kernel/arch/xtensa/include/asm/cmpxchg.h, branch linux-rolling-stable

xtensa: Replace ASSEMBLY with ASSEMBLER in non-uapi headers

2025-06-06T08:03:35Z

While the GCC and Clang compilers already define __ASSEMBLER__ automatically when compiling assembly code, __ASSEMBLY__ is a macro that only gets defined by the Makefiles in the kernel. This can be very confusing when switching between userspace and kernelspace coding, or when dealing with uapi headers that rather should use __ASSEMBLER__ instead. So let's standardize on the __ASSEMBLER__ macro that is provided by the compilers now. This is a completely mechanical patch (done with a simple "sed -i" statement). Cc: Chris Zankel Cc: Max Filippov Signed-off-by: Thomas Huth Message-Id: <20250314071013.1575167-40-thuth@redhat.com> Signed-off-by: Max Filippov

xtensa: Emulate one-byte cmpxchg

2024-09-13T14:10:38Z

Use the new cmpxchg_emu_u8() to emulate one-byte cmpxchg() on xtensa. [ paulmck: Apply kernel test robot feedback. ] [ paulmck: Drop two-byte support per Arnd Bergmann feedback. ] [ Apply Geert Uytterhoeven feedback. ] Signed-off-by: Paul E. McKenney Tested-by: Yujie Liu Cc: Andi Shyti Cc: Geert Uytterhoeven Cc: Arnd Bergmann Cc: "Peter Zijlstra (Intel)"

locking/arch: Rename all internal xchg() names to arch_xchg()

2023-04-29T07:08:44Z

Decrease the probability of this internal facility to be used by driver code. Signed-off-by: Andrzej Hajda Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Arnd Bergmann Reviewed-by: Andi Shyti Acked-by: Geert Uytterhoeven [m68k] Acked-by: Palmer Dabbelt [riscv] Link: https://lore.kernel.org/r/20230118154450.73842-1-andrzej.hajda@intel.com Cc: Linus Torvalds

xtensa: use a14 instead of a15 in inline assembly

2021-10-19T05:19:34Z

a15 is a frame pointer in the call0 xtensa ABI, don't use it explicitly in the inline assembly. Use a14 instead, as it has the same properties as a15 w.r.t. window overflow. Signed-off-by: Max Filippov

locking/atomic: xtensa: move to ARCH_ATOMIC

2021-05-26T11:20:52Z

We'd like all architectures to convert to ARCH_ATOMIC, as once all architectures are converted it will be possible to make significant cleanups to the atomics headers, and this will make it much easier to generically enable atomic functionality (e.g. debug logic in the instrumented wrappers). As a step towards that, this patch migrates xtensa to ARCH_ATOMIC. The arch code provides arch_{atomic,atomic64,xchg,cmpxchg}*(), and common code wraps these with optional instrumentation to provide the regular functions. Signed-off-by: Mark Rutland Acked-by: Max Filippov Cc: Boqun Feng Cc: Chris Zankel Cc: Peter Zijlstra Cc: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210525140232.53872-32-mark.rutland@arm.com

locking/atomic: cmpxchg: make `generic` a prefix

2021-05-26T11:20:50Z

The asm-generic implementations of cmpxchg_local() and cmpxchg64_local() use a `_generic` suffix to distinguish themselves from arch code or wrappers used elsewhere. Subsequent patches will add ARCH_ATOMIC support to these implementations, and will distinguish more functions with a `generic` portion. To align with how ARCH_ATOMIC uses an `arch_` prefix, it would be helpful to use a `generic_` prefix rather than a `_generic` suffix. In preparation for this, this patch renames the existing functions to make `generic` a prefix rather than a suffix. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Acked-by: Geert Uytterhoeven Cc: Arnd Bergmann Cc: Boqun Feng Cc: Peter Zijlstra Cc: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210525140232.53872-12-mark.rutland@arm.com

xtensa: use "m" constraint instead of "a" in cmpxchg.h assembly

2019-11-26T19:33:39Z

Use "m" constraint instead of "r" for the address, as "m" allows compiler to access adjacent locations using base + offset, while "r" requires updating the base register every time. Signed-off-by: Max Filippov

xtensa: use named assembly arguments in cmpxchg.h

2019-11-26T19:33:39Z

Numeric assembly arguments are hard to understand and assembly code that uses them is hard to modify. Use named arguments in __cmpxchg_u32 and xchg_u32. Signed-off-by: Max Filippov

xtensa: add exclusive atomics support

2019-05-07T17:36:31Z

Implement atomic primitives using exclusive access opcodes available in the recent xtensa cores. Since l32ex/s32ex don't have any memory ordering guarantees don't define __smp_mb__before_atomic/__smp_mb__after_atomic to make them use memw. Signed-off-by: Max Filippov

xtensa: provide xchg for sizes 1 and 2

2019-02-07T20:24:17Z

This is required for generic queued spinlocks, implement it. Signed-off-by: Max Filippov