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Use PROT/MAP flags rather than PTEs to improve portability.

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This commit is contained in:
Ali Mashtizadeh 2023-10-23 21:53:07 -04:00
parent d1a7bc9020
commit 51b61e3316
7 changed files with 56 additions and 16 deletions
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2
sys/amd64/include/cpu.h
View File

@ -12,7 +12,7 @@
* Page Tables
*/
#define PGNUMMASK 0xFFFFFFFFFFFFF000ULL
#define PGNUMMASK 0x7FFFFFFFFFFFF000ULL
#define PGIDXSHIFT 9
#define PGIDXMASK (512 - 1)

47
sys/amd64/pmap.c
View File

@ -6,6 +6,7 @@
#include <sys/kassert.h>
#include <sys/kdebug.h>
#include <sys/kmem.h>
#include <sys/mman.h>
#include <machine/cpu.h>
#include <machine/cpuop.h>
@ -15,6 +16,30 @@
AS systemAS;
AS *currentAS[MAX_CPUS];
static uint64_t
PMapProtToPTE(uint64_t flags)
{
uint64_t pte = 0;
ASSERT(flags != 0);
if (flags & PROT_READ)
pte |= PTE_P;
if (flags & PROT_WRITE)
pte |= PTE_P|PTE_W;
if (flags & PROT_EXEC)
pte |= PTE_P;
else
pte |= PTE_NX;
ASSERT(pte != 0);
if (flags & MAP_NOCACHE)
pte |= PTE_PCD;
return pte;
}
void
PMap_Init()
{
@ -52,11 +77,11 @@ PMap_Init()
// Setup system mappings
PMap_SystemLMap(0x0, MEM_DIRECTMAP_BASE + 0x0,
3*512, 0); // 3GB RWX
3*512, PROT_ALL); // 3GB RWX
PMap_SystemLMap(0xC0000000, MEM_DIRECTMAP_BASE + 0xC0000000,
512, PTE_NX|PTE_PCD); // 1GB RW + PCD
512, PROT_ALL|MAP_NOCACHE); // 1GB RW + PCD
PMap_SystemLMap(0x100000000, MEM_DIRECTMAP_BASE + 0x100000000,
60*512, 0); // 60GB RWX
60*512, PROT_ALL); // 60GB RWX
PMap_LoadAS(&systemAS);
@ -248,7 +273,7 @@ PMap_Translate(AS *space, uintptr_t va)
if ((pte & PTE_PS) == PTE_PS) {
// Handle 2MB pages
entry = &table->entries[k];
return (*entry & ~(LARGE_PGMASK | PTE_NX)) + (va & LARGE_PGMASK);
return (*entry & PGNUMMASK) + (va & LARGE_PGMASK);
}
if (pte == 0) {
ASSERT(pte);
@ -259,7 +284,7 @@ PMap_Translate(AS *space, uintptr_t va)
// Handle 4KB pages
entry = &table->entries[l];
return (*entry & ~(PGMASK | PTE_NX)) + (va & PGMASK);
return (*entry & PGNUMMASK) + (va & PGMASK);
}
/**
@ -356,6 +381,7 @@ PMap_Map(AS *as, uint64_t phys, uint64_t virt, uint64_t pages, uint64_t flags)
{
int i;
PageEntry *entry;
uint64_t pteflags = PMapProtToPTE(flags);
for (i = 0; i < pages; i++) {
uint64_t va = virt + PGSIZE * i;
@ -365,7 +391,7 @@ PMap_Map(AS *as, uint64_t phys, uint64_t virt, uint64_t pages, uint64_t flags)
return false;
}
*entry = (phys + PGSIZE * i) | PTE_P | PTE_W | PTE_U | flags;
*entry = (phys + PGSIZE * i) | PTE_U | pteflags;
}
return true;
@ -425,6 +451,7 @@ PMap_AllocMap(AS *as, uint64_t virt, uint64_t len, uint64_t flags)
int i;
uint64_t pages = (len + PGSIZE - 1) / PGSIZE;
PageEntry *entry;
uint64_t pteflags = PMapProtToPTE(flags);
ASSERT((virt & PGMASK) == 0);
@ -438,7 +465,7 @@ PMap_AllocMap(AS *as, uint64_t virt, uint64_t len, uint64_t flags)
if ((*entry & PTE_P) != PTE_P) {
void *pg = PAlloc_AllocPage();
*entry = (uint64_t)DMVA2PA(pg) | PTE_P | PTE_U | flags;
*entry = (uint64_t)DMVA2PA(pg) | PTE_U | pteflags;
}
}
@ -481,6 +508,7 @@ PMap_SystemLMap(uint64_t phys, uint64_t virt, uint64_t lpages, uint64_t flags)
{
int i;
PageEntry *entry;
uint64_t pteflags = PMapProtToPTE(flags);
for (i = 0; i < lpages; i++) {
uint64_t va = virt + LARGE_PGSIZE * i;
@ -490,7 +518,7 @@ PMap_SystemLMap(uint64_t phys, uint64_t virt, uint64_t lpages, uint64_t flags)
return false;
}
*entry = (phys + LARGE_PGSIZE * i) | PTE_P | PTE_W | PTE_PS | flags;
*entry = (phys + LARGE_PGSIZE * i) | PTE_PS | pteflags;
}
return true;
@ -515,6 +543,7 @@ PMap_SystemMap(uint64_t phys, uint64_t virt, uint64_t pages, uint64_t flags)
{
int i;
PageEntry *entry;
uint64_t pteflags = PMapProtToPTE(flags);
for (i = 0; i < pages; i++) {
uint64_t va = virt + PGSIZE * i;
@ -524,7 +553,7 @@ PMap_SystemMap(uint64_t phys, uint64_t virt, uint64_t pages, uint64_t flags)
return false;
}
*entry = (phys + PGSIZE * i) | PTE_P | PTE_W | flags;
*entry = (phys + PGSIZE * i) | pteflags;
}
return true;

3
sys/amd64/xmem.c
View File

@ -6,6 +6,7 @@
#include <sys/kassert.h>
#include <sys/kdebug.h>
#include <sys/kmem.h>
#include <sys/mman.h>
#include <machine/cpu.h>
#include <machine/cpuop.h>
@ -106,7 +107,7 @@ XMem_Allocate(XMem *xmem, uintptr_t length)
if (pg == NULL)
return false;
PMap_SystemMap(DMVA2PA((uint64_t)pg), xmem->base + off, 1, 0);
PMap_SystemMap(DMVA2PA((uint64_t)pg), xmem->base + off, 1, PROT_ALL);
xmem->length += PGSIZE;
}

5
sys/include/mman.h
View File

@ -6,11 +6,16 @@
#define PROT_READ 0x01
#define PROT_WRITE 0x02
#define PROT_EXEC 0x04
#define PROT_ALL (PROT_READ|PROT_WRITE|PROT_EXEC)
#define MAP_FILE 0x0010
#define MAP_ANON 0x0020
#define MAP_FIXED 0x0040
#ifdef _KERNEL
#define MAP_NOCACHE 0x1000
#endif
#ifdef _KERNEL
#else /* _KERNEL */

10
sys/kern/loader.c
View File

@ -13,8 +13,8 @@
#include <sys/queue.h>
#include <sys/disk.h>
#include <sys/elf64.h>
#include <sys/mman.h>
#include <machine/cpu.h>
#include <machine/trap.h>
#include <machine/pmap.h>
#include <sys/thread.h>
@ -158,7 +158,7 @@ Loader_Load(Thread *thr, VNode *vn, void *buf, uint64_t len)
memsz += phdr[i].p_vaddr - va;
Log(loader, "AllocMap %016llx %08llx\n", va, memsz);
if (!PMap_AllocMap(as, va, memsz, PTE_W)) {
if (!PMap_AllocMap(as, va, memsz, PROT_ALL)) {
// XXX: Cleanup!
ASSERT(false);
return false;
@ -166,7 +166,7 @@ Loader_Load(Thread *thr, VNode *vn, void *buf, uint64_t len)
}
}
PMap_AllocMap(as, MEM_USERSPACE_STKBASE, MEM_USERSPACE_STKLEN, PTE_W);
PMap_AllocMap(as, MEM_USERSPACE_STKBASE, MEM_USERSPACE_STKLEN, PROT_READ|PROT_WRITE);
for (i = 0; i < ehdr->e_phnum; i++)
{
@ -238,6 +238,7 @@ Loader_LoadInit()
*/
PMap_LoadAS(thr->space); // Reload CR3
#if defined(__x86_64__)
/*
* Pass in zero arguments with null pointers to init
*/
@ -263,6 +264,9 @@ Loader_LoadInit()
tf.rflags = RFLAGS_IF;
tf.rdi = rsp;
Trap_Pop(&tf);
#elif defined(__aarch64__)
NOT_IMPLEMENTED();
#endif
/*
* We should never reach this point!

2
sys/kern/syscall.c
View File

@ -228,7 +228,7 @@ Syscall_MMap(uint64_t addr, uint64_t len, uint64_t prot)
Thread *cur = Sched_Current();
bool status;
status = PMap_AllocMap(cur->space, addr, len, PTE_W);
status = PMap_AllocMap(cur->space, addr, len, prot);
Thread_Release(cur);
if (!status) {
// XXX: Need to unmap PMap_Unmap(cur->space, addr, pgs);

3
sys/kern/thread.c
View File

@ -15,6 +15,7 @@
#include <sys/kdebug.h>
#include <sys/kmem.h>
#include <sys/ktime.h>
#include <sys/mman.h>
#include <sys/mp.h>
#include <sys/spinlock.h>
#include <sys/thread.h>
@ -171,7 +172,7 @@ Thread_UThreadCreate(Thread *oldThr, uint64_t rip, uint64_t arg)
proc->ustackNext += MEM_USERSPACE_STKLEN;
Spinlock_Unlock(&proc->lock);
PMap_AllocMap(thr->space, thr->ustack, MEM_USERSPACE_STKLEN, PTE_W);
PMap_AllocMap(thr->space, thr->ustack, MEM_USERSPACE_STKLEN, PROT_READ|PROT_WRITE);
// XXX: Check failure
Thread_InitArch(thr);