powerpc: Make prom.c device tree accesses endian safe

On PowerPC the device tree is always big endian, but the CPU could be
either, so add be32_to_cpu where appropriate and change the types of
device tree data to __be32 etc to allow sparse to locate endian issues.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 31 insertions, 29 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 2de07e52c356..d8a687c5e3ee 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -215,16 +215,16 @@ static void __init check_cpu_pa_features(unsigned long node)
 #ifdef CONFIG_PPC_STD_MMU_64
 static void __init check_cpu_slb_size(unsigned long node)
 {
-        u32 *slb_size_ptr;
+        __be32 *slb_size_ptr;
 
         slb_size_ptr = of_get_flat_dt_prop(node, "slb-size", NULL);
         if (slb_size_ptr != NULL) {
-                mmu_slb_size = *slb_size_ptr;
+                mmu_slb_size = be32_to_cpup(slb_size_ptr);
                 return;
         }
         slb_size_ptr = of_get_flat_dt_prop(node, "ibm,slb-size", NULL);
         if (slb_size_ptr != NULL) {
-                mmu_slb_size = *slb_size_ptr;
+                mmu_slb_size = be32_to_cpup(slb_size_ptr);
         }
 }
 #else
@@ -279,11 +279,11 @@ static void __init check_cpu_feature_properties(unsigned long node)
 {
         unsigned long i;
         struct feature_property *fp = feature_properties;
-        const u32 *prop;
+        const __be32 *prop;
 
         for (i = 0; i < ARRAY_SIZE(feature_properties); ++i, ++fp) {
                 prop = of_get_flat_dt_prop(node, fp->name, NULL);
-                if (prop && *prop >= fp->min_value) {
+                if (prop && be32_to_cpup(prop) >= fp->min_value) {
                         cur_cpu_spec->cpu_features |= fp->cpu_feature;
                         cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftr;
                 }
@@ -295,8 +295,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
                                           void *data)
 {
         char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-        const u32 *prop;
-        const u32 *intserv;
+        const __be32 *prop;
+        const __be32 *intserv;
         int i, nthreads;
         unsigned long len;
         int found = -1;
@@ -324,8 +324,9 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
                  * version 2 of the kexec param format adds the phys cpuid of
                  * booted proc.
                  */
-                if (initial_boot_params->version >= 2) {
-                        if (intserv[i] == initial_boot_params->boot_cpuid_phys) {
+                if (be32_to_cpu(initial_boot_params->version) >= 2) {
+                        if (be32_to_cpu(intserv[i]) ==
+                            be32_to_cpu(initial_boot_params->boot_cpuid_phys)) {
                                 found = boot_cpu_count;
                                 found_thread = i;
                         }
@@ -347,9 +348,10 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 
         if (found >= 0) {
                 DBG("boot cpu: logical %d physical %d\n", found,
-                        intserv[found_thread]);
+                        be32_to_cpu(intserv[found_thread]));
                 boot_cpuid = found;
-                set_hard_smp_processor_id(found, intserv[found_thread]);
+                set_hard_smp_processor_id(found,
+                        be32_to_cpu(intserv[found_thread]));
 
                 /*
                  * PAPR defines "logical" PVR values for cpus that
@@ -366,8 +368,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
                  * it uses 0x0f000001.
                  */
                 prop = of_get_flat_dt_prop(node, "cpu-version", NULL);
-                if (prop && (*prop & 0xff000000) == 0x0f000000)
-                        identify_cpu(0, *prop);
+                if (prop && (be32_to_cpup(prop) & 0xff000000) == 0x0f000000)
+                        identify_cpu(0, be32_to_cpup(prop));
 
                 identical_pvr_fixup(node);
         }
@@ -389,7 +391,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 int __init early_init_dt_scan_chosen_ppc(unsigned long node, const char *uname,
                                          int depth, void *data)
 {
-        unsigned long *lprop;
+        unsigned long *lprop; /* All these set by kernel, so no need to convert endian */
 
         /* Use common scan routine to determine if this is the chosen node */
         if (early_init_dt_scan_chosen(node, uname, depth, data) == 0)
@@ -591,16 +593,16 @@ static void __init early_reserve_mem_dt(void)
 static void __init early_reserve_mem(void)
 {
         u64 base, size;
-        u64 *reserve_map;
+        __be64 *reserve_map;
         unsigned long self_base;
         unsigned long self_size;
 
-        reserve_map = (u64 *)(((unsigned long)initial_boot_params) +
-                                        initial_boot_params->off_mem_rsvmap);
+        reserve_map = (__be64 *)(((unsigned long)initial_boot_params) +
+                        be32_to_cpu(initial_boot_params->off_mem_rsvmap));
 
         /* before we do anything, lets reserve the dt blob */
         self_base = __pa((unsigned long)initial_boot_params);
-        self_size = initial_boot_params->totalsize;
+        self_size = be32_to_cpu(initial_boot_params->totalsize);
         memblock_reserve(self_base, self_size);
 
         /* Look for the new "reserved-regions" property in the DT */
@@ -620,15 +622,15 @@ static void __init early_reserve_mem(void)
          * Handle the case where we might be booting from an old kexec
          * image that setup the mem_rsvmap as pairs of 32-bit values
          */
-        if (*reserve_map > 0xffffffffull) {
+        if (be64_to_cpup(reserve_map) > 0xffffffffull) {
                 u32 base_32, size_32;
-                u32 *reserve_map_32 = (u32 *)reserve_map;
+                __be32 *reserve_map_32 = (__be32 *)reserve_map;
 
                 DBG("Found old 32-bit reserve map\n");
 
                 while (1) {
-                        base_32 = *(reserve_map_32++);
-                        size_32 = *(reserve_map_32++);
+                        base_32 = be32_to_cpup(reserve_map_32++);
+                        size_32 = be32_to_cpup(reserve_map_32++);
                         if (size_32 == 0)
                                 break;
                         /* skip if the reservation is for the blob */
@@ -644,8 +646,8 @@ static void __init early_reserve_mem(void)
 
         /* Handle the reserve map in the fdt blob if it exists */
         while (1) {
-                base = *(reserve_map++);
-                size = *(reserve_map++);
+                base = be64_to_cpup(reserve_map++);
+                size = be64_to_cpup(reserve_map++);
                 if (size == 0)
                         break;
                 DBG("reserving: %llx -> %llx\n", base, size);
@@ -903,7 +905,7 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
         hardid = get_hard_smp_processor_id(cpu);
 
         for_each_node_by_type(np, "cpu") {
-                const u32 *intserv;
+                const __be32 *intserv;
                 unsigned int plen, t;
 
                 /* Check for ibm,ppc-interrupt-server#s. If it doesn't exist
@@ -912,10 +914,10 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
                 intserv = of_get_property(np, "ibm,ppc-interrupt-server#s",
                                 &plen);
                 if (intserv == NULL) {
-                        const u32 *reg = of_get_property(np, "reg", NULL);
+                        const __be32 *reg = of_get_property(np, "reg", NULL);
                         if (reg == NULL)
                                 continue;
-                        if (*reg == hardid) {
+                        if (be32_to_cpup(reg) == hardid) {
                                 if (thread)
                                         *thread = 0;
                                 return np;
@@ -923,7 +925,7 @@ struct device_node *of_get_cpu_node(int cpu, unsigned int *thread)
                 } else {
                         plen /= sizeof(u32);
                         for (t = 0; t < plen; t++) {
-                                if (hardid == intserv[t]) {
+                                if (hardid == be32_to_cpu(intserv[t])) {
                                         if (thread)
                                                 *thread = t;
                                         return np;
@@ -943,7 +945,7 @@ static int __init export_flat_device_tree(void)
         struct dentry *d;
 
         flat_dt_blob.data = initial_boot_params;
-        flat_dt_blob.size = initial_boot_params->totalsize;
+        flat_dt_blob.size = be32_to_cpu(initial_boot_params->totalsize);
 
         d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
                                 powerpc_debugfs_root, &flat_dt_blob);