Allow to use reserved memory for interrupt controller tables.
Currently, it is not possible to do kexec reboots without possible memory
corruption using device tree and GICv3 interrupt controller.
GICv3 can be configured once during boot, and location of tables cannot
be changed thereafter.
The fix is to allow to reserve memory region in interrupt controller device
property, and use it to do allocations.
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 82 ++++++++++++++++++++++++++++----
1 file changed, 72 insertions(+), 10 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index d5f3508ca11f..aeda8760cc4e 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -47,6 +47,54 @@
static u32 lpi_id_bits;
+/*
+ * Describes reserved memory region in interrupt controller.
+ * The memory reserved: [pa_start, pa_end)
+ */
+struct of_resv {
+ unsigned long pa_start;
+ unsigned long pa_end;
+};
+
+static struct page __init *get_of_page(struct of_resv *resv, unsigned long size)
+{
+ unsigned long pa = ALIGN(resv->pa_start, size);
+ unsigned long pa_next = pa + size;
+
+ /* Check if there is enough memory reserved to do another allocation */
+ if (pa_next > resv->pa_end)
+ return NULL;
+
+ resv->pa_start = pa_next;
+ memset(phys_to_virt(pa), 0, size);
+
+ return phys_to_page(pa);
+}
+
+/*
+ * Memory controller might have a reserved memory region to be used for table
+ * allocations. This is a requirement for kexec reboots.
+ */
+static void __init its_of_mem_region(struct device_node *node,
+ struct of_resv **resv,
+ struct of_resv *resv_buf)
+{
+ struct device_node *np = of_parse_phandle(node, "memory-region", 0);
+ struct resource mem_res;
+
+ if (!np)
+ return;
+
+ if (of_address_to_resource(np, 0, &mem_res)) {
+ pr_warn("%pOF: address to resource failed\n", np);
+ return;
+ }
+
+ resv_buf->pa_start = mem_res.start;
+ resv_buf->pa_end = mem_res.start + resource_size(&mem_res);
+ *resv = resv_buf;
+}
+
/*
* We allocate memory for PROPBASE to cover 2 ^ lpi_id_bits LPIs to
* deal with (one configuration byte per interrupt). PENDBASE has to
@@ -1665,7 +1713,7 @@ static int gic_reserve_range(phys_addr_t addr, unsigned long size)
return 0;
}
-static int __init its_setup_lpi_prop_table(void)
+static int __init its_setup_lpi_prop_table(struct of_resv *resv)
{
if (gic_rdists->flags & RDIST_FLAGS_RD_TABLES_PREALLOCATED) {
unsigned long pa;
@@ -1676,7 +1724,10 @@ static int __init its_setup_lpi_prop_table(void)
lpi_id_bits = (val & GICR_PROPBASER_IDBITS_MASK) + 1;
pa = val & GENMASK_ULL(51, 12);
- va = memremap(pa, LPI_PROPBASE_SZ, MEMREMAP_WB);
+ if (resv)
+ va = phys_to_virt(pa);
+ else
+ va = memremap(pa, LPI_PROPBASE_SZ, MEMREMAP_WB);
gic_rdists->prop_table_pa = pa;
gic_rdists->prop_table_va = va;
} else {
@@ -1685,7 +1736,10 @@ static int __init its_setup_lpi_prop_table(void)
lpi_id_bits = min_t(u32,
GICD_TYPER_ID_BITS(gic_rdists->gicd_typer),
ITS_MAX_LPI_NRBITS);
- page = its_allocate_prop_table(GFP_NOWAIT);
+ if (resv)
+ page = get_of_page(resv, LPI_PROPBASE_SZ);
+ else
+ page = its_allocate_prop_table(GFP_NOWAIT);
if (!page) {
pr_err("Failed to allocate PROPBASE\n");
return -ENOMEM;
@@ -2009,7 +2063,8 @@ static void its_free_pending_table(struct page *pt)
/*
* Booting with kdump and LPIs enabled is generally fine. Any other
- * case is wrong in the absence of firmware/EFI support.
+ * case is wrong in the absence of firmware/EFI support or reserve-memory
+ * in device tree for interrupt controller.
*/
static bool enabled_lpis_allowed(void)
{
@@ -2023,7 +2078,7 @@ static bool enabled_lpis_allowed(void)
return gic_check_reserved_range(addr, LPI_PROPBASE_SZ);
}
-static int __init allocate_lpi_tables(void)
+static int __init allocate_lpi_tables(struct of_resv *resv)
{
u64 val;
int err, cpu;
@@ -2039,7 +2094,7 @@ static int __init allocate_lpi_tables(void)
pr_info("GICv3: Using preallocated redistributor tables\n");
}
- err = its_setup_lpi_prop_table();
+ err = its_setup_lpi_prop_table(resv);
if (err)
return err;
@@ -2051,7 +2106,10 @@ static int __init allocate_lpi_tables(void)
for_each_possible_cpu(cpu) {
struct page *pend_page;
- pend_page = its_allocate_pending_table(GFP_NOWAIT);
+ if (resv)
+ pend_page = get_of_page(resv, LPI_PENDBASE_SZ);
+ else
+ pend_page = its_allocate_pending_table(GFP_NOWAIT);
if (!pend_page) {
pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu);
return -ENOMEM;
@@ -3957,16 +4015,20 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
struct irq_domain *parent_domain)
{
struct device_node *of_node;
+ struct of_resv resv_buf;
+ struct of_resv *resv = NULL;
struct its_node *its;
bool has_v4 = false;
int err;
its_parent = parent_domain;
of_node = to_of_node(handle);
- if (of_node)
+ if (of_node) {
its_of_probe(of_node);
- else
+ its_of_mem_region(of_node, &resv, &resv_buf);
+ } else {
its_acpi_probe();
+ }
if (list_empty(&its_nodes)) {
pr_warn("ITS: No ITS available, not enabling LPIs\n");
@@ -3975,7 +4037,7 @@ int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
gic_rdists = rdists;
- err = allocate_lpi_tables();
+ err = allocate_lpi_tables(resv);
if (err)
return err;
--
2.23.0
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