Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033609AbbKFTjf (ORCPT ); Fri, 6 Nov 2015 14:39:35 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:47936 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033478AbbKFTcq (ORCPT ); Fri, 6 Nov 2015 14:32:46 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Walleij , Mika Westerberg , Lucas De Marchi Subject: [PATCH 4.1 83/86] pinctrl: baytrail: Use raw_spinlock for locking Date: Fri, 6 Nov 2015 11:23:22 -0800 Message-Id: <20151106192209.411870781@linuxfoundation.org> X-Mailer: git-send-email 2.6.2 In-Reply-To: <20151106192205.351595349@linuxfoundation.org> References: <20151106192205.351595349@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7769 Lines: 255 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mika Westerberg commit 78e1c896932df5b8bcdff7bf5417d8e72a4d0d6b upstream. The Intel Baytrail pinctrl driver implements irqchip callbacks which are called with desc->lock raw_spinlock held. In mainline this is fine because spinlock resolves to raw_spinlock. However, running the same code in -rt we get: BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/0 Preemption disabled at:[] cpu_startup_entry+0x17f/0x480 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.5-rt5 #13 ... Call Trace: [] dump_stack+0x4a/0x61 [] ___might_sleep+0xe7/0x170 [] rt_spin_lock+0x1f/0x50 [] byt_gpio_clear_triggering+0x38/0x60 [] byt_irq_mask+0x11/0x20 [] handle_level_irq+0x83/0x150 [] generic_handle_irq+0x27/0x40 [] byt_gpio_irq_handler+0x7f/0xc0 [] handle_irq+0xaa/0x190 ... This is because in -rt spinlocks are preemptible so taking the driver private spinlock in irqchip callbacks causes might_sleep() to trigger. In order to keep -rt happy but at the same time make sure that register accesses get serialized, convert the driver to use raw_spinlock instead. Also shorten the critical section a bit in few places. Suggested-by: Linus Walleij Signed-off-by: Mika Westerberg Signed-off-by: Linus Walleij Cc: Lucas De Marchi Signed-off-by: Greg Kroah-Hartman --- drivers/pinctrl/intel/pinctrl-baytrail.c | 50 +++++++++++++++---------------- 1 file changed, 25 insertions(+), 25 deletions(-) --- a/drivers/pinctrl/intel/pinctrl-baytrail.c +++ b/drivers/pinctrl/intel/pinctrl-baytrail.c @@ -146,7 +146,7 @@ struct byt_gpio_pin_context { struct byt_gpio { struct gpio_chip chip; struct platform_device *pdev; - spinlock_t lock; + raw_spinlock_t lock; void __iomem *reg_base; struct pinctrl_gpio_range *range; struct byt_gpio_pin_context *saved_context; @@ -174,11 +174,11 @@ static void byt_gpio_clear_triggering(st unsigned long flags; u32 value; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); value = readl(reg); value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL); writel(value, reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); } static u32 byt_get_gpio_mux(struct byt_gpio *vg, unsigned offset) @@ -203,7 +203,7 @@ static int byt_gpio_request(struct gpio_ u32 value, gpio_mux; unsigned long flags; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); /* * In most cases, func pin mux 000 means GPIO function. @@ -225,7 +225,7 @@ static int byt_gpio_request(struct gpio_ "pin %u forcibly re-configured as GPIO\n", offset); } - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); pm_runtime_get(&vg->pdev->dev); @@ -251,7 +251,7 @@ static int byt_irq_type(struct irq_data if (offset >= vg->chip.ngpio) return -EINVAL; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); value = readl(reg); WARN(value & BYT_DIRECT_IRQ_EN, @@ -270,7 +270,7 @@ static int byt_irq_type(struct irq_data else if (type & IRQ_TYPE_LEVEL_MASK) __irq_set_handler_locked(d->irq, handle_level_irq); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); return 0; } @@ -282,9 +282,9 @@ static int byt_gpio_get(struct gpio_chip unsigned long flags; u32 val; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); val = readl(reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); return val & BYT_LEVEL; } @@ -296,7 +296,7 @@ static void byt_gpio_set(struct gpio_chi unsigned long flags; u32 old_val; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); old_val = readl(reg); @@ -305,7 +305,7 @@ static void byt_gpio_set(struct gpio_chi else writel(old_val & ~BYT_LEVEL, reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); } static int byt_gpio_direction_input(struct gpio_chip *chip, unsigned offset) @@ -315,13 +315,13 @@ static int byt_gpio_direction_input(stru unsigned long flags; u32 value; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); value = readl(reg) | BYT_DIR_MASK; value &= ~BYT_INPUT_EN; /* active low */ writel(value, reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); return 0; } @@ -335,7 +335,7 @@ static int byt_gpio_direction_output(str unsigned long flags; u32 reg_val; - spin_lock_irqsave(&vg->lock, flags); + raw_spin_lock_irqsave(&vg->lock, flags); /* * Before making any direction modifications, do a check if gpio @@ -354,7 +354,7 @@ static int byt_gpio_direction_output(str else writel(reg_val & ~BYT_LEVEL, reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); return 0; } @@ -363,18 +363,19 @@ static void byt_gpio_dbg_show(struct seq { struct byt_gpio *vg = to_byt_gpio(chip); int i; - unsigned long flags; u32 conf0, val, offs; - spin_lock_irqsave(&vg->lock, flags); - for (i = 0; i < vg->chip.ngpio; i++) { const char *pull_str = NULL; const char *pull = NULL; + unsigned long flags; const char *label; offs = vg->range->pins[i] * 16; + + raw_spin_lock_irqsave(&vg->lock, flags); conf0 = readl(vg->reg_base + offs + BYT_CONF0_REG); val = readl(vg->reg_base + offs + BYT_VAL_REG); + raw_spin_unlock_irqrestore(&vg->lock, flags); label = gpiochip_is_requested(chip, i); if (!label) @@ -427,7 +428,6 @@ static void byt_gpio_dbg_show(struct seq seq_puts(s, "\n"); } - spin_unlock_irqrestore(&vg->lock, flags); } static void byt_gpio_irq_handler(unsigned irq, struct irq_desc *desc) @@ -459,10 +459,10 @@ static void byt_irq_ack(struct irq_data unsigned offset = irqd_to_hwirq(d); void __iomem *reg; - spin_lock(&vg->lock); + raw_spin_lock(&vg->lock); reg = byt_gpio_reg(&vg->chip, offset, BYT_INT_STAT_REG); writel(BIT(offset % 32), reg); - spin_unlock(&vg->lock); + raw_spin_unlock(&vg->lock); } static void byt_irq_unmask(struct irq_data *d) @@ -474,9 +474,9 @@ static void byt_irq_unmask(struct irq_da void __iomem *reg; u32 value; - spin_lock_irqsave(&vg->lock, flags); - reg = byt_gpio_reg(&vg->chip, offset, BYT_CONF0_REG); + + raw_spin_lock_irqsave(&vg->lock, flags); value = readl(reg); switch (irqd_get_trigger_type(d)) { @@ -497,7 +497,7 @@ static void byt_irq_unmask(struct irq_da writel(value, reg); - spin_unlock_irqrestore(&vg->lock, flags); + raw_spin_unlock_irqrestore(&vg->lock, flags); } static void byt_irq_mask(struct irq_data *d) @@ -589,7 +589,7 @@ static int byt_gpio_probe(struct platfor if (IS_ERR(vg->reg_base)) return PTR_ERR(vg->reg_base); - spin_lock_init(&vg->lock); + raw_spin_lock_init(&vg->lock); gc = &vg->chip; gc->label = dev_name(&pdev->dev); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/