s390: Implement dump-guest-memory support for target s390x

With this patch dump-guest-memory on s390 produces an ELF formatted,
crash-readable dump.
In order to implement this, the arch-specific part of dump-guest-memory
was added:
target-s390x/arch_dump.c contains the whole set of function for writing
Elf note sections of all types for s390x.

Signed-off-by: Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
[fixed indentation, use CamelCase, rename note_t to Note, use S390CPU]
Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>

include/elf.h

@@ -1348,11 +1348,17 @@ typedef struct elf64_shdr {
 
 /* Notes used in ET_CORE */
 #define NT_PRSTATUS	1
+#define NT_FPREGSET     2
 #define NT_PRFPREG	2
 #define NT_PRPSINFO	3
 #define NT_TASKSTRUCT	4
 #define NT_AUXV		6
 #define NT_PRXFPREG     0x46e62b7f      /* copied from gdb5.1/include/elf/common.h */
+#define NT_S390_PREFIX  0x305           /* s390 prefix register */
+#define NT_S390_CTRS    0x304           /* s390 control registers */
+#define NT_S390_TODPREG 0x303           /* s390 TOD programmable register */
+#define NT_S390_TODCMP  0x302           /* s390 TOD clock comparator register */
+#define NT_S390_TIMER   0x301           /* s390 timer register */
 
 
 /* Note header in a PT_NOTE section */

target-s390x/Makefile.objs

@@ -1,5 +1,5 @@
 obj-y += translate.o helper.o cpu.o interrupt.o
 obj-y += int_helper.o fpu_helper.o cc_helper.o mem_helper.o misc_helper.o
 obj-y += gdbstub.o
-obj-$(CONFIG_SOFTMMU) += ioinst.o
+obj-$(CONFIG_SOFTMMU) += ioinst.o arch_dump.o
 obj-$(CONFIG_KVM) += kvm.o

target-s390x/arch_dump.c

@@ -0,0 +1,212 @@
+/*
+ * writing ELF notes for s390x arch
+ *
+ *
+ * Copyright IBM Corp. 2012, 2013
+ *
+ *     Ekaterina Tumanova <tumanova@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "cpu.h"
+#include "elf.h"
+#include "exec/cpu-all.h"
+#include "sysemu/dump.h"
+#include "sysemu/kvm.h"
+
+
+struct S390xUserRegsStruct {
+    uint64_t psw[2];
+    uint64_t gprs[16];
+    uint32_t acrs[16];
+} QEMU_PACKED;
+
+typedef struct S390xUserRegsStruct S390xUserRegs;
+
+struct S390xElfPrstatusStruct {
+    uint8_t pad1[32];
+    uint32_t pid;
+    uint8_t pad2[76];
+    S390xUserRegs regs;
+    uint8_t pad3[16];
+} QEMU_PACKED;
+
+typedef struct S390xElfPrstatusStruct S390xElfPrstatus;
+
+struct S390xElfFpregsetStruct {
+    uint32_t fpc;
+    uint32_t pad;
+    uint64_t fprs[16];
+} QEMU_PACKED;
+
+typedef struct S390xElfFpregsetStruct S390xElfFpregset;
+
+typedef struct noteStruct {
+    Elf64_Nhdr hdr;
+    char name[5];
+    char pad3[3];
+    union {
+        S390xElfPrstatus prstatus;
+        S390xElfFpregset fpregset;
+        uint32_t prefix;
+        uint64_t timer;
+        uint64_t todcmp;
+        uint32_t todpreg;
+        uint64_t ctrs[16];
+    } contents;
+} QEMU_PACKED Note;
+
+static void s390x_write_elf64_prstatus(Note *note, S390CPU *cpu)
+{
+    int i;
+    S390xUserRegs *regs;
+
+    note->hdr.n_type = cpu_to_be32(NT_PRSTATUS);
+
+    regs = &(note->contents.prstatus.regs);
+    regs->psw[0] = cpu_to_be64(cpu->env.psw.mask);
+    regs->psw[1] = cpu_to_be64(cpu->env.psw.addr);
+    for (i = 0; i <= 15; i++) {
+        regs->acrs[i] = cpu_to_be32(cpu->env.aregs[i]);
+        regs->gprs[i] = cpu_to_be64(cpu->env.regs[i]);
+    }
+}
+
+static void s390x_write_elf64_fpregset(Note *note, S390CPU *cpu)
+{
+    int i;
+
+    note->hdr.n_type = cpu_to_be32(NT_FPREGSET);
+    note->contents.fpregset.fpc = cpu_to_be32(cpu->env.fpc);
+    for (i = 0; i <= 15; i++) {
+        note->contents.fpregset.fprs[i] = cpu_to_be64(cpu->env.fregs[i].ll);
+    }
+}
+
+
+static void s390x_write_elf64_timer(Note *note, S390CPU *cpu)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TIMER);
+    note->contents.timer = cpu_to_be64((uint64_t)(cpu->env.cputm));
+}
+
+static void s390x_write_elf64_todcmp(Note *note, S390CPU *cpu)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TODCMP);
+    note->contents.todcmp = cpu_to_be64((uint64_t)(cpu->env.ckc));
+}
+
+static void s390x_write_elf64_todpreg(Note *note, S390CPU *cpu)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TODPREG);
+    note->contents.todpreg = cpu_to_be32((uint32_t)(cpu->env.todpr));
+}
+
+static void s390x_write_elf64_ctrs(Note *note, S390CPU *cpu)
+{
+    int i;
+
+    note->hdr.n_type = cpu_to_be32(NT_S390_CTRS);
+
+    for (i = 0; i <= 15; i++) {
+        note->contents.ctrs[i] = cpu_to_be64(cpu->env.cregs[i]);
+    }
+}
+
+static void s390x_write_elf64_prefix(Note *note, S390CPU *cpu)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_PREFIX);
+    note->contents.prefix = cpu_to_be32((uint32_t)(cpu->env.psa));
+}
+
+
+struct NoteFuncDescStruct {
+    int contents_size;
+    void (*note_contents_func)(Note *note, S390CPU *cpu);
+} note_func[] = {
+    {sizeof(((Note *)0)->contents.prstatus), s390x_write_elf64_prstatus},
+    {sizeof(((Note *)0)->contents.prefix),   s390x_write_elf64_prefix},
+    {sizeof(((Note *)0)->contents.fpregset), s390x_write_elf64_fpregset},
+    {sizeof(((Note *)0)->contents.ctrs),     s390x_write_elf64_ctrs},
+    {sizeof(((Note *)0)->contents.timer),    s390x_write_elf64_timer},
+    {sizeof(((Note *)0)->contents.todcmp),   s390x_write_elf64_todcmp},
+    {sizeof(((Note *)0)->contents.todpreg),  s390x_write_elf64_todpreg},
+    { 0, NULL}
+};
+
+typedef struct NoteFuncDescStruct NoteFuncDesc;
+
+
+static int s390x_write_all_elf64_notes(const char *note_name,
+                                       WriteCoreDumpFunction f,
+                                       S390CPU *cpu, int id,
+                                       void *opaque)
+{
+    Note note;
+    NoteFuncDesc *nf;
+    int note_size;
+    int ret = -1;
+
+    for (nf = note_func; nf->note_contents_func; nf++) {
+        note.hdr.n_namesz = cpu_to_be32(sizeof(note.name));
+        note.hdr.n_descsz = cpu_to_be32(nf->contents_size);
+        strncpy(note.name, note_name, sizeof(note.name));
+        (*nf->note_contents_func)(&note, cpu);
+
+        note_size = sizeof(note) - sizeof(note.contents) + nf->contents_size;
+        ret = f(&note, note_size, opaque);
+
+        if (ret < 0) {
+            return -1;
+        }
+
+    }
+
+    return 0;
+}
+
+
+int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
+                              int cpuid, void *opaque)
+{
+    S390CPU *cpu = S390_CPU(cs);
+    return s390x_write_all_elf64_notes("CORE", f, cpu, cpuid, opaque);
+}
+
+int cpu_get_dump_info(ArchDumpInfo *info)
+{
+    info->d_machine = EM_S390;
+    info->d_endian = ELFDATA2MSB;
+    info->d_class = ELFCLASS64;
+
+    return 0;
+}
+
+ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
+{
+    int name_size = 8; /* "CORE" or "QEMU" rounded */
+    size_t elf_note_size = 0;
+    int note_head_size;
+    NoteFuncDesc *nf;
+
+    assert(class == ELFCLASS64);
+    assert(machine == EM_S390);
+
+    note_head_size = sizeof(Elf64_Nhdr);
+
+    for (nf = note_func; nf->note_contents_func; nf++) {
+        elf_note_size = elf_note_size + note_head_size + name_size +
+                        nf->contents_size;
+    }
+
+    return (elf_note_size) * nr_cpus;
+}
+
+int s390_cpu_write_elf64_qemunote(WriteCoreDumpFunction f,
+                                  CPUState *cpu, void *opaque)
+{
+    return 0;
+}

target-s390x/cpu-qom.h

@@ -74,6 +74,11 @@ static inline S390CPU *s390_env_get_cpu(CPUS390XState *env)
 void s390_cpu_do_interrupt(CPUState *cpu);
 void s390_cpu_dump_state(CPUState *cpu, FILE *f, fprintf_function cpu_fprintf,
                          int flags);
+int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cs,
+                              int cpuid, void *opaque);
+
+int s390_cpu_write_elf64_qemunote(WriteCoreDumpFunction f,
+                                  CPUState *cpu, void *opaque);
 hwaddr s390_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 int s390_cpu_gdb_read_register(CPUState *cpu, uint8_t *buf, int reg);
 int s390_cpu_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);

target-s390x/cpu.c

@@ -178,6 +178,8 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
     cc->gdb_write_register = s390_cpu_gdb_write_register;
 #ifndef CONFIG_USER_ONLY
     cc->get_phys_page_debug = s390_cpu_get_phys_page_debug;
+    cc->write_elf64_note = s390_cpu_write_elf64_note;
+    cc->write_elf64_qemunote = s390_cpu_write_elf64_qemunote;
 #endif
     dc->vmsd = &vmstate_s390_cpu;
     cc->gdb_num_core_regs = S390_NUM_REGS;