Currently virt_to_phys() and phys_to_virt() return passed
address, because identity paging is used.
With this change the virtual memory layout is redefined
in three regions as follows (PO stands for PAGE_OFFSET):
0..&edata code, stack, data
PO..<PO + RAM size> dynamic RAM pages
<PO + RAM size>..<VA limit> MMIO, virtual mappings
As result, virt_to_phys() and phys_to_virt() functions apply
PAGE_OFFSET to passed addresses.
Furthermore 1:1 mapping at 3GB of physical memory is removed
and memory-mapped hardware devices should be ioremap()-ed and
referred using MMIO accessors.
Cc: Radim Krčmář <rkrcmar@xxxxxxxxxx>
Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
---
lib/x86/asm/io.h | 12 ----------
lib/x86/asm/page.h | 5 ++++
lib/x86/vm.c | 70 +++++++++++++++++++++++++++++++++++-------------------
3 files changed, 51 insertions(+), 36 deletions(-)
diff --git a/lib/x86/asm/io.h b/lib/x86/asm/io.h
index 35a5c7347411..4a6447448a77 100644
--- a/lib/x86/asm/io.h
+++ b/lib/x86/asm/io.h
@@ -45,18 +45,6 @@ static inline void outl(uint32_t value, unsigned long port)
asm volatile("outl %0, %w1" : : "a"(value), "Nd"((unsigned short)port));
}
-#define virt_to_phys virt_to_phys
-static inline unsigned long virt_to_phys(const void *virt)
-{
- return (unsigned long)virt;
-}
-
-#define phys_to_virt phys_to_virt
-static inline void *phys_to_virt(unsigned long phys)
-{
- return (void *)phys;
-}
-
#define ioremap ioremap
void __iomem *ioremap(phys_addr_t phys_addr, size_t size);
diff --git a/lib/x86/asm/page.h b/lib/x86/asm/page.h
index c43bab28ca2e..8e7002776c7a 100644
--- a/lib/x86/asm/page.h
+++ b/lib/x86/asm/page.h
@@ -10,6 +10,8 @@
#include <linux/const.h>
#include <bitops.h>
+#define PAGE_OFFSET 0x40000000
+
#define PAGE_SHIFT 12
#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
@@ -44,5 +46,8 @@
#define PGDIR_BITS(lvl) (((lvl) - 1) * PGDIR_WIDTH + PAGE_SHIFT)
#define PGDIR_OFFSET(va, lvl) (((va) >> PGDIR_BITS(lvl)) & PGDIR_MASK)
+#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
+#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
+
#endif /* !__ASSEMBLY__ */
#endif
diff --git a/lib/x86/vm.c b/lib/x86/vm.c
index 85625e5c934e..994c69df94d0 100644
--- a/lib/x86/vm.c
+++ b/lib/x86/vm.c
@@ -2,12 +2,18 @@
#include "vm.h"
#include "libcflat.h"
#include "apic.h"
+#include "asm/page.h"
-static void *free = 0;
+extern char edata;
+static void *free = &edata;
static void *vfree_top = 0;
+static unsigned long end_of_memory;
+static int pg_on = 0;
static void free_memory(void *mem, unsigned long size)
{
+ free = NULL;
+
while (size >= PAGE_SIZE) {
*(void **)mem = free;
free = mem;
@@ -35,8 +41,29 @@ void free_page(void *page)
free = page;
}
-extern char edata;
-static unsigned long end_of_memory;
+static void *alloc_page_no_pg()
+{
+ void *p = free;
+
+ free += PAGE_SIZE;
+
+ return p;
+}
+
+static void *__alloc_page_table()
+{
+ return pg_on ? alloc_page() : alloc_page_no_pg();
+}
+
+static inline unsigned long __virt_to_phys(void *virt)
+{
+ return pg_on ? virt_to_phys(virt) : (unsigned long)virt;
+}
+
+static inline void *__phys_to_virt(unsigned long phys)
+{
+ return pg_on ? phys_to_virt(phys) : (void *)phys;
+}
unsigned long *install_pte(unsigned long *cr3,
int pte_level,
@@ -50,11 +77,11 @@ unsigned long *install_pte(unsigned long *cr3,
for (level = PAGE_LEVEL; level > pte_level; --level) {
offset = PGDIR_OFFSET((unsigned long)virt, level);
if (!(pt[offset] & PT_PRESENT_MASK)) {
- unsigned long *new_pt = alloc_page();
+ unsigned long *new_pt = __alloc_page_table();
memset(new_pt, 0, PAGE_SIZE);
- pt[offset] = virt_to_phys(new_pt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
+ pt[offset] = __virt_to_phys(new_pt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK;
}
- pt = phys_to_virt(pt[offset] & PT_ADDR_MASK);
+ pt = __phys_to_virt(pt[offset] & PT_ADDR_MASK);
}
offset = PGDIR_OFFSET((unsigned long)virt, level);
pt[offset] = pte;
@@ -84,8 +111,7 @@ unsigned long *install_large_page(unsigned long *cr3,
unsigned long phys,
void *virt)
{
- return install_pte(cr3, 2, virt,
- phys | PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK | PT_PAGE_SIZE_MASK);
+ return install_pte(cr3, 2, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK | PT_USER_MASK | PT_PAGE_SIZE_MASK);
}
unsigned long *install_page(unsigned long *cr3,
@@ -121,26 +147,19 @@ static void setup_mmu_range(unsigned long *cr3, unsigned long start, void *virt,
}
}
+#define MAX_PT_NR (2048 + 4)
+#define PT_START ((unsigned long)&edata)
+#define PT_END (PT_START + (MAX_PT_NR * PAGE_SIZE))
+
static void setup_mmu(unsigned long len)
{
- unsigned long *cr3 = alloc_page();
+ unsigned long *cr3 = alloc_page_no_pg();
memset(cr3, 0, PAGE_SIZE);
-#ifdef __x86_64__
- if (len < (1ul << 32))
- len = (1ul << 32); /* map mmio 1:1 */
-
- setup_mmu_range(cr3, 0, (void *)0, len);
-#else
- if (len > (1ul << 31))
- len = (1ul << 31);
-
- /* 0 - 2G memory, 2G-3G valloc area, 3G-4G mmio */
- setup_mmu_range(cr3, 0, (void *)0, len);
- setup_mmu_range(cr3, 3ul << 30, (void *)(3ul << 30), (1ul << 30));
- vfree_top = (void*)(3ul << 30);
-#endif
+ assert(len >= PT_END);
+ setup_mmu_range(cr3, 0, (void *)0, PT_START);
+ setup_mmu_range(cr3, PT_START, phys_to_virt(PT_START), len - PT_START);
write_cr3((unsigned long)cr3);
#ifndef __x86_64__
@@ -148,6 +167,8 @@ static void setup_mmu(unsigned long len)
#endif
write_cr0(X86_CR0_PG |X86_CR0_PE | X86_CR0_WP);
+ pg_on = 1;
+
printf("paging enabled\n");
printf("cr0 = %lx\n", read_cr0());
printf("cr3 = %lx\n", read_cr3());
@@ -158,8 +179,9 @@ void setup_vm()
{
assert(!end_of_memory);
end_of_memory = fwcfg_get_u64(FW_CFG_RAM_SIZE);
- free_memory(&edata, end_of_memory - (unsigned long)&edata);
+ end_of_memory -= 0x20 * PAGE_SIZE; /* s3 ACPI tables hack */
setup_mmu(end_of_memory);
+ free_memory(phys_to_virt(PT_END), end_of_memory - PT_END);
ioremap_apic();
}
--
1.8.3.1
--
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