[PATCH 03/75] ARM: l2c: avoid calling outer_flush_all() unnecessarily (Spear)
From: Russell King <hidden>
Date: 2014-03-28 15:14:34
Subsystem:
arm port, spear platform/clock/pinctrl support, the rest · Maintainers:
Russell King, Viresh Kumar, Linus Torvalds
Spear calls outer_flush_all() from it's SMP bringup function. This is potentially dangerous as the L2C set/way operations which implement this don't take kindly to concurrent operations. Besides, there's better solutions to this, as implemented on other platforms. Signed-off-by: Russell King <redacted> --- arch/arm/mach-spear/platsmp.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mach-spear/platsmp.c b/arch/arm/mach-spear/platsmp.c
index 5c4a19887b2b..eb9f2ef1e974 100644
--- a/arch/arm/mach-spear/platsmp.c
+++ b/arch/arm/mach-spear/platsmp.c@@ -20,6 +20,18 @@ #include <mach/spear.h> #include "generic.h" +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + sync_cache_w(&pen_release); +} + static DEFINE_SPINLOCK(boot_lock); static void __iomem *scu_base = IOMEM(VA_SCU_BASE);
@@ -30,8 +42,7 @@ static void spear13xx_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; - smp_wmb(); + write_pen_release(-1); /* * Synchronise with the boot thread.
@@ -58,9 +69,7 @@ static int spear13xx_boot_secondary(unsigned int cpu, struct task_struct *idle) * Note that "pen_release" is the hardware CPU ID, whereas * "cpu" is Linux's internal ID. */ - pen_release = cpu; - flush_cache_all(); - outer_flush_all(); + write_pen_release(cpu); timeout = jiffies + (1 * HZ); while (time_before(jiffies, timeout)) {
--
1.8.3.1