From a08588ea486a5590b50c36f437dc86350271b250 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Thu, 21 Sep 2017 23:24:39 -0700 Subject: 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 Signed-off-by: Thomas Gleixner Cc: Marc Zyngier Cc: Jason Cooper Link: https://lkml.kernel.org/r/20170922062440.23701-2-paul.burton@imgtec.com --- drivers/irqchip/irq-mips-gic.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers') 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) { -- cgit v1.2.3