forked from mirrors/linux
x86/boot/64: Rewrite startup_64() in C
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
Ingo Molnar
parent
34bbb0009f
commit
c88d71508e
2 changed files with 87 additions and 93 deletions
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@ -35,9 +35,92 @@
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*/
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extern pgd_t early_level4_pgt[PTRS_PER_PGD];
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extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD];
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static unsigned int __initdata next_early_pgt = 2;
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static unsigned int __initdata next_early_pgt;
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pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
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static void __init *fixup_pointer(void *ptr, unsigned long physaddr)
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{
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return ptr - (void *)_text + (void *)physaddr;
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}
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void __init __startup_64(unsigned long physaddr)
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{
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unsigned long load_delta, *p;
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pgdval_t *pgd;
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pudval_t *pud;
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pmdval_t *pmd, pmd_entry;
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int i;
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/* Is the address too large? */
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if (physaddr >> MAX_PHYSMEM_BITS)
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for (;;);
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/*
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* Compute the delta between the address I am compiled to run at
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* and the address I am actually running at.
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*/
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load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map);
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/* Is the address not 2M aligned? */
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if (load_delta & ~PMD_PAGE_MASK)
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for (;;);
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/* Fixup the physical addresses in the page table */
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pgd = fixup_pointer(&early_level4_pgt, physaddr);
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pgd[pgd_index(__START_KERNEL_map)] += load_delta;
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pud = fixup_pointer(&level3_kernel_pgt, physaddr);
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pud[510] += load_delta;
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pud[511] += load_delta;
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pmd = fixup_pointer(level2_fixmap_pgt, physaddr);
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pmd[506] += load_delta;
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/*
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* Set up the identity mapping for the switchover. These
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* entries should *NOT* have the global bit set! This also
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* creates a bunch of nonsense entries but that is fine --
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* it avoids problems around wraparound.
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*/
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pud = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
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pmd = fixup_pointer(early_dynamic_pgts[next_early_pgt++], physaddr);
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i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD;
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pgd[i + 0] = (pgdval_t)pud + _KERNPG_TABLE;
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pgd[i + 1] = (pgdval_t)pud + _KERNPG_TABLE;
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i = (physaddr >> PUD_SHIFT) % PTRS_PER_PUD;
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pud[i + 0] = (pudval_t)pmd + _KERNPG_TABLE;
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pud[i + 1] = (pudval_t)pmd + _KERNPG_TABLE;
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pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
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pmd_entry += physaddr;
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for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) {
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int idx = i + (physaddr >> PMD_SHIFT) % PTRS_PER_PMD;
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pmd[idx] = pmd_entry + i * PMD_SIZE;
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}
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/*
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* Fixup the kernel text+data virtual addresses. Note that
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* we might write invalid pmds, when the kernel is relocated
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* cleanup_highmap() fixes this up along with the mappings
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* beyond _end.
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*/
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pmd = fixup_pointer(level2_kernel_pgt, physaddr);
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for (i = 0; i < PTRS_PER_PMD; i++) {
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if (pmd[i] & _PAGE_PRESENT)
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pmd[i] += load_delta;
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}
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/* Fixup phys_base */
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p = fixup_pointer(&phys_base, physaddr);
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*p += load_delta;
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}
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/* Wipe all early page tables except for the kernel symbol map */
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static void __init reset_early_page_tables(void)
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{
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@ -72,100 +72,11 @@ startup_64:
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/* Sanitize CPU configuration */
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call verify_cpu
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/*
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* Compute the delta between the address I am compiled to run at and the
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* address I am actually running at.
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*/
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leaq _text(%rip), %rbp
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subq $_text - __START_KERNEL_map, %rbp
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/* Is the address not 2M aligned? */
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testl $~PMD_PAGE_MASK, %ebp
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jnz bad_address
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/*
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* Is the address too large?
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*/
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leaq _text(%rip), %rax
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shrq $MAX_PHYSMEM_BITS, %rax
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jnz bad_address
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/*
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* Fixup the physical addresses in the page table
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*/
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addq %rbp, early_level4_pgt + (L4_START_KERNEL*8)(%rip)
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addq %rbp, level3_kernel_pgt + (510*8)(%rip)
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addq %rbp, level3_kernel_pgt + (511*8)(%rip)
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addq %rbp, level2_fixmap_pgt + (506*8)(%rip)
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/*
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* Set up the identity mapping for the switchover. These
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* entries should *NOT* have the global bit set! This also
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* creates a bunch of nonsense entries but that is fine --
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* it avoids problems around wraparound.
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*/
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leaq _text(%rip), %rdi
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leaq early_level4_pgt(%rip), %rbx
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pushq %rsi
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call __startup_64
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popq %rsi
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movq %rdi, %rax
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shrq $PGDIR_SHIFT, %rax
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leaq (PAGE_SIZE + _KERNPG_TABLE)(%rbx), %rdx
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movq %rdx, 0(%rbx,%rax,8)
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movq %rdx, 8(%rbx,%rax,8)
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addq $PAGE_SIZE, %rdx
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movq %rdi, %rax
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shrq $PUD_SHIFT, %rax
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andl $(PTRS_PER_PUD-1), %eax
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movq %rdx, PAGE_SIZE(%rbx,%rax,8)
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incl %eax
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andl $(PTRS_PER_PUD-1), %eax
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movq %rdx, PAGE_SIZE(%rbx,%rax,8)
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addq $PAGE_SIZE * 2, %rbx
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movq %rdi, %rax
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shrq $PMD_SHIFT, %rdi
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addq $(__PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL), %rax
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leaq (_end - 1)(%rip), %rcx
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shrq $PMD_SHIFT, %rcx
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subq %rdi, %rcx
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incl %ecx
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1:
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andq $(PTRS_PER_PMD - 1), %rdi
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movq %rax, (%rbx,%rdi,8)
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incq %rdi
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addq $PMD_SIZE, %rax
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decl %ecx
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jnz 1b
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test %rbp, %rbp
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jz .Lskip_fixup
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/*
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* Fixup the kernel text+data virtual addresses. Note that
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* we might write invalid pmds, when the kernel is relocated
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* cleanup_highmap() fixes this up along with the mappings
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* beyond _end.
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*/
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leaq level2_kernel_pgt(%rip), %rdi
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leaq PAGE_SIZE(%rdi), %r8
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/* See if it is a valid page table entry */
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1: testb $_PAGE_PRESENT, 0(%rdi)
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jz 2f
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addq %rbp, 0(%rdi)
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/* Go to the next page */
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2: addq $8, %rdi
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cmp %r8, %rdi
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jne 1b
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/* Fixup phys_base */
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addq %rbp, phys_base(%rip)
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.Lskip_fixup:
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movq $(early_level4_pgt - __START_KERNEL_map), %rax
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jmp 1f
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ENTRY(secondary_startup_64)
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