVE(__nops(1), sc_append,		\
+				    0, RISCV_ISA_EXT_ZALASR, 1)		\
 			"1:\n"						\
 			: "=&r" (r), "=&r" (__rc), "+A" (*(p))		\
 			: "rJ" (co o), "rJ" (n)				\
@@ -207,9 +215,8 @@ 
 	}								\
 })
 
-#define _arch_cmpxchg(ptr, old, new, sc_sfx, cas_sfx,			\
-		      sc_prepend, sc_append,				\
-		      cas_prepend, cas_append)				\
+#define _arch_cmpxchg(ptr, old, new, lr_sfx, sc_sfx, cas_sfx,		\
+		      sc_prepend, sc_append)				\
 ({									\
 	__typeof__(ptr) __ptr = (ptr);					\
 	__typeof__(*(__ptr)) __old = (old);				\
@@ -218,27 +225,23 @@ 
 									\
 	switch (sizeof(*__ptr)) {					\
 	case 1:								\
-		__arch_cmpxchg_masked(sc_sfx, ".b" cas_sfx,		\
+		__arch_cmpxchg_masked(lr_sfx, sc_sfx, ".b" cas_sfx,	\
 				      sc_prepend, sc_append,		\
-				      cas_prepend, cas_append,		\
 				      __ret, __ptr, __old, __new);	\
 		break;							\
 	case 2:								\
-		__arch_cmpxchg_masked(sc_sfx, ".h" cas_sfx,		\
+		__arch_cmpxchg_masked(lr_sfx, sc_sfx, ".h" cas_sfx,	\
 				      sc_prepend, sc_append,		\
-				      cas_prepend, cas_append,		\
 				      __ret, __ptr, __old, __new);	\
 		break;							\
 	case 4:								\
-		__arch_cmpxchg(".w", ".w" sc_sfx, ".w" cas_sfx,		\
+		__arch_cmpxchg(".w" lr_sfx, ".w" sc_sfx, ".w" cas_sfx,	\
 			       sc_prepend, sc_append,			\
-			       cas_prepend, cas_append,			\
 			       __ret, __ptr, (long)(int)(long), __old, __new);	\
 		break;							\
 	case 8:								\
-		__arch_cmpxchg(".d", ".d" sc_sfx, ".d" cas_sfx,		\
+		__arch_cmpxchg(".d" lr_sfx, ".d" sc_sfx, ".d" cas_sfx,	\
 			       sc_prepend, sc_append,			\
-			       cas_prepend, cas_append,			\
 			       __ret, __ptr, /**/, __old, __new);	\
 		break;							\
 	default:							\
@@ -247,40 +250,27 @@ 
 	(__typeof__(*(__ptr)))__ret;					\
 })
 
-/*
- * These macros are here to improve the readability of the arch_cmpxchg_XXX()
- * macros.
- */
-#define SC_SFX(x)	x
-#define CAS_SFX(x)	x
-#define SC_PREPEND(x)	x
-#define SC_APPEND(x)	x
-#define CAS_PREPEND(x)	x
-#define CAS_APPEND(x)	x
-
 #define arch_cmpxchg_relaxed(ptr, o, n)					\
 	_arch_cmpxchg((ptr), (o), (n),					\
-		      SC_SFX(""), CAS_SFX(""),				\
-		      SC_PREPEND(""), SC_APPEND(""),			\
-		      CAS_PREPEND(""), CAS_APPEND(""))
+		      LR_SFX(""), SC_SFX(""), CAS_SFX(""),		\
+		      SC_PREPEND(__nops(1)), SC_APPEND(__nops(1)))
 
 #define arch_cmpxchg_acquire(ptr, o, n)					\
 	_arch_cmpxchg((ptr), (o), (n),					\
-		      SC_SFX(""), CAS_SFX(""),				\
-		      SC_PREPEND(""), SC_APPEND(RISCV_ACQUIRE_BARRIER),	\
-		      CAS_PREPEND(""), CAS_APPEND(RISCV_ACQUIRE_BARRIER))
+		      LR_SFX(".aq"), SC_SFX(""), CAS_SFX(".aq"),	\
+		      SC_PREPEND(__nops(1)),				\
+		      SC_APPEND(RISCV_ACQUIRE_BARRIER))
 
 #define arch_cmpxchg_release(ptr, o, n)					\
 	_arch_cmpxchg((ptr), (o), (n),					\
-		      SC_SFX(""), CAS_SFX(""),				\
-		      SC_PREPEND(RISCV_RELEASE_BARRIER), SC_APPEND(""),	\
-		      CAS_PREPEND(RISCV_RELEASE_BARRIER), CAS_APPEND(""))
+		      LR_SFX(""), SC_SFX(".rl"), CAS_SFX(".rl"),	\
+		      SC_PREPEND(RISCV_RELEASE_BARRIER),		\
+		      SC_APPEND(__nops(1)))
 
 #define arch_cmpxchg(ptr, o, n)						\
 	_arch_cmpxchg((ptr), (o), (n),					\
-		      SC_SFX(".rl"), CAS_SFX(".aqrl"),			\
-		      SC_PREPEND(""), SC_APPEND(RISCV_FULL_BARRIER),	\
-		      CAS_PREPEND(""), CAS_APPEND(""))
+		      LR_SFX(""), SC_SFX(".aqrl"), CAS_SFX(".aqrl"),	\
+		      SC_PREPEND(__nops(1)), SC_APPEND(__nops(1)))
 
 #define arch_cmpxchg_local(ptr, o, n)					\
 	arch_cmpxchg_relaxed((ptr), (o), (n))