[PATCH v5 17/27] irqchip/gic-v3: Factor group0 detection into functions

From: Julien Thierry
Date: Tue Aug 28 2018 - 11:52:31 EST


The code to detect whether Linux has access to group0 interrupts can
prove useful in other parts of the driver.

Provide a separate function to do this.

Tested-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Signed-off-by: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Jason Cooper <jason@xxxxxxxxxxxxxx>
Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
---
drivers/irqchip/irq-gic-v3.c | 55 +++++++++++++++++++++++++++++---------------
1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index d5912f1..fef6688 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -392,6 +392,39 @@ static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs
} while (irqnr != ICC_IAR1_EL1_SPURIOUS);
}

+static u32 gic_get_pribits(void)
+{
+ u32 pribits;
+
+ pribits = gic_read_ctlr();
+ pribits &= ICC_CTLR_EL1_PRI_BITS_MASK;
+ pribits >>= ICC_CTLR_EL1_PRI_BITS_SHIFT;
+ pribits++;
+
+ return pribits;
+}
+
+static bool gic_has_group0(void)
+{
+ u32 val;
+
+ /*
+ * Let's find out if Group0 is under control of EL3 or not by
+ * setting the highest possible, non-zero priority in PMR.
+ *
+ * If SCR_EL3.FIQ is set, the priority gets shifted down in
+ * order for the CPU interface to set bit 7, and keep the
+ * actual priority in the non-secure range. In the process, it
+ * looses the least significant bit and the actual priority
+ * becomes 0x80. Reading it back returns 0, indicating that
+ * we're don't have access to Group0.
+ */
+ gic_write_pmr(BIT(8 - gic_get_pribits()));
+ val = gic_read_pmr();
+
+ return val != 0;
+}
+
static void __init gic_dist_init(void)
{
unsigned int i;
@@ -533,7 +566,7 @@ static void gic_cpu_sys_reg_init(void)
u64 mpidr = cpu_logical_map(cpu);
u64 need_rss = MPIDR_RS(mpidr);
bool group0;
- u32 val, pribits;
+ u32 pribits;

/*
* Need to check that the SRE bit has actually been set. If
@@ -545,25 +578,9 @@ static void gic_cpu_sys_reg_init(void)
if (!gic_enable_sre())
pr_err("GIC: unable to set SRE (disabled at EL2), panic ahead\n");

- pribits = gic_read_ctlr();
- pribits &= ICC_CTLR_EL1_PRI_BITS_MASK;
- pribits >>= ICC_CTLR_EL1_PRI_BITS_SHIFT;
- pribits++;
+ pribits = gic_get_pribits();

- /*
- * Let's find out if Group0 is under control of EL3 or not by
- * setting the highest possible, non-zero priority in PMR.
- *
- * If SCR_EL3.FIQ is set, the priority gets shifted down in
- * order for the CPU interface to set bit 7, and keep the
- * actual priority in the non-secure range. In the process, it
- * looses the least significant bit and the actual priority
- * becomes 0x80. Reading it back returns 0, indicating that
- * we're don't have access to Group0.
- */
- write_gicreg(BIT(8 - pribits), ICC_PMR_EL1);
- val = read_gicreg(ICC_PMR_EL1);
- group0 = val != 0;
+ group0 = gic_has_group0();

/* Set priority mask register */
write_gicreg(DEFAULT_PMR_VALUE, ICC_PMR_EL1);
--
1.9.1