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authorBoris Ostrovsky <boris.ostrovsky@oracle.com>2016-12-08 19:44:31 +0300
committerIngo Molnar <mingo@kernel.org>2017-01-06 10:39:26 +0300
commit1e620f9b23e598ab936ece12233e98e97930b692 (patch)
tree741db210a86dde332f119b05a20224704ac5a0fd /arch/x86/kernel/head_32.S
parentb4ed1d15b453c86b4b9362128bd7a0ecd95a105c (diff)
downloadlinux-1e620f9b23e598ab936ece12233e98e97930b692.tar.xz
x86/boot/32: Convert the 32-bit pgtable setup code from assembly to C
The new Xen PVH entry point requires page tables to be setup by the kernel since it is entered with paging disabled. Pull the common code out of head_32.S so that mk_early_pgtbl_32() can be invoked from both the new Xen entry point and the existing startup_32() code. Convert resulting common code to C. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.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: matt@codeblueprint.co.uk Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1481215471-9639-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/head_32.S')
-rw-r--r--arch/x86/kernel/head_32.S121
1 files changed, 7 insertions, 114 deletions
diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index 4e8577d03372..1f85ee8f9439 100644
--- a/arch/x86/kernel/head_32.S
+++ b/arch/x86/kernel/head_32.S
@@ -24,6 +24,7 @@
#include <asm/nops.h>
#include <asm/bootparam.h>
#include <asm/export.h>
+#include <asm/pgtable_32.h>
/* Physical address */
#define pa(X) ((X) - __PAGE_OFFSET)
@@ -41,44 +42,10 @@
#define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability
#define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id
-/*
- * This is how much memory in addition to the memory covered up to
- * and including _end we need mapped initially.
- * We need:
- * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE)
- * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE)
- *
- * Modulo rounding, each megabyte assigned here requires a kilobyte of
- * memory, which is currently unreclaimed.
- *
- * This should be a multiple of a page.
- *
- * KERNEL_IMAGE_SIZE should be greater than pa(_end)
- * and small than max_low_pfn, otherwise will waste some page table entries
- */
-
-#if PTRS_PER_PMD > 1
-#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
-#else
-#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
-#endif
#define SIZEOF_PTREGS 17*4
/*
- * Number of possible pages in the lowmem region.
- *
- * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
- * gas warning about overflowing shift count when gas has been compiled
- * with only a host target support using a 32-bit type for internal
- * representation.
- */
-LOWMEM_PAGES = (((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)
-
-/* Enough space to fit pagetables for the low memory linear map */
-MAPPING_BEYOND_END = PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT
-
-/*
* Worst-case size of the kernel mapping we need to make:
* a relocatable kernel can live anywhere in lowmem, so we need to be able
* to map all of lowmem.
@@ -160,90 +127,15 @@ ENTRY(startup_32)
call load_ucode_bsp
#endif
-/*
- * Initialize page tables. This creates a PDE and a set of page
- * tables, which are located immediately beyond __brk_base. The variable
- * _brk_end is set up to point to the first "safe" location.
- * Mappings are created both at virtual address 0 (identity mapping)
- * and PAGE_OFFSET for up to _end.
- */
-#ifdef CONFIG_X86_PAE
-
- /*
- * In PAE mode initial_page_table is statically defined to contain
- * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
- * entries). The identity mapping is handled by pointing two PGD entries
- * to the first kernel PMD.
- *
- * Note the upper half of each PMD or PTE are always zero at this stage.
- */
-
-#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
-
- xorl %ebx,%ebx /* %ebx is kept at zero */
-
- movl $pa(__brk_base), %edi
- movl $pa(initial_pg_pmd), %edx
- movl $PTE_IDENT_ATTR, %eax
-10:
- leal PDE_IDENT_ATTR(%edi),%ecx /* Create PMD entry */
- movl %ecx,(%edx) /* Store PMD entry */
- /* Upper half already zero */
- addl $8,%edx
- movl $512,%ecx
-11:
- stosl
- xchgl %eax,%ebx
- stosl
- xchgl %eax,%ebx
- addl $0x1000,%eax
- loop 11b
-
- /*
- * End condition: we must map up to the end + MAPPING_BEYOND_END.
- */
- movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
- cmpl %ebp,%eax
- jb 10b
-1:
- addl $__PAGE_OFFSET, %edi
- movl %edi, pa(_brk_end)
- shrl $12, %eax
- movl %eax, pa(max_pfn_mapped)
+ /* Create early pagetables. */
+ call mk_early_pgtbl_32
/* Do early initialization of the fixmap area */
movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
+#ifdef CONFIG_X86_PAE
+#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
-#else /* Not PAE */
-
-page_pde_offset = (__PAGE_OFFSET >> 20);
-
- movl $pa(__brk_base), %edi
- movl $pa(initial_page_table), %edx
- movl $PTE_IDENT_ATTR, %eax
-10:
- leal PDE_IDENT_ATTR(%edi),%ecx /* Create PDE entry */
- movl %ecx,(%edx) /* Store identity PDE entry */
- movl %ecx,page_pde_offset(%edx) /* Store kernel PDE entry */
- addl $4,%edx
- movl $1024, %ecx
-11:
- stosl
- addl $0x1000,%eax
- loop 11b
- /*
- * End condition: we must map up to the end + MAPPING_BEYOND_END.
- */
- movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp
- cmpl %ebp,%eax
- jb 10b
- addl $__PAGE_OFFSET, %edi
- movl %edi, pa(_brk_end)
- shrl $12, %eax
- movl %eax, pa(max_pfn_mapped)
-
- /* Do early initialization of the fixmap area */
- movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
+#else
movl %eax,pa(initial_page_table+0xffc)
#endif
@@ -666,6 +558,7 @@ ENTRY(setup_once_ref)
__PAGE_ALIGNED_BSS
.align PAGE_SIZE
#ifdef CONFIG_X86_PAE
+.globl initial_pg_pmd
initial_pg_pmd:
.fill 1024*KPMDS,4,0
#else