[S390] kdump backend code

This patch provides the architecture specific part of the s390 kdump
support.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 427 insertions, 0 deletions

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
new file mode 100644
index 000000000000..2a9a3f405574
--- /dev/null
+++ b/arch/s390/kernel/crash_dump.c
@@ -0,0 +1,427 @@
+/*
+ * S390 kdump implementation
+ *
+ * Copyright IBM Corp. 2011
+ * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#include <linux/crash_dump.h>
+#include <asm/lowcore.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/crash_dump.h>
+#include <linux/bootmem.h>
+#include <linux/elf.h>
+#include <asm/ipl.h>
+
+#define PTR_ADD(x, y) (((char *) (x)) + ((unsigned long) (y)))
+#define PTR_SUB(x, y) (((char *) (x)) - ((unsigned long) (y)))
+#define PTR_DIFF(x, y) ((unsigned long)(((char *) (x)) - ((unsigned long) (y))))
+
+/*
+ * Copy one page from "oldmem"
+ *
+ * For the kdump reserved memory this functions performs a swap operation:
+ *  - [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE] is mapped to [0 - OLDMEM_SIZE].
+ *  - [0 - OLDMEM_SIZE] is mapped to [OLDMEM_BASE - OLDMEM_BASE + OLDMEM_SIZE]
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+			 size_t csize, unsigned long offset, int userbuf)
+{
+	unsigned long src;
+	int rc;
+
+	if (!csize)
+		return 0;
+
+	src = (pfn << PAGE_SHIFT) + offset;
+	if (src < OLDMEM_SIZE)
+		src += OLDMEM_BASE;
+	else if (src > OLDMEM_BASE &&
+		 src < OLDMEM_BASE + OLDMEM_SIZE)
+		src -= OLDMEM_BASE;
+	if (userbuf)
+		rc = copy_to_user_real((void __user *) buf, (void *) src,
+				       csize);
+	else
+		rc = memcpy_real(buf, (void *) src, csize);
+	return rc < 0 ? rc : csize;
+}
+
+/*
+ * Copy memory from old kernel
+ */
+static int copy_from_oldmem(void *dest, void *src, size_t count)
+{
+	unsigned long copied = 0;
+	int rc;
+
+	if ((unsigned long) src < OLDMEM_SIZE) {
+		copied = min(count, OLDMEM_SIZE - (unsigned long) src);
+		rc = memcpy_real(dest, src + OLDMEM_BASE, copied);
+		if (rc)
+			return rc;
+	}
+	return memcpy_real(dest + copied, src + copied, count - copied);
+}
+
+/*
+ * Alloc memory and panic in case of ENOMEM
+ */
+static void *kzalloc_panic(int len)
+{
+	void *rc;
+
+	rc = kzalloc(len, GFP_KERNEL);
+	if (!rc)
+		panic("s390 kdump kzalloc (%d) failed", len);
+	return rc;
+}
+
+/*
+ * Get memory layout and create hole for oldmem
+ */
+static struct mem_chunk *get_memory_layout(void)
+{
+	struct mem_chunk *chunk_array;
+
+	chunk_array = kzalloc_panic(MEMORY_CHUNKS * sizeof(struct mem_chunk));
+	detect_memory_layout(chunk_array);
+	create_mem_hole(chunk_array, OLDMEM_BASE, OLDMEM_SIZE, CHUNK_CRASHK);
+	return chunk_array;
+}
+
+/*
+ * Initialize ELF note
+ */
+static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
+		     const char *name)
+{
+	Elf64_Nhdr *note;
+	u64 len;
+
+	note = (Elf64_Nhdr *)buf;
+	note->n_namesz = strlen(name) + 1;
+	note->n_descsz = d_len;
+	note->n_type = type;
+	len = sizeof(Elf64_Nhdr);
+
+	memcpy(buf + len, name, note->n_namesz);
+	len = roundup(len + note->n_namesz, 4);
+
+	memcpy(buf + len, desc, note->n_descsz);
+	len = roundup(len + note->n_descsz, 4);
+
+	return PTR_ADD(buf, len);
+}
+
+/*
+ * Initialize prstatus note
+ */
+static void *nt_prstatus(void *ptr, struct save_area *sa)
+{
+	struct elf_prstatus nt_prstatus;
+	static int cpu_nr = 1;
+
+	memset(&nt_prstatus, 0, sizeof(nt_prstatus));
+	memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
+	memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
+	memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
+	nt_prstatus.pr_pid = cpu_nr;
+	cpu_nr++;
+
+	return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
+			 "CORE");
+}
+
+/*
+ * Initialize fpregset (floating point) note
+ */
+static void *nt_fpregset(void *ptr, struct save_area *sa)
+{
+	elf_fpregset_t nt_fpregset;
+
+	memset(&nt_fpregset, 0, sizeof(nt_fpregset));
+	memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
+	memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));
+
+	return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
+		       "CORE");
+}
+
+/*
+ * Initialize timer note
+ */
+static void *nt_s390_timer(void *ptr, struct save_area *sa)
+{
+	return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
+			 KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Initialize TOD clock comparator note
+ */
+static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
+{
+	return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
+		       sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Initialize TOD programmable register note
+ */
+static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
+{
+	return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
+		       sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Initialize control register note
+ */
+static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
+{
+	return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
+		       sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Initialize prefix register note
+ */
+static void *nt_s390_prefix(void *ptr, struct save_area *sa)
+{
+	return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
+			 sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Fill ELF notes for one CPU with save area registers
+ */
+void *fill_cpu_elf_notes(void *ptr, struct save_area *sa)
+{
+	ptr = nt_prstatus(ptr, sa);
+	ptr = nt_fpregset(ptr, sa);
+	ptr = nt_s390_timer(ptr, sa);
+	ptr = nt_s390_tod_cmp(ptr, sa);
+	ptr = nt_s390_tod_preg(ptr, sa);
+	ptr = nt_s390_ctrs(ptr, sa);
+	ptr = nt_s390_prefix(ptr, sa);
+	return ptr;
+}
+
+/*
+ * Initialize prpsinfo note (new kernel)
+ */
+static void *nt_prpsinfo(void *ptr)
+{
+	struct elf_prpsinfo prpsinfo;
+
+	memset(&prpsinfo, 0, sizeof(prpsinfo));
+	prpsinfo.pr_sname = 'R';
+	strcpy(prpsinfo.pr_fname, "vmlinux");
+	return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
+		       KEXEC_CORE_NOTE_NAME);
+}
+
+/*
+ * Initialize vmcoreinfo note (new kernel)
+ */
+static void *nt_vmcoreinfo(void *ptr)
+{
+	char nt_name[11], *vmcoreinfo;
+	Elf64_Nhdr note;
+	void *addr;
+
+	if (copy_from_oldmem(&addr, &S390_lowcore.vmcore_info, sizeof(addr)))
+		return ptr;
+	memset(nt_name, 0, sizeof(nt_name));
+	if (copy_from_oldmem(&note, addr, sizeof(note)))
+		return ptr;
+	if (copy_from_oldmem(nt_name, addr + sizeof(note), sizeof(nt_name) - 1))
+		return ptr;
+	if (strcmp(nt_name, "VMCOREINFO") != 0)
+		return ptr;
+	vmcoreinfo = kzalloc_panic(note.n_descsz + 1);
+	if (copy_from_oldmem(vmcoreinfo, addr + 24, note.n_descsz))
+		return ptr;
+	vmcoreinfo[note.n_descsz + 1] = 0;
+	return nt_init(ptr, 0, vmcoreinfo, note.n_descsz, "VMCOREINFO");
+}
+
+/*
+ * Initialize ELF header (new kernel)
+ */
+static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
+{
+	memset(ehdr, 0, sizeof(*ehdr));
+	memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
+	ehdr->e_ident[EI_CLASS] = ELFCLASS64;
+	ehdr->e_ident[EI_DATA] = ELFDATA2MSB;
+	ehdr->e_ident[EI_VERSION] = EV_CURRENT;
+	memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
+	ehdr->e_type = ET_CORE;
+	ehdr->e_machine = EM_S390;
+	ehdr->e_version = EV_CURRENT;
+	ehdr->e_phoff = sizeof(Elf64_Ehdr);
+	ehdr->e_ehsize = sizeof(Elf64_Ehdr);
+	ehdr->e_phentsize = sizeof(Elf64_Phdr);
+	ehdr->e_phnum = mem_chunk_cnt + 1;
+	return ehdr + 1;
+}
+
+/*
+ * Return CPU count for ELF header (new kernel)
+ */
+static int get_cpu_cnt(void)
+{
+	int i, cpus = 0;
+
+	for (i = 0; zfcpdump_save_areas[i]; i++) {
+		if (zfcpdump_save_areas[i]->pref_reg == 0)
+			continue;
+		cpus++;
+	}
+	return cpus;
+}
+
+/*
+ * Return memory chunk count for ELF header (new kernel)
+ */
+static int get_mem_chunk_cnt(void)
+{
+	struct mem_chunk *chunk_array, *mem_chunk;
+	int i, cnt = 0;
+
+	chunk_array = get_memory_layout();
+	for (i = 0; i < MEMORY_CHUNKS; i++) {
+		mem_chunk = &chunk_array[i];
+		if (chunk_array[i].type != CHUNK_READ_WRITE &&
+		    chunk_array[i].type != CHUNK_READ_ONLY)
+			continue;
+		if (mem_chunk->size == 0)
+			continue;
+		cnt++;
+	}
+	kfree(chunk_array);
+	return cnt;
+}
+
+/*
+ * Relocate pointer in order to allow vmcore code access the data
+ */
+static inline unsigned long relocate(unsigned long addr)
+{
+	return OLDMEM_BASE + addr;
+}
+
+/*
+ * Initialize ELF loads (new kernel)
+ */
+static int loads_init(Elf64_Phdr *phdr, u64 loads_offset)
+{
+	struct mem_chunk *chunk_array, *mem_chunk;
+	int i;
+
+	chunk_array = get_memory_layout();
+	for (i = 0; i < MEMORY_CHUNKS; i++) {
+		mem_chunk = &chunk_array[i];
+		if (mem_chunk->size == 0)
+			break;
+		if (chunk_array[i].type != CHUNK_READ_WRITE &&
+		    chunk_array[i].type != CHUNK_READ_ONLY)
+			continue;
+		else
+			phdr->p_filesz = mem_chunk->size;
+		phdr->p_type = PT_LOAD;
+		phdr->p_offset = mem_chunk->addr;
+		phdr->p_vaddr = mem_chunk->addr;
+		phdr->p_paddr = mem_chunk->addr;
+		phdr->p_memsz = mem_chunk->size;
+		phdr->p_flags = PF_R | PF_W | PF_X;
+		phdr->p_align = PAGE_SIZE;
+		phdr++;
+	}
+	kfree(chunk_array);
+	return i;
+}
+
+/*
+ * Initialize notes (new kernel)
+ */
+static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
+{
+	struct save_area *sa;
+	void *ptr_start = ptr;
+	int i;
+
+	ptr = nt_prpsinfo(ptr);
+
+	for (i = 0; zfcpdump_save_areas[i]; i++) {
+		sa = zfcpdump_save_areas[i];
+		if (sa->pref_reg == 0)
+			continue;
+		ptr = fill_cpu_elf_notes(ptr, sa);
+	}
+	ptr = nt_vmcoreinfo(ptr);
+	memset(phdr, 0, sizeof(*phdr));
+	phdr->p_type = PT_NOTE;
+	phdr->p_offset = relocate(notes_offset);
+	phdr->p_filesz = (unsigned long) PTR_SUB(ptr, ptr_start);
+	phdr->p_memsz = phdr->p_filesz;
+	return ptr;
+}
+
+/*
+ * Create ELF core header (new kernel)
+ */
+static void s390_elf_corehdr_create(char **elfcorebuf, size_t *elfcorebuf_sz)
+{
+	Elf64_Phdr *phdr_notes, *phdr_loads;
+	int mem_chunk_cnt;
+	void *ptr, *hdr;
+	u32 alloc_size;
+	u64 hdr_off;
+
+	mem_chunk_cnt = get_mem_chunk_cnt();
+
+	alloc_size = 0x1000 + get_cpu_cnt() * 0x300 +
+		mem_chunk_cnt * sizeof(Elf64_Phdr);
+	hdr = kzalloc_panic(alloc_size);
+	/* Init elf header */
+	ptr = ehdr_init(hdr, mem_chunk_cnt);
+	/* Init program headers */
+	phdr_notes = ptr;
+	ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr));
+	phdr_loads = ptr;
+	ptr = PTR_ADD(ptr, sizeof(Elf64_Phdr) * mem_chunk_cnt);
+	/* Init notes */
+	hdr_off = PTR_DIFF(ptr, hdr);
+	ptr = notes_init(phdr_notes, ptr, ((unsigned long) hdr) + hdr_off);
+	/* Init loads */
+	hdr_off = PTR_DIFF(ptr, hdr);
+	loads_init(phdr_loads, ((unsigned long) hdr) + hdr_off);
+	*elfcorebuf_sz = hdr_off;
+	*elfcorebuf = (void *) relocate((unsigned long) hdr);
+	BUG_ON(*elfcorebuf_sz > alloc_size);
+}
+
+/*
+ * Create kdump ELF core header in new kernel, if it has not been passed via
+ * the "elfcorehdr" kernel parameter
+ */
+static int setup_kdump_elfcorehdr(void)
+{
+	size_t elfcorebuf_sz;
+	char *elfcorebuf;
+
+	if (!OLDMEM_BASE || is_kdump_kernel())
+		return -EINVAL;
+	s390_elf_corehdr_create(&elfcorebuf, &elfcorebuf_sz);
+	elfcorehdr_addr = (unsigned long long) elfcorebuf;
+	elfcorehdr_size = elfcorebuf_sz;
+	return 0;
+}
+
+subsys_initcall(setup_kdump_elfcorehdr);