From: Samuel Holland Date: Wed, 27 Mar 2024 04:49:46 +0000 (-0700) Subject: riscv: Only send remote fences when some other CPU is online X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9546f00410ed88b8117388cfd74ea59f4616a158;p=linux.git riscv: Only send remote fences when some other CPU is online If no other CPU is online, a local cache or TLB flush is sufficient. These checks can be constant-folded when SMP is disabled. Signed-off-by: Samuel Holland Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/20240327045035.368512-6-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt --- diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c index d76fc73e594b2..f5be1fec8191c 100644 --- a/arch/riscv/mm/cacheflush.c +++ b/arch/riscv/mm/cacheflush.c @@ -21,7 +21,9 @@ void flush_icache_all(void) { local_flush_icache_all(); - if (riscv_use_sbi_for_rfence()) + if (num_online_cpus() < 2) + return; + else if (riscv_use_sbi_for_rfence()) sbi_remote_fence_i(NULL); else on_each_cpu(ipi_remote_fence_i, NULL, 1); diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c index da821315d43ee..0901aa47b58fe 100644 --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -79,7 +79,9 @@ static void __ipi_flush_tlb_all(void *info) void flush_tlb_all(void) { - if (riscv_use_sbi_for_rfence()) + if (num_online_cpus() < 2) + local_flush_tlb_all(); + else if (riscv_use_sbi_for_rfence()) sbi_remote_sfence_vma_asid(NULL, 0, FLUSH_TLB_MAX_SIZE, FLUSH_TLB_NO_ASID); else on_each_cpu(__ipi_flush_tlb_all, NULL, 1);