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linux-next/drivers/irqchip/irq-gic-common.c
Aniruddha Banerjee aa08192a25 irqchip/gic: Take lock when updating irq type
Most MMIO GIC register accesses use a 1-hot bit scheme that
avoids requiring any form of locking. This isn't true for the
GICD_ICFGRn registers, which require a RMW sequence.

Unfortunately, we seem to be missing a lock for these particular
accesses, which could result in a race condition if changing the
trigger type on any two interrupts within the same set of 16
interrupts (and thus controlled by the same CFGR register).

Introduce a private lock in the GIC common comde for this
particular case, making it cover both GIC implementations
in one go.

Cc: stable@vger.kernel.org
Signed-off-by: Aniruddha Banerjee <aniruddhab@nvidia.com>
[maz: updated changelog]
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-03-29 11:47:50 +01:00

157 lines
4.2 KiB
C

/*
* Copyright (C) 2002 ARM Limited, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip/arm-gic.h>
#include "irq-gic-common.h"
static DEFINE_RAW_SPINLOCK(irq_controller_lock);
static const struct gic_kvm_info *gic_kvm_info;
const struct gic_kvm_info *gic_get_kvm_info(void)
{
return gic_kvm_info;
}
void gic_set_kvm_info(const struct gic_kvm_info *info)
{
BUG_ON(gic_kvm_info != NULL);
gic_kvm_info = info;
}
void gic_enable_quirks(u32 iidr, const struct gic_quirk *quirks,
void *data)
{
for (; quirks->desc; quirks++) {
if (quirks->iidr != (quirks->mask & iidr))
continue;
if (quirks->init(data))
pr_info("GIC: enabling workaround for %s\n",
quirks->desc);
}
}
int gic_configure_irq(unsigned int irq, unsigned int type,
void __iomem *base, void (*sync_access)(void))
{
u32 confmask = 0x2 << ((irq % 16) * 2);
u32 confoff = (irq / 16) * 4;
u32 val, oldval;
int ret = 0;
unsigned long flags;
/*
* Read current configuration register, and insert the config
* for "irq", depending on "type".
*/
raw_spin_lock_irqsave(&irq_controller_lock, flags);
val = oldval = readl_relaxed(base + GIC_DIST_CONFIG + confoff);
if (type & IRQ_TYPE_LEVEL_MASK)
val &= ~confmask;
else if (type & IRQ_TYPE_EDGE_BOTH)
val |= confmask;
/* If the current configuration is the same, then we are done */
if (val == oldval) {
raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
return 0;
}
/*
* Write back the new configuration, and possibly re-enable
* the interrupt. If we fail to write a new configuration for
* an SPI then WARN and return an error. If we fail to write the
* configuration for a PPI this is most likely because the GIC
* does not allow us to set the configuration or we are in a
* non-secure mode, and hence it may not be catastrophic.
*/
writel_relaxed(val, base + GIC_DIST_CONFIG + confoff);
if (readl_relaxed(base + GIC_DIST_CONFIG + confoff) != val) {
if (WARN_ON(irq >= 32))
ret = -EINVAL;
else
pr_warn("GIC: PPI%d is secure or misconfigured\n",
irq - 16);
}
raw_spin_unlock_irqrestore(&irq_controller_lock, flags);
if (sync_access)
sync_access();
return ret;
}
void gic_dist_config(void __iomem *base, int gic_irqs,
void (*sync_access)(void))
{
unsigned int i;
/*
* Set all global interrupts to be level triggered, active low.
*/
for (i = 32; i < gic_irqs; i += 16)
writel_relaxed(GICD_INT_ACTLOW_LVLTRIG,
base + GIC_DIST_CONFIG + i / 4);
/*
* Set priority on all global interrupts.
*/
for (i = 32; i < gic_irqs; i += 4)
writel_relaxed(GICD_INT_DEF_PRI_X4, base + GIC_DIST_PRI + i);
/*
* Deactivate and disable all SPIs. Leave the PPI and SGIs
* alone as they are in the redistributor registers on GICv3.
*/
for (i = 32; i < gic_irqs; i += 32) {
writel_relaxed(GICD_INT_EN_CLR_X32,
base + GIC_DIST_ACTIVE_CLEAR + i / 8);
writel_relaxed(GICD_INT_EN_CLR_X32,
base + GIC_DIST_ENABLE_CLEAR + i / 8);
}
if (sync_access)
sync_access();
}
void gic_cpu_config(void __iomem *base, void (*sync_access)(void))
{
int i;
/*
* Deal with the banked PPI and SGI interrupts - disable all
* PPI interrupts, ensure all SGI interrupts are enabled.
* Make sure everything is deactivated.
*/
writel_relaxed(GICD_INT_EN_CLR_X32, base + GIC_DIST_ACTIVE_CLEAR);
writel_relaxed(GICD_INT_EN_CLR_PPI, base + GIC_DIST_ENABLE_CLEAR);
writel_relaxed(GICD_INT_EN_SET_SGI, base + GIC_DIST_ENABLE_SET);
/*
* Set priority on PPI and SGI interrupts
*/
for (i = 0; i < 32; i += 4)
writel_relaxed(GICD_INT_DEF_PRI_X4,
base + GIC_DIST_PRI + i * 4 / 4);
if (sync_access)
sync_access();
}