From: Jisheng Zhang jszhang@kernel.org
stable inclusion from stable-v6.6.11 commit b649a7fe9a8b41a01b608e129a90af09d4b5f52f bugzilla: https://gitee.com/openeuler/kernel/issues/I99TJK
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit c20d36cc2a2073d4cdcda92bd7a1bb9b3b3b7c79 ]
If misaligned_access_speed percpu var isn't so called "HWPROBE MISALIGNED UNKNOWN", it means the probe has happened(this is possible for example, hotplug off then hotplug on one cpu), and the percpu var has been set, don't probe again in this case.
Signed-off-by: Jisheng Zhang jszhang@kernel.org Fixes: 584ea6564bca ("RISC-V: Probe for unaligned access speed") Reviewed-by: Conor Dooley conor.dooley@microchip.com Link: https://lore.kernel.org/r/20230912154040.3306-1-jszhang@kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: ZhangPeng zhangpeng362@huawei.com --- arch/riscv/kernel/cpufeature.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c index 1cfbba65d11a..e12cd22755c7 100644 --- a/arch/riscv/kernel/cpufeature.c +++ b/arch/riscv/kernel/cpufeature.c @@ -568,6 +568,10 @@ void check_unaligned_access(int cpu) void *src; long speed = RISCV_HWPROBE_MISALIGNED_SLOW;
+ /* We are already set since the last check */ + if (per_cpu(misaligned_access_speed, cpu) != RISCV_HWPROBE_MISALIGNED_UNKNOWN) + return; + page = alloc_pages(GFP_NOWAIT, get_order(MISALIGNED_BUFFER_SIZE)); if (!page) { pr_warn("Can't alloc pages to measure memcpy performance");