[PATCH] Kexec / Kdump: Unify elf note code

The elf note saving code is currently duplicated over several
architectures.  This cleanup patch simply adds code to a common file and
then replaces the arch-specific code with calls to the newly added code.

The only drawback with this approach is that s390 doesn't fully support
kexec-on-panic which for that arch leads to introduction of unused code.

Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

5 files changed, 63 insertions, 188 deletions

diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index 144b43288965..a5e0e990ea95 100644
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -31,68 +31,6 @@
 /* This keeps a track of which one is crashing cpu. */
 static int crashing_cpu;
 
-static u32 *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 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 void crash_save_this_cpu(struct pt_regs *regs, int cpu)
-{
-        struct elf_prstatus prstatus;
-        u32 *buf;
-
-        if ((cpu < 0) || (cpu >= NR_CPUS))
-                return;
-
-        /* Using ELF notes here is opportunistic.
-         * I need a well defined structure format
-         * for the data I pass, and I need tags
-         * on the data to indicate what information I have
-         * squirrelled away.  ELF notes happen to provide
-         * all of that, so there is no need to invent something new.
-         */
-        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
-        if (!buf)
-                return;
-        memset(&prstatus, 0, sizeof(prstatus));
-        prstatus.pr_pid = current->pid;
-        elf_core_copy_regs(&prstatus.pr_reg, regs);
-        buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
-                                sizeof(prstatus));
-        final_note(buf);
-}
-
-static void crash_save_self(struct pt_regs *regs)
-{
-        int cpu;
-
-        cpu = safe_smp_processor_id();
-        crash_save_this_cpu(regs, cpu);
-}
-
 #if defined(CONFIG_SMP) && defined(CONFIG_X86_LOCAL_APIC)
 static atomic_t waiting_for_crash_ipi;
 
@@ -121,7 +59,7 @@ static int crash_nmi_callback(struct notifier_block *self,
                 crash_fixup_ss_esp(&fixed_regs, regs);
                 regs = &fixed_regs;
         }
-        crash_save_this_cpu(regs, cpu);
+        crash_save_cpu(regs, cpu);
         disable_local_APIC();
         atomic_dec(&waiting_for_crash_ipi);
         /* Assume hlt works */
@@ -195,5 +133,5 @@ void machine_crash_shutdown(struct pt_regs *regs)
 #if defined(CONFIG_X86_IO_APIC)
         disable_IO_APIC();
 #endif
-        crash_save_self(regs);
+        crash_save_cpu(regs, safe_smp_processor_id());
 }
diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 89b03c8da9d2..d3f2080d2eee 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -46,61 +46,6 @@ int crashing_cpu = -1;
 static cpumask_t cpus_in_crash = CPU_MASK_NONE;
 cpumask_t cpus_in_sr = CPU_MASK_NONE;
 
-static u32 *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 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 void crash_save_this_cpu(struct pt_regs *regs, int cpu)
-{
-        struct elf_prstatus prstatus;
-        u32 *buf;
-
-        if ((cpu < 0) || (cpu >= NR_CPUS))
-                return;
-
-        /* Using ELF notes here is opportunistic.
-         * I need a well defined structure format
-         * for the data I pass, and I need tags
-         * on the data to indicate what information I have
-         * squirrelled away.  ELF notes happen to provide
-         * all of that that no need to invent something new.
-         */
-        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
-        if (!buf) 
-                return;
-
-        memset(&prstatus, 0, sizeof(prstatus));
-        prstatus.pr_pid = current->pid;
-        elf_core_copy_regs(&prstatus.pr_reg, regs);
-        buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
-                        sizeof(prstatus));
-        final_note(buf);
-}
-
 #ifdef CONFIG_SMP
 static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
 
@@ -113,7 +58,7 @@ void crash_ipi_callback(struct pt_regs *regs)
 
         hard_irq_disable();
         if (!cpu_isset(cpu, cpus_in_crash))
-                crash_save_this_cpu(regs, cpu);
+                crash_save_cpu(regs, cpu);
         cpu_set(cpu, cpus_in_crash);
 
         /*
@@ -306,7 +251,7 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
          * such that another IPI will not be sent.
          */
         crashing_cpu = smp_processor_id();
-        crash_save_this_cpu(regs, crashing_cpu);
+        crash_save_cpu(regs, crashing_cpu);
         crash_kexec_prepare_cpus(crashing_cpu);
         cpu_set(crashing_cpu, cpus_in_crash);
         if (ppc_md.kexec_cpu_down)
diff --git a/arch/x86_64/kernel/crash.c b/arch/x86_64/kernel/crash.c
index 3525f884af82..95a7a2c13131 100644
--- a/arch/x86_64/kernel/crash.c
+++ b/arch/x86_64/kernel/crash.c
@@ -28,71 +28,6 @@
 /* This keeps a track of which one is crashing cpu. */
 static int crashing_cpu;
 
-static u32 *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 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 void crash_save_this_cpu(struct pt_regs *regs, int cpu)
-{
-        struct elf_prstatus prstatus;
-        u32 *buf;
-
-        if ((cpu < 0) || (cpu >= NR_CPUS))
-                return;
-
-        /* Using ELF notes here is opportunistic.
-         * I need a well defined structure format
-         * for the data I pass, and I need tags
-         * on the data to indicate what information I have
-         * squirrelled away.  ELF notes happen to provide
-         * all of that, no need to invent something new.
-         */
-
-        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
-
-        if (!buf)
-                return;
-
-        memset(&prstatus, 0, sizeof(prstatus));
-        prstatus.pr_pid = current->pid;
-        elf_core_copy_regs(&prstatus.pr_reg, regs);
-        buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
-                                        sizeof(prstatus));
-        final_note(buf);
-}
-
-static void crash_save_self(struct pt_regs *regs)
-{
-        int cpu;
-
-        cpu = smp_processor_id();
-        crash_save_this_cpu(regs, cpu);
-}
-
 #ifdef CONFIG_SMP
 static atomic_t waiting_for_crash_ipi;
 
@@ -117,7 +52,7 @@ static int crash_nmi_callback(struct notifier_block *self,
                 return NOTIFY_STOP;
         local_irq_disable();
 
-        crash_save_this_cpu(regs, cpu);
+        crash_save_cpu(regs, cpu);
         disable_local_APIC();
         atomic_dec(&waiting_for_crash_ipi);
         /* Assume hlt works */
@@ -196,5 +131,5 @@ void machine_crash_shutdown(struct pt_regs *regs)
 
         disable_IO_APIC();
 
-        crash_save_self(regs);
+        crash_save_cpu(regs, smp_processor_id());
 }
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index a4ede62b339d..e3abcec6c51c 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -105,6 +105,7 @@ extern struct page *kimage_alloc_control_pages(struct kimage *image,
                                                 unsigned int order);
 extern void crash_kexec(struct pt_regs *);
 int kexec_should_crash(struct task_struct *);
+void crash_save_cpu(struct pt_regs *regs, int cpu);
 extern struct kimage *kexec_image;
 extern struct kimage *kexec_crash_image;
 
diff --git a/kernel/kexec.c b/kernel/kexec.c
index d43692cf2321..afbbbe981be2 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -20,6 +20,8 @@
 #include <linux/syscalls.h>
 #include <linux/ioport.h>
 #include <linux/hardirq.h>
+#include <linux/elf.h>
+#include <linux/elfcore.h>
 
 #include <asm/page.h>
 #include <asm/uaccess.h>
@@ -1066,6 +1068,60 @@ void crash_kexec(struct pt_regs *regs)
         }
 }
 
+static u32 *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 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));
+}
+
+void crash_save_cpu(struct pt_regs *regs, int cpu)
+{
+        struct elf_prstatus prstatus;
+        u32 *buf;
+
+        if ((cpu < 0) || (cpu >= NR_CPUS))
+                return;
+
+        /* Using ELF notes here is opportunistic.
+         * I need a well defined structure format
+         * for the data I pass, and I need tags
+         * on the data to indicate what information I have
+         * squirrelled away.  ELF notes happen to provide
+         * all of that, so there is no need to invent something new.
+         */
+        buf = (u32*)per_cpu_ptr(crash_notes, cpu);
+        if (!buf)
+                return;
+        memset(&prstatus, 0, sizeof(prstatus));
+        prstatus.pr_pid = current->pid;
+        elf_core_copy_regs(&prstatus.pr_reg, regs);
+        buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
+                                sizeof(prstatus));
+        final_note(buf);
+}
+
 static int __init crash_notes_memory_init(void)
 {
         /* Allocate memory for saving cpu registers. */