powerpc/fadump: Fix endianess issues in firmware assisted dump handling

Firmware-assisted dump (fadump) kernel code is not endian safe. The
below patch fixes this issue. Tested this patch with upstream kernel.
Below output shows crash tool successfully opening LE fadump vmcore.

    # crash vmlinux vmcore
    GNU gdb (GDB) 7.6
    This GDB was configured as "powerpc64le-unknown-linux-gnu"...

          KERNEL: vmlinux
        DUMPFILE: vmcore
    	CPUS: 16
    	DATE: Wed Dec 31 19:00:00 1969
          UPTIME: 00:03:28
    LOAD AVERAGE: 0.46, 0.86, 0.41
           TASKS: 268
        NODENAME: linux-dhr2
         RELEASE: 3.17.0-rc5-7-default
         VERSION: #6 SMP Tue Sep 30 01:06:34 EDT 2014
         MACHINE: ppc64le  (4116 Mhz)
          MEMORY: 40 GB
           PANIC: "Oops: Kernel access of bad area, sig: 11 [#1]" (check log for details)
    	 PID: 6223
         COMMAND: "bash"
    	TASK: c0000009661b2500  [THREAD_INFO: c000000967ac0000]
    	 CPU: 2
           STATE: TASK_RUNNING (PANIC)

Signed-off-by: Hari Bathini <hbathini@linux.vnet.ibm.com>
[mpe: Make the comment in pSeries_lpar_hptab_clear() clearer]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

3 files changed, 95 insertions, 85 deletions

diff --git a/arch/powerpc/include/asm/fadump.h b/arch/powerpc/include/asm/fadump.h
index a6774560afe3..493e72f64b35 100644
--- a/arch/powerpc/include/asm/fadump.h
+++ b/arch/powerpc/include/asm/fadump.h
@@ -70,39 +70,39 @@
 #define CPU_UNKNOWN             (~((u32)0))
 
 /* Utility macros */
-#define SKIP_TO_NEXT_CPU(reg_entry)                     \
-({                                                      \
-        while (reg_entry->reg_id != REG_ID("CPUEND"))   \
-                reg_entry++;                            \
-        reg_entry++;                                    \
+#define SKIP_TO_NEXT_CPU(reg_entry)                                     \
+({                                                                      \
+        while (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND"))      \
+                reg_entry++;                                            \
+        reg_entry++;                                                    \
 })
 
 /* Kernel Dump section info */
 struct fadump_section {
-        u32     request_flag;
-        u16     source_data_type;
-        u16     error_flags;
-        u64     source_address;
-        u64     source_len;
-        u64     bytes_dumped;
-        u64     destination_address;
+        __be32  request_flag;
+        __be16  source_data_type;
+        __be16  error_flags;
+        __be64  source_address;
+        __be64  source_len;
+        __be64  bytes_dumped;
+        __be64  destination_address;
 };
 
 /* ibm,configure-kernel-dump header. */
 struct fadump_section_header {
-        u32     dump_format_version;
-        u16     dump_num_sections;
-        u16     dump_status_flag;
-        u32     offset_first_dump_section;
+        __be32  dump_format_version;
+        __be16  dump_num_sections;
+        __be16  dump_status_flag;
+        __be32  offset_first_dump_section;
 
         /* Fields for disk dump option. */
-        u32     dd_block_size;
-        u64     dd_block_offset;
-        u64     dd_num_blocks;
-        u32     dd_offset_disk_path;
+        __be32  dd_block_size;
+        __be64  dd_block_offset;
+        __be64  dd_num_blocks;
+        __be32  dd_offset_disk_path;
 
         /* Maximum time allowed to prevent an automatic dump-reboot. */
-        u32     max_time_auto;
+        __be32  max_time_auto;
 };
 
 /*
@@ -174,15 +174,15 @@ static inline u64 str_to_u64(const char *str)
 
 /* Register save area header. */
 struct fadump_reg_save_area_header {
-        u64             magic_number;
-        u32             version;
-        u32             num_cpu_offset;
+        __be64          magic_number;
+        __be32          version;
+        __be32          num_cpu_offset;
 };
 
 /* Register entry. */
 struct fadump_reg_entry {
-        u64             reg_id;
-        u64             reg_value;
+        __be64          reg_id;
+        __be64          reg_value;
 };
 
 /* fadump crash info structure */
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 742694c1d852..26d091a1a54c 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -58,7 +58,7 @@ int __init early_init_dt_scan_fw_dump(unsigned long node,
         const __be32 *sections;
         int i, num_sections;
         int size;
-        const int *token;
+        const __be32 *token;
 
         if (depth != 1 || strcmp(uname, "rtas") != 0)
                 return 0;
@@ -72,7 +72,7 @@ int __init early_init_dt_scan_fw_dump(unsigned long node,
                 return 1;
 
         fw_dump.fadump_supported = 1;
-        fw_dump.ibm_configure_kernel_dump = *token;
+        fw_dump.ibm_configure_kernel_dump = be32_to_cpu(*token);
 
         /*
          * The 'ibm,kernel-dump' rtas node is present only if there is
@@ -147,11 +147,11 @@ static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm,
         memset(fdm, 0, sizeof(struct fadump_mem_struct));
         addr = addr & PAGE_MASK;
 
-        fdm->header.dump_format_version = 0x00000001;
-        fdm->header.dump_num_sections = 3;
+        fdm->header.dump_format_version = cpu_to_be32(0x00000001);
+        fdm->header.dump_num_sections = cpu_to_be16(3);
         fdm->header.dump_status_flag = 0;
         fdm->header.offset_first_dump_section =
-                (u32)offsetof(struct fadump_mem_struct, cpu_state_data);
+                cpu_to_be32((u32)offsetof(struct fadump_mem_struct, cpu_state_data));
 
         /*
          * Fields for disk dump option.
@@ -167,27 +167,27 @@ static unsigned long init_fadump_mem_struct(struct fadump_mem_struct *fdm,
 
         /* Kernel dump sections */
         /* cpu state data section. */
-        fdm->cpu_state_data.request_flag = FADUMP_REQUEST_FLAG;
-        fdm->cpu_state_data.source_data_type = FADUMP_CPU_STATE_DATA;
+        fdm->cpu_state_data.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
+        fdm->cpu_state_data.source_data_type = cpu_to_be16(FADUMP_CPU_STATE_DATA);
         fdm->cpu_state_data.source_address = 0;
-        fdm->cpu_state_data.source_len = fw_dump.cpu_state_data_size;
-        fdm->cpu_state_data.destination_address = addr;
+        fdm->cpu_state_data.source_len = cpu_to_be64(fw_dump.cpu_state_data_size);
+        fdm->cpu_state_data.destination_address = cpu_to_be64(addr);
         addr += fw_dump.cpu_state_data_size;
 
         /* hpte region section */
-        fdm->hpte_region.request_flag = FADUMP_REQUEST_FLAG;
-        fdm->hpte_region.source_data_type = FADUMP_HPTE_REGION;
+        fdm->hpte_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
+        fdm->hpte_region.source_data_type = cpu_to_be16(FADUMP_HPTE_REGION);
         fdm->hpte_region.source_address = 0;
-        fdm->hpte_region.source_len = fw_dump.hpte_region_size;
-        fdm->hpte_region.destination_address = addr;
+        fdm->hpte_region.source_len = cpu_to_be64(fw_dump.hpte_region_size);
+        fdm->hpte_region.destination_address = cpu_to_be64(addr);
         addr += fw_dump.hpte_region_size;
 
         /* RMA region section */
-        fdm->rmr_region.request_flag = FADUMP_REQUEST_FLAG;
-        fdm->rmr_region.source_data_type = FADUMP_REAL_MODE_REGION;
-        fdm->rmr_region.source_address = RMA_START;
-        fdm->rmr_region.source_len = fw_dump.boot_memory_size;
-        fdm->rmr_region.destination_address = addr;
+        fdm->rmr_region.request_flag = cpu_to_be32(FADUMP_REQUEST_FLAG);
+        fdm->rmr_region.source_data_type = cpu_to_be16(FADUMP_REAL_MODE_REGION);
+        fdm->rmr_region.source_address = cpu_to_be64(RMA_START);
+        fdm->rmr_region.source_len = cpu_to_be64(fw_dump.boot_memory_size);
+        fdm->rmr_region.destination_address = cpu_to_be64(addr);
         addr += fw_dump.boot_memory_size;
 
         return addr;
@@ -272,7 +272,7 @@ int __init fadump_reserve_mem(void)
          * first kernel.
          */
         if (fdm_active)
-                fw_dump.boot_memory_size = fdm_active->rmr_region.source_len;
+                fw_dump.boot_memory_size = be64_to_cpu(fdm_active->rmr_region.source_len);
         else
                 fw_dump.boot_memory_size = fadump_calculate_reserve_size();
 
@@ -314,8 +314,8 @@ int __init fadump_reserve_mem(void)
                                 (unsigned long)(base >> 20));
 
                 fw_dump.fadumphdr_addr =
-                                fdm_active->rmr_region.destination_address +
-                                fdm_active->rmr_region.source_len;
+                                be64_to_cpu(fdm_active->rmr_region.destination_address) +
+                                be64_to_cpu(fdm_active->rmr_region.source_len);
                 pr_debug("fadumphdr_addr = %p\n",
                                 (void *) fw_dump.fadumphdr_addr);
         } else {
@@ -472,9 +472,9 @@ fadump_read_registers(struct fadump_reg_entry *reg_entry, struct pt_regs *regs)
 {
         memset(regs, 0, sizeof(struct pt_regs));
 
-        while (reg_entry->reg_id != REG_ID("CPUEND")) {
-                fadump_set_regval(regs, reg_entry->reg_id,
-                                        reg_entry->reg_value);
+        while (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUEND")) {
+                fadump_set_regval(regs, be64_to_cpu(reg_entry->reg_id),
+                                        be64_to_cpu(reg_entry->reg_value));
                 reg_entry++;
         }
         reg_entry++;
@@ -603,20 +603,20 @@ static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
         if (!fdm->cpu_state_data.bytes_dumped)
                 return -EINVAL;
 
-        addr = fdm->cpu_state_data.destination_address;
+        addr = be64_to_cpu(fdm->cpu_state_data.destination_address);
         vaddr = __va(addr);
 
         reg_header = vaddr;
-        if (reg_header->magic_number != REGSAVE_AREA_MAGIC) {
+        if (be64_to_cpu(reg_header->magic_number) != REGSAVE_AREA_MAGIC) {
                 printk(KERN_ERR "Unable to read register save area.\n");
                 return -ENOENT;
         }
         pr_debug("--------CPU State Data------------\n");
-        pr_debug("Magic Number: %llx\n", reg_header->magic_number);
-        pr_debug("NumCpuOffset: %x\n", reg_header->num_cpu_offset);
+        pr_debug("Magic Number: %llx\n", be64_to_cpu(reg_header->magic_number));
+        pr_debug("NumCpuOffset: %x\n", be32_to_cpu(reg_header->num_cpu_offset));
 
-        vaddr += reg_header->num_cpu_offset;
-        num_cpus = *((u32 *)(vaddr));
+        vaddr += be32_to_cpu(reg_header->num_cpu_offset);
+        num_cpus = be32_to_cpu(*((__be32 *)(vaddr)));
         pr_debug("NumCpus     : %u\n", num_cpus);
         vaddr += sizeof(u32);
         reg_entry = (struct fadump_reg_entry *)vaddr;
@@ -639,13 +639,13 @@ static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
                 fdh = __va(fw_dump.fadumphdr_addr);
 
         for (i = 0; i < num_cpus; i++) {
-                if (reg_entry->reg_id != REG_ID("CPUSTRT")) {
+                if (be64_to_cpu(reg_entry->reg_id) != REG_ID("CPUSTRT")) {
                         printk(KERN_ERR "Unable to read CPU state data\n");
                         rc = -ENOENT;
                         goto error_out;
                 }
                 /* Lower 4 bytes of reg_value contains logical cpu id */
-                cpu = reg_entry->reg_value & FADUMP_CPU_ID_MASK;
+                cpu = be64_to_cpu(reg_entry->reg_value) & FADUMP_CPU_ID_MASK;
                 if (fdh && !cpumask_test_cpu(cpu, &fdh->cpu_online_mask)) {
                         SKIP_TO_NEXT_CPU(reg_entry);
                         continue;
@@ -692,7 +692,7 @@ static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
                 return -EINVAL;
 
         /* Check if the dump data is valid. */
-        if ((fdm_active->header.dump_status_flag == FADUMP_ERROR_FLAG) ||
+        if ((be16_to_cpu(fdm_active->header.dump_status_flag) == FADUMP_ERROR_FLAG) ||
                         (fdm_active->cpu_state_data.error_flags != 0) ||
                         (fdm_active->rmr_region.error_flags != 0)) {
                 printk(KERN_ERR "Dump taken by platform is not valid\n");
@@ -828,7 +828,7 @@ static void fadump_setup_crash_memory_ranges(void)
 static inline unsigned long fadump_relocate(unsigned long paddr)
 {
         if (paddr > RMA_START && paddr < fw_dump.boot_memory_size)
-                return fdm.rmr_region.destination_address + paddr;
+                return be64_to_cpu(fdm.rmr_region.destination_address) + paddr;
         else
                 return paddr;
 }
@@ -902,7 +902,7 @@ static int fadump_create_elfcore_headers(char *bufp)
                          * to the specified destination_address. Hence set
                          * the correct offset.
                          */
-                        phdr->p_offset = fdm.rmr_region.destination_address;
+                        phdr->p_offset = be64_to_cpu(fdm.rmr_region.destination_address);
                 }
 
                 phdr->p_paddr = mbase;
@@ -951,7 +951,7 @@ static void register_fadump(void)
 
         fadump_setup_crash_memory_ranges();
 
-        addr = fdm.rmr_region.destination_address + fdm.rmr_region.source_len;
+        addr = be64_to_cpu(fdm.rmr_region.destination_address) + be64_to_cpu(fdm.rmr_region.source_len);
         /* Initialize fadump crash info header. */
         addr = init_fadump_header(addr);
         vaddr = __va(addr);
@@ -1023,7 +1023,7 @@ void fadump_cleanup(void)
         /* Invalidate the registration only if dump is active. */
         if (fw_dump.dump_active) {
                 init_fadump_mem_struct(&fdm,
-                        fdm_active->cpu_state_data.destination_address);
+                        be64_to_cpu(fdm_active->cpu_state_data.destination_address));
                 fadump_invalidate_dump(&fdm);
         }
 }
@@ -1063,7 +1063,7 @@ static void fadump_invalidate_release_mem(void)
                 return;
         }
 
-        destination_address = fdm_active->cpu_state_data.destination_address;
+        destination_address = be64_to_cpu(fdm_active->cpu_state_data.destination_address);
         fadump_cleanup();
         mutex_unlock(&fadump_mutex);
 
@@ -1183,31 +1183,31 @@ static int fadump_region_show(struct seq_file *m, void *private)
         seq_printf(m,
                         "CPU : [%#016llx-%#016llx] %#llx bytes, "
                         "Dumped: %#llx\n",
-                        fdm_ptr->cpu_state_data.destination_address,
-                        fdm_ptr->cpu_state_data.destination_address +
-                        fdm_ptr->cpu_state_data.source_len - 1,
-                        fdm_ptr->cpu_state_data.source_len,
-                        fdm_ptr->cpu_state_data.bytes_dumped);
+                        be64_to_cpu(fdm_ptr->cpu_state_data.destination_address),
+                        be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) +
+                        be64_to_cpu(fdm_ptr->cpu_state_data.source_len) - 1,
+                        be64_to_cpu(fdm_ptr->cpu_state_data.source_len),
+                        be64_to_cpu(fdm_ptr->cpu_state_data.bytes_dumped));
         seq_printf(m,
                         "HPTE: [%#016llx-%#016llx] %#llx bytes, "
                         "Dumped: %#llx\n",
-                        fdm_ptr->hpte_region.destination_address,
-                        fdm_ptr->hpte_region.destination_address +
-                        fdm_ptr->hpte_region.source_len - 1,
-                        fdm_ptr->hpte_region.source_len,
-                        fdm_ptr->hpte_region.bytes_dumped);
+                        be64_to_cpu(fdm_ptr->hpte_region.destination_address),
+                        be64_to_cpu(fdm_ptr->hpte_region.destination_address) +
+                        be64_to_cpu(fdm_ptr->hpte_region.source_len) - 1,
+                        be64_to_cpu(fdm_ptr->hpte_region.source_len),
+                        be64_to_cpu(fdm_ptr->hpte_region.bytes_dumped));
         seq_printf(m,
                         "DUMP: [%#016llx-%#016llx] %#llx bytes, "
                         "Dumped: %#llx\n",
-                        fdm_ptr->rmr_region.destination_address,
-                        fdm_ptr->rmr_region.destination_address +
-                        fdm_ptr->rmr_region.source_len - 1,
-                        fdm_ptr->rmr_region.source_len,
-                        fdm_ptr->rmr_region.bytes_dumped);
+                        be64_to_cpu(fdm_ptr->rmr_region.destination_address),
+                        be64_to_cpu(fdm_ptr->rmr_region.destination_address) +
+                        be64_to_cpu(fdm_ptr->rmr_region.source_len) - 1,
+                        be64_to_cpu(fdm_ptr->rmr_region.source_len),
+                        be64_to_cpu(fdm_ptr->rmr_region.bytes_dumped));
 
         if (!fdm_active ||
                 (fw_dump.reserve_dump_area_start ==
-                fdm_ptr->cpu_state_data.destination_address))
+                be64_to_cpu(fdm_ptr->cpu_state_data.destination_address)))
                 goto out;
 
         /* Dump is active. Show reserved memory region. */
@@ -1215,10 +1215,10 @@ static int fadump_region_show(struct seq_file *m, void *private)
                         "    : [%#016llx-%#016llx] %#llx bytes, "
                         "Dumped: %#llx\n",
                         (unsigned long long)fw_dump.reserve_dump_area_start,
-                        fdm_ptr->cpu_state_data.destination_address - 1,
-                        fdm_ptr->cpu_state_data.destination_address -
+                        be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) - 1,
+                        be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
                         fw_dump.reserve_dump_area_start,
-                        fdm_ptr->cpu_state_data.destination_address -
+                        be64_to_cpu(fdm_ptr->cpu_state_data.destination_address) -
                         fw_dump.reserve_dump_area_start);
 out:
         if (fdm_active)
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 8c509d5397c6..f6880d2a40fb 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -43,6 +43,7 @@
 #include <asm/trace.h>
 #include <asm/firmware.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/fadump.h>
 
 #include "pseries.h"
 
@@ -247,8 +248,17 @@ static void pSeries_lpar_hptab_clear(void)
         }
 
 #ifdef __LITTLE_ENDIAN__
-        /* Reset exceptions to big endian */
-        if (firmware_has_feature(FW_FEATURE_SET_MODE)) {
+        /*
+         * Reset exceptions to big endian.
+         *
+         * FIXME this is a hack for kexec, we need to reset the exception
+         * endian before starting the new kernel and this is a convenient place
+         * to do it.
+         *
+         * This is also called on boot when a fadump happens. In that case we
+         * must not change the exception endian mode.
+         */
+        if (firmware_has_feature(FW_FEATURE_SET_MODE) && !is_fadump_active()) {
                 long rc;
 
                 rc = pseries_big_endian_exceptions();