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Kexec-hardboot patch for hammerhead
From a550e9f996b20ea00866bf115f95b5aeb122de0c Mon Sep 17 00:00:00 2001
From: Vojtech Bocek <vbocek@gmail.com>
Date: Fri, 6 Dec 2013 22:56:29 +0100
Subject: [PATCH] Implement 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>
Vojtech Bocek <vbocek@gmail.com>:
I've ported it to hammerhead, it is based of my mako/grouper port, which is
based of Asus TF201 patch ported by Jens Andersen <jens.andersen@gmail.com>
Hammerhead is the first device I've ported this patch to which uses
device tree binary instead of atags. It is also rather picky - its
bootloader erases first 128MB of RAM on reboot, so following hacks had
to be applied:
* Copy dtb to location passed in r2 before jumping to kexecd' kernel,
the kernel would just freeze when I left dtb above 128MB of RAM.
* Copy kexecd' kernel to location in the first 128MB before jumping to it,
the decompressor operates very slowly if the kernel is above the cached
area, copying it lower and decompressing it afterwards is much faster.
Same as my mako/flo patches, the guest kernel does not require any
modifications, kexec-hardboot is equivalent to standard kexec.
To support dtb, following commit was backported from the mainline:
commit 4cabd1d9625c7d88acd143f4021fbef75394f154
Author: Matthew Leach <matthew.leach@arm.com>
Date: Fri Sep 21 18:56:02 2012 +0100
ARM: 7539/1: kexec: scan for dtb magic in segments
This patch allows a dtb to be passed to a new kernel using the kexec
mechinism.
When loading segments from userspace, scan each segment's first four
bytes for the dtb magic. If this is found set the kexec_boot_atags
parameter to the relocate_kernel code to the phyical address of this
segment.
and fixes of this commit:
c564df4db85aac8d1d65a56176a0a25f46138064
2456f44dd7a9aaffc2cd21a13f78198b3d94da08
ayysir <dresadd09691@gmail.com>:
kexec: use mem_text_write_kernel_word to set reboot_code_buffer args
in order to avoid protection faults (writes to read-only
kernel memory) when CONFIG_STRICT_MEMORY_RWX is enabled.
Signed-off-by: Vojtech Bocek <vbocek@gmail.com>
---
arch/arm/Kconfig | 26 ++++++++++++
arch/arm/boot/compressed/head.S | 63 +++++++++++++++++++++++++++
arch/arm/include/asm/kexec.h | 8 ++++
arch/arm/kernel/machine_kexec.c | 58 +++++++++++++++++++++++--
arch/arm/kernel/relocate_kernel.S | 75 +++++++++++++++++++++++++++++++++
arch/arm/mach-msm/include/mach/memory.h | 13 ++++++
arch/arm/mach-msm/lge/devices_lge.c | 25 +++++++++++
arch/arm/mach-msm/restart.c | 28 ++++++++++++
include/linux/kexec.h | 19 +++++++--
kernel/kexec.c | 4 ++
10 files changed, 312 insertions(+), 7 deletions(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 69b2cd2..f853a89 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -2212,6 +2212,32 @@ 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 64a6d6f..29e8a3a 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -10,6 +10,11 @@
*/
#include <linux/linkage.h>
+#ifdef CONFIG_KEXEC_HARDBOOT
+ #include <asm/kexec.h>
+ #include <asm/memory.h>
+#endif
+
/*
* Debugging stuff
*
@@ -135,6 +140,64 @@ start:
1: mov r7, r1 @ save architecture ID
mov 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]
+
+ /*
+ * Copy dtb from location up high in memory to default location.
+ * Kernel freezes if this is not done.
+ */
+ ldr r1, [r3, #12] @ kexec_boot_atags
+ ldr r2, [r3, #16] @ kexec_boot_atags_len
+ mov r5, #0 @ iterator
+catags_cpy:
+ ldr r0, [r1, r5] @ from kexec_boot_atags
+ str r0, [r8, r5] @ to atags_pointer
+ add r5, r5, #4
+ cmp r5, r2
+ blo catags_cpy
+
+#ifdef KEXEC_HB_KERNEL_LOC
+ /*
+ * Copy kernel from location up high in memory to location in first 128MB.
+ * Bootloader on hammerhead erases first 128MB of ram on reboot, so it can't
+ * be in there before reboot, but decompressing in location above 128MB takes
+ * a long time. This memcpy is much quicker, for some reason.
+ */
+ ldr r2, [r3, #4] @ kexec_start_address
+ ldr r4, [r3, #20] @ kexec_kernel_len
+ ldr r6, =KEXEC_HB_KERNEL_LOC @ target
+ mov r5, #0 @ iterator
+kernel_cpy:
+ ldr r0, [r2, r5] @ from kexec_start_address
+ str r0, [r6, r5] @ to KEXEC_HB_KERNEL_LOC
+ add r5, r5, #4
+ cmp r5, r4
+ blo kernel_cpy
+#else
+ ldr r6, [r3, #4] @ kexec_start_address
+#endif
+
+ /* set registers and boot kexecd' kernel */
+ mov r0, #0
+ ldr r1, [r3, #8] @ kexec_mach_type
+ mov r2, r8 @ atags pointer
+ mov pc, r6
+
+ .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 c355aeb..2abfc8a 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -14,6 +14,9 @@
#include <asm/cacheflush.h>
#include <asm/mach-types.h>
#include <asm/system_misc.h>
+#include <linux/memblock.h>
+#include <linux/of_fdt.h>
+#include <asm/mmu_writeable.h>
extern const unsigned char relocate_new_kernel[];
extern const unsigned int relocate_new_kernel_size;
@@ -22,6 +25,12 @@ 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;
+extern unsigned long kexec_boot_atags_len;
+extern unsigned long kexec_kernel_len;
+void (*kexec_hardboot_hook)(void);
+#endif
static atomic_t waiting_for_crash_ipi;
@@ -32,6 +41,37 @@ static atomic_t waiting_for_crash_ipi;
int machine_kexec_prepare(struct kimage *image)
{
+ struct kexec_segment *current_segment;
+ __be32 header;
+ int i, err;
+
+ /* No segment at default ATAGs address. try to locate
+ * a dtb using magic */
+ for (i = 0; i < image->nr_segments; i++) {
+ current_segment = &image->segment[i];
+
+ err = memblock_is_region_memory(current_segment->mem,
+ current_segment->memsz);
+ if (!err)
+ return - EINVAL;
+
+#ifdef CONFIG_KEXEC_HARDBOOT
+ if(current_segment->mem == image->start)
+ mem_text_write_kernel_word(&kexec_kernel_len, current_segment->memsz);
+#endif
+
+ err = get_user(header, (__be32*)current_segment->buf);
+ if (err)
+ return err;
+
+ if (be32_to_cpu(header) == OF_DT_HEADER)
+ {
+ mem_text_write_kernel_word(&kexec_boot_atags, current_segment->mem);
+#ifdef CONFIG_KEXEC_HARDBOOT
+ mem_text_write_kernel_word(&kexec_boot_atags_len, current_segment->memsz);
+#endif
+ }
+ }
return 0;
}
@@ -120,10 +160,14 @@ void machine_kexec(struct kimage *image)
reboot_code_buffer = page_address(image->control_code_page);
/* Prepare parameters for reboot_code_buffer*/
- kexec_start_address = image->start;
- kexec_indirection_page = page_list;
- kexec_mach_type = machine_arch_type;
- kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
+ mem_text_write_kernel_word(&kexec_start_address, image->start);
+ mem_text_write_kernel_word(&kexec_indirection_page, page_list);
+ mem_text_write_kernel_word(&kexec_mach_type, machine_arch_type);
+ if (!kexec_boot_atags)
+ mem_text_write_kernel_word(&kexec_boot_atags, image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET);
+#ifdef CONFIG_KEXEC_HARDBOOT
+ mem_text_write_kernel_word(&kexec_hardboot, image->hardboot);
+#endif
/* copy our kernel relocation code to the control code page */
memcpy(reboot_code_buffer,
@@ -137,5 +181,11 @@ void machine_kexec(struct kimage *image)
if (kexec_reinit)
kexec_reinit();
+#ifdef CONFIG_KEXEC_HARDBOOT
+ /* Run any final machine-specific shutdown code. */
+ if (image->hardboot && kexec_hardboot_hook)
+ kexec_hardboot_hook();
+#endif
+
soft_restart(reboot_code_buffer_phys);
}
diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
index d0cdedf..0e45ffc 100644
--- a/arch/arm/kernel/relocate_kernel.S
+++ b/arch/arm/kernel/relocate_kernel.S
@@ -4,6 +4,15 @@
#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>
+#elif defined(CONFIG_ARCH_APQ8064) || defined(CONFIG_ARCH_MSM8974)
+ #include <mach/msm_iomap.h>
+#endif
+#endif
+
.globl relocate_new_kernel
relocate_new_kernel:
@@ -52,6 +61,12 @@ 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 +75,52 @@ 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
+ * 16: kexec_boot_atags_len
+ * 20: kexec_kernel_len */
+ 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_boot_atags_len
+ str r1, [r0, #16]
+ ldr r1, kexec_kernel_len
+ str r1, [r0, #20]
+ 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
+#elif defined(CONFIG_ARCH_APQ8064)
+ /* Restart using the PMIC chip, see mach-msm/restart.c */
+ ldr r0, =APQ8064_TLMM_PHYS
+ mov r1, #0
+ str r1, [r0, #0x820] @ PSHOLD_CTL_SU
+loop: b loop
+#elif defined(CONFIG_ARCH_MSM8974)
+ /* Restart using the PMIC chip, see mach-msm/restart.c */
+ ldr r0, =MSM8974_MPM2_PSHOLD_PHYS
+ mov r1, #0
+ str r1, [r0, #0]
+loop: b loop
+#else
+#error "No reboot method defined for hardboot."
+#endif
+
+ .ltorg
+#endif
.align
.globl kexec_start_address
@@ -79,6 +140,20 @@ kexec_mach_type:
kexec_boot_atags:
.long 0x0
+#ifdef CONFIG_KEXEC_HARDBOOT
+ .globl kexec_boot_atags_len
+kexec_boot_atags_len:
+ .long 0x0
+
+ .globl kexec_kernel_len
+kexec_kernel_len:
+ .long 0x0
+
+ .globl kexec_hardboot
+kexec_hardboot:
+ .long 0x0
+#endif
+
relocate_new_kernel_end:
.globl relocate_new_kernel_size
diff --git a/arch/arm/mach-msm/include/mach/memory.h b/arch/arm/mach-msm/include/mach/memory.h
index 6119a3c..9a265f4 100644
--- a/arch/arm/mach-msm/include/mach/memory.h
+++ b/arch/arm/mach-msm/include/mach/memory.h
@@ -20,6 +20,19 @@
/* physical offset of RAM */
#define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
+#if defined(CONFIG_KEXEC_HARDBOOT)
+#if defined(CONFIG_MACH_APQ8064_FLO)
+#define KEXEC_HB_PAGE_ADDR UL(0x88C00000)
+#elif defined(CONFIG_MACH_APQ8064_MAKO)
+#define KEXEC_HB_PAGE_ADDR UL(0x88600000)
+#elif defined(CONFIG_MACH_MSM8974_HAMMERHEAD)
+#define KEXEC_HB_PAGE_ADDR UL(0x10100000)
+#define KEXEC_HB_KERNEL_LOC UL(0x3208000)
+#else
+#error "Adress for kexec hardboot page not defined"
+#endif
+#endif
+
#define MAX_PHYSMEM_BITS 32
#define SECTION_SIZE_BITS 28
diff --git a/arch/arm/mach-msm/lge/devices_lge.c b/arch/arm/mach-msm/lge/devices_lge.c
index 3d176fc..c5b4e98 100644
--- a/arch/arm/mach-msm/lge/devices_lge.c
+++ b/arch/arm/mach-msm/lge/devices_lge.c
@@ -27,6 +27,10 @@
#endif
#include <ram_console.h>
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <linux/memblock.h>
+#endif
+
#ifdef CONFIG_ANDROID_RAM_CONSOLE
#define LGE_RAM_CONSOLE_SIZE (128 * SZ_1K * 2)
static char bootreason[128] = {0,};
@@ -113,6 +117,27 @@ static void __init lge_add_persist_ram_devices(void)
void __init lge_reserve(void)
{
+#ifdef CONFIG_KEXEC_HARDBOOT
+ // Reserve space for hardboot page - just after ram_console,
+ // at the start of second memory bank
+ int ret;
+ phys_addr_t start;
+ struct membank* bank;
+
+ if (meminfo.nr_banks < 2) {
+ pr_err("%s: not enough membank\n", __func__);
+ return;
+ }
+
+ bank = &meminfo.bank[1];
+ start = bank->start + SZ_1M + LGE_PERSISTENT_RAM_SIZE;
+ ret = memblock_remove(start, SZ_1M);
+ if(!ret)
+ pr_info("Hardboot page reserved at 0x%X\n", start);
+ else
+ pr_err("Failed to reserve space for hardboot page at 0x%X!\n", start);
+#endif
+
#if defined(CONFIG_ANDROID_PERSISTENT_RAM)
lge_add_persist_ram_devices();
#endif
diff --git a/arch/arm/mach-msm/restart.c b/arch/arm/mach-msm/restart.c
index d208b4c..7e1caef 100644
--- a/arch/arm/mach-msm/restart.c
+++ b/arch/arm/mach-msm/restart.c
@@ -41,6 +41,10 @@
#include <mach/lge_handle_panic.h>
#endif
+#ifdef CONFIG_KEXEC_HARDBOOT
+#include <asm/kexec.h>
+#endif
+
#define WDT0_RST 0x38
#define WDT0_EN 0x40
#define WDT0_BARK_TIME 0x4C
@@ -353,6 +357,26 @@ static int __init msm_pmic_restart_init(void)
late_initcall(msm_pmic_restart_init);
+#ifdef CONFIG_KEXEC_HARDBOOT
+static void msm_kexec_hardboot_hook(void)
+{
+ set_dload_mode(0);
+
+ // Set PMIC to restart-on-poweroff
+ pm8xxx_reset_pwr_off(1);
+
+ // These are executed on normal reboot, but with kexec-hardboot,
+ // they reboot/panic the system immediately.
+#if 0
+ qpnp_pon_system_pwr_off(PON_POWER_OFF_WARM_RESET);
+
+ /* Needed to bypass debug image on some chips */
+ msm_disable_wdog_debug();
+ halt_spmi_pmic_arbiter();
+#endif
+}
+#endif
+
static int __init msm_restart_init(void)
{
#ifdef CONFIG_MSM_DLOAD_MODE
@@ -377,6 +401,10 @@ static int __init msm_restart_init(void)
if (scm_is_call_available(SCM_SVC_PWR, SCM_IO_DISABLE_PMIC_ARBITER) > 0)
scm_pmic_arbiter_disable_supported = true;
+#ifdef CONFIG_KEXEC_HARDBOOT
+ kexec_hardboot_hook = msm_kexec_hardboot_hook;
+#endif
+
return 0;
}
early_initcall(msm_restart_init);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index af84a25..a4509ad 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -111,6 +111,10 @@ 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
@@ -178,6 +182,11 @@ 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.
@@ -196,10 +205,14 @@ 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 4e2e472..aef7893 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1004,6 +1004,10 @@ 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;
--
1.8.5.1
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