File kexec-hardboot.patch of Package kernel-adaptation-google-nexus7

File kexec-hardboot.patch of Package kernel-adaptation-google-nexus7 (Revision 2fcee4f084184500efc2439b3e2f2d2a)

Currently displaying revision 2fcee4f084184500efc2439b3e2f2d2a, show latest

From 043abc1a244087b568c354c533f85d128bd6f723 Mon Sep 17 00:00:00 2001
From: Mike Kasick <mike@kasick.org>
Date: Tue, 27 Nov 2012 16:39:12 +0100
Subject: [PATCH 1/1] Add support for kexec-hardboot

"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."
More info in /arch/arm/Kconfig.

Original author: Mike Kasick <mike@kasick.org>
These patches are ported from Asus TF201, to which it
was ported by Jens Andersen <jens.andersen@gmail.com>.

Change-Id: Ibee734f61ffa97577bfbcdd9a8cd567bd2d89f32
---
 arch/arm/Kconfig                          |   26 ++++++++++++++++
 arch/arm/boot/compressed/head.S           |   26 ++++++++++++++++
 arch/arm/include/asm/kexec.h              |    8 +++++
 arch/arm/kernel/machine_kexec.c           |   25 +++++++++++++--
 arch/arm/kernel/relocate_kernel.S         |   47 +++++++++++++++++++++++++++++
 arch/arm/mach-tegra/common.c              |    9 +++++-
 arch/arm/mach-tegra/include/mach/memory.h |    8 +++++
 arch/arm/mach-tegra/reset.c               |   23 ++++++++++++++
 include/linux/kexec.h                     |   19 ++++++++++--
 kernel/kexec.c                            |    4 ++
 10 files changed, 188 insertions(+), 7 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 3c3b868..5903cec 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1993,6 +1993,32 @@ 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
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 99fa555..8d04dec 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/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
diff --git a/arch/arm/include/asm/kexec.h b/arch/arm/include/asm/kexec.h
index c2b9b4b..564c55b 100644
--- a/arch/arm/include/asm/kexec.h
+++ b/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__
 
 /**
@@ -53,6 +57,10 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 /* Function pointer to optional machine-specific reinitialization */
 extern void (*kexec_reinit)(void);
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+extern void (*kexec_hardboot_hook)(void);
+#endif
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* CONFIG_KEXEC */
diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index e59bbd4..812c0cb 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -22,6 +22,10 @@ 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;
+void (*kexec_hardboot_hook)(void);
+#endif
 
 static atomic_t waiting_for_crash_ipi;
 
@@ -99,6 +103,9 @@ 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,
@@ -114,11 +121,23 @@ void machine_kexec(struct kimage *image)
 	local_irq_disable();
 	local_fiq_disable();
 	setup_mm_for_reboot(0); /* mode is not used, so just pass 0*/
+
+#ifdef CONFIG_KEXEC_HARDBOOT
+	/* Run any final machine-specific shutdown code. */
+	if (image->hardboot && kexec_hardboot_hook)
+		kexec_hardboot_hook();
+#endif
+
 	flush_cache_all();
 	outer_flush_all();
 	outer_disable();
 	cpu_proc_fin();
-	outer_inv_all();
-	flush_cache_all();
-	cpu_reset(reboot_code_buffer_phys);
+
+	// Freezes the tegra 3
+	//outer_inv_all();
+	//flush_cache_all();
+
+	/* Must call cpu_reset via physical address since ARMv7 (& v6) stalls the
+	 * pipeline after disabling the MMU. */
+	((typeof(cpu_reset) *)virt_to_phys(cpu_reset))(reboot_code_buffer_phys);
 }
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
index d0cdedf..98e0a89 100644
--- a/arch/arm/kernel/relocate_kernel.S
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -4,6 +4,13 @@
 
 #include <asm/kexec.h>
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <asm/memory.h>
+#if defined(CONFIG_ARCH_TEGRA_2x_SOC) || defined(CONFIG_ARCH_TEGRA_3x_SOC)
+  #include <mach/iomap.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 +73,34 @@ 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]
+
+#if defined(CONFIG_ARCH_TEGRA_2x_SOC) || defined(CONFIG_ARCH_TEGRA_3x_SOC)
+	ldr     r0, =TEGRA_PMC_BASE
+	ldr	r1, [r0]
+	orr	r1, r1, #0x10
+	str	r1, [r0]
+loop:	b	loop
+#else
+#error "No reboot method defined for hardboot."
+#endif
+
+	.ltorg
+#endif
 	.align
 
 	.globl kexec_start_address
@@ -79,6 +120,12 @@ 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
diff --git a/arch/arm/mach-tegra/common.c b/arch/arm/mach-tegra/common.c
index d91ad83..89dede3 100755
--- a/arch/arm/mach-tegra/common.c
+++ b/arch/arm/mach-tegra/common.c
@@ -961,13 +961,20 @@ void __init tegra_ram_console_debug_reserve(unsigned long ram_console_size)
 {
 	struct resource *res;
 	long ret;
+	unsigned long real_start, real_size;
 
 	res = platform_get_resource(&ram_console_device, IORESOURCE_MEM, 0);
 	if (!res)
 		goto fail;
+
 	res->start = memblock_end_of_DRAM() - ram_console_size;
 	res->end = res->start + ram_console_size - 1;
-	ret = memblock_remove(res->start, ram_console_size);
+
+	// Register an extra 1M before ramconsole to store kexec stuff
+	real_start = res->start - SZ_1M;
+	real_size = ram_console_size + SZ_1M;
+
+	ret = memblock_remove(real_start, real_size);
 	if (ret)
 		goto fail;
 
diff --git a/arch/arm/mach-tegra/include/mach/memory.h b/arch/arm/mach-tegra/include/mach/memory.h
index c243a32..84dd44e 100644
--- a/arch/arm/mach-tegra/include/mach/memory.h
+++ b/arch/arm/mach-tegra/include/mach/memory.h
@@ -33,6 +33,14 @@
 #define END_MEM		            UL(0xBEA00000)
 #endif
 
+#if defined(CONFIG_KEXEC_HARDBOOT)
+#if defined(CONFIG_MACH_GROUPER)
+#define KEXEC_HB_PAGE_ADDR		UL(0xBEA00000)
+#else
+#error "Adress for kexec hardboot page not defined"
+#endif
+#endif
+
 /*
  * Unaligned DMA causes tegra dma to place data on 4-byte boundary after
  * expected address. Call to skb_reserve(skb, NET_IP_ALIGN) was causing skb
diff --git a/arch/arm/mach-tegra/reset.c b/arch/arm/mach-tegra/reset.c
index 3ab2c13..d91ba95 100644
--- a/arch/arm/mach-tegra/reset.c
+++ b/arch/arm/mach-tegra/reset.c
@@ -27,6 +27,10 @@
 #include "sleep.h"
 #include "pm.h"
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <asm/kexec.h>
+#endif
+
 static bool is_enabled;
 
 static void tegra_cpu_reset_handler_enable(void)
@@ -88,6 +92,21 @@ void tegra_cpu_reset_handler_restore(void)
 }
 #endif
 
+#ifdef CONFIG_KEXEC_HARDBOOT
+#define RECOVERY_MODE	BIT(31)
+void tegra_kexec_hardboot(void)
+{
+	/* Reboot with the recovery kernel since the boot kernel decompressor may
+	 * not support the hardboot jump. */
+
+	void __iomem *reset = IO_ADDRESS(TEGRA_PMC_BASE + 0x00);
+
+	u32 reg = readl_relaxed(reset + PMC_SCRATCH0);
+	reg |= RECOVERY_MODE;
+	writel_relaxed(reg, reset + PMC_SCRATCH0);
+}
+#endif
+
 void __init tegra_cpu_reset_handler_init(void)
 {
 #ifdef CONFIG_SMP
@@ -112,4 +131,8 @@ void __init tegra_cpu_reset_handler_init(void)
 			  __pa(&__tegra_cpu_reset_handler_data[TEGRA_RESET_DATA_SIZE]));
 
 	tegra_cpu_reset_handler_enable();
+
+#ifdef CONFIG_KEXEC_HARDBOOT
+	kexec_hardboot_hook = tegra_kexec_hardboot;
+#endif
 }
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index c2478a3..e0f1cee 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -101,6 +101,10 @@ struct kimage {
 #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;
 #endif
@@ -165,6 +169,11 @@ 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 +192,14 @@ 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)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 296fbc8..2e2f1df 100644
--- a/kernel/kexec.c
+++ b/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;
-- 
1.7.2.5