[XEN v2 04/11] xen/arm: Typecast the DT values into paddr_t

[Ayan Kumar Halder <ayan.kumar.halder@amd.com>]

In future, we wish to support 32 bit physical address.
However, one can only read u64 values from the DT. Thus, we need to
typecast the values appropriately from u64 to paddr_t.

device_tree_get_reg() should now be able to return paddr_t. This is
invoked by various callers to get DT address and size.
Similarly, dt_read_number() is invoked as well to get DT address and
size. The return value is typecasted to paddr_t.
fdt_get_mem_rsv() can only accept u64 values. So, we provide a warpper
for this called fdt_get_mem_rsv_paddr() which will do the necessary
typecasting before invoking fdt_get_mem_rsv() and while returning.

Signed-off-by: Ayan Kumar Halder <ayan.kumar.halder@amd.com>
---

Changes from

v1 - 1. Dropped "[XEN v1 2/9] xen/arm: Define translate_dt_address_size() for the translation between u64 and paddr_t" and
"[XEN v1 4/9] xen/arm: Use translate_dt_address_size() to translate between device tree addr/size and paddr_t", instead
this approach achieves the same purpose.

2. No need to check for truncation while converting values from u64 to paddr_t.

 xen/arch/arm/bootfdt.c                 | 23 +++++++++------
 xen/arch/arm/domain_build.c            |  2 +-
 xen/arch/arm/include/asm/device_tree.h | 40 ++++++++++++++++++++++++++
 xen/arch/arm/include/asm/setup.h       |  2 +-
 xen/arch/arm/setup.c                   | 14 ++++-----
 xen/arch/arm/smpboot.c                 |  2 +-
 6 files changed, 65 insertions(+), 18 deletions(-)
 create mode 100644 xen/arch/arm/include/asm/device_tree.h

diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
index 0085c28d74..f536a3f3ab 100644
--- a/xen/arch/arm/bootfdt.c
+++ b/xen/arch/arm/bootfdt.c
@@ -11,9 +11,9 @@
 #include <xen/efi.h>
 #include <xen/device_tree.h>
 #include <xen/lib.h>
-#include <xen/libfdt/libfdt.h>
 #include <xen/sort.h>
 #include <xsm/xsm.h>
+#include <asm/device_tree.h>
 #include <asm/setup.h>
 
 static bool __init device_tree_node_matches(const void *fdt, int node,
@@ -53,10 +53,15 @@ static bool __init device_tree_node_compatible(const void *fdt, int node,
 }
 
 void __init device_tree_get_reg(const __be32 **cell, u32 address_cells,
-                                u32 size_cells, u64 *start, u64 *size)
+                                u32 size_cells, paddr_t *start, paddr_t *size)
 {
-    *start = dt_next_cell(address_cells, cell);
-    *size = dt_next_cell(size_cells, cell);
+    /*
+     * dt_next_cell will return u64 whereas paddr_t may be u64 or u32. Thus, one
+     * needs to cast paddr_t to u32. Note that we do not check for truncation as
+     * it is user's responsibility to provide the correct values in the DT.
+     */
+    *start = (paddr_t) dt_next_cell(address_cells, cell);
+    *size = (paddr_t) dt_next_cell(size_cells, cell);
 }
 
 static int __init device_tree_get_meminfo(const void *fdt, int node,
@@ -326,7 +331,7 @@ static int __init process_chosen_node(const void *fdt, int node,
         printk("linux,initrd-start property has invalid length %d\n", len);
         return -EINVAL;
     }
-    start = dt_read_number((void *)&prop->data, dt_size_to_cells(len));
+    start = (paddr_t) dt_read_number((void *)&prop->data, dt_size_to_cells(len));
 
     prop = fdt_get_property(fdt, node, "linux,initrd-end", &len);
     if ( !prop )
@@ -339,7 +344,7 @@ static int __init process_chosen_node(const void *fdt, int node,
         printk("linux,initrd-end property has invalid length %d\n", len);
         return -EINVAL;
     }
-    end = dt_read_number((void *)&prop->data, dt_size_to_cells(len));
+    end = (paddr_t) dt_read_number((void *)&prop->data, dt_size_to_cells(len));
 
     if ( start >= end )
     {
@@ -594,9 +599,11 @@ static void __init early_print_info(void)
     for ( i = 0; i < nr_rsvd; i++ )
     {
         paddr_t s, e;
-        if ( fdt_get_mem_rsv(device_tree_flattened, i, &s, &e) < 0 )
+
+        if ( fdt_get_mem_rsv_paddr(device_tree_flattened, i, &s, &e) < 0 )
             continue;
-        /* fdt_get_mem_rsv returns length */
+
+        /* fdt_get_mem_rsv_paddr returns length */
         e += s;
         printk(" RESVD[%u]: %"PRIpaddr" - %"PRIpaddr"\n", i, s, e);
     }
diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index f904f12408..72b9afbb4c 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -949,7 +949,7 @@ static int __init process_shm(struct domain *d, struct kernel_info *kinfo,
         BUG_ON(!prop);
         cells = (const __be32 *)prop->value;
         device_tree_get_reg(&cells, addr_cells, addr_cells, &pbase, &gbase);
-        psize = dt_read_number(cells, size_cells);
+        psize = (paddr_t) dt_read_number(cells, size_cells);
         if ( !IS_ALIGNED(pbase, PAGE_SIZE) || !IS_ALIGNED(gbase, PAGE_SIZE) )
         {
             printk("%pd: physical address 0x%"PRIpaddr", or guest address 0x%"PRIpaddr" is not suitably aligned.\n",
diff --git a/xen/arch/arm/include/asm/device_tree.h b/xen/arch/arm/include/asm/device_tree.h
new file mode 100644
index 0000000000..51e0f0ae20
--- /dev/null
+++ b/xen/arch/arm/include/asm/device_tree.h
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * xen/arch/arm/include/asm/device_tree.h
+ * 
+ * Wrapper functions for device tree. This helps to convert dt values
+ * between u64 and paddr_t.
+ *
+ * Copyright (C) 2023, Advanced Micro Devices, Inc. All Rights Reserved.
+ */
+
+#ifndef __ARCH_ARM_DEVICE_TREE__
+#define __ARCH_ARM_DEVICE_TREE__
+
+#include <xen/libfdt/libfdt.h>
+
+inline int fdt_get_mem_rsv_paddr(const void *fdt, int n,
+                                 paddr_t *address,
+                                 paddr_t *size)
+{
+    uint64_t dt_addr;
+    uint64_t dt_size;
+    int ret = 0;
+
+    ret = fdt_get_mem_rsv(fdt, n, &dt_addr, &dt_size);
+
+    *address = (paddr_t) dt_addr;
+    *size = (paddr_t) dt_size;
+
+    return ret;
+}
+
+#endif /* __ARCH_ARM_DEVICE_TREE__ */
+/*
+ * Local variables:
+ * mode: C
+ * c-file-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/arch/arm/include/asm/setup.h b/xen/arch/arm/include/asm/setup.h
index a926f30a2b..6105e5cae3 100644
--- a/xen/arch/arm/include/asm/setup.h
+++ b/xen/arch/arm/include/asm/setup.h
@@ -158,7 +158,7 @@ extern uint32_t hyp_traps_vector[];
 void init_traps(void);
 
 void device_tree_get_reg(const __be32 **cell, u32 address_cells,
-                         u32 size_cells, u64 *start, u64 *size);
+                         u32 size_cells, paddr_t *start, paddr_t *size);
 
 u32 device_tree_get_u32(const void *fdt, int node,
                         const char *prop_name, u32 dflt);
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 1f26f67b90..da13439e62 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -29,7 +29,6 @@
 #include <xen/virtual_region.h>
 #include <xen/vmap.h>
 #include <xen/trace.h>
-#include <xen/libfdt/libfdt.h>
 #include <xen/acpi.h>
 #include <xen/warning.h>
 #include <asm/alternative.h>
@@ -39,6 +38,7 @@
 #include <asm/gic.h>
 #include <asm/cpuerrata.h>
 #include <asm/cpufeature.h>
+#include <asm/device_tree.h>
 #include <asm/platform.h>
 #include <asm/procinfo.h>
 #include <asm/setup.h>
@@ -222,11 +222,11 @@ static void __init dt_unreserved_regions(paddr_t s, paddr_t e,
     {
         paddr_t r_s, r_e;
 
-        if ( fdt_get_mem_rsv(device_tree_flattened, i, &r_s, &r_e ) < 0 )
+        if ( fdt_get_mem_rsv_paddr(device_tree_flattened, i, &r_s, &r_e ) < 0 )
             /* If we can't read it, pretend it doesn't exist... */
             continue;
 
-        r_e += r_s; /* fdt_get_mem_rsv returns length */
+        r_e += r_s; /* fdt_get_mem_rsv_paddr returns length */
 
         if ( s < r_e && r_s < e )
         {
@@ -502,13 +502,13 @@ static paddr_t __init consider_modules(paddr_t s, paddr_t e,
     {
         paddr_t mod_s, mod_e;
 
-        if ( fdt_get_mem_rsv(device_tree_flattened,
-                             i - mi->nr_mods,
-                             &mod_s, &mod_e ) < 0 )
+        if ( fdt_get_mem_rsv_paddr(device_tree_flattened,
+                                   i - mi->nr_mods,
+                                   &mod_s, &mod_e ) < 0 )
             /* If we can't read it, pretend it doesn't exist... */
             continue;
 
-        /* fdt_get_mem_rsv returns length */
+        /* fdt_get_mem_rsv_paddr returns length */
         mod_e += mod_s;
 
         if ( s < mod_e && mod_s < e )
diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
index 412ae22869..ee59b1d379 100644
--- a/xen/arch/arm/smpboot.c
+++ b/xen/arch/arm/smpboot.c
@@ -159,7 +159,7 @@ static void __init dt_smp_init_cpus(void)
             continue;
         }
 
-        addr = dt_read_number(prop, dt_n_addr_cells(cpu));
+        addr = (paddr_t) dt_read_number(prop, dt_n_addr_cells(cpu));
 
         hwid = addr;
         if ( hwid != addr )
-- 
2.17.1