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