generic: improve MIPS kexec support

It is based on patches from the linux-longsoon-community git tree:
http://dev.lemote.com/cgit/linux-loongson-community.git/

Now the kernel can use the command line parameter from kexec-tools.

Runtime tested on ar71xx with 2.6.39.4 (the wathdog must be stopped
before executing the new kernel). Compile tested with lantiq (3.1.4)
and brcm47xx (3.0.12).

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@29674 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 616 insertions, 0 deletions

diff --git a/target/linux/generic/patches-2.6.39/330-mips-add-crash-and-kdump-support.patch b/target/linux/generic/patches-2.6.39/330-mips-add-crash-and-kdump-support.patch
new file mode 100644
index 000000000..2e3766f18
--- /dev/null
+++ b/target/linux/generic/patches-2.6.39/330-mips-add-crash-and-kdump-support.patch
@@ -0,0 +1,616 @@
+From eee16330c9de9adf7880cce9f1d32e13f89706bb Mon Sep 17 00:00:00 2001
+From: Wu Zhangjin <wuzhangjin@gmail.com>
+Date: Tue, 11 Jan 2011 13:16:47 +0000
+Subject: MIPS: Add crash and kdump support
+
+From: http://patchwork.linux-mips.org/patch/1025/
+
+Hello folks,
+
+Please find here MIPS crash and kdump patches.
+This is patch set of 3 patches:
+1. generic MIPS changes (kernel);
+2. MIPS Cavium Octeon board kexec/kdump code (kernel);
+3. Kexec user space MIPS changes.
+
+Patches were tested on the latest linux-mips@ git kernel and the latest
+kexec-tools git on Cavium Octeon 50xx board.
+
+I also made the same code working on RMI XLR/XLS boards for both
+mips32 and mips64 kernels.
+
+Best regards,
+Maxim Uvarov.
+
+------
+[ Zhangjin: Several trivial building failure has been fixed.
+
+Note: the 2nd patch can not be cleanly applied, but may be a good
+reference for the other board development:
+
+	+ MIPS Cavium Octeon board kexec,kdump support
+	http://patchwork.linux-mips.org/patch/1026/
+
+And the 3rd patch has already been merged into the mainline kexec-tools:
+
+	+ some kexec MIPS improvements
+	http://patchwork.linux-mips.org/patch/1027/
+
+kexec-tools is available here:
+
+	+ http://horms.net/projects/kexec/
+	git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
+]
+Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
+---
+(limited to 'arch/mips/kernel')
+
+--- a/arch/mips/kernel/Makefile
++++ b/arch/mips/kernel/Makefile
+@@ -92,7 +92,8 @@ obj-$(CONFIG_I8253)		+= i8253.o
+ 
+ obj-$(CONFIG_GPIO_TXX9)		+= gpio_txx9.o
+ 
+-obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o
++obj-$(CONFIG_KEXEC)		+= machine_kexec.o relocate_kernel.o crash.o
++obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
+ obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
+ obj-$(CONFIG_SPINLOCK_TEST)	+= spinlock_test.o
+ obj-$(CONFIG_MIPS_MACHINE)	+= mips_machine.o
+--- /dev/null
++++ b/arch/mips/kernel/crash.c
+@@ -0,0 +1,75 @@
++#include <linux/kernel.h>
++#include <linux/smp.h>
++#include <linux/reboot.h>
++#include <linux/kexec.h>
++#include <linux/bootmem.h>
++#include <linux/crash_dump.h>
++#include <linux/delay.h>
++#include <linux/init.h>
++#include <linux/irq.h>
++#include <linux/types.h>
++#include <linux/sched.h>
++
++#ifdef CONFIG_CRASH_DUMP
++unsigned long long elfcorehdr_addr = ELFCORE_ADDR_MAX;
++#endif
++
++/* This keeps a track of which one is crashing cpu. */
++int crashing_cpu = -1;
++static cpumask_t cpus_in_crash = CPU_MASK_NONE;
++
++#ifdef CONFIG_SMP
++void crash_shutdown_secondary(void *ignore)
++{
++	struct pt_regs *regs;
++	int cpu = smp_processor_id();
++
++	regs = task_pt_regs(current);
++
++	if (!cpu_online(cpu))
++		return;
++
++	local_irq_disable();
++	if (!cpu_isset(cpu, cpus_in_crash))
++		crash_save_cpu(regs, cpu);
++	cpu_set(cpu, cpus_in_crash);
++
++	while (!atomic_read(&kexec_ready_to_reboot))
++		cpu_relax();
++	relocated_kexec_smp_wait(NULL);
++	/* NOTREACHED */
++}
++
++static void crash_kexec_prepare_cpus(void)
++{
++	unsigned int msecs;
++
++	unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
++
++	dump_send_ipi(crash_shutdown_secondary);
++	smp_wmb();
++
++	/*
++	 * The crash CPU sends an IPI and wait for other CPUs to
++	 * respond. Delay of at least 10 seconds.
++	 */
++	printk(KERN_EMERG "Sending IPI to other cpus...\n");
++	msecs = 10000;
++	while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) {
++		cpu_relax();
++		mdelay(1);
++	}
++}
++
++#else
++static void crash_kexec_prepare_cpus(void) {}
++#endif
++
++void default_machine_crash_shutdown(struct pt_regs *regs)
++{
++	local_irq_disable();
++	crashing_cpu = smp_processor_id();
++	crash_save_cpu(regs, crashing_cpu);
++	crash_kexec_prepare_cpus();
++	cpu_set(crashing_cpu, cpus_in_crash);
++}
+--- /dev/null
++++ b/arch/mips/kernel/crash_dump.c
+@@ -0,0 +1,86 @@
++#include <linux/highmem.h>
++#include <linux/bootmem.h>
++#include <linux/crash_dump.h>
++#include <asm/uaccess.h>
++
++#ifdef CONFIG_PROC_VMCORE
++static int __init parse_elfcorehdr(char *p)
++{
++	if (p)
++		elfcorehdr_addr = memparse(p, &p);
++	return 1;
++}
++__setup("elfcorehdr=", parse_elfcorehdr);
++#endif
++
++static int __init parse_savemaxmem(char *p)
++{
++	if (p)
++		saved_max_pfn = (memparse(p, &p) >> PAGE_SHIFT) - 1;
++
++	return 1;
++}
++__setup("savemaxmem=", parse_savemaxmem);
++
++
++static void *kdump_buf_page;
++
++/**
++ * copy_oldmem_page - copy one page from "oldmem"
++ * @pfn: page frame number to be copied
++ * @buf: target memory address for the copy; this can be in kernel address
++ *	space or user address space (see @userbuf)
++ * @csize: number of bytes to copy
++ * @offset: offset in bytes into the page (based on pfn) to begin the copy
++ * @userbuf: if set, @buf is in user address space, use copy_to_user(),
++ *	otherwise @buf is in kernel address space, use memcpy().
++ *
++ * Copy a page from "oldmem". For this page, there is no pte mapped
++ * in the current kernel.
++ *
++ * Calling copy_to_user() in atomic context is not desirable. Hence first
++ * copying the data to a pre-allocated kernel page and then copying to user
++ * space in non-atomic context.
++ */
++ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
++		size_t csize, unsigned long offset, int userbuf)
++{
++	void  *vaddr;
++
++	if (!csize)
++		return 0;
++
++	vaddr = kmap_atomic_pfn(pfn, KM_PTE0);
++
++	if (!userbuf) {
++		memcpy(buf, (vaddr + offset), csize);
++		kunmap_atomic(vaddr, KM_PTE0);
++	} else {
++		if (!kdump_buf_page) {
++			printk(KERN_WARNING "Kdump: Kdump buffer page not"
++				" allocated\n");
++			return -EFAULT;
++		}
++		copy_page(kdump_buf_page, vaddr);
++		kunmap_atomic(vaddr, KM_PTE0);
++		if (copy_to_user(buf, (kdump_buf_page + offset), csize))
++			return -EFAULT;
++	}
++
++	return csize;
++}
++
++static int __init kdump_buf_page_init(void)
++{
++	int ret = 0;
++
++	kdump_buf_page = kmalloc(PAGE_SIZE, GFP_KERNEL);
++	if (!kdump_buf_page) {
++		printk(KERN_WARNING "Kdump: Failed to allocate kdump buffer"
++			 " page\n");
++		ret = -ENOMEM;
++	}
++
++	return ret;
++}
++arch_initcall(kdump_buf_page_init);
+--- a/arch/mips/kernel/machine_kexec.c
++++ b/arch/mips/kernel/machine_kexec.c
+@@ -19,9 +19,19 @@ extern const size_t relocate_new_kernel_
+ extern unsigned long kexec_start_address;
+ extern unsigned long kexec_indirection_page;
+ 
++int (*_machine_kexec_prepare)(struct kimage *) = NULL;
++void (*_machine_kexec_shutdown)(void) = NULL;
++void (*_machine_crash_shutdown)(struct pt_regs *regs) = NULL;
++#ifdef CONFIG_SMP
++void (*relocated_kexec_smp_wait) (void *);
++atomic_t kexec_ready_to_reboot = ATOMIC_INIT(0);
++#endif
++
+ int
+ machine_kexec_prepare(struct kimage *kimage)
+ {
++	if (_machine_kexec_prepare)
++		return _machine_kexec_prepare(kimage);
+ 	return 0;
+ }
+ 
+@@ -33,11 +43,17 @@ machine_kexec_cleanup(struct kimage *kim
+ void
+ machine_shutdown(void)
+ {
++	if (_machine_kexec_shutdown)
++		_machine_kexec_shutdown();
+ }
+ 
+ void
+ machine_crash_shutdown(struct pt_regs *regs)
+ {
++	if (_machine_crash_shutdown)
++		_machine_crash_shutdown(regs);
++	else
++		default_machine_crash_shutdown(regs);
+ }
+ 
+ typedef void (*noretfun_t)(void) __attribute__((noreturn));
+@@ -52,7 +68,9 @@ machine_kexec(struct kimage *image)
+ 	reboot_code_buffer =
+ 	  (unsigned long)page_address(image->control_code_page);
+ 
+-	kexec_start_address = (unsigned long) phys_to_virt(image->start);
++	kexec_start_address =
++	  (unsigned long) phys_to_virt(image->start);
++
+ 	kexec_indirection_page =
+ 		(unsigned long) phys_to_virt(image->head & PAGE_MASK);
+ 
+@@ -63,7 +81,7 @@ machine_kexec(struct kimage *image)
+ 	 * The generic kexec code builds a page list with physical
+ 	 * addresses. they are directly accessible through KSEG0 (or
+ 	 * CKSEG0 or XPHYS if on 64bit system), hence the
+-	 * pys_to_virt() call.
++	 * phys_to_virt() call.
+ 	 */
+ 	for (ptr = &image->head; (entry = *ptr) && !(entry &IND_DONE);
+ 	     ptr = (entry & IND_INDIRECTION) ?
+@@ -81,5 +99,13 @@ machine_kexec(struct kimage *image)
+ 	printk("Will call new kernel at %08lx\n", image->start);
+ 	printk("Bye ...\n");
+ 	__flush_cache_all();
++#ifdef CONFIG_SMP
++	/* All secondary cpus now may jump to kexec_wait cycle */
++	relocated_kexec_smp_wait = reboot_code_buffer +
++		(void *)(kexec_smp_wait - relocate_new_kernel);
++	smp_wmb();
++	atomic_set(&kexec_ready_to_reboot, 1);
++#endif
+ 	((noretfun_t) reboot_code_buffer)();
+ }
++
+--- a/arch/mips/kernel/relocate_kernel.S
++++ b/arch/mips/kernel/relocate_kernel.S
+@@ -15,6 +15,11 @@
+ #include <asm/addrspace.h>
+ 
+ LEAF(relocate_new_kernel)
++	PTR_L a0,	arg0
++	PTR_L a1,	arg1
++	PTR_L a2,	arg2
++	PTR_L a3,	arg3
++
+ 	PTR_L		s0, kexec_indirection_page
+ 	PTR_L		s1, kexec_start_address
+ 
+@@ -26,7 +31,6 @@ process_entry:
+ 	and		s3, s2, 0x1
+ 	beq		s3, zero, 1f
+ 	and		s4, s2, ~0x1	/* store destination addr in s4 */
+-	move		a0, s4
+ 	b		process_entry
+ 
+ 1:
+@@ -60,23 +64,100 @@ copy_word:
+ 	b		process_entry
+ 
+ done:
++#ifdef CONFIG_SMP
++	/* kexec_flag reset is signal to other CPUs what kernel
++ 	   was moved to it's location. Note - we need relocated address
++ 	   of kexec_flag.  */
++
++ 	bal		1f
++ 1: 	move		t1,ra;
++ 	PTR_LA		t2,1b
++ 	PTR_LA		t0,kexec_flag
++ 	PTR_SUB		t0,t0,t2;
++ 	PTR_ADD		t0,t1,t0;
++ 	LONG_S		zero,(t0)
++#endif
++
++	sync
+ 	/* jump to kexec_start_address */
+ 	j		s1
+ 	END(relocate_new_kernel)
+ 
+-kexec_start_address:
+-	EXPORT(kexec_start_address)
++#ifdef CONFIG_SMP
++/*
++ * Other CPUs should wait until code is relocated and
++ * then start at entry (?) point.
++ */
++LEAF(kexec_smp_wait)
++	PTR_L		a0, s_arg0
++	PTR_L		a1, s_arg1
++	PTR_L		a2, s_arg2
++	PTR_L		a3, s_arg3
++	PTR_L		s1, kexec_start_address
++
++	/* Non-relocated address works for args and kexec_start_address ( old
++	 * kernel is not overwritten). But we need relocated address of
++	 * kexec_flag.
++	 */
++
++	bal		1f
++1:	move		t1,ra;
++	PTR_LA		t2,1b
++	PTR_LA		t0,kexec_flag
++	PTR_SUB		t0,t0,t2;
++	PTR_ADD		t0,t1,t0;
++
++1:	LONG_L		s0, (t0)
++	bne		s0, zero,1b
++
++	sync
++	j		s1
++	END(kexec_smp_wait)
++#endif
++
++#ifdef __mips64
++       /* all PTR's must be aligned to 8 byte in 64-bit mode */
++       .align  3
++#endif
++
++/* All parameters to new kernel are passed in registers a0-a3.
++ * kexec_args[0..3] are uses to prepare register values.
++ */
++
++EXPORT(kexec_args)
++arg0:	PTR		0x0
++arg1:	PTR		0x0
++arg2:	PTR		0x0
++arg3:	PTR		0x0
++	.size	kexec_args,PTRSIZE*4
++
++#ifdef CONFIG_SMP
++/*
++ * Secondary CPUs may have different kernel parameters in
++ * their registers a0-a3. secondary_kexec_args[0..3] are used
++ * to prepare register values.
++ */
++EXPORT(secondary_kexec_args)
++s_arg0:	PTR		0x0
++s_arg1:	PTR		0x0
++s_arg2:	PTR		0x0
++s_arg3:	PTR		0x0
++	.size	secondary_kexec_args,PTRSIZE*4
++kexec_flag:
++	LONG		0x1
++
++#endif
++
++EXPORT(kexec_start_address)
+ 	PTR		0x0
+ 	.size		kexec_start_address, PTRSIZE
+ 
+-kexec_indirection_page:
+-	EXPORT(kexec_indirection_page)
++EXPORT(kexec_indirection_page)
+ 	PTR		0
+ 	.size		kexec_indirection_page, PTRSIZE
+ 
+ relocate_new_kernel_end:
+ 
+-relocate_new_kernel_size:
+-	EXPORT(relocate_new_kernel_size)
++EXPORT(relocate_new_kernel_size)
+ 	PTR		relocate_new_kernel_end - relocate_new_kernel
+ 	.size		relocate_new_kernel_size, PTRSIZE
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -21,6 +21,7 @@
+ #include <linux/console.h>
+ #include <linux/pfn.h>
+ #include <linux/debugfs.h>
++#include <linux/kexec.h>
+ 
+ #include <asm/addrspace.h>
+ #include <asm/bootinfo.h>
+@@ -488,12 +489,62 @@ static void __init arch_mem_init(char **
+ 	}
+ 
+ 	bootmem_init();
++#ifdef CONFIG_KEXEC
++	if (crashk_res.start != crashk_res.end)
++		reserve_bootmem(crashk_res.start,
++			crashk_res.end - crashk_res.start + 1,
++			BOOTMEM_DEFAULT);
++#endif
+ 	device_tree_init();
+ 	sparse_init();
+ 	plat_swiotlb_setup();
+ 	paging_init();
+ }
+ 
++#ifdef CONFIG_KEXEC
++static inline unsigned long long get_total_mem(void)
++{
++	unsigned long long total;
++	total = max_pfn - min_low_pfn;
++	return total << PAGE_SHIFT;
++}
++
++static void __init mips_parse_crashkernel(void)
++{
++	unsigned long long total_mem;
++	unsigned long long crash_size, crash_base;
++	int ret;
++
++	total_mem = get_total_mem();
++	ret = parse_crashkernel(boot_command_line, total_mem,
++			&crash_size, &crash_base);
++	if (ret != 0 || crash_size <= 0)
++		return;
++
++	crashk_res.start = crash_base;
++	crashk_res.end   = crash_base + crash_size - 1;
++}
++static void __init request_crashkernel(struct resource *res)
++{
++	int ret;
++
++	ret = request_resource(res, &crashk_res);
++	if (!ret)
++		printk(KERN_INFO "Reserving %ldMB of memory at %ldMB "
++			"for crashkernel\n",
++			(unsigned long)((crashk_res.end -
++				crashk_res.start + 1) >> 20),
++			(unsigned long)(crashk_res.start  >> 20));
++}
++#else
++static void __init mips_parse_crashkernel(void)
++{
++}
++static void __init request_crashkernel(struct resource *res)
++{
++}
++#endif
++
+ static void __init resource_init(void)
+ {
+ 	int i;
+@@ -509,6 +560,8 @@ static void __init resource_init(void)
+ 	/*
+ 	 * Request address space for all standard RAM.
+ 	 */
++	mips_parse_crashkernel();
++
+ 	for (i = 0; i < boot_mem_map.nr_map; i++) {
+ 		struct resource *res;
+ 		unsigned long start, end;
+@@ -544,6 +597,7 @@ static void __init resource_init(void)
+ 		 */
+ 		request_resource(res, &code_resource);
+ 		request_resource(res, &data_resource);
++		request_crashkernel(res);
+ 	}
+ }
+ 
+--- a/arch/mips/kernel/smp.c
++++ b/arch/mips/kernel/smp.c
+@@ -433,3 +433,21 @@ void flush_tlb_one(unsigned long vaddr)
+ 
+ EXPORT_SYMBOL(flush_tlb_page);
+ EXPORT_SYMBOL(flush_tlb_one);
++
++#if defined(CONFIG_KEXEC)
++void (*dump_ipi_function_ptr)(void *) = NULL;
++void dump_send_ipi(void (*dump_ipi_callback)(void *))
++{
++	int i;
++	int cpu = smp_processor_id();
++
++	dump_ipi_function_ptr = dump_ipi_callback;
++	smp_mb();
++	for_each_online_cpu(i)
++		if (i != cpu)
++			core_send_ipi(i, SMP_DUMP);
++
++}
++EXPORT_SYMBOL(dump_send_ipi);
++#endif
++
+--- a/arch/mips/include/asm/kexec.h
++++ b/arch/mips/include/asm/kexec.h
+@@ -9,22 +9,45 @@
+ #ifndef _MIPS_KEXEC
+ # define _MIPS_KEXEC
+ 
++#include <asm/stacktrace.h>
++
++extern unsigned long long elfcorehdr_addr;
++
+ /* Maximum physical address we can use pages from */
+ #define KEXEC_SOURCE_MEMORY_LIMIT (0x20000000)
+ /* Maximum address we can reach in physical address mode */
+ #define KEXEC_DESTINATION_MEMORY_LIMIT (0x20000000)
+  /* Maximum address we can use for the control code buffer */
+ #define KEXEC_CONTROL_MEMORY_LIMIT (0x20000000)
+-
+-#define KEXEC_CONTROL_PAGE_SIZE 4096
++/* Reserve 3*4096 bytes for board-specific info */
++#define KEXEC_CONTROL_PAGE_SIZE (4096 + 3*4096)
+ 
+ /* The native architecture */
+ #define KEXEC_ARCH KEXEC_ARCH_MIPS
++#define MAX_NOTE_BYTES 1024
+ 
+ static inline void crash_setup_regs(struct pt_regs *newregs,
+-				    struct pt_regs *oldregs)
++					struct pt_regs *oldregs)
+ {
+-	/* Dummy implementation for now */
++	if (oldregs)
++		memcpy(newregs, oldregs, sizeof(*newregs));
++	else
++		prepare_frametrace(newregs);
+ }
+ 
++#ifdef CONFIG_KEXEC
++struct kimage;
++extern unsigned long kexec_args[4];
++extern int (*_machine_kexec_prepare)(struct kimage *);
++extern void (*_machine_kexec_shutdown)(void);
++extern void (*_machine_crash_shutdown)(struct pt_regs *regs);
++extern void default_machine_crash_shutdown(struct pt_regs *regs);
++#ifdef CONFIG_SMP
++extern const unsigned char kexec_smp_wait[];
++extern unsigned long secondary_kexec_args[4];
++extern void (*relocated_kexec_smp_wait) (void *);
++extern atomic_t kexec_ready_to_reboot;
++#endif
++#endif
++
+ #endif /* !_MIPS_KEXEC */
+--- a/arch/mips/include/asm/smp.h
++++ b/arch/mips/include/asm/smp.h
+@@ -40,6 +40,8 @@ extern int __cpu_logical_map[NR_CPUS];
+ #define SMP_CALL_FUNCTION	0x2
+ /* Octeon - Tell another core to flush its icache */
+ #define SMP_ICACHE_FLUSH	0x4
++/* Used by kexec crashdump to save all cpu's state */
++#define SMP_DUMP		0x8
+ 
+ extern volatile cpumask_t cpu_callin_map;
+ 
+@@ -91,4 +93,9 @@ static inline void arch_send_call_functi
+ 	mp_ops->send_ipi_mask(mask, SMP_CALL_FUNCTION);
+ }
+ 
++extern void core_send_ipi(int cpu, unsigned int action);
++#if defined(CONFIG_KEXEC)
++extern void (*dump_ipi_function_ptr)(void *);
++void dump_send_ipi(void (*dump_ipi_callback)(void *));
++#endif
+ #endif /* __ASM_SMP_H */