[PATCH v3 4/4] xen/arm: handle irq_set_type() failures

Several Arm firmware initialization paths discard irq_set_type()'s return
value, violating MISRA C Rule 17.7. If trigger configuration fails,
initialization continues with an IRQ that was not configured as requested.

GTDT and MADT retain rejected timer and maintenance INTIDs.
check_timer_irq_cfg() and release_irq() later perform unconditional
descriptor lookups on those values. Xen has no backing descriptors for
INTIDs 1024 through 4095, so retaining one can cause an out-of-bounds
access.

Check the return value in the GTDT, MADT, SPCR, and FF-A paths. Store timer
INTIDs only after successful trigger configuration, make GTDT parsing
failure fatal, and stop UART or notification setup when trigger
configuration fails.

Signed-off-by: Mykola Kvach <[email protected]>
---
Changes in v3:
- Avoid partial state updates and simplify maintenance IRQ setup.

Changes in v2:
- New patch.
---
 xen/arch/arm/gic-v2.c        | 15 +++++++++------
 xen/arch/arm/gic-v3.c        | 15 +++++++++------
 xen/arch/arm/tee/ffa_notif.c | 11 ++++++++++-
 xen/arch/arm/time.c          | 18 ++++++++++++++----
 xen/drivers/char/ns16550.c   |  8 ++++++--
 xen/drivers/char/pl011.c     |  4 +++-
 6 files changed, 51 insertions(+), 20 deletions(-)

diff --git a/xen/arch/arm/gic-v2.c b/xen/arch/arm/gic-v2.c
index 43a379fdda..a24d387e7d 100644
--- a/xen/arch/arm/gic-v2.c
+++ b/xen/arch/arm/gic-v2.c
@@ -1166,17 +1166,20 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
     /* Read from APIC table and fill up the GIC variables */
     if ( cpu_base_assigned == 0 )
     {
+        int rc;
+
+        rc = irq_set_type(processor->vgic_interrupt,
+                          processor->flags & ACPI_MADT_VGIC_IRQ_MODE ?
+                          IRQ_TYPE_EDGE_BOTH : IRQ_TYPE_LEVEL_MASK);
+
+        if ( rc )
+            return rc;
+
         cbase = processor->base_address;
         csize = SZ_8K;
         hbase = processor->gich_base_address;
         vbase = processor->gicv_base_address;
         gicv2_info.maintenance_irq = processor->vgic_interrupt;
-
-        if ( processor->flags & ACPI_MADT_VGIC_IRQ_MODE )
-            irq_set_type(gicv2_info.maintenance_irq, IRQ_TYPE_EDGE_BOTH);
-        else
-            irq_set_type(gicv2_info.maintenance_irq, IRQ_TYPE_LEVEL_MASK);
-
         cpu_base_assigned = 1;
     }
     else
diff --git a/xen/arch/arm/gic-v3.c b/xen/arch/arm/gic-v3.c
index acdac22953..b32a9b5009 100644
--- a/xen/arch/arm/gic-v3.c
+++ b/xen/arch/arm/gic-v3.c
@@ -1743,15 +1743,18 @@ gic_acpi_parse_madt_cpu(struct acpi_subtable_header *header,
     /* Read from APIC table and fill up the GIC variables */
     if ( !cpu_base_assigned )
     {
+        int rc;
+
+        rc = irq_set_type(processor->vgic_interrupt,
+                          processor->flags & ACPI_MADT_VGIC_IRQ_MODE ?
+                          IRQ_TYPE_EDGE_BOTH : IRQ_TYPE_LEVEL_MASK);
+
+        if ( rc )
+            return rc;
+
         cbase = processor->base_address;
         vbase = processor->gicv_base_address;
         gicv3_info.maintenance_irq = processor->vgic_interrupt;
-
-        if ( processor->flags & ACPI_MADT_VGIC_IRQ_MODE )
-            irq_set_type(gicv3_info.maintenance_irq, IRQ_TYPE_EDGE_BOTH);
-        else
-            irq_set_type(gicv3_info.maintenance_irq, IRQ_TYPE_LEVEL_MASK);
-
         cpu_base_assigned = 1;
     }
     else
diff --git a/xen/arch/arm/tee/ffa_notif.c b/xen/arch/arm/tee/ffa_notif.c
index 186e726412..d08d0a3366 100644
--- a/xen/arch/arm/tee/ffa_notif.c
+++ b/xen/arch/arm/tee/ffa_notif.c
@@ -407,7 +407,16 @@ void ffa_notif_init(void)
         irq = resp.a2;
         notif_sri_irq = irq;
         if ( irq >= NR_GIC_SGI )
-            irq_set_type(irq, IRQ_TYPE_EDGE_RISING);
+        {
+            ret = irq_set_type(irq, IRQ_TYPE_EDGE_RISING);
+            if ( ret )
+            {
+                printk(XENLOG_ERR
+                       "ffa: irq_set_type irq %u failed: error %d\n",
+                       irq, ret);
+                return;
+            }
+        }
         ret = request_irq(irq, 0, notif_irq_handler, "FF-A notif", NULL);
         if ( ret )
         {
diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index 6955b2788f..39b5eabe7c 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -60,20 +60,27 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *header)
 {
     u32 irq_type;
     struct acpi_table_gtdt *gtdt;
+    int rc;
 
     gtdt = container_of(header, struct acpi_table_gtdt, header);
 
     /* Initialize all the generic timer IRQ variable from GTDT table */
     irq_type = acpi_get_timer_irq_type(gtdt->non_secure_el1_flags);
-    irq_set_type(gtdt->non_secure_el1_interrupt, irq_type);
+    rc = irq_set_type(gtdt->non_secure_el1_interrupt, irq_type);
+    if ( rc )
+        return rc;
     timer_irq[TIMER_PHYS_NONSECURE_PPI] = gtdt->non_secure_el1_interrupt;
 
     irq_type = acpi_get_timer_irq_type(gtdt->virtual_timer_flags);
-    irq_set_type(gtdt->virtual_timer_interrupt, irq_type);
+    rc = irq_set_type(gtdt->virtual_timer_interrupt, irq_type);
+    if ( rc )
+        return rc;
     timer_irq[TIMER_VIRT_PPI] = gtdt->virtual_timer_interrupt;
 
     irq_type = acpi_get_timer_irq_type(gtdt->non_secure_el2_flags);
-    irq_set_type(gtdt->non_secure_el2_interrupt, irq_type);
+    rc = irq_set_type(gtdt->non_secure_el2_interrupt, irq_type);
+    if ( rc )
+        return rc;
     timer_irq[TIMER_HYP_PPI] = gtdt->non_secure_el2_interrupt;
 
     return 0;
@@ -81,7 +88,10 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *header)
 
 static void __init preinit_acpi_xen_time(void)
 {
-    acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
+    int rc = acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
+
+    if ( rc )
+        panic("Timer: Failed to configure interrupts from GTDT: %d\n", rc);
 }
 #else
 static void __init preinit_acpi_xen_time(void) { }
diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
index 120ac09d23..eb608ab8b4 100644
--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -1928,6 +1928,7 @@ static int __init ns16550_acpi_uart_init(const void *data)
     struct acpi_table_header *table;
     struct acpi_table_spcr *spcr;
     acpi_status status;
+    int rc;
     /*
      * Same as the DT part.
      * Only support one UART on ARM which happen to be ns16550_com[0].
@@ -1959,6 +1960,11 @@ static int __init ns16550_acpi_uart_init(const void *data)
         return -EINVAL;
     }
 
+    /* The trigger/polarity information is not available in spcr. */
+    rc = irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
+    if ( rc )
+        return rc;
+
     ns16550_init_common(uart);
 
     /*
@@ -1975,8 +1981,6 @@ static int __init ns16550_acpi_uart_init(const void *data)
     uart->reg_shift = spcr->serial_port.bit_offset;
     uart->reg_width = spcr->serial_port.access_width;
 
-    /* The trigger/polarity information is not available in spcr. */
-    irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
     uart->irq = spcr->interrupt;
 
     uart->vuart.base_addr = uart->io_base;
diff --git a/xen/drivers/char/pl011.c b/xen/drivers/char/pl011.c
index a336241033..97c53c11e0 100644
--- a/xen/drivers/char/pl011.c
+++ b/xen/drivers/char/pl011.c
@@ -363,7 +363,9 @@ static int __init pl011_acpi_uart_init(const void *data)
             spcr->interface_type == ACPI_DBG2_SBSA_32);
 
     /* trigger/polarity information is not available in spcr */
-    irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
+    res = irq_set_type(spcr->interrupt, IRQ_TYPE_LEVEL_HIGH);
+    if ( res )
+        return res;
 
     /* TODO - mmio32 proper handling (for now set to true) */
     res = pl011_uart_init(spcr->interrupt, spcr->serial_port.address,
-- 
2.43.0