target/linux/generic/patches-3.2/331-mips-kexec-enhanche-the-support.patch

   1 From 03cd81fbca6b91317ec1a7b3b3c09fb8d08f83a6 Mon Sep 17 00:00:00 2001
   2 From: Wu Zhangjin <wuzhangjin@gmail.com>
   3 Date: Tue, 11 Jan 2011 18:42:08 +0000
   4 Subject: MIPS: Kexec: Enhance the support
   5
   6 Changes:
   7   o Print more information in machine_kexec() for debugging
   8     E.g. with this information, the kexec_start_address has been found
   9     it was wrong with 64bit kernel / o32 kexec-tools. Which must be
  10     fixed later.
  11   o Link relocate_kernel.S to a section for future extension
  12     This allows more functions can be added for the kexec relocation
  13     part even written in C. to add code into that section, you just need
  14     to mark your function or data with __kexec or
  15     __attribute__((__section__(".__kexec.relocate")))
  16
  17 TODO:
  18
  19 1. Make 64bit kernel / o32|n32|64 kexec-tools works
  20
  21 Fix the user-space kexec-tools, seems the tool only work for 32bit
  22 machine. So, we need to add 64bit support for it. The address of the
  23 entry point(kexec_start_address) is wrong and make the "kexec -e" fail.
  24 the real entry point must be read from the new kernel image by the
  25 user-space kexec-tools, otherwise, it will not work.  The above 64bit
  26 support tested is 64bit kernel with o32 user-space kexec-tools. The root
  27 cause may be the different definition of virt_to_phys() and
  28 phys_to_virt() in the kexec-tools and kernel space for 64bit system /
  29 o32 kernel.
  30
  31 Ref: http://www.linux-mips.org/archives/linux-mips/2009-08/msg00149.html
  32
  33 2. Pass the arguments from kexec-tools to the new kernel image
  34
  35 Please refer to: "MIPS: Loongson: Kexec: Pass parameters to new kernel"
  36
  37 Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
  38 ---
  39 --- a/arch/mips/include/asm/kexec.h
  40 +++ b/arch/mips/include/asm/kexec.h
  41 @@ -36,6 +36,16 @@ static inline void crash_setup_regs(stru
  42  }
  43
  44  #ifdef CONFIG_KEXEC
  45 +
  46 +#define __kexec __attribute__((__section__(".__kexec.relocate")))
  47 +
  48 +/* The linker tells us where the relocate_new_kernel part is. */
  49 +extern const unsigned char __start___kexec_relocate;
  50 +extern const unsigned char __end___kexec_relocate;
  51 +
  52 +extern unsigned long kexec_start_address;
  53 +extern unsigned long kexec_indirection_page;
  54 +
  55  struct kimage;
  56  extern unsigned long kexec_args[4];
  57  extern int (*_machine_kexec_prepare)(struct kimage *);
  58 --- a/arch/mips/kernel/machine_kexec.c
  59 +++ b/arch/mips/kernel/machine_kexec.c
  60 @@ -13,12 +13,6 @@
  61  #include <asm/cacheflush.h>
  62  #include <asm/page.h>
  63
  64 -extern const unsigned char relocate_new_kernel[];
  65 -extern const size_t relocate_new_kernel_size;
  66 -
  67 -extern unsigned long kexec_start_address;
  68 -extern unsigned long kexec_indirection_page;
  69 -
  70  int (*_machine_kexec_prepare)(struct kimage *) = NULL;
  71  void (*_machine_kexec_shutdown)(void) = NULL;
  72  void (*_machine_crash_shutdown)(struct pt_regs *regs) = NULL;
  73 @@ -61,21 +55,34 @@ typedef void (*noretfun_t)(void) __attri
  74  void
  75  machine_kexec(struct kimage *image)
  76  {
  77 +       unsigned long kexec_relocate_size;
  78         unsigned long reboot_code_buffer;
  79         unsigned long entry;
  80         unsigned long *ptr;
  81
  82 +       kexec_relocate_size = (unsigned long)(&__end___kexec_relocate) -
  83 +               (unsigned long)(&__start___kexec_relocate);
  84 +       pr_info("kexec_relocate_size = %lu\n", kexec_relocate_size);
  85 +
  86         reboot_code_buffer =
  87           (unsigned long)page_address(image->control_code_page);
  88 +       pr_info("reboot_code_buffer = %p\n", (void *)reboot_code_buffer);
  89
  90         kexec_start_address =
  91           (unsigned long) phys_to_virt(image->start);
  92 +       pr_info("kexec_start_address(entry point of new kernel) = %p\n",
  93 +                       (void *)kexec_start_address);
  94
  95         kexec_indirection_page =
  96                 (unsigned long) phys_to_virt(image->head & PAGE_MASK);
  97 +       pr_info("kexec_indirection_page = %p\n",
  98 +                       (void *)kexec_indirection_page);
  99
 100 -       memcpy((void*)reboot_code_buffer, relocate_new_kernel,
 101 -              relocate_new_kernel_size);
 102 +       memcpy((void *)reboot_code_buffer, &__start___kexec_relocate,
 103 +              kexec_relocate_size);
 104 +
 105 +       pr_info("Copy kexec_relocate section from %p to reboot_code_buffer: %p\n",
 106 +                       &__start___kexec_relocate, (void *)reboot_code_buffer);
 107
 108         /*
 109          * The generic kexec code builds a page list with physical
 110 @@ -96,8 +103,8 @@ machine_kexec(struct kimage *image)
 111          */
 112         local_irq_disable();
 113
 114 -       printk("Will call new kernel at %08lx\n", image->start);
 115 -       printk("Bye ...\n");
 116 +       pr_info("Will call new kernel at %p\n", (void *)kexec_start_address);
 117 +       pr_info("Bye ...\n");
 118         __flush_cache_all();
 119  #ifdef CONFIG_SMP
 120         /* All secondary cpus now may jump to kexec_wait cycle */
 121 @@ -108,4 +115,3 @@ machine_kexec(struct kimage *image)
 122  #endif
 123         ((noretfun_t) reboot_code_buffer)();
 124  }
 125 -
 126 --- a/arch/mips/kernel/relocate_kernel.S
 127 +++ b/arch/mips/kernel/relocate_kernel.S
 128 @@ -14,6 +14,8 @@
 129  #include <asm/stackframe.h>
 130  #include <asm/addrspace.h>
 131
 132 +       .section        .kexec.relocate, "ax"
 133 +
 134  LEAF(relocate_new_kernel)
 135         PTR_L a0,       arg0
 136         PTR_L a1,       arg1
 137 @@ -155,9 +157,3 @@ EXPORT(kexec_start_address)
 138  EXPORT(kexec_indirection_page)
 139         PTR             0
 140         .size           kexec_indirection_page, PTRSIZE
 141 -
 142 -relocate_new_kernel_end:
 143 -
 144 -EXPORT(relocate_new_kernel_size)
 145 -       PTR             relocate_new_kernel_end - relocate_new_kernel
 146 -       .size           relocate_new_kernel_size, PTRSIZE
 147 --- a/arch/mips/kernel/vmlinux.lds.S
 148 +++ b/arch/mips/kernel/vmlinux.lds.S
 149 @@ -50,6 +50,10 @@ SECTIONS
 150                 *(.text.*)
 151                 *(.fixup)
 152                 *(.gnu.warning)
 153 +               __start___kexec_relocate = .;
 154 +               KEEP(*(.kexec.relocate))
 155 +               KEEP(*(.__kexec.relocate))
 156 +               __end___kexec_relocate = .;
 157         } :text = 0
 158         _etext = .;     /* End of text section */
 159