linux.git/arch/mips/include/asm/cmpxchg.h, branch bh1745

MIPS: retire "asm/llsc.h"

2022-01-05T10:16:35+00:00

all that "asm/llsc.h" does is just to help inline asm, which can be stringifyed from "asm/asm.h" +. Since "asm/asm.h" has all we need, retire "asm/llsc.h" +. remove unused header file Inspired-by: Maciej W. Rozycki Signed-off-by: Huang Pei Signed-off-by: Thomas Bogendoerfer

MIPS: Fix assembly error from MIPSr2 code used within MIPS_ISA_ARCH_LEVEL

2021-10-24T15:15:29+00:00

Fix assembly errors like: {standard input}: Assembler messages: {standard input}:287: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32' {standard input}:680: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32' {standard input}:1274: Error: opcode not supported on this processor: mips3 (mips3) `dins $12,$9,32,32' {standard input}:2175: Error: opcode not supported on this processor: mips3 (mips3) `dins $10,$7,32,32' make[1]: *** [scripts/Makefile.build:277: mm/highmem.o] Error 1 with code produced from `__cmpxchg64' for MIPS64r2 CPU configurations using CONFIG_32BIT and CONFIG_PHYS_ADDR_T_64BIT. This is due to MIPS_ISA_ARCH_LEVEL downgrading the assembly architecture to `r4000' i.e. MIPS III for MIPS64r2 configurations, while there is a block of code containing a DINS MIPS64r2 instruction conditionalized on MIPS_ISA_REV >= 2 within the scope of the downgrade. The assembly architecture override code pattern has been put there for LL/SC instructions, so that code compiles for configurations that select a processor to build for that does not support these instructions while still providing run-time support for processors that do, dynamically switched by non-constant `cpu_has_llsc'. It went in with linux-mips.org commit aac8aa7717a2 ("Enable a suitable ISA for the assembler around ll/sc so that code builds even for processors that don't support the instructions. Plus minor formatting fixes.") back in 2005. Fix the problem by wrapping these instructions along with the adjacent SYNC instructions only, following the practice established with commit cfd54de3b0e4 ("MIPS: Avoid move psuedo-instruction whilst using MIPS_ISA_LEVEL") and commit 378ed6f0e3c5 ("MIPS: Avoid using .set mips0 to restore ISA"). Strictly speaking the SYNC instructions do not have to be wrapped as they are only used as a Loongson3 erratum workaround, so they will be enabled in the assembler by default, but do this so as to keep code consistent with other places. Reported-by: kernel test robot Signed-off-by: Maciej W. Rozycki Fixes: c7e2d71dda7a ("MIPS: Fix set_pte() for Netlogic XLR using cmpxchg64()") Cc: stable@vger.kernel.org # v5.1+ Signed-off-by: Thomas Bogendoerfer

locking/atomic: mips: move to ARCH_ATOMIC

2021-05-26T11:20:51+00:00

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 mips 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 Cc: Boqun Feng Cc: Peter Zijlstra Cc: Thomas Bogendoerfer Cc: Will Deacon Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210525140232.53872-23-mark.rutland@arm.com

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

2021-05-26T11:20:50+00:00

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

MIPS: Compare __SYNC_loongson3_war against 0

2021-01-15T14:32:47+00:00

When building with clang when CONFIG_CPU_LOONGSON3_WORKAROUNDS is enabled: In file included from lib/errseq.c:4: In file included from ./include/linux/atomic.h:7: ./arch/mips/include/asm/atomic.h:52:1: warning: converting the result of '<<' to a boolean always evaluates to true [-Wtautological-constant-compare] ATOMIC_OPS(atomic64, s64) ^ ./arch/mips/include/asm/atomic.h:40:9: note: expanded from macro 'ATOMIC_OPS' return cmpxchg(&v->counter, o, n); ^ ./arch/mips/include/asm/cmpxchg.h:194:7: note: expanded from macro 'cmpxchg' if (!__SYNC_loongson3_war) ^ ./arch/mips/include/asm/sync.h:147:34: note: expanded from macro '__SYNC_loongson3_war' # define __SYNC_loongson3_war (1 << 31) ^ While it is not wrong that the result of this shift is always true in a boolean context, it is not a problem here. Regardless, the warning is really noisy so rather than making the shift a boolean implicitly, use it in an equality comparison so the shift is used as an integer value. Fixes: 4d1dbfe6cbec ("MIPS: atomic: Emit Loongson3 sync workarounds within asm") Fixes: a91f2a1dba44 ("MIPS: cmpxchg: Omit redundant barriers for Loongson3") Reported-by: kernel test robot Signed-off-by: Nathan Chancellor Acked-by: Nick Desaulniers Signed-off-by: Thomas Bogendoerfer

Merge tag 'mips_fixes_5.4_3' into mips-next

2019-11-01T21:36:44+00:00

Pull in mips-fixes primarily to gain build fixes in order to allow better testing of mips-next. A few MIPS fixes: - Fix VDSO time-related function behavior for systems where we need to fall back to syscalls, but were instead returning bogus results. - A fix to TLB exception handlers for Cavium Octeon systems where they would inadvertently clobber the $1/$at register. - A build fix for bcm63xx configurations. - Switch to using my @kernel.org email address. Signed-off-by: Paul Burton

MIPS: include: Mark xchg as always_inline

2019-10-09T19:45:31+00:00

Commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") allows compiler to uninline functions marked as 'inline'. In cace of __xchg this would cause to reference function __xchg_called_with_bad_pointer, which is an error case for catching bugs and will not happen for correct code, if __xchg is inlined. Signed-off-by: Thomas Bogendoerfer Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Paul Burton Cc: Ralf Baechle Cc: James Hogan Cc: linux-mips@vger.kernel.org Cc: linux-kernel@vger.kernel.org

MIPS: cmpxchg: Omit redundant barriers for Loongson3

2019-10-07T16:43:01+00:00

When building a kernel configured to support Loongson3 LL/SC workarounds (ie. CONFIG_CPU_LOONGSON3_WORKAROUNDS=y) the inline assembly in __xchg_asm() & __cmpxchg_asm() already emits completion barriers, and as such we don't need to emit extra barriers from the xchg() or cmpxchg() macros. Add compile-time constant checks causing us to omit the redundant memory barriers. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Huacai Chen Cc: Jiaxun Yang Cc: linux-kernel@vger.kernel.org

MIPS: cmpxchg: Emit Loongson3 sync workarounds within asm

2019-10-07T16:43:00+00:00

Generate the sync instructions required to workaround Loongson3 LL/SC errata within inline asm blocks, which feels a little safer than doing it from C where strictly speaking the compiler would be well within its rights to insert a memory access between the separate asm statements we previously had, containing sync & ll instructions respectively. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Huacai Chen Cc: Jiaxun Yang Cc: linux-kernel@vger.kernel.org

MIPS: Unify sc beqz definition

2019-10-07T16:42:13+00:00

We currently duplicate the definition of __scbeqz in asm/atomic.h & asm/cmpxchg.h. Move it to asm/llsc.h & rename it to __SC_BEQZ to fit better with the existing __SC macro provided there. We include a tab in the string in order to avoid the need for users to indent code any further to include whitespace of their own after the instruction mnemonic. Signed-off-by: Paul Burton Cc: linux-mips@vger.kernel.org Cc: Huacai Chen Cc: Jiaxun Yang Cc: linux-kernel@vger.kernel.org