[Qemu-devel] [PATCH 2/2] s390: dump guest memory implementation

[Jens Freimann <jfrei@linux.vnet.ibm.com>]

Implement dump-guest-memory support for target s390x.

dump-guest-memory QEMU monitor command didn't work for s390 architecture.
The result of the command is supposed to be ELF format 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>
---
 configure                  |   2 +-
 include/elf.h              |   6 ++
 target-s390x/Makefile.objs |   2 +-
 target-s390x/arch_dump.c   | 231 +++++++++++++++++++++++++++++++++++++++++++++
 target-s390x/cpu-qom.h     |  21 +++++
 target-s390x/cpu.c         |   7 ++
 6 files changed, 267 insertions(+), 2 deletions(-)
 create mode 100644 target-s390x/arch_dump.c

diff --git a/configure b/configure
index ed49f91..90dc58b 100755
--- a/configure
+++ b/configure
@@ -4326,7 +4326,7 @@ fi
 if test "$target_softmmu" = "yes" ; then
   echo "CONFIG_SOFTMMU=y" >> $config_target_mak
   case "$target_arch2" in
-    i386|x86_64)
+    i386|x86_64|s390x)
       echo "CONFIG_HAVE_CORE_DUMP=y" >> $config_target_mak
   esac
 fi
diff --git a/include/elf.h b/include/elf.h
index a21ea53..ba4b3a7 100644
--- a/include/elf.h
+++ b/include/elf.h
@@ -1219,11 +1219,17 @@ 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 */
diff --git a/target-s390x/Makefile.objs b/target-s390x/Makefile.objs
index 4e63417..c34f654 100644
--- a/target-s390x/Makefile.objs
+++ b/target-s390x/Makefile.objs
@@ -1,4 +1,4 @@
 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-$(CONFIG_SOFTMMU) += ioinst.o
+obj-$(CONFIG_SOFTMMU) += ioinst.o arch_dump.o
 obj-$(CONFIG_KVM) += kvm.o
diff --git a/target-s390x/arch_dump.c b/target-s390x/arch_dump.c
new file mode 100644
index 0000000..f908257
--- /dev/null
+++ b/target-s390x/arch_dump.c
@@ -0,0 +1,231 @@
+/*
+ * writing ELF notes for s390x arch
+ *
+ *
+ * Copyright IBM Corp. 2012
+ *
+ *     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 s390x_user_regs_struct {
+    uint64_t        psw[2];
+    uint64_t        gprs[16];
+    uint32_t        acrs[16];
+} QEMU_PACKED;
+
+typedef struct s390x_user_regs_struct s390x_user_regs;
+
+struct s390x_elf_prstatus_struct {
+    uint8_t pad1[32];
+    uint32_t pid;
+    uint8_t pad2[76];
+    s390x_user_regs regs;
+    uint8_t pad3[16];
+} QEMU_PACKED;
+
+typedef struct s390x_elf_prstatus_struct s390x_elf_prstatus;
+
+struct s390x_elf_fpregset_struct {
+        uint32_t        fpc;
+        uint32_t        pad;
+        uint64_t        fprs[16];
+} QEMU_PACKED;
+
+typedef struct s390x_elf_fpregset_struct s390x_elf_fpregset;
+
+    typedef struct note_struct {
+        Elf64_Nhdr hdr;
+        char name[5];
+        char pad3[3];
+        union {
+            s390x_elf_prstatus prstatus;
+            s390x_elf_fpregset fpregset;
+            uint32_t prefix;
+            uint64_t timer;
+            uint64_t todcmp;
+            uint32_t todpreg;
+            uint64_t ctrs[16];
+        } contents;
+    } QEMU_PACKED note_t;
+
+static int s390x_write_elf64_prstatus(note_t *note, CPUArchState *env)
+{
+    int i;
+    s390x_user_regs *regs;
+
+    note->hdr.n_type = cpu_to_be32(NT_PRSTATUS);
+
+    regs = &(note->contents.prstatus.regs);
+    regs->psw[0] =  cpu_to_be32(env->psw.mask);
+    regs->psw[1] =  cpu_to_be32(env->psw.addr);
+    for (i = 0; i <= 15; i++) {
+        regs->acrs[i] = cpu_to_be32(env->aregs[i]);
+        regs->gprs[i] = cpu_to_be32(env->regs[i]);
+    }
+
+    return 0;
+}
+
+static int s390x_write_elf64_fpregset(note_t *note, CPUArchState *env)
+{
+    int i;
+
+    note->hdr.n_type = cpu_to_be32(NT_FPREGSET);
+
+    note->contents.fpregset.fpc = cpu_to_be32(env->fpc);
+    for (i = 0; i <= 15; i++) {
+        note->contents.fpregset.fprs[i] =  cpu_to_be64(env->fregs[i].ll);
+    }
+
+    return 0;
+}
+
+
+static int s390x_write_elf64_timer(note_t *note, CPUArchState *env)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TIMER);
+
+    note->contents.timer = cpu_to_be64((uint64_t)(env->cputm));
+
+    return 0;
+}
+
+static int s390x_write_elf64_todcmp(note_t *note, CPUArchState *env)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TODCMP);
+
+    note->contents.todcmp = cpu_to_be64((uint64_t)(env->ckc));
+
+    return 0;
+}
+
+static int s390x_write_elf64_todpreg(note_t *note, CPUArchState *env)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_TODPREG);
+
+    note->contents.todpreg = cpu_to_be32((uint32_t)(env->todpr));
+
+    return 0;
+}
+
+static int s390x_write_elf64_ctrs(note_t *note, CPUArchState *env)
+{
+    int i;
+
+    note->hdr.n_type = cpu_to_be32(NT_S390_CTRS);
+
+    for (i = 0; i <= 15; i++) {
+        note->contents.ctrs[i] =  cpu_to_be32(env->cregs[i]);
+    }
+
+    return 0;
+}
+
+static int s390x_write_elf64_prefix(note_t *note, CPUArchState *env)
+{
+    note->hdr.n_type = cpu_to_be32(NT_S390_PREFIX);
+
+    note->contents.prefix = cpu_to_be32((uint32_t)(env->psa));
+
+    return 0;
+}
+
+
+struct note_func_desc_struct {
+    int contents_size;
+    int (*note_contents_func)(note_t *note, CPUArchState *env);
+} note_func[] = {
+    { sizeof(((note_t *)0)->contents.prstatus), s390x_write_elf64_prstatus },
+    { sizeof(((note_t *)0)->contents.prefix),   s390x_write_elf64_prefix },
+    { sizeof(((note_t *)0)->contents.fpregset), s390x_write_elf64_fpregset },
+    { sizeof(((note_t *)0)->contents.ctrs),     s390x_write_elf64_ctrs },
+    { sizeof(((note_t *)0)->contents.timer),    s390x_write_elf64_timer },
+    { sizeof(((note_t *)0)->contents.todcmp),   s390x_write_elf64_todcmp },
+    { sizeof(((note_t *)0)->contents.todpreg),  s390x_write_elf64_todpreg },
+
+    { 0, NULL}
+};
+
+
+static int s390x_write_all_elf64_notes(const char *note_name,
+            WriteCoreDumpFunction f,
+            CPUArchState *env,
+            int id,
+            void *opaque)
+{
+    note_t note;
+    struct note_func_desc_struct *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));
+        ret = (*nf->note_contents_func)(&note, env);
+
+        note_size = cpu_to_be32(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->env, 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;
+    struct note_func_desc_struct *nf;
+
+    assert(class == ELFCLASS64);
+    note_head_size = sizeof(Elf64_Nhdr);
+
+    assert(machine == EM_S390);
+
+    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;
+
+}
+
diff --git a/target-s390x/cpu-qom.h b/target-s390x/cpu-qom.h
index 34d45c2..3370fb9 100644
--- a/target-s390x/cpu-qom.h
+++ b/target-s390x/cpu-qom.h
@@ -73,4 +73,25 @@ static inline S390CPU *s390_env_get_cpu(CPUS390XState *env)
 
 void s390_cpu_do_interrupt(CPUState *cpu);
 
+int s390_cpu_write_elf64_note(WriteCoreDumpFunction f, CPUState *cpu,
+        int cpuid, void *opaque);
+
+static inline int s390_cpu_write_elf64_qemunote(WriteCoreDumpFunction f,
+        CPUState *env, void *opaque)
+{
+    return 0;
+}
+
+static inline int s390_cpu_write_elf32_qemunote(WriteCoreDumpFunction f,
+        CPUState *env, void *opaque)
+{
+    return 0;
+}
+
+static inline int s390_cpu_write_elf32_note(WriteCoreDumpFunction f,
+        CPUState *env, int cpuid, void *opaque)
+{
+    return 0;
+}
+
 #endif
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 23fe51f..27cfbc0 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -27,6 +27,7 @@
 #include "qemu-common.h"
 #include "qemu/timer.h"
 #include "hw/hw.h"
+#include "cpu-qom.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
 #endif
@@ -168,6 +169,12 @@ static void s390_cpu_class_init(ObjectClass *oc, void *data)
 
     scc->parent_reset = cc->reset;
     cc->reset = s390_cpu_reset;
+#if !defined(CONFIG_USER_ONLY)
+    cc->write_elf64_note = s390_cpu_write_elf64_note;
+    cc->write_elf64_qemunote = s390_cpu_write_elf64_qemunote;
+    cc->write_elf32_note = s390_cpu_write_elf32_note;
+    cc->write_elf32_qemunote = s390_cpu_write_elf32_qemunote;
+#endif
 
     cc->do_interrupt = s390_cpu_do_interrupt;
     dc->vmsd = &vmstate_s390_cpu;
-- 
1.7.12.4