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Subject[PATCH RT 11/22] irqchip/gic-v3-its: Move ITS ->pend_page allocation into an early CPU up hook
4.14.63-rt41-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

[ Upstream commit e083f14dc2e98ced872bf077b4d1cccf95b7e4f8 ]

The AP-GIC-starting hook allocates memory for the ->pend_page while the
CPU is started during boot-up. This callback is invoked on the target
CPU with disabled interrupts.
This does not work on -RT beacuse memory allocations are not possible
with disabled interrupts.
Move the memory allocation to an earlier hotplug step which invoked with
enabled interrupts on the boot CPU.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
drivers/irqchip/irq-gic-v3-its.c | 60 ++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index e8217ebe8c1e..60533a795124 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -165,6 +165,7 @@ static DEFINE_RAW_SPINLOCK(vmovp_lock);
static DEFINE_IDA(its_vpeid_ida);

#define gic_data_rdist() (raw_cpu_ptr(gic_rdists->rdist))
+#define gic_data_rdist_cpu(cpu) (per_cpu_ptr(gic_rdists->rdist, cpu))
#define gic_data_rdist_rd_base() (gic_data_rdist()->rd_base)
#define gic_data_rdist_vlpi_base() (gic_data_rdist_rd_base() + SZ_128K)

@@ -1734,15 +1735,17 @@ static int its_alloc_collections(struct its_node *its)
return 0;
}

-static struct page *its_allocate_pending_table(gfp_t gfp_flags)
+static struct page *its_allocate_pending_table(unsigned int cpu)
{
struct page *pend_page;
+ unsigned int order;
/*
* The pending pages have to be at least 64kB aligned,
* hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below.
*/
- pend_page = alloc_pages(gfp_flags | __GFP_ZERO,
- get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
+ order = get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K));
+ pend_page = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL | __GFP_ZERO,
+ order);
if (!pend_page)
return NULL;

@@ -1758,6 +1761,28 @@ static void its_free_pending_table(struct page *pt)
get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
}

+static int its_alloc_pend_page(unsigned int cpu)
+{
+ struct page *pend_page;
+ phys_addr_t paddr;
+
+ pend_page = gic_data_rdist_cpu(cpu)->pend_page;
+ if (pend_page)
+ return 0;
+
+ pend_page = its_allocate_pending_table(cpu);
+ if (!pend_page) {
+ pr_err("Failed to allocate PENDBASE for CPU%d\n",
+ smp_processor_id());
+ return -ENOMEM;
+ }
+
+ paddr = page_to_phys(pend_page);
+ pr_info("CPU%d: using LPI pending table @%pa\n", cpu, &paddr);
+ gic_data_rdist_cpu(cpu)->pend_page = pend_page;
+ return 0;
+}
+
static void its_cpu_init_lpis(void)
{
void __iomem *rbase = gic_data_rdist_rd_base();
@@ -1766,21 +1791,8 @@ static void its_cpu_init_lpis(void)

/* If we didn't allocate the pending table yet, do it now */
pend_page = gic_data_rdist()->pend_page;
- if (!pend_page) {
- phys_addr_t paddr;
-
- pend_page = its_allocate_pending_table(GFP_NOWAIT);
- if (!pend_page) {
- pr_err("Failed to allocate PENDBASE for CPU%d\n",
- smp_processor_id());
- return;
- }
-
- paddr = page_to_phys(pend_page);
- pr_info("CPU%d: using LPI pending table @%pa\n",
- smp_processor_id(), &paddr);
- gic_data_rdist()->pend_page = pend_page;
- }
+ if (!pend_page)
+ return;

/* Disable LPIs */
val = readl_relaxed(rbase + GICR_CTLR);
@@ -2599,7 +2611,7 @@ static int its_vpe_init(struct its_vpe *vpe)
return vpe_id;

/* Allocate VPT */
- vpt_page = its_allocate_pending_table(GFP_KERNEL);
+ vpt_page = its_allocate_pending_table(raw_smp_processor_id());
if (!vpt_page) {
its_vpe_id_free(vpe_id);
return -ENOMEM;
@@ -3282,6 +3294,16 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
if (err)
return err;

+ err = cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "irqchip/arm/gicv3:prepare",
+ its_alloc_pend_page, NULL);
+ if (err < 0) {
+ pr_warn("ITS: Can't register CPU-hoplug callback.\n");
+ return err;
+ }
+ err = its_alloc_pend_page(smp_processor_id());
+ if (err < 0)
+ return err;
+
list_for_each_entry(its, &its_nodes, entry)
has_v4 |= its->is_v4;

--
2.18.0

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