diff options
Diffstat (limited to 'arch/x86/kernel/relocate_kernel_32.S')
| -rw-r--r-- | arch/x86/kernel/relocate_kernel_32.S | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/arch/x86/kernel/relocate_kernel_32.S b/arch/x86/kernel/relocate_kernel_32.S index 2064d0aa8d28..41235531b11c 100644 --- a/arch/x86/kernel/relocate_kernel_32.S +++ b/arch/x86/kernel/relocate_kernel_32.S | |||
| @@ -17,7 +17,8 @@ | |||
| 17 | 17 | ||
| 18 | #define PTR(x) (x << 2) | 18 | #define PTR(x) (x << 2) |
| 19 | 19 | ||
| 20 | /* control_page + KEXEC_CONTROL_CODE_MAX_SIZE | 20 | /* |
| 21 | * control_page + KEXEC_CONTROL_CODE_MAX_SIZE | ||
| 21 | * ~ control_page + PAGE_SIZE are used as data storage and stack for | 22 | * ~ control_page + PAGE_SIZE are used as data storage and stack for |
| 22 | * jumping back | 23 | * jumping back |
| 23 | */ | 24 | */ |
| @@ -76,8 +77,10 @@ relocate_kernel: | |||
| 76 | movl %eax, CP_PA_SWAP_PAGE(%edi) | 77 | movl %eax, CP_PA_SWAP_PAGE(%edi) |
| 77 | movl %ebx, CP_PA_BACKUP_PAGES_MAP(%edi) | 78 | movl %ebx, CP_PA_BACKUP_PAGES_MAP(%edi) |
| 78 | 79 | ||
| 79 | /* get physical address of control page now */ | 80 | /* |
| 80 | /* this is impossible after page table switch */ | 81 | * get physical address of control page now |
| 82 | * this is impossible after page table switch | ||
| 83 | */ | ||
| 81 | movl PTR(PA_CONTROL_PAGE)(%ebp), %edi | 84 | movl PTR(PA_CONTROL_PAGE)(%ebp), %edi |
| 82 | 85 | ||
| 83 | /* switch to new set of page tables */ | 86 | /* switch to new set of page tables */ |
| @@ -97,7 +100,8 @@ identity_mapped: | |||
| 97 | /* store the start address on the stack */ | 100 | /* store the start address on the stack */ |
| 98 | pushl %edx | 101 | pushl %edx |
| 99 | 102 | ||
| 100 | /* Set cr0 to a known state: | 103 | /* |
| 104 | * Set cr0 to a known state: | ||
| 101 | * - Paging disabled | 105 | * - Paging disabled |
| 102 | * - Alignment check disabled | 106 | * - Alignment check disabled |
| 103 | * - Write protect disabled | 107 | * - Write protect disabled |
| @@ -113,7 +117,8 @@ identity_mapped: | |||
| 113 | /* clear cr4 if applicable */ | 117 | /* clear cr4 if applicable */ |
| 114 | testl %ecx, %ecx | 118 | testl %ecx, %ecx |
| 115 | jz 1f | 119 | jz 1f |
| 116 | /* Set cr4 to a known state: | 120 | /* |
| 121 | * Set cr4 to a known state: | ||
| 117 | * Setting everything to zero seems safe. | 122 | * Setting everything to zero seems safe. |
| 118 | */ | 123 | */ |
| 119 | xorl %eax, %eax | 124 | xorl %eax, %eax |
| @@ -132,15 +137,18 @@ identity_mapped: | |||
| 132 | call swap_pages | 137 | call swap_pages |
| 133 | addl $8, %esp | 138 | addl $8, %esp |
| 134 | 139 | ||
| 135 | /* To be certain of avoiding problems with self-modifying code | 140 | /* |
| 141 | * To be certain of avoiding problems with self-modifying code | ||
| 136 | * I need to execute a serializing instruction here. | 142 | * I need to execute a serializing instruction here. |
| 137 | * So I flush the TLB, it's handy, and not processor dependent. | 143 | * So I flush the TLB, it's handy, and not processor dependent. |
| 138 | */ | 144 | */ |
| 139 | xorl %eax, %eax | 145 | xorl %eax, %eax |
| 140 | movl %eax, %cr3 | 146 | movl %eax, %cr3 |
| 141 | 147 | ||
| 142 | /* set all of the registers to known values */ | 148 | /* |
| 143 | /* leave %esp alone */ | 149 | * set all of the registers to known values |
| 150 | * leave %esp alone | ||
| 151 | */ | ||
| 144 | 152 | ||
| 145 | testl %esi, %esi | 153 | testl %esi, %esi |
| 146 | jnz 1f | 154 | jnz 1f |