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authorPaul Burton <paul.burton@imgtec.com>2017-09-21 23:24:39 -0700
committerThomas Gleixner <tglx@linutronix.de>2017-09-25 21:23:43 +0200
commita08588ea486a5590b50c36f437dc86350271b250 (patch)
tree18db0b04b2255a4e2f40cd3769a028fc966b61b8 /drivers/irqchip/irq-mips-gic.c
parent2827a418ca1b23e432e62c9b3d0e7cf3255dfe88 (diff)
downloadlinux-a08588ea486a5590b50c36f437dc86350271b250.tar.bz2
irqchip/mips-gic: Fix shifts to extract register fields
The MIPS GIC driver is incorrectly using __fls to shift registers, intending to shift to the least significant bit of a value based upon its mask but instead shifting off all but the value's top bit. It should actually be using __ffs to shift to the first, not last, bit of the value. Apparently the system I used when testing commit 3680746abd87 ("irqchip: mips-gic: Convert remaining shared reg access to new accessors") and commit b2b2e584ceab ("irqchip: mips-gic: Clean up mti, reserved-cpu-vectors handling") managed to work correctly despite this issue, but not all systems do... Fixes: 3680746abd87 ("irqchip: mips-gic: Convert remaining shared reg access to new accessors") Fixes: b2b2e584ceab ("irqchip: mips-gic: Clean up mti, reserved-cpu-vectors handling") Signed-off-by: Paul Burton <paul.burton@imgtec.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Jason Cooper <jason@lakedaemon.net> Link: https://lkml.kernel.org/r/20170922062440.23701-2-paul.burton@imgtec.com
Diffstat (limited to 'drivers/irqchip/irq-mips-gic.c')
-rw-r--r--drivers/irqchip/irq-mips-gic.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c
index 40159ac12ac8..0022b31ad2c5 100644
--- a/drivers/irqchip/irq-mips-gic.c
+++ b/drivers/irqchip/irq-mips-gic.c
@@ -645,7 +645,7 @@ static int __init gic_of_init(struct device_node *node,
/* Find the first available CPU vector. */
i = 0;
- reserved = (C_SW0 | C_SW1) >> __fls(C_SW0);
+ reserved = (C_SW0 | C_SW1) >> __ffs(C_SW0);
while (!of_property_read_u32_index(node, "mti,reserved-cpu-vectors",
i++, &cpu_vec))
reserved |= BIT(cpu_vec);
@@ -684,11 +684,11 @@ static int __init gic_of_init(struct device_node *node,
gicconfig = read_gic_config();
gic_shared_intrs = gicconfig & GIC_CONFIG_NUMINTERRUPTS;
- gic_shared_intrs >>= __fls(GIC_CONFIG_NUMINTERRUPTS);
+ gic_shared_intrs >>= __ffs(GIC_CONFIG_NUMINTERRUPTS);
gic_shared_intrs = (gic_shared_intrs + 1) * 8;
gic_vpes = gicconfig & GIC_CONFIG_PVPS;
- gic_vpes >>= __fls(GIC_CONFIG_PVPS);
+ gic_vpes >>= __ffs(GIC_CONFIG_PVPS);
gic_vpes = gic_vpes + 1;
if (cpu_has_veic) {