From: Marc Zyngier <marc.zyng...@arm.com>

commit 4a0819bb25d12d39c0390636122eefba232596c1 from linux-rt-devel.

Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
[bigeasy: backport commit effe377d415 ("irqchip/gic-v3-its: Move pending
          table allocation to init time")]
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
 drivers/irqchip/irq-gic-v3-its.c   | 94 +++++++++++++++++++-------------------
 include/linux/irqchip/arm-gic-v3.h |  1 +
 2 files changed, 49 insertions(+), 46 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 4bca2439ee7d..907e5c5169e9 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1556,7 +1556,7 @@ static void its_free_prop_table(struct page *prop_page)
                   get_order(LPI_PROPBASE_SZ));
 }
 
-static int __init its_alloc_lpi_tables(void)
+static int __init its_alloc_lpi_prop_table(void)
 {
        phys_addr_t paddr;
 
@@ -1854,17 +1854,15 @@ static int its_alloc_collections(struct its_node *its)
        return 0;
 }
 
-static struct page *its_allocate_pending_table(unsigned int cpu)
+static struct page *its_allocate_pending_table(gfp_t gfp_flags)
 {
        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.
         */
-       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);
+       pend_page = alloc_pages(gfp_flags | __GFP_ZERO,
+                               get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
        if (!pend_page)
                return NULL;
 
@@ -1880,25 +1878,31 @@ 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)
+static int __init allocate_lpi_tables(void)
 {
-       struct page *pend_page;
-       phys_addr_t paddr;
+       int err, cpu;
 
-       pend_page = gic_data_rdist_cpu(cpu)->pend_page;
-       if (pend_page)
-               return 0;
+       err = its_alloc_lpi_prop_table();
+       if (err)
+               return err;
 
-       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;
+       /*
+        * We allocate all the pending tables anyway, as we may have a
+        * mix of RDs that have had LPIs enabled, and some that
+        * don't. We'll free the unused ones as each CPU comes online.
+        */
+       for_each_possible_cpu(cpu) {
+               struct page *pend_page;
+
+               pend_page = its_allocate_pending_table(GFP_NOWAIT);
+               if (!pend_page) {
+                       pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu);
+                       return -ENOMEM;
+               }
+
+               gic_data_rdist_cpu(cpu)->pend_page = pend_page;
        }
 
-       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;
 }
 
@@ -1906,13 +1910,15 @@ static void its_cpu_init_lpis(void)
 {
        void __iomem *rbase = gic_data_rdist_rd_base();
        struct page *pend_page;
+       phys_addr_t paddr;
        u64 val, tmp;
 
-       /* If we didn't allocate the pending table yet, do it now */
-       pend_page = gic_data_rdist()->pend_page;
-       if (!pend_page)
+       if (gic_data_rdist()->lpi_enabled)
                return;
 
+       pend_page = gic_data_rdist()->pend_page;
+       paddr = page_to_phys(pend_page);
+
        /* set PROPBASE */
        val = (page_to_phys(gic_rdists->prop_page) |
               GICR_PROPBASER_InnerShareable |
@@ -1964,6 +1970,10 @@ static void its_cpu_init_lpis(void)
 
        /* Make sure the GIC has seen the above */
        dsb(sy);
+       gic_data_rdist()->lpi_enabled = true;
+       pr_info("GICv3: CPU%d: using LPI pending table @%pa\n",
+               smp_processor_id(),
+               &paddr);
 }
 
 static void its_cpu_init_collection(struct its_node *its)
@@ -2744,7 +2754,7 @@ static int its_vpe_init(struct its_vpe *vpe)
                return vpe_id;
 
        /* Allocate VPT */
-       vpt_page = its_allocate_pending_table(raw_smp_processor_id());
+       vpt_page = its_allocate_pending_table(GFP_KERNEL);
        if (!vpt_page) {
                its_vpe_id_free(vpe_id);
                return -ENOMEM;
@@ -3439,16 +3449,6 @@ static int redist_disable_lpis(void)
        u64 timeout = USEC_PER_SEC;
        u64 val;
 
-       /*
-        * If coming via a CPU hotplug event, we don't need to disable
-        * LPIs before trying to re-enable them. They are already
-        * configured and all is well in the world. Detect this case
-        * by checking the allocation of the pending table for the
-        * current CPU.
-        */
-       if (gic_data_rdist()->pend_page)
-               return 0;
-
        if (!gic_rdists_supports_plpis()) {
                pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
                return -ENXIO;
@@ -3458,7 +3458,18 @@ static int redist_disable_lpis(void)
        if (!(val & GICR_CTLR_ENABLE_LPIS))
                return 0;
 
-       pr_warn("CPU%d: Booted with LPIs enabled, memory probably corrupted\n",
+       /*
+        * If coming via a CPU hotplug event, we don't need to disable
+        * LPIs before trying to re-enable them. They are already
+        * configured and all is well in the world.
+        */
+       if (gic_data_rdist()->lpi_enabled)
+               return 0;
+
+       /*
+        * From that point on, we only try to do some damage control.
+        */
+       pr_warn("GICv3: CPU%d: Booted with LPIs enabled, memory probably 
corrupted\n",
                smp_processor_id());
        add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
 
@@ -3714,18 +3725,9 @@ int __init its_init(struct fwnode_handle *handle, struct 
rdists *rdists,
        }
 
        gic_rdists = rdists;
-       err = its_alloc_lpi_tables();
-       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)
+       err = allocate_lpi_tables();
+       if (err)
                return err;
 
        list_for_each_entry(its, &its_nodes, entry)
diff --git a/include/linux/irqchip/arm-gic-v3.h 
b/include/linux/irqchip/arm-gic-v3.h
index cbb872c1b607..f4bf3bd5f3db 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -574,6 +574,7 @@ struct rdists {
                void __iomem    *rd_base;
                struct page     *pend_page;
                phys_addr_t     phys_base;
+               bool            lpi_enabled;
        } __percpu              *rdist;
        struct page             *prop_page;
        int                     id_bits;
-- 
2.15.0

-- 
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