From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Piggin Date: Fri, 24 Jul 2020 13:14:23 +0000 Subject: [PATCH v4 6/6] powerpc: implement smp_cond_load_relaxed Message-Id: <20200724131423.1362108-7-npiggin@gmail.com> List-Id: References: <20200724131423.1362108-1-npiggin@gmail.com> In-Reply-To: <20200724131423.1362108-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linuxppc-dev@lists.ozlabs.org Cc: Nicholas Piggin , Will Deacon , Peter Zijlstra , Boqun Feng , Ingo Molnar , Waiman Long , Anton Blanchard , =?UTF-8?q?Michal=20Such=C3=A1nek?= , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org This implements smp_cond_load_relaed with the slowpath busy loop using the preferred SMT priority pattern. Signed-off-by: Nicholas Piggin --- arch/powerpc/include/asm/barrier.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h index 123adcefd40f..9b4671d38674 100644 --- a/arch/powerpc/include/asm/barrier.h +++ b/arch/powerpc/include/asm/barrier.h @@ -76,6 +76,20 @@ do { \ ___p1; \ }) +#define smp_cond_load_relaxed(ptr, cond_expr) ({ \ + typeof(ptr) __PTR = (ptr); \ + __unqual_scalar_typeof(*ptr) VAL; \ + VAL = READ_ONCE(*__PTR); \ + if (unlikely(!(cond_expr))) { \ + spin_begin(); \ + do { \ + VAL = READ_ONCE(*__PTR); \ + } while (!(cond_expr)); \ + spin_end(); \ + } \ + (typeof(*ptr))VAL; \ +}) + #ifdef CONFIG_PPC_BOOK3S_64 #define NOSPEC_BARRIER_SLOT nop #elif defined(CONFIG_PPC_FSL_BOOK3E) -- 2.23.0