#include <linux/linkage.h>
#include <asm/segment.h>
+#include <asm/pgtable.h>
#include <asm/page.h>
+#include <asm/msr.h>
+.section ".text.head"
.code32
.globl startup_32
-
+
startup_32:
cld
cli
- movl $(__KERNEL_DS),%eax
- movl %eax,%ds
- movl %eax,%es
- movl %eax,%fs
- movl %eax,%gs
-
- lss stack_start,%esp
- xorl %eax,%eax
-1: incl %eax # check that A20 really IS enabled
- movl %eax,0x000000 # loop forever if it isn't
- cmpl %eax,0x100000
- je 1b
+ movl $(__KERNEL_DS), %eax
+ movl %eax, %ds
+ movl %eax, %es
+ movl %eax, %ss
+
+/* Calculate the delta between where we were compiled to run
+ * at and where we were actually loaded at. This can only be done
+ * with a short local call on x86. Nothing else will tell us what
+ * address we are running at. The reserved chunk of the real-mode
+ * data at 0x1e4 (defined as a scratch field) are used as the stack
+ * for this calculation. Only 4 bytes are needed.
+ */
+ leal (0x1e4+4)(%esi), %esp
+ call 1f
+1: popl %ebp
+ subl $1b, %ebp
+
+/* setup a stack and make sure cpu supports long mode. */
+ movl $user_stack_end, %eax
+ addl %ebp, %eax
+ movl %eax, %esp
+
+ call verify_cpu
+ testl %eax, %eax
+ jnz no_longmode
+
+/* Compute the delta between where we were compiled to run at
+ * and where the code will actually run at.
+ */
+/* %ebp contains the address we are loaded at by the boot loader and %ebx
+ * contains the address where we should move the kernel image temporarily
+ * for safe in-place decompression.
+ */
+
+#ifdef CONFIG_RELOCATABLE
+ movl %ebp, %ebx
+ addl $(LARGE_PAGE_SIZE -1), %ebx
+ andl $LARGE_PAGE_MASK, %ebx
+#else
+ movl $CONFIG_PHYSICAL_START, %ebx
+#endif
+
+ /* Replace the compressed data size with the uncompressed size */
+ subl input_len(%ebp), %ebx
+ movl output_len(%ebp), %eax
+ addl %eax, %ebx
+ /* Add 8 bytes for every 32K input block */
+ shrl $12, %eax
+ addl %eax, %ebx
+ /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */
+ addl $(32768 + 18 + 4095), %ebx
+ andl $~4095, %ebx
/*
- * Initialize eflags. Some BIOS's leave bits like NT set. This would
- * confuse the debugger if this code is traced.
- * XXX - best to initialize before switching to protected mode.
+ * Prepare for entering 64 bit mode
*/
- pushl $0
- popfl
+
+ /* Load new GDT with the 64bit segments using 32bit descriptor */
+ leal gdt(%ebp), %eax
+ movl %eax, gdt+2(%ebp)
+ lgdt gdt(%ebp)
+
+ /* Enable PAE mode */
+ xorl %eax, %eax
+ orl $(1 << 5), %eax
+ movl %eax, %cr4
+
+ /*
+ * Build early 4G boot pagetable
+ */
+ /* Initialize Page tables to 0*/
+ leal pgtable(%ebx), %edi
+ xorl %eax, %eax
+ movl $((4096*6)/4), %ecx
+ rep stosl
+
+ /* Build Level 4 */
+ leal pgtable + 0(%ebx), %edi
+ leal 0x1007 (%edi), %eax
+ movl %eax, 0(%edi)
+
+ /* Build Level 3 */
+ leal pgtable + 0x1000(%ebx), %edi
+ leal 0x1007(%edi), %eax
+ movl $4, %ecx
+1: movl %eax, 0x00(%edi)
+ addl $0x00001000, %eax
+ addl $8, %edi
+ decl %ecx
+ jnz 1b
+
+ /* Build Level 2 */
+ leal pgtable + 0x2000(%ebx), %edi
+ movl $0x00000183, %eax
+ movl $2048, %ecx
+1: movl %eax, 0(%edi)
+ addl $0x00200000, %eax
+ addl $8, %edi
+ decl %ecx
+ jnz 1b
+
+ /* Enable the boot page tables */
+ leal pgtable(%ebx), %eax
+ movl %eax, %cr3
+
+ /* Enable Long mode in EFER (Extended Feature Enable Register) */
+ movl $MSR_EFER, %ecx
+ rdmsr
+ btsl $_EFER_LME, %eax
+ wrmsr
+
+ /* Setup for the jump to 64bit mode
+ *
+ * When the jump is performend we will be in long mode but
+ * in 32bit compatibility mode with EFER.LME = 1, CS.L = 0, CS.D = 1
+ * (and in turn EFER.LMA = 1). To jump into 64bit mode we use
+ * the new gdt/idt that has __KERNEL_CS with CS.L = 1.
+ * We place all of the values on our mini stack so lret can
+ * used to perform that far jump.
+ */
+ pushl $__KERNEL_CS
+ leal startup_64(%ebp), %eax
+ pushl %eax
+
+ /* Enter paged protected Mode, activating Long Mode */
+ movl $0x80000001, %eax /* Enable Paging and Protected mode */
+ movl %eax, %cr0
+
+ /* Jump from 32bit compatibility mode into 64bit mode. */
+ lret
+
+no_longmode:
+ /* This isn't an x86-64 CPU so hang */
+1:
+ hlt
+ jmp 1b
+
+#include "../../kernel/verify_cpu.S"
+
+ /* Be careful here startup_64 needs to be at a predictable
+ * address so I can export it in an ELF header. Bootloaders
+ * should look at the ELF header to find this address, as
+ * it may change in the future.
+ */
+ .code64
+ .org 0x200
+ENTRY(startup_64)
+ /* We come here either from startup_32 or directly from a
+ * 64bit bootloader. If we come here from a bootloader we depend on
+ * an identity mapped page table being provied that maps our
+ * entire text+data+bss and hopefully all of memory.
+ */
+
+ /* Setup data segments. */
+ xorl %eax, %eax
+ movl %eax, %ds
+ movl %eax, %es
+ movl %eax, %ss
+ movl %eax, %fs
+ movl %eax, %gs
+ lldt %ax
+ movl $0x20, %eax
+ ltr %ax
+
+ /* Compute the decompressed kernel start address. It is where
+ * we were loaded at aligned to a 2M boundary. %rbp contains the
+ * decompressed kernel start address.
+ *
+ * If it is a relocatable kernel then decompress and run the kernel
+ * from load address aligned to 2MB addr, otherwise decompress and
+ * run the kernel from CONFIG_PHYSICAL_START
+ */
+
+ /* Start with the delta to where the kernel will run at. */
+#ifdef CONFIG_RELOCATABLE
+ leaq startup_32(%rip) /* - $startup_32 */, %rbp
+ addq $(LARGE_PAGE_SIZE - 1), %rbp
+ andq $LARGE_PAGE_MASK, %rbp
+ movq %rbp, %rbx
+#else
+ movq $CONFIG_PHYSICAL_START, %rbp
+ movq %rbp, %rbx
+#endif
+
+ /* Replace the compressed data size with the uncompressed size */
+ movl input_len(%rip), %eax
+ subq %rax, %rbx
+ movl output_len(%rip), %eax
+ addq %rax, %rbx
+ /* Add 8 bytes for every 32K input block */
+ shrq $12, %rax
+ addq %rax, %rbx
+ /* Add 32K + 18 bytes of extra slack and align on a 4K boundary */
+ addq $(32768 + 18 + 4095), %rbx
+ andq $~4095, %rbx
+
+/* Copy the compressed kernel to the end of our buffer
+ * where decompression in place becomes safe.
+ */
+ leaq _end(%rip), %r8
+ leaq _end(%rbx), %r9
+ movq $_end /* - $startup_32 */, %rcx
+1: subq $8, %r8
+ subq $8, %r9
+ movq 0(%r8), %rax
+ movq %rax, 0(%r9)
+ subq $8, %rcx
+ jnz 1b
+
+/*
+ * Jump to the relocated address.
+ */
+ leaq relocated(%rbx), %rax
+ jmp *%rax
+
+.section ".text"
+relocated:
+
/*
* Clear BSS
*/
- xorl %eax,%eax
- movl $_edata,%edi
- movl $_end,%ecx
- subl %edi,%ecx
+ xorq %rax, %rax
+ leaq _edata(%rbx), %rdi
+ leaq _end(%rbx), %rcx
+ subq %rdi, %rcx
cld
rep
stosb
+
+ /* Setup the stack */
+ leaq user_stack_end(%rip), %rsp
+
+ /* zero EFLAGS after setting rsp */
+ pushq $0
+ popfq
+
/*
* Do the decompression, and jump to the new kernel..
*/
- subl $16,%esp # place for structure on the stack
- movl %esp,%eax
- pushl %esi # real mode pointer as second arg
- pushl %eax # address of structure as first arg
- call decompress_kernel
- orl %eax,%eax
- jnz 3f
- addl $8,%esp
- xorl %ebx,%ebx
- ljmp $(__KERNEL_CS), $__PHYSICAL_START
+ pushq %rsi # Save the real mode argument
+ movq %rsi, %rdi # real mode address
+ leaq _heap(%rip), %rsi # _heap
+ leaq input_data(%rip), %rdx # input_data
+ movl input_len(%rip), %eax
+ movq %rax, %rcx # input_len
+ movq %rbp, %r8 # output
+ call decompress_kernel
+ popq %rsi
-/*
- * We come here, if we were loaded high.
- * We need to move the move-in-place routine down to 0x1000
- * and then start it with the buffer addresses in registers,
- * which we got from the stack.
- */
-3:
- movl %esi,%ebx
- movl $move_routine_start,%esi
- movl $0x1000,%edi
- movl $move_routine_end,%ecx
- subl %esi,%ecx
- addl $3,%ecx
- shrl $2,%ecx
- cld
- rep
- movsl
-
- popl %esi # discard the address
- addl $4,%esp # real mode pointer
- popl %esi # low_buffer_start
- popl %ecx # lcount
- popl %edx # high_buffer_start
- popl %eax # hcount
- movl $__PHYSICAL_START,%edi
- cli # make sure we don't get interrupted
- ljmp $(__KERNEL_CS), $0x1000 # and jump to the move routine
/*
- * Routine (template) for moving the decompressed kernel in place,
- * if we were high loaded. This _must_ PIC-code !
+ * Jump to the decompressed kernel.
*/
-move_routine_start:
- movl %ecx,%ebp
- shrl $2,%ecx
- rep
- movsl
- movl %ebp,%ecx
- andl $3,%ecx
- rep
- movsb
- movl %edx,%esi
- movl %eax,%ecx # NOTE: rep movsb won't move if %ecx == 0
- addl $3,%ecx
- shrl $2,%ecx
- rep
- movsl
- movl %ebx,%esi # Restore setup pointer
- xorl %ebx,%ebx
- ljmp $(__KERNEL_CS), $__PHYSICAL_START
-move_routine_end:
+ jmp *%rbp
-
-/* Stack for uncompression */
- .align 32
-user_stack:
+ .data
+gdt:
+ .word gdt_end - gdt
+ .long gdt
+ .word 0
+ .quad 0x0000000000000000 /* NULL descriptor */
+ .quad 0x00af9a000000ffff /* __KERNEL_CS */
+ .quad 0x00cf92000000ffff /* __KERNEL_DS */
+ .quad 0x0080890000000000 /* TS descriptor */
+ .quad 0x0000000000000000 /* TS continued */
+gdt_end:
+ .bss
+/* Stack for uncompression */
+ .balign 4
+user_stack:
.fill 4096,4,0
-stack_start:
- .long user_stack+4096
- .word __KERNEL_DS
-
+user_stack_end:
projects / firefly-linux-kernel-4.4.55.git / blobdiff