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Commit 85916f81 authored by Magnus Damm's avatar Magnus Damm Committed by Linus Torvalds
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[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: default avatarMagnus 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6d4df677

arch/i386/kernel/crash.c

+2 −64
Original line number Diff line number Diff line
@@ -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());

}

arch/powerpc/kernel/crash.c

+2 −57
Original line number Diff line number Diff line
@@ -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)

arch/x86_64/kernel/crash.c

+2 −67
Original line number Diff line number Diff line
@@ -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());

}

include/linux/kexec.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

kernel/kexec.c

+56 −0
Original line number Diff line number Diff line
@@ -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. */