From 27e6e7d63fc2b43334ce79070a727a9ca6e58700 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Thu, 30 May 2019 12:30:58 +0100 Subject: [PATCH] arm64/cpufeature: Convert hook_lock to raw_spin_lock_t in cpu_enable_ssbs() cpu_enable_ssbs() is called via stop_machine() as part of the cpu_enable callback. A spin lock is used to ensure the hook is registered before the rest of the callback is executed. On -RT spin_lock() may sleep. However, all the callees in stop_machine() are expected to not sleep. Therefore a raw_spin_lock() is required here. Given this is already done under stop_machine() and the work done under the lock is quite small, the latency should not increase too much. Signed-off-by: Julien Grall Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpufeature.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index ca27e08e3d8a..2a7159fda3ce 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1194,14 +1194,14 @@ static struct undef_hook ssbs_emulation_hook = { static void cpu_enable_ssbs(const struct arm64_cpu_capabilities *__unused) { static bool undef_hook_registered = false; - static DEFINE_SPINLOCK(hook_lock); + static DEFINE_RAW_SPINLOCK(hook_lock); - spin_lock(&hook_lock); + raw_spin_lock(&hook_lock); if (!undef_hook_registered) { register_undef_hook(&ssbs_emulation_hook); undef_hook_registered = true; } - spin_unlock(&hook_lock); + raw_spin_unlock(&hook_lock); if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) { sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS); -- 2.11.0