Skip to content

X
xv6-public
提交 c47ea542 创建 作者: Silas Boyd-Wickizer's avatar Silas Boyd-Wickizer
浏览文件
操作

Set NX on non-code kernel pages

上级 769c3a47
显示空白字符变更
内嵌 并排
正在显示 包含 22 行增加 和 24 行删除
boot.S
浏览文件 @ c47ea542
...@@ -206,10 +206,11 @@ init32e: ...@@ -206,10 +206,11 @@ init32e:
movl %eax, %cr3 movl %eax, %cr3
# Enable IA-32e mode by setting IA32_EFER.LME = 1. # Enable IA-32e mode by setting IA32_EFER.LME = 1.
# Also turn on IA32_EFER.SCE (syscall enable). # Also turn on IA32_EFER.SCE (syscall enable) and
# IA32_EFER.NXE (no-execute enable).
movl $0xc0000080, %ecx movl $0xc0000080, %ecx
rdmsr rdmsr
orl $0x101, %eax orl $((1<<8)|(1<<0)|(1<<11)), %eax
wrmsr wrmsr
# Enable paging by setting CR0.PG = 1. # Enable paging by setting CR0.PG = 1.
......
hwvm.c
浏览文件 @ c47ea542
...@@ -83,34 +83,28 @@ updatepages(pme_t *pml4, void *begin, void *end, int perm) ...@@ -83,34 +83,28 @@ updatepages(pme_t *pml4, void *begin, void *end, int perm)
} }
} }
static void // Map from 0 to 128Gbytes starting at KBASE.
pgmap(void *va, void *last, paddr pa) void
initpg(char* (*alloc)(void))
{ {
pme_t *pdp; extern char end[];
pme_t *pd; void *va = (void*)KBASE;
pme_t *sp; paddr pa = 0;
for (;;) { while (va < (void*)(KBASE+(128ull<<30))) {
pdp = descend(kpml4, va, 0, 1, 3); pme_t *pdp = descend(kpml4, va, 0, 1, 3);
pd = descend(pdp, va, 0, 1, 2); pme_t *pd = descend(pdp, va, 0, 1, 2);
sp = &pd[PX(1,va)]; pme_t *sp = &pd[PX(1,va)];
*sp = pa | PTE_W | PTE_P | PTE_PS; u64 flags = PTE_W | PTE_P | PTE_PS;
if(va == last) // Set NX for non-code pages
break; if (va >= (void*) end)
flags |= PTE_NX;
*sp = pa | flags;
va += PGSIZE*512; va += PGSIZE*512;
pa += PGSIZE*512; pa += PGSIZE*512;
} }
} }
// set up a page table to get off the ground
void
initpg(char* (*alloc)(void))
{
// Map first 4GB to KBASE
pgmap((void *) (KBASE+(1ull<<30)), (void *) (KBASE+(128ull<<30)), (1ull<<30));
// boot.S maps first 1GB to KBASE and gets us running with kpml4
}
// Set up kernel part of a page table. // Set up kernel part of a page table.
pml4e_t* pml4e_t*
setupkvm(void) setupkvm(void)
......
kernel.ld
浏览文件 @ c47ea542
...@@ -26,5 +26,7 @@ SECTIONS ...@@ -26,5 +26,7 @@ SECTIONS
.bss : { .bss : {
*(.bss) *(.bss)
} }
/* 2MByte align, because we set NX on 2MByte super pages. */
. = ALIGN(0x200000);
PROVIDE(end = .); PROVIDE(end = .);
} }
mmu.h
浏览文件 @ c47ea542
...@@ -17,6 +17,7 @@ ...@@ -17,6 +17,7 @@
#define PTE_PS 0x080 // Page Size #define PTE_PS 0x080 // Page Size
#define PTE_MBZ 0x180 // Bits must be zero #define PTE_MBZ 0x180 // Bits must be zero
#define PTE_COW 0x800 // copy-on-write #define PTE_COW 0x800 // copy-on-write
#define PTE_NX 0x8000000000000000ull // No-execute enable
#define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1)) #define PGROUNDUP(sz) (((sz)+PGSIZE-1) & ~(PGSIZE-1))
#define PGROUNDDOWN(a) ((__typeof__(a))((((uptr)(a)) & ~(PGSIZE-1)))) #define PGROUNDDOWN(a) ((__typeof__(a))((((uptr)(a)) & ~(PGSIZE-1))))
......
您添加了 0 人 到此讨论。请谨慎行事。
请先完成此评论的编辑！
请 注册 或者 后发表评论