Jan Beulich
2012-May-24 13:07 UTC
[PATCH RFC 9/9] x86: construct static part of 1:1 mapping at build time
... rather than at boot time, removing unnecessary redundancy between
EFI and legacy boot code.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/boot/head.S
+++ b/xen/arch/x86/boot/head.S
@@ -109,14 +109,11 @@ __start:
bt $29,%edx
jnc bad_cpu
/* Initialise L2 identity-map and xen page table entries (16MB). */
- mov $sym_phys(l2_identmap),%edi
mov $sym_phys(l2_xenmap),%esi
mov $sym_phys(l2_bootmap),%edx
mov $0x1e3,%eax /* PRESENT+RW+A+D+2MB+GLOBAL */
mov $8,%ecx
-1: mov %eax,(%edi)
- add $8,%edi
- mov %eax,(%esi)
+1: mov %eax,(%esi)
add $8,%esi
mov %eax,(%edx)
add $8,%edx
@@ -148,54 +145,11 @@ __start:
mov %eax,sym_phys(idle_pg_table) +
l4_table_offset(DIRECTMAP_VIRT_START)*8
mov $(sym_phys(l3_xenmap)+7),%eax
mov %eax,sym_phys(idle_pg_table) +
l4_table_offset(XEN_VIRT_START)*8
-#else
- /* Initialize low and high mappings of memory with 2MB pages */
- mov $sym_phys(idle_pg_table_l2),%edi
- mov $0xe3,%eax /* PRESENT+RW+A+D+2MB */
-1: mov %eax,__PAGE_OFFSET>>18(%edi) /* high mapping */
- stosl /* low mapping */
- add $4,%edi
- add $(1<<L2_PAGETABLE_SHIFT),%eax
- cmp $DIRECTMAP_PHYS_END+0xe3,%eax
- jne 1b
-1: stosl /* low mappings cover up to 16MB */
- add $4,%edi
- add $(1<<L2_PAGETABLE_SHIFT),%eax
- cmp $(16<<20)+0xe3,%eax
- jne 1b
- /* Initialise L2 fixmap page directory entry. */
- mov $(sym_phys(l1_fixmap)+7),%eax
- mov %eax,sym_phys(idle_pg_table_l2) +
l2_table_offset(FIXADDR_TOP-1)*8
-#endif
-
- /* Initialize 4kB mappings of first 2MB or 4MB of memory. */
- mov $sym_phys(l1_identmap),%edi
- mov $0x263,%eax /* PRESENT+RW+A+D+SMALL_PAGES */
-#if defined(__x86_64__)
- or $0x100,%eax /* GLOBAL */
-#endif
- xor %ecx,%ecx
-1: stosl
- add $4,%edi
- add $PAGE_SIZE,%eax
- inc %ecx
- /* VGA hole (0xa0000-0xc0000) should be mapped UC. */
- cmp $0xa0,%ecx
- jne 2f
- or $0x10,%eax /* +PCD */
-2: cmp $0xc0,%ecx
- jne 2f
- and $~0x10,%eax /* -PCD */
-2: cmp $L1_PAGETABLE_ENTRIES,%ecx
- jne 1b
- sub $(PAGE_SIZE-0x63),%edi
-#if defined(__x86_64__)
+ /* Hook 4kB mappings of first 2MB of memory into L2. */
+ mov $sym_phys(l1_identmap)+__PAGE_HYPERVISOR,%edi
mov %edi,sym_phys(l2_identmap)
mov %edi,sym_phys(l2_xenmap)
mov %edi,sym_phys(l2_bootmap)
-#else
- mov %edi,sym_phys(idle_pg_table_l2)
- mov %edi,sym_phys(idle_pg_table_l2) + (__PAGE_OFFSET>>18)
#endif
/* Apply relocations to bootstrap trampoline. */
@@ -241,3 +195,25 @@ __high_start:
#else
#include "x86_32.S"
#endif
+
+ .section .data.page_aligned, "aw", @progbits
+ .p2align PAGE_SHIFT
+/*
+ * Mapping of first 2 megabytes of memory. This is mapped with 4kB mappings
+ * to avoid type conflicts with fixed-range MTRRs covering the lowest megabyte
+ * of physical memory. In any case the VGA hole should be mapped with type UC.
+ */
+ .globl l1_identmap
+l1_identmap:
+ pfn = 0
+ .rept L1_PAGETABLE_ENTRIES
+ /* VGA hole (0xa0000-0xc0000) should be mapped UC. */
+ .if pfn >= 0xa0 && pfn < 0xc0
+ .long (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR_NOCACHE |
MAP_SMALL_PAGES
+ .else
+ .long (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | MAP_SMALL_PAGES
+ .endif
+ .long 0
+ pfn = pfn + 1
+ .endr
+ .size l1_identmap, . - l1_identmap
--- a/xen/arch/x86/boot/x86_32.S
+++ b/xen/arch/x86/boot/x86_32.S
@@ -108,3 +108,24 @@ ENTRY(boot_cpu_gdt_table)
.fill (PER_CPU_GDT_ENTRY - FLAT_RING3_DS / 8 - 1), 8, 0
.quad 0x0000910000000000 /* per-CPU entry (limit == cpu) */
.align PAGE_SIZE,0
+
+#define PAGE_HYPERVISOR __PAGE_HYPERVISOR
+#define PAGE_HYPERVISOR_NOCACHE __PAGE_HYPERVISOR_NOCACHE
+
+/* Mapping of first 16 megabytes of memory. */
+ .globl idle_pg_table_l2
+idle_pg_table_l2:
+ range = 8
+ .irp count, l2_linear_offset(__PAGE_OFFSET), \
+ (4 * L2_PAGETABLE_ENTRIES - l2_linear_offset(__PAGE_OFFSET)
- 1)
+ .long sym_phys(l1_identmap) + PAGE_HYPERVISOR, 0
+ pfn = 1 << PAGETABLE_ORDER
+ .rept range - 1
+ .long (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | _PAGE_PSE, 0
+ pfn = pfn + (1 << PAGETABLE_ORDER)
+ .endr
+ .fill \count - range, 8, 0
+ range = DIRECTMAP_MBYTES / 2
+ .endr
+ .long sym_phys(l1_fixmap) + PAGE_HYPERVISOR, 0
+ .size idle_pg_table_l2, . - idle_pg_table_l2
--- a/xen/arch/x86/boot/x86_64.S
+++ b/xen/arch/x86/boot/x86_64.S
@@ -127,3 +127,15 @@ ENTRY(boot_cpu_compat_gdt_table)
.fill (PER_CPU_GDT_ENTRY - __HYPERVISOR_CS32 / 8 - 1), 8, 0
.quad 0x0000910000000000 /* per-CPU entry (limit == cpu) */
.align PAGE_SIZE, 0
+
+/* Mapping of first 16 megabytes of memory. */
+ .globl l2_identmap
+l2_identmap:
+ .quad 0
+ pfn = 1 << PAGETABLE_ORDER
+ .rept 7
+ .quad (pfn << PAGE_SHIFT) | PAGE_HYPERVISOR | _PAGE_PSE
+ pfn = pfn + (1 << PAGETABLE_ORDER)
+ .endr
+ .fill 4 * L2_PAGETABLE_ENTRIES - 8, 8, 0
+ .size l2_identmap, . - l2_identmap
--- a/xen/arch/x86/efi/boot.c
+++ b/xen/arch/x86/efi/boot.c
@@ -1119,8 +1119,6 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SY
unsigned int slot = (xen_phys_start >> L2_PAGETABLE_SHIFT) + i;
paddr_t addr = slot << L2_PAGETABLE_SHIFT;
- l2_identmap[i] = l2e_from_paddr(i << L2_PAGETABLE_SHIFT,
- PAGE_HYPERVISOR|_PAGE_PSE);
l2_identmap[slot] = l2e_from_paddr(addr, PAGE_HYPERVISOR|_PAGE_PSE);
l2_xenmap[i] = l2e_from_paddr(addr, PAGE_HYPERVISOR|_PAGE_PSE);
slot &= L2_PAGETABLE_ENTRIES - 1;
@@ -1150,16 +1148,7 @@ efi_start(EFI_HANDLE ImageHandle, EFI_SY
l4e_from_paddr((UINTN)l3_identmap, __PAGE_HYPERVISOR);
idle_pg_table[l4_table_offset(XEN_VIRT_START)]
l4e_from_paddr((UINTN)l3_xenmap, __PAGE_HYPERVISOR);
- /* Initialize 4kB mappings of first 2MB of memory. */
- for ( i = 0; i < L1_PAGETABLE_ENTRIES; ++i )
- {
- unsigned int attr = PAGE_HYPERVISOR|MAP_SMALL_PAGES;
-
- /* VGA hole (0xa0000-0xc0000) should be mapped UC. */
- if ( i >= 0xa0 && i < 0xc0 )
- attr |= _PAGE_PCD;
- l1_identmap[i] = l1e_from_pfn(i, attr);
- }
+ /* Hook 4kB mappings of first 2MB of memory into L2. */
l2_identmap[0] = l2e_from_paddr((UINTN)l1_identmap, __PAGE_HYPERVISOR);
if ( gop )
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -121,15 +121,6 @@
#include <asm/setup.h>
#include <asm/fixmap.h>
-/*
- * Mapping of first 2 or 4 megabytes of memory. This is mapped with 4kB
- * mappings to avoid type conflicts with fixed-range MTRRs covering the
- * lowest megabyte of physical memory. In any case the VGA hole should be
- * mapped with type UC.
- */
-l1_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
- l1_identmap[L1_PAGETABLE_ENTRIES];
-
/* Mapping of the fixmap space needed early. */
l1_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
l1_fixmap[L1_PAGETABLE_ENTRIES];
--- a/xen/arch/x86/x86_32/mm.c
+++ b/xen/arch/x86/x86_32/mm.c
@@ -31,9 +31,6 @@
#include <asm/setup.h>
#include <public/memory.h>
-l2_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
- idle_pg_table_l2[4 * L2_PAGETABLE_ENTRIES];
-
unsigned int __read_mostly PAGE_HYPERVISOR = __PAGE_HYPERVISOR;
unsigned int __read_mostly PAGE_HYPERVISOR_NOCACHE = __PAGE_HYPERVISOR_NOCACHE;
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -56,8 +56,6 @@ l4_pgentry_t __attribute__ ((__section__
/* Enough page directories to map bottom 4GB of the memory map. */
l3_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
l3_identmap[L3_PAGETABLE_ENTRIES];
-l2_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
- l2_identmap[4*L2_PAGETABLE_ENTRIES];
/* Enough page directories to map the Xen text and static data. */
l3_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
--- a/xen/include/asm-x86/page.h
+++ b/xen/include/asm-x86/page.h
@@ -1,15 +1,13 @@
#ifndef __X86_PAGE_H__
#define __X86_PAGE_H__
+#include <xen/const.h>
+
/*
* It is important that the masks are signed quantities. This ensures that
* the compiler sign-extends a 32-bit mask to 64 bits if that is required.
*/
-#ifndef __ASSEMBLY__
-#define PAGE_SIZE (1L << PAGE_SHIFT)
-#else
-#define PAGE_SIZE (1 << PAGE_SHIFT)
-#endif
+#define PAGE_SIZE (_AC(1,L) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
#define PAGE_FLAG_MASK (~0)
@@ -319,21 +317,22 @@ void paging_init(void);
void setup_idle_pagetable(void);
#endif /* !defined(__ASSEMBLY__) */
-#define _PAGE_PRESENT 0x001U
-#define _PAGE_RW 0x002U
-#define _PAGE_USER 0x004U
-#define _PAGE_PWT 0x008U
-#define _PAGE_PCD 0x010U
-#define _PAGE_ACCESSED 0x020U
-#define _PAGE_DIRTY 0x040U
-#define _PAGE_PAT 0x080U
-#define _PAGE_PSE 0x080U
-#define _PAGE_GLOBAL 0x100U
-#define _PAGE_AVAIL0 0x200U
-#define _PAGE_AVAIL1 0x400U
-#define _PAGE_AVAIL2 0x800U
-#define _PAGE_AVAIL 0xE00U
-#define _PAGE_PSE_PAT 0x1000U
+#define _PAGE_PRESENT _AC(0x001,U)
+#define _PAGE_RW _AC(0x002,U)
+#define _PAGE_USER _AC(0x004,U)
+#define _PAGE_PWT _AC(0x008,U)
+#define _PAGE_PCD _AC(0x010,U)
+#define _PAGE_ACCESSED _AC(0x020,U)
+#define _PAGE_DIRTY _AC(0x040,U)
+#define _PAGE_PAT _AC(0x080,U)
+#define _PAGE_PSE _AC(0x080,U)
+#define _PAGE_GLOBAL _AC(0x100,U)
+#define _PAGE_AVAIL0 _AC(0x200,U)
+#define _PAGE_AVAIL1 _AC(0x400,U)
+#define _PAGE_AVAIL2 _AC(0x800,U)
+#define _PAGE_AVAIL _AC(0xE00,U)
+#define _PAGE_PSE_PAT _AC(0x1000,U)
+/* non-architectural flags */
#define _PAGE_PAGED 0x2000U
#define _PAGE_SHARED 0x4000U
@@ -354,6 +353,8 @@ void setup_idle_pagetable(void);
#define __PAGE_HYPERVISOR_NOCACHE \
(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_PCD | _PAGE_ACCESSED)
+#define MAP_SMALL_PAGES _PAGE_AVAIL0 /* don''t use superpages mappings
*/
+
#ifndef __ASSEMBLY__
/* Allocator functions for Xen pagetables. */
@@ -367,7 +368,6 @@ l3_pgentry_t *virt_to_xen_l3e(unsigned l
extern void set_pdx_range(unsigned long smfn, unsigned long emfn);
/* Map machine page range in Xen virtual address space. */
-#define MAP_SMALL_PAGES _PAGE_AVAIL0 /* don''t use superpages for the
mapping */
int map_pages_to_xen(
unsigned long virt,
unsigned long mfn,
--- /dev/null
+++ b/xen/include/xen/const.h
@@ -0,0 +1,24 @@
+/* const.h: Macros for dealing with constants. */
+
+#ifndef __XEN_CONST_H__
+#define __XEN_CONST_H__
+
+/* Some constant macros are used in both assembler and
+ * C code. Therefore we cannot annotate them always with
+ * ''UL'' and other type specifiers unilaterally. We
+ * use the following macros to deal with this.
+ *
+ * Similarly, _AT() will cast an expression with a type in C, but
+ * leave it unchanged in asm.
+ */
+
+#ifdef __ASSEMBLY__
+#define _AC(X,Y) X
+#define _AT(T,X) X
+#else
+#define __AC(X,Y) (X##Y)
+#define _AC(X,Y) __AC(X,Y)
+#define _AT(T,X) ((T)(X))
+#endif
+
+#endif /* __XEN_CONST_H__ */
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