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x86/boot/64: Rewrite startup_64() in C

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The patch write most of startup_64 logic in C.

This is preparation for 5-level paging enabling.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170606113133.22974-8-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Kirill A. Shutemov
2017-06-06 14:31:26 +03:00
committed by Ingo Molnar
parent 34bbb0009f
commit c88d71508e
2 changed files with 87 additions and 93 deletions
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95
arch/x86/kernel/head_64.S
View File

@@ -72,100 +72,11 @@ startup_64:
/* Sanitize CPU configuration */
call verify_cpu
/*
* Compute the delta between the address I am compiled to run at and the
* address I am actually running at.
*/
leaq _text(%rip), %rbp
subq $_text - __START_KERNEL_map, %rbp
/* Is the address not 2M aligned? */
testl $~PMD_PAGE_MASK, %ebp
jnz bad_address
/*
* Is the address too large?
*/
leaq _text(%rip), %rax
shrq $MAX_PHYSMEM_BITS, %rax
jnz bad_address
/*
* Fixup the physical addresses in the page table
*/
addq %rbp, early_level4_pgt + (L4_START_KERNEL*8)(%rip)
addq %rbp, level3_kernel_pgt + (510*8)(%rip)
addq %rbp, level3_kernel_pgt + (511*8)(%rip)
addq %rbp, level2_fixmap_pgt + (506*8)(%rip)
/*
* Set up the identity mapping for the switchover. These
* entries should *NOT* have the global bit set! This also
* creates a bunch of nonsense entries but that is fine --
* it avoids problems around wraparound.
*/
leaq _text(%rip), %rdi
leaq early_level4_pgt(%rip), %rbx
pushq %rsi
call __startup_64
popq %rsi
movq %rdi, %rax
shrq $PGDIR_SHIFT, %rax
leaq (PAGE_SIZE + _KERNPG_TABLE)(%rbx), %rdx
movq %rdx, 0(%rbx,%rax,8)
movq %rdx, 8(%rbx,%rax,8)
addq $PAGE_SIZE, %rdx
movq %rdi, %rax
shrq $PUD_SHIFT, %rax
andl $(PTRS_PER_PUD-1), %eax
movq %rdx, PAGE_SIZE(%rbx,%rax,8)
incl %eax
andl $(PTRS_PER_PUD-1), %eax
movq %rdx, PAGE_SIZE(%rbx,%rax,8)
addq $PAGE_SIZE * 2, %rbx
movq %rdi, %rax
shrq $PMD_SHIFT, %rdi
addq $(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL), %rax
leaq (_end - 1)(%rip), %rcx
shrq $PMD_SHIFT, %rcx
subq %rdi, %rcx
incl %ecx
1:
andq $(PTRS_PER_PMD - 1), %rdi
movq %rax, (%rbx,%rdi,8)
incq %rdi
addq $PMD_SIZE, %rax
decl %ecx
jnz 1b
test %rbp, %rbp
jz .Lskip_fixup
/*
* Fixup the kernel text+data virtual addresses. Note that
* we might write invalid pmds, when the kernel is relocated
* cleanup_highmap() fixes this up along with the mappings
* beyond _end.
*/
leaq level2_kernel_pgt(%rip), %rdi
leaq PAGE_SIZE(%rdi), %r8
/* See if it is a valid page table entry */
1: testb $_PAGE_PRESENT, 0(%rdi)
jz 2f
addq %rbp, 0(%rdi)
/* Go to the next page */
2: addq $8, %rdi
cmp %r8, %rdi
jne 1b
/* Fixup phys_base */
addq %rbp, phys_base(%rip)
.Lskip_fixup:
movq $(early_level4_pgt - __START_KERNEL_map), %rax
jmp 1f
ENTRY(secondary_startup_64)