fadump: Convert firmware-assisted cpu state dump data into elf notes.
[deliverable/linux.git] / arch / powerpc / kernel / fadump.c
index 63857e183de50dbb828d396f5f3836d87035a439..da68bdad194af52a059cc5459bac7097f2976124 100644 (file)
@@ -240,6 +240,7 @@ static unsigned long get_fadump_area_size(void)
        size += fw_dump.boot_memory_size;
        size += sizeof(struct fadump_crash_info_header);
        size += sizeof(struct elfhdr); /* ELF core header.*/
+       size += sizeof(struct elf_phdr); /* place holder for cpu notes */
        /* Program headers for crash memory regions. */
        size += sizeof(struct elf_phdr) * (memblock_num_regions(memory) + 2);
 
@@ -393,6 +394,285 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
        }
 }
 
+void crash_fadump(struct pt_regs *regs, const char *str)
+{
+       struct fadump_crash_info_header *fdh = NULL;
+
+       if (!fw_dump.dump_registered || !fw_dump.fadumphdr_addr)
+               return;
+
+       fdh = __va(fw_dump.fadumphdr_addr);
+       crashing_cpu = smp_processor_id();
+       fdh->crashing_cpu = crashing_cpu;
+       crash_save_vmcoreinfo();
+
+       if (regs)
+               fdh->regs = *regs;
+       else
+               ppc_save_regs(&fdh->regs);
+
+       fdh->cpu_online_mask = *cpu_online_mask;
+
+       /* Call ibm,os-term rtas call to trigger firmware assisted dump */
+       rtas_os_term((char *)str);
+}
+
+#define GPR_MASK       0xffffff0000000000
+static inline int fadump_gpr_index(u64 id)
+{
+       int i = -1;
+       char str[3];
+
+       if ((id & GPR_MASK) == REG_ID("GPR")) {
+               /* get the digits at the end */
+               id &= ~GPR_MASK;
+               id >>= 24;
+               str[2] = '\0';
+               str[1] = id & 0xff;
+               str[0] = (id >> 8) & 0xff;
+               sscanf(str, "%d", &i);
+               if (i > 31)
+                       i = -1;
+       }
+       return i;
+}
+
+static inline void fadump_set_regval(struct pt_regs *regs, u64 reg_id,
+                                                               u64 reg_val)
+{
+       int i;
+
+       i = fadump_gpr_index(reg_id);
+       if (i >= 0)
+               regs->gpr[i] = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("NIA"))
+               regs->nip = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("MSR"))
+               regs->msr = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("CTR"))
+               regs->ctr = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("LR"))
+               regs->link = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("XER"))
+               regs->xer = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("CR"))
+               regs->ccr = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("DAR"))
+               regs->dar = (unsigned long)reg_val;
+       else if (reg_id == REG_ID("DSISR"))
+               regs->dsisr = (unsigned long)reg_val;
+}
+
+static struct fadump_reg_entry*
+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);
+               reg_entry++;
+       }
+       reg_entry++;
+       return reg_entry;
+}
+
+static u32 *fadump_append_elf_note(u32 *buf, char *name, unsigned type,
+                                               void *data, size_t data_len)
+{
+       struct elf_note note;
+
+       note.n_namesz = strlen(name) + 1;
+       note.n_descsz = data_len;
+       note.n_type   = type;
+       memcpy(buf, &note, sizeof(note));
+       buf += (sizeof(note) + 3)/4;
+       memcpy(buf, name, note.n_namesz);
+       buf += (note.n_namesz + 3)/4;
+       memcpy(buf, data, note.n_descsz);
+       buf += (note.n_descsz + 3)/4;
+
+       return buf;
+}
+
+static void fadump_final_note(u32 *buf)
+{
+       struct elf_note note;
+
+       note.n_namesz = 0;
+       note.n_descsz = 0;
+       note.n_type   = 0;
+       memcpy(buf, &note, sizeof(note));
+}
+
+static u32 *fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
+{
+       struct elf_prstatus prstatus;
+
+       memset(&prstatus, 0, sizeof(prstatus));
+       /*
+        * FIXME: How do i get PID? Do I really need it?
+        * prstatus.pr_pid = ????
+        */
+       elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
+       buf = fadump_append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
+                               &prstatus, sizeof(prstatus));
+       return buf;
+}
+
+static void fadump_update_elfcore_header(char *bufp)
+{
+       struct elfhdr *elf;
+       struct elf_phdr *phdr;
+
+       elf = (struct elfhdr *)bufp;
+       bufp += sizeof(struct elfhdr);
+
+       /* First note is a place holder for cpu notes info. */
+       phdr = (struct elf_phdr *)bufp;
+
+       if (phdr->p_type == PT_NOTE) {
+               phdr->p_paddr = fw_dump.cpu_notes_buf;
+               phdr->p_offset  = phdr->p_paddr;
+               phdr->p_filesz  = fw_dump.cpu_notes_buf_size;
+               phdr->p_memsz = fw_dump.cpu_notes_buf_size;
+       }
+       return;
+}
+
+static void *fadump_cpu_notes_buf_alloc(unsigned long size)
+{
+       void *vaddr;
+       struct page *page;
+       unsigned long order, count, i;
+
+       order = get_order(size);
+       vaddr = (void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
+       if (!vaddr)
+               return NULL;
+
+       count = 1 << order;
+       page = virt_to_page(vaddr);
+       for (i = 0; i < count; i++)
+               SetPageReserved(page + i);
+       return vaddr;
+}
+
+static void fadump_cpu_notes_buf_free(unsigned long vaddr, unsigned long size)
+{
+       struct page *page;
+       unsigned long order, count, i;
+
+       order = get_order(size);
+       count = 1 << order;
+       page = virt_to_page(vaddr);
+       for (i = 0; i < count; i++)
+               ClearPageReserved(page + i);
+       __free_pages(page, order);
+}
+
+/*
+ * Read CPU state dump data and convert it into ELF notes.
+ * The CPU dump starts with magic number "REGSAVE". NumCpusOffset should be
+ * used to access the data to allow for additional fields to be added without
+ * affecting compatibility. Each list of registers for a CPU starts with
+ * "CPUSTRT" and ends with "CPUEND". Each register entry is of 16 bytes,
+ * 8 Byte ASCII identifier and 8 Byte register value. The register entry
+ * with identifier "CPUSTRT" and "CPUEND" contains 4 byte cpu id as part
+ * of register value. For more details refer to PAPR document.
+ *
+ * Only for the crashing cpu we ignore the CPU dump data and get exact
+ * state from fadump crash info structure populated by first kernel at the
+ * time of crash.
+ */
+static int __init fadump_build_cpu_notes(const struct fadump_mem_struct *fdm)
+{
+       struct fadump_reg_save_area_header *reg_header;
+       struct fadump_reg_entry *reg_entry;
+       struct fadump_crash_info_header *fdh = NULL;
+       void *vaddr;
+       unsigned long addr;
+       u32 num_cpus, *note_buf;
+       struct pt_regs regs;
+       int i, rc = 0, cpu = 0;
+
+       if (!fdm->cpu_state_data.bytes_dumped)
+               return -EINVAL;
+
+       addr = fdm->cpu_state_data.destination_address;
+       vaddr = __va(addr);
+
+       reg_header = vaddr;
+       if (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);
+
+       vaddr += reg_header->num_cpu_offset;
+       num_cpus = *((u32 *)(vaddr));
+       pr_debug("NumCpus     : %u\n", num_cpus);
+       vaddr += sizeof(u32);
+       reg_entry = (struct fadump_reg_entry *)vaddr;
+
+       /* Allocate buffer to hold cpu crash notes. */
+       fw_dump.cpu_notes_buf_size = num_cpus * sizeof(note_buf_t);
+       fw_dump.cpu_notes_buf_size = PAGE_ALIGN(fw_dump.cpu_notes_buf_size);
+       note_buf = fadump_cpu_notes_buf_alloc(fw_dump.cpu_notes_buf_size);
+       if (!note_buf) {
+               printk(KERN_ERR "Failed to allocate 0x%lx bytes for "
+                       "cpu notes buffer\n", fw_dump.cpu_notes_buf_size);
+               return -ENOMEM;
+       }
+       fw_dump.cpu_notes_buf = __pa(note_buf);
+
+       pr_debug("Allocated buffer for cpu notes of size %ld at %p\n",
+                       (num_cpus * sizeof(note_buf_t)), note_buf);
+
+       if (fw_dump.fadumphdr_addr)
+               fdh = __va(fw_dump.fadumphdr_addr);
+
+       for (i = 0; i < num_cpus; i++) {
+               if (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;
+               if (!cpumask_test_cpu(cpu, &fdh->cpu_online_mask)) {
+                       SKIP_TO_NEXT_CPU(reg_entry);
+                       continue;
+               }
+               pr_debug("Reading register data for cpu %d...\n", cpu);
+               if (fdh && fdh->crashing_cpu == cpu) {
+                       regs = fdh->regs;
+                       note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
+                       SKIP_TO_NEXT_CPU(reg_entry);
+               } else {
+                       reg_entry++;
+                       reg_entry = fadump_read_registers(reg_entry, &regs);
+                       note_buf = fadump_regs_to_elf_notes(note_buf, &regs);
+               }
+       }
+       fadump_final_note(note_buf);
+
+       pr_debug("Updating elfcore header (%llx) with cpu notes\n",
+                                                       fdh->elfcorehdr_addr);
+       fadump_update_elfcore_header((char *)__va(fdh->elfcorehdr_addr));
+       return 0;
+
+error_out:
+       fadump_cpu_notes_buf_free((unsigned long)__va(fw_dump.cpu_notes_buf),
+                                       fw_dump.cpu_notes_buf_size);
+       fw_dump.cpu_notes_buf = 0;
+       fw_dump.cpu_notes_buf_size = 0;
+       return rc;
+
+}
+
 /*
  * Validate and process the dump data stored by firmware before exporting
  * it through '/proc/vmcore'.
@@ -400,18 +680,21 @@ static void register_fw_dump(struct fadump_mem_struct *fdm)
 static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
 {
        struct fadump_crash_info_header *fdh;
+       int rc = 0;
 
        if (!fdm_active || !fw_dump.fadumphdr_addr)
                return -EINVAL;
 
        /* Check if the dump data is valid. */
        if ((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");
                return -EINVAL;
        }
-       if (fdm_active->rmr_region.bytes_dumped !=
-                       fdm_active->rmr_region.source_len) {
+       if ((fdm_active->rmr_region.bytes_dumped !=
+                       fdm_active->rmr_region.source_len) ||
+                       !fdm_active->cpu_state_data.bytes_dumped) {
                printk(KERN_ERR "Dump taken by platform is incomplete\n");
                return -EINVAL;
        }
@@ -423,6 +706,10 @@ static int __init process_fadump(const struct fadump_mem_struct *fdm_active)
                return -EINVAL;
        }
 
+       rc = fadump_build_cpu_notes(fdm_active);
+       if (rc)
+               return rc;
+
        /*
         * We are done validating dump info and elfcore header is now ready
         * to be exported. set elfcorehdr_addr so that vmcore module will
@@ -537,6 +824,27 @@ static int fadump_create_elfcore_headers(char *bufp)
        elf = (struct elfhdr *)bufp;
        bufp += sizeof(struct elfhdr);
 
+       /*
+        * setup ELF PT_NOTE, place holder for cpu notes info. The notes info
+        * will be populated during second kernel boot after crash. Hence
+        * this PT_NOTE will always be the first elf note.
+        *
+        * NOTE: Any new ELF note addition should be placed after this note.
+        */
+       phdr = (struct elf_phdr *)bufp;
+       bufp += sizeof(struct elf_phdr);
+       phdr->p_type = PT_NOTE;
+       phdr->p_flags = 0;
+       phdr->p_vaddr = 0;
+       phdr->p_align = 0;
+
+       phdr->p_offset = 0;
+       phdr->p_paddr = 0;
+       phdr->p_filesz = 0;
+       phdr->p_memsz = 0;
+
+       (elf->e_phnum)++;
+
        /* setup PT_LOAD sections. */
 
        for (i = 0; i < crash_mem_ranges; i++) {
@@ -588,6 +896,8 @@ static unsigned long init_fadump_header(unsigned long addr)
        memset(fdh, 0, sizeof(struct fadump_crash_info_header));
        fdh->magic_number = FADUMP_CRASH_INFO_MAGIC;
        fdh->elfcorehdr_addr = addr;
+       /* We will set the crashing cpu id in crash_fadump() during crash. */
+       fdh->crashing_cpu = CPU_UNKNOWN;
 
        return addr;
 }
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