Support hard booting to a kexec kernel.

See KEXEC_HARDBOOT config option help for details.

Conflicts:

	arch/arm/configs/crespo_defconfig

arch/arm/Kconfig

@@ -1941,6 +1941,32 @@ config ATAGS_PROC
 	  Should the atags used to boot the kernel be exported in an "atags"
 	  file in procfs. Useful with kexec.
 
+config KEXEC_HARDBOOT
+	bool "Support hard booting to a kexec kernel"
+	depends on KEXEC
+	help
+	  Allows hard booting (i.e., with a full hardware reboot) to a kernel
+	  previously loaded in memory by kexec.  This works around the problem of
+	  soft-booted kernel hangs due to improper device shutdown and/or
+	  reinitialization.  Support is comprised of two components:
+
+	  First, a "hardboot" flag is added to the kexec syscall to force a hard
+	  reboot in relocate_new_kernel() (which requires machine-specific assembly
+	  code).  This also requires the kexec userspace tool to load the kexec'd
+	  kernel in memory region left untouched by the bootloader (i.e., not
+	  explicitly cleared and not overwritten by the boot kernel).  Just prior
+	  to reboot, the kexec kernel arguments are stashed in a machine-specific
+	  memory page that must also be preserved.  Note that this hardboot page
+	  need not be reserved during regular kernel execution.
+
+	  Second, the zImage decompresor of the boot (bootloader-loaded) kernel is
+	  modified to check the hardboot page for fresh kexec arguments, and if
+	  present, attempts to jump to the kexec'd kernel preserved in memory.
+
+	  Note that hardboot support is only required in the boot kernel and any
+	  kernel capable of performing a hardboot kexec.  It is _not_ required by a
+	  kexec'd kernel.
+
 config CRASH_DUMP
 	bool "Build kdump crash kernel (EXPERIMENTAL)"
 	depends on EXPERIMENTAL

arch/arm/boot/compressed/head.S

@@ -11,6 +11,10 @@
 #include <linux/linkage.h>
 #include <asm/memory.h>
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <asm/kexec.h>
+#endif
+
 /*
  * Debugging stuff
  *
@@ -138,6 +142,28 @@ start:
 		movne	r8, r0			@ Save kexec_boot_tags.
 		moveq	r8, r2			@ save atags pointer
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+		/* Check hardboot page for a kexec kernel. */
+		ldr	r3, =KEXEC_HB_PAGE_ADDR
+		ldr	r0, [r3]
+		ldr	r1, =KEXEC_HB_PAGE_MAGIC
+		teq	r0, r1
+		bne	not_booting_other
+
+		/* Clear hardboot page magic to avoid boot loop. */
+		mov	r0, #0
+		str	r0, [r3]
+
+		/* Load boot arguments and jump to kexec kernel. */
+		ldr	r0, [r3, #12]	@ kexec_boot_atags (r2: boot_atags)
+		ldr	r1, [r3, #8]	@ kexec_mach_type
+		ldr	pc, [r3, #4]	@ kexec_start_address
+
+		.ltorg
+
+not_booting_other:
+#endif
+
 #ifndef __ARM_ARCH_2__
 		/*
 		 * Booting from Angel - need to enter SVC mode and disable

arch/arm/include/asm/kexec.h

@@ -17,6 +17,10 @@
 #define KEXEC_ARM_ATAGS_OFFSET  0x1000
 #define KEXEC_ARM_ZIMAGE_OFFSET 0x8000
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#define KEXEC_HB_PAGE_MAGIC 0x4a5db007
+#endif
+
 #ifndef __ASSEMBLY__
 
 /**

arch/arm/kernel/machine_kexec.c

@@ -13,6 +13,10 @@
 #include <asm/cacheflush.h>
 #include <asm/mach-types.h>
 
+#if defined(CONFIG_KEXEC_HARDBOOT) && defined(CONFIG_ARCH_S5PV210)
+#include <mach/regs-clock.h>
+#endif
+
 extern const unsigned char relocate_new_kernel[];
 extern const unsigned int relocate_new_kernel_size;
 
@@ -22,6 +26,10 @@ extern unsigned long kexec_start_address;
 extern unsigned long kexec_indirection_page;
 extern unsigned long kexec_mach_type;
 extern unsigned long kexec_boot_atags;
+#ifdef CONFIG_KEXEC_HARDBOOT
+extern unsigned long kexec_hardboot;
+#endif
+
 
 static atomic_t waiting_for_crash_ipi;
 
@@ -99,6 +107,10 @@ void machine_kexec(struct kimage *image)
 	kexec_indirection_page = page_list;
 	kexec_mach_type = machine_arch_type;
 	kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
+#ifdef CONFIG_KEXEC_HARDBOOT
+	kexec_hardboot = image->hardboot;
+#endif
+
 
 	/* copy our kernel relocation code to the control code page */
 	memcpy(reboot_code_buffer,

arch/arm/kernel/relocate_kernel.S

@@ -4,6 +4,13 @@
 
 #include <asm/kexec.h>
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <asm/memory.h>
+#ifdef CONFIG_ARCH_S5PV210
+#include <mach/map.h>
+#endif
+#endif
+
 	.globl relocate_new_kernel
 relocate_new_kernel:
 
@@ -52,6 +59,12 @@ relocate_new_kernel:
 	b 0b
 
 2:
+#ifdef CONFIG_KEXEC_HARDBOOT
+	ldr	r0, kexec_hardboot
+	teq	r0, #0
+	bne	hardboot
+#endif
+
 	/* Jump to relocated kernel */
 	mov lr,r1
 	mov r0,#0
@@ -60,6 +73,41 @@ relocate_new_kernel:
  ARM(	mov pc, lr	)
  THUMB(	bx lr		)
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+hardboot:
+	/* Stash boot arguments in hardboot page:
+	 *  0: KEXEC_HB_PAGE_MAGIC
+	 *  4: kexec_start_address
+	 *  8: kexec_mach_type
+	 * 12: kexec_boot_atags */
+	ldr	r0, =KEXEC_HB_PAGE_ADDR
+	str	r1, [r0, #4]
+	ldr	r1, kexec_mach_type
+	str	r1, [r0, #8]
+	ldr	r1, kexec_boot_atags
+	str	r1, [r0, #12]
+	ldr	r1, =KEXEC_HB_PAGE_MAGIC
+	str	r1, [r0]
+
+#ifdef CONFIG_ARCH_S5PV210
+	/* Hard reset via watchdog, decompressor jumps to kernel. */
+	ldr	r0, =S3C_PA_WDT
+	mov	r1, #0x8000
+	str	r1, [r0, #4]
+	mov	r1, #1
+	str	r1, [r0, #4]
+	mov	r1, #8
+	str	r1, [r0, #8]
+	movw	r1, #0x8021
+	str	r1, [r0]
+loop:	b	loop
+#else
+#error "No reboot method defined for hardboot."
+#endif
+
+	.ltorg
+#endif
+
 	.align
 
 	.globl kexec_start_address
@@ -79,6 +127,12 @@ kexec_mach_type:
 kexec_boot_atags:
 	.long	0x0
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+	.globl kexec_hardboot
+kexec_hardboot:
+	.long	0x0
+#endif
+
 relocate_new_kernel_end:
 
 	.globl relocate_new_kernel_size

arch/arm/mach-tegra/board-tf201.c

@@ -807,15 +807,21 @@ static void __init tf201_ramconsole_reserve(unsigned long size)
 {
 	struct resource *res;
 	long ret;
+	unsigned long real_start, real_size;
 
 	res = platform_get_resource(&ram_console_device, IORESOURCE_MEM, 0);
 	if (!res) {
 		pr_err("Failed to find memory resource for ram console\n");
 		return;
 	}
+	
 	res->start = memblock_end_of_DRAM() - size;
 	res->end = res->start + size - 1;
-	ret = memblock_remove(res->start, size);
+	// Register an extra 1M before ramconsole to store kexec stuff
+	real_start = res->start - SZ_1M;
+	real_size = size + SZ_1M;
+
+	ret = memblock_remove(real_start, real_size);
 	if (ret) {
 		ram_console_device.resource = NULL;
 		ram_console_device.num_resources = 0;

arch/arm/mach-tegra/include/mach/memory.h

@@ -26,9 +26,15 @@
 #if defined(CONFIG_ARCH_TEGRA_2x_SOC)
 #define PLAT_PHYS_OFFSET		UL(0)
 #define END_MEM				UL(0x40000000)
+#if defined(CONFIG_KEXEC_HARDBOOT)
+#define KEXEC_HB_PAGE_ADDR 		UL(0x3FE00000)
+#endif
 #else
 #define PLAT_PHYS_OFFSET		UL(0x80000000)
 #define END_MEM				UL(0xC0000000)
+#if defined(CONFIG_KEXEC_HARDBOOT)
+#define KEXEC_HB_PAGE_ADDR 		UL(0xBFE00000)
+#endif
 #endif
 
 /*
@@ -41,5 +47,7 @@
 
 #define CONSISTENT_DMA_SIZE	(14 * SZ_1M)
 
+
+
 #endif
 

include/linux/kexec.h

@@ -100,6 +100,9 @@ struct kimage {
 #define KEXEC_TYPE_DEFAULT 0
 #define KEXEC_TYPE_CRASH   1
 	unsigned int preserve_context : 1;
+#ifdef CONFIG_KEXEC_HARDBOOT
+	unsigned int hardboot : 1;
+#endif
 
 #ifdef ARCH_HAS_KIMAGE_ARCH
 	struct kimage_arch arch;
@@ -165,6 +168,9 @@ extern struct kimage *kexec_crash_image;
 
 #define KEXEC_ON_CRASH		0x00000001
 #define KEXEC_PRESERVE_CONTEXT	0x00000002
+#ifdef CONFIG_KEXEC_HARDBOOT
+#define KEXEC_HARDBOOT		0x00000004
+#endif
 #define KEXEC_ARCH_MASK		0xffff0000
 
 /* These values match the ELF architecture values.
@@ -183,10 +189,14 @@ extern struct kimage *kexec_crash_image;
 #define KEXEC_ARCH_MIPS    ( 8 << 16)
 
 /* List of defined/legal kexec flags */
-#ifndef CONFIG_KEXEC_JUMP
-#define KEXEC_FLAGS    KEXEC_ON_CRASH
-#else
+#if defined(CONFIG_KEXEC_JUMP) && defined(CONFIG_KEXEC_HARDBOOT)
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT | KEXEC_HARDBOOT)
+#elif defined(CONFIG_KEXEC_JUMP)
 #define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT)
+#elif defined(CONFIG_KEXEC_HARDBOOT)
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH | KEXEC_HARDBOOT)
+#else
+#define KEXEC_FLAGS    (KEXEC_ON_CRASH)
 #endif
 
 #define VMCOREINFO_BYTES           (4096)

kernel/kexec.c

@@ -1005,6 +1005,10 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
 
 		if (flags & KEXEC_PRESERVE_CONTEXT)
 			image->preserve_context = 1;
+#ifdef CONFIG_KEXEC_HARDBOOT
+		if (flags & KEXEC_HARDBOOT)
+			image->hardboot = 1;
+#endif
 		result = machine_kexec_prepare(image);
 		if (result)
 			goto out;
@@ -1537,7 +1541,15 @@ int kernel_kexec(void)
 	} else
 #endif
 	{
-		kernel_restart_prepare(NULL);
+#ifdef CONFIG_KEXEC_HARDBOOT
+		if (kexec_image->hardboot)
+			/* Reboot with the recovery kernel since the boot kernel decompressor may
+			 * not support the hardboot jump. */
+			kernel_restart_prepare("recovery");
+		else
+#endif
+			kernel_restart_prepare(NULL);
+
 		printk(KERN_EMERG "Starting new kernel\n");
 		machine_shutdown();
 	}