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authorSamuel Holland <samuel.holland@sifive.com>2024-03-27 07:49:46 +0300
committerPalmer Dabbelt <palmer@rivosinc.com>2024-04-29 20:49:28 +0300
commit9546f00410ed88b8117388cfd74ea59f4616a158 (patch)
tree1c0d8fc79fd666a1caf2c7a501ffef7d16a6354d /arch/riscv
parent038ac18aae935c89c874649acde5a82f588a12b4 (diff)
downloadlinux-9546f00410ed88b8117388cfd74ea59f4616a158.tar.xz
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 <samuel.holland@sifive.com> Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20240327045035.368512-6-samuel.holland@sifive.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/mm/cacheflush.c4
-rw-r--r--arch/riscv/mm/tlbflush.c4
2 files changed, 6 insertions, 2 deletions
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index d76fc73e594b..f5be1fec8191 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 da821315d43e..0901aa47b58f 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);