arch/mips/kernel/relocate_kernel.S

   1 /*
   2  * relocate_kernel.S for kexec
   3  * Created by <nschichan@corp.free.fr> on Thu Oct 12 17:49:57 2006
   4  *
   5  * This source code is licensed under the GNU General Public License,
   6  * Version 2.  See the file COPYING for more details.
   7  */
   8
   9 #include <asm/asm.h>
  10 #include <asm/asmmacro.h>
  11 #include <asm/regdef.h>
  12 #include <asm/mipsregs.h>
  13 #include <asm/stackframe.h>
  14 #include <asm/addrspace.h>
  15
  16 LEAF(relocate_new_kernel)
  17         PTR_L a0,       arg0
  18         PTR_L a1,       arg1
  19         PTR_L a2,       arg2
  20         PTR_L a3,       arg3
  21
  22         PTR_L           s0, kexec_indirection_page
  23         PTR_L           s1, kexec_start_address
  24
  25 process_entry:
  26         PTR_L           s2, (s0)
  27         PTR_ADDIU       s0, s0, SZREG
  28
  29         /*
  30          * In case of a kdump/crash kernel, the indirection page is not
  31          * populated as the kernel is directly copied to a reserved location
  32          */
  33         beqz            s2, done
  34
  35         /* destination page */
  36         and             s3, s2, 0x1
  37         beq             s3, zero, 1f
  38         and             s4, s2, ~0x1    /* store destination addr in s4 */
  39         b               process_entry
  40
  41 1:
  42         /* indirection page, update s0  */
  43         and             s3, s2, 0x2
  44         beq             s3, zero, 1f
  45         and             s0, s2, ~0x2
  46         b               process_entry
  47
  48 1:
  49         /* done page */
  50         and             s3, s2, 0x4
  51         beq             s3, zero, 1f
  52         b               done
  53 1:
  54         /* source page */
  55         and             s3, s2, 0x8
  56         beq             s3, zero, process_entry
  57         and             s2, s2, ~0x8
  58         li              s6, (1 << _PAGE_SHIFT) / SZREG
  59
  60 copy_word:
  61         /* copy page word by word */
  62         REG_L           s5, (s2)
  63         REG_S           s5, (s4)
  64         PTR_ADDIU       s4, s4, SZREG
  65         PTR_ADDIU       s2, s2, SZREG
  66         LONG_ADDIU      s6, s6, -1
  67         beq             s6, zero, process_entry
  68         b               copy_word
  69         b               process_entry
  70
  71 done:
  72 #ifdef CONFIG_SMP
  73         /* kexec_flag reset is signal to other CPUs what kernel
  74            was moved to it's location. Note - we need relocated address
  75            of kexec_flag.  */
  76
  77         bal             1f
  78  1:     move            t1,ra;
  79         PTR_LA          t2,1b
  80         PTR_LA          t0,kexec_flag
  81         PTR_SUB         t0,t0,t2;
  82         PTR_ADD         t0,t1,t0;
  83         LONG_S          zero,(t0)
  84 #endif
  85
  86 #ifdef CONFIG_CPU_CAVIUM_OCTEON
  87         /* We need to flush I-cache before jumping to new kernel.
  88          * Unfortunatelly, this code is cpu-specific.
  89          */
  90         .set push
  91         .set noreorder
  92         syncw
  93         syncw
  94         synci           0($0)
  95         .set pop
  96 #else
  97         sync
  98 #endif
  99         /* jump to kexec_start_address */
 100         j               s1
 101         END(relocate_new_kernel)
 102
 103 #ifdef CONFIG_SMP
 104 /*
 105  * Other CPUs should wait until code is relocated and
 106  * then start at entry (?) point.
 107  */
 108 LEAF(kexec_smp_wait)
 109         PTR_L           a0, s_arg0
 110         PTR_L           a1, s_arg1
 111         PTR_L           a2, s_arg2
 112         PTR_L           a3, s_arg3
 113         PTR_L           s1, kexec_start_address
 114
 115         /* Non-relocated address works for args and kexec_start_address ( old
 116          * kernel is not overwritten). But we need relocated address of
 117          * kexec_flag.
 118          */
 119
 120         bal             1f
 121 1:      move            t1,ra;
 122         PTR_LA          t2,1b
 123         PTR_LA          t0,kexec_flag
 124         PTR_SUB         t0,t0,t2;
 125         PTR_ADD         t0,t1,t0;
 126
 127 1:      LONG_L          s0, (t0)
 128         bne             s0, zero,1b
 129
 130 #ifdef CONFIG_CPU_CAVIUM_OCTEON
 131         .set push
 132         .set noreorder
 133         synci           0($0)
 134         .set pop
 135 #else
 136         sync
 137 #endif
 138         j               s1
 139         END(kexec_smp_wait)
 140 #endif
 141
 142 #ifdef __mips64
 143        /* all PTR's must be aligned to 8 byte in 64-bit mode */
 144        .align  3
 145 #endif
 146
 147 /* All parameters to new kernel are passed in registers a0-a3.
 148  * kexec_args[0..3] are uses to prepare register values.
 149  */
 150
 151 kexec_args:
 152         EXPORT(kexec_args)
 153 arg0:   PTR             0x0
 154 arg1:   PTR             0x0
 155 arg2:   PTR             0x0
 156 arg3:   PTR             0x0
 157         .size   kexec_args,PTRSIZE*4
 158
 159 #ifdef CONFIG_SMP
 160 /*
 161  * Secondary CPUs may have different kernel parameters in
 162  * their registers a0-a3. secondary_kexec_args[0..3] are used
 163  * to prepare register values.
 164  */
 165 secondary_kexec_args:
 166         EXPORT(secondary_kexec_args)
 167 s_arg0: PTR             0x0
 168 s_arg1: PTR             0x0
 169 s_arg2: PTR             0x0
 170 s_arg3: PTR             0x0
 171         .size   secondary_kexec_args,PTRSIZE*4
 172 kexec_flag:
 173         LONG            0x1
 174
 175 #endif
 176
 177 kexec_start_address:
 178         EXPORT(kexec_start_address)
 179         PTR             0x0
 180         .size           kexec_start_address, PTRSIZE
 181
 182 kexec_indirection_page:
 183         EXPORT(kexec_indirection_page)
 184         PTR             0
 185         .size           kexec_indirection_page, PTRSIZE
 186
 187 relocate_new_kernel_end:
 188
 189 relocate_new_kernel_size:
 190         EXPORT(relocate_new_kernel_size)
 191         PTR             relocate_new_kernel_end - relocate_new_kernel
 192         .size           relocate_new_kernel_size, PTRSIZE