#define PTR(x) (x << 3)
#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
+/*
+ * control_page + KEXEC_CONTROL_CODE_MAX_SIZE
+ * ~ control_page + PAGE_SIZE are used as data storage and stack for
+ * jumping back
+ */
+#define DATA(offset) (KEXEC_CONTROL_CODE_MAX_SIZE+(offset))
+
+/* Minimal CPU state */
+#define RSP DATA(0x0)
+#define CR0 DATA(0x8)
+#define CR3 DATA(0x10)
+#define CR4 DATA(0x18)
+
+/* other data */
+#define CP_PA_TABLE_PAGE DATA(0x20)
+#define CP_PA_SWAP_PAGE DATA(0x28)
+#define CP_PA_BACKUP_PAGES_MAP DATA(0x30)
+
.text
.align PAGE_SIZE
.code64
.globl relocate_kernel
relocate_kernel:
- /* %rdi indirection_page
+ /*
+ * %rdi indirection_page
* %rsi page_list
* %rdx start address
+ * %rcx preserve_context
*/
+ /* Save the CPU context, used for jumping back */
+ pushq %rbx
+ pushq %rbp
+ pushq %r12
+ pushq %r13
+ pushq %r14
+ pushq %r15
+ pushf
+
+ movq PTR(VA_CONTROL_PAGE)(%rsi), %r11
+ movq %rsp, RSP(%r11)
+ movq %cr0, %rax
+ movq %rax, CR0(%r11)
+ movq %cr3, %rax
+ movq %rax, CR3(%r11)
+ movq %cr4, %rax
+ movq %rax, CR4(%r11)
+
/* zero out flags, and disable interrupts */
pushq $0
popfq
- /* get physical address of control page now */
- /* this is impossible after page table switch */
+ /*
+ * get physical address of control page now
+ * this is impossible after page table switch
+ */
movq PTR(PA_CONTROL_PAGE)(%rsi), %r8
/* get physical address of page table now too */
- movq PTR(PA_TABLE_PAGE)(%rsi), %rcx
+ movq PTR(PA_TABLE_PAGE)(%rsi), %r9
+
+ /* get physical address of swap page now */
+ movq PTR(PA_SWAP_PAGE)(%rsi), %r10
+
+ /* save some information for jumping back */
+ movq %r9, CP_PA_TABLE_PAGE(%r11)
+ movq %r10, CP_PA_SWAP_PAGE(%r11)
+ movq %rdi, CP_PA_BACKUP_PAGES_MAP(%r11)
/* Switch to the identity mapped page tables */
- movq %rcx, %cr3
+ movq %r9, %cr3
/* setup a new stack at the end of the physical control page */
lea PAGE_SIZE(%r8), %rsp
/* store the start address on the stack */
pushq %rdx
- /* Set cr0 to a known state:
+ /*
+ * Set cr0 to a known state:
* - Paging enabled
* - Alignment check disabled
* - Write protect disabled
orl $(X86_CR0_PG | X86_CR0_PE), %eax
movq %rax, %cr0
- /* Set cr4 to a known state:
+ /*
+ * Set cr4 to a known state:
* - physical address extension enabled
*/
movq $X86_CR4_PAE, %rax
1:
/* Flush the TLB (needed?) */
- movq %rcx, %cr3
+ movq %r9, %cr3
+
+ movq %rcx, %r11
+ call swap_pages
+
+ /*
+ * To be certain of avoiding problems with self-modifying code
+ * I need to execute a serializing instruction here.
+ * So I flush the TLB by reloading %cr3 here, it's handy,
+ * and not processor dependent.
+ */
+ movq %cr3, %rax
+ movq %rax, %cr3
+
+ /*
+ * set all of the registers to known values
+ * leave %rsp alone
+ */
+
+ testq %r11, %r11
+ jnz 1f
+ xorq %rax, %rax
+ xorq %rbx, %rbx
+ xorq %rcx, %rcx
+ xorq %rdx, %rdx
+ xorq %rsi, %rsi
+ xorq %rdi, %rdi
+ xorq %rbp, %rbp
+ xorq %r8, %r8
+ xorq %r9, %r9
+ xorq %r10, %r9
+ xorq %r11, %r11
+ xorq %r12, %r12
+ xorq %r13, %r13
+ xorq %r14, %r14
+ xorq %r15, %r15
+
+ ret
+
+1:
+ popq %rdx
+ leaq PAGE_SIZE(%r10), %rsp
+ call *%rdx
+
+ /* get the re-entry point of the peer system */
+ movq 0(%rsp), %rbp
+ call 1f
+1:
+ popq %r8
+ subq $(1b - relocate_kernel), %r8
+ movq CP_PA_SWAP_PAGE(%r8), %r10
+ movq CP_PA_BACKUP_PAGES_MAP(%r8), %rdi
+ movq CP_PA_TABLE_PAGE(%r8), %rax
+ movq %rax, %cr3
+ lea PAGE_SIZE(%r8), %rsp
+ call swap_pages
+ movq $virtual_mapped, %rax
+ pushq %rax
+ ret
+
+virtual_mapped:
+ movq RSP(%r8), %rsp
+ movq CR4(%r8), %rax
+ movq %rax, %cr4
+ movq CR3(%r8), %rax
+ movq CR0(%r8), %r8
+ movq %rax, %cr3
+ movq %r8, %cr0
+ movq %rbp, %rax
+
+ popf
+ popq %r15
+ popq %r14
+ popq %r13
+ popq %r12
+ popq %rbp
+ popq %rbx
+ ret
/* Do the copies */
+swap_pages:
movq %rdi, %rcx /* Put the page_list in %rcx */
xorq %rdi, %rdi
xorq %rsi, %rsi
movq %rcx, %rsi /* For ever source page do a copy */
andq $0xfffffffffffff000, %rsi
+ movq %rdi, %rdx
+ movq %rsi, %rax
+
+ movq %r10, %rdi
movq $512, %rcx
rep ; movsq
- jmp 0b
-3:
-
- /* To be certain of avoiding problems with self-modifying code
- * I need to execute a serializing instruction here.
- * So I flush the TLB by reloading %cr3 here, it's handy,
- * and not processor dependent.
- */
- movq %cr3, %rax
- movq %rax, %cr3
- /* set all of the registers to known values */
- /* leave %rsp alone */
+ movq %rax, %rdi
+ movq %rdx, %rsi
+ movq $512, %rcx
+ rep ; movsq
- xorq %rax, %rax
- xorq %rbx, %rbx
- xorq %rcx, %rcx
- xorq %rdx, %rdx
- xorq %rsi, %rsi
- xorq %rdi, %rdi
- xorq %rbp, %rbp
- xorq %r8, %r8
- xorq %r9, %r9
- xorq %r10, %r9
- xorq %r11, %r11
- xorq %r12, %r12
- xorq %r13, %r13
- xorq %r14, %r14
- xorq %r15, %r15
+ movq %rdx, %rdi
+ movq %r10, %rsi
+ movq $512, %rcx
+ rep ; movsq
+ lea PAGE_SIZE(%rax), %rsi
+ jmp 0b
+3:
ret
+
+ .globl kexec_control_code_size
+.set kexec_control_code_size, . - relocate_kernel
git.openpandora.org / pandora-kernel.git / blobdiff