From 44694ba9492b03042e3cda7eae717b854905e25e Mon Sep 17 00:00:00 2001
From: Freya Murphy <freya@freyacat.org>
Date: Thu, 27 Mar 2025 17:56:39 -0400
Subject: [PATCH] track changes
---
include/vm.h | 4 +--
kernel/cio.c | 5 +--
kernel/user.c | 2 +-
kernel/vm.c | 91 +++++++++++++++++++++++++++++++++--------------
kernel/vmtables.c | 6 ++--
5 files changed, 74 insertions(+), 34 deletions(-)
diff --git a/include/vm.h b/include/vm.h
index 6c4441f..8eac999 100644
--- a/include/vm.h
+++ b/include/vm.h
@@ -432,12 +432,12 @@ int vm_map(pde_t *pdir, void *va, uint32_t pa, uint32_t size, int perm);
** hierarchy. We assume that the "new" page directory exists and
** the system portions of it should not be touched.
**
-** @param old Existing page directory
** @param new New page directory
+** @param old Existing page directory
**
** @return status of the duplication attempt
*/
-int vm_uvmdup(pde_t *old, pde_t *new);
+int vm_uvmdup(pde_t *new, pde_t *old);
#endif /* !ASM_SRC */
diff --git a/kernel/cio.c b/kernel/cio.c
index 1e5cb3c..deb6b76 100644
--- a/kernel/cio.c
+++ b/kernel/cio.c
@@ -67,8 +67,9 @@ static void (*notify)(int);
// calculate the memory address of a specific character position
// within VGA memory
-#define VIDEO_ADDR(x, y) \
- (unsigned short *)(VID_BASE_ADDR + 2 * ((y) * SCREEN_X_SIZE + (x)))
+#define VIDEO_ADDR(x, y) \
+ (unsigned short *)((VID_BASE_ADDR + 2 * ((y) * SCREEN_X_SIZE + (x))) | \
+ 0x80000000)
// port addresses
#define VGA_CTRL_IX_ADDR 0x3d4
diff --git a/kernel/user.c b/kernel/user.c
index 7c475e8..f444b6c 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -748,7 +748,7 @@ int user_duplicate(pcb_t *new, pcb_t *old)
// Next, add a USER_PDE page table that's a duplicate of the
// current process' page table
- if (!vm_uvmdup(old->pdir, new->pdir)) {
+ if (!vm_uvmdup(new->pdir, old->pdir)) {
// check for memory leak?
return E_NO_MEMORY;
}
diff --git a/kernel/vm.c b/kernel/vm.c
index 2ab5720..7d43bb8 100644
--- a/kernel/vm.c
+++ b/kernel/vm.c
@@ -168,9 +168,17 @@ void vm_init(void)
kpdir = vm_mkkvm();
assert(kpdir != NULL);
+#if TRACING_VM
+ cio_printf("vm_init: kpdir is %08x\n", kpdir);
+#endif
+
// switch to it
vm_set_kvm();
+#if TRACING_VM
+ cio_puts("vm_init: running on new kpdir\n");
+#endif
+
// install the page fault handler
install_isr(VEC_PAGE_FAULT, vm_isr);
}
@@ -327,9 +335,9 @@ pde_t *vm_mkkvm(void)
if (pdir == NULL) {
return NULL;
}
-#if TRACING_VM
- cio_puts("\nEntering vm_mkkvm\n");
- ptdump(pdir, true, 0, N_PDE);
+#if 0 && TRACING_VM
+ cio_puts( "\nEntering vm_mkkvm\n" );
+ ptdump( pdir, true, 0, N_PDE );
#endif
// clear it out to disable all the entries
@@ -351,10 +359,10 @@ pde_t *vm_mkkvm(void)
return 0;
}
}
-#if TRACING_VM
- cio_puts("\nvm_mkkvm() final PD:\n");
- ptdump(pdir, true, 0, 16);
- ptdump(pdir, true, 0x200, 16);
+#if 0 && TRACING_VM
+ cio_puts( "\nvm_mkkvm() final PD:\n" );
+ ptdump( pdir, true, 0, 16 );
+ ptdump( pdir, true, 0x200, 16 );
#endif
return pdir;
@@ -399,7 +407,13 @@ pde_t *vm_mkuvm(void)
*/
void vm_set_kvm(void)
{
+#if TRACING_VM
+ cio_puts("Entering vm_set_kvm()\n");
+#endif
w_cr3(V2P(kpdir)); // switch to the kernel page table
+#if TRACING_VM
+ cio_puts("Exiting vm_set_kvm()\n");
+#endif
}
/**
@@ -411,10 +425,16 @@ void vm_set_kvm(void)
*/
void vm_set_uvm(pcb_t *p)
{
+#if TRACING_VM
+ cio_puts("Entering vm_set_uvm()\n");
+#endif
assert(p != NULL);
assert(p->pdir != NULL);
w_cr3(V2P(p->pdir)); // switch to process's address space
+#if TRACING_VM
+ cio_puts("Entering vm_set_uvm()\n");
+#endif
}
/**
@@ -449,8 +469,8 @@ int vm_add(pde_t *pdir, bool_t wr, bool_t sys, void *va, uint32_t size,
}
#if TRACING_VM
- cio_printf("vm_add: pdir %08x, %s, va %08x (%u, %u pgs)\n", (uint32_t)pdir,
- wr ? "W" : "!W", (uint32_t)va, size);
+ cio_printf("vm_add: pdir %08x, %s, va %08x size %u (%u pgs)\n",
+ (uint32_t)pdir, wr ? "W" : "!W", (uint32_t)va, size, npages);
cio_printf(" from %08x, %u bytes, perms %08x\n", (uint32_t)data,
bytes, entrybase);
#endif
@@ -511,6 +531,10 @@ int vm_add(pde_t *pdir, bool_t wr, bool_t sys, void *va, uint32_t size,
*/
void vm_free(pde_t *pdir)
{
+#if TRACING_VM
+ cio_printf("vm_free(%08x)\n", (uint32_t)pdir);
+#endif
+
// do we have anything to do?
if (pdir == NULL) {
return;
@@ -519,6 +543,8 @@ void vm_free(pde_t *pdir)
// iterate through the page directory entries, freeing the
// PMTS and the frames they point to
pde_t *curr = pdir;
+ int nf = 0;
+ int nt = 0;
for (int i = 0; i < N_PDE; ++i) {
// the entry itself
pde_t entry = *curr;
@@ -537,6 +563,7 @@ void vm_free(pde_t *pdir)
if (IS_PRESENT(*pmt)) {
// yes - free the frame
km_page_free((void *)PTE_ADDR(*pmt));
+ ++nf;
// mark it so we don't get surprised
*pmt = 0;
}
@@ -545,6 +572,7 @@ void vm_free(pde_t *pdir)
}
// now, free the PMT itself
km_page_free((void *)PDE_ADDR(entry));
+ ++nt;
*curr = 0;
}
@@ -554,6 +582,11 @@ void vm_free(pde_t *pdir)
// finally, free the PDIR itself
km_page_free((void *)pdir);
+ ++nt;
+
+#if TRACING_VM
+ cio_printf("vm_free: %d pages, %d tables\n", nf, nt);
+#endif
}
/*
@@ -580,7 +613,7 @@ int vm_map(pde_t *pdir, void *va, uint32_t pa, uint32_t size, int perm)
char *last = (char *)PGDOWN(((uint32_t)va) + size - 1);
#if TRACING_VM
- cio_printf("\n\nvm_map pdir %08x va %08x pa %08x size %08x perm %03x\n",
+ cio_printf("vm_map pdir %08x va %08x pa %08x size %08x perm %03x\n",
(uint32_t)pdir, (uint32_t)va, pa, size, perm);
#endif
@@ -591,24 +624,27 @@ int vm_map(pde_t *pdir, void *va, uint32_t pa, uint32_t size, int perm)
// couldn't find it
return E_NO_PTE;
}
- // #if TRACING_VM
- // cio_printf( " addr %08x pa %08x last %08x pte %08x *pte %08x\n",
- // (uint32_t) addr, pa, (uint32_t) last, (uint32_t) pte, *pte
- // );
- //#endif
+#if 0 && TRACING_VM
+ cio_printf( " addr %08x pa %08x last %08x pte %08x *pte %08x\n",
+ (uint32_t) addr, pa, (uint32_t) last, (uint32_t) pte, *pte
+ );
+#endif
- // create the new entry
- pde_t entry = pa | perm | PTE_P;
+ // create the new entry for the page table
+ pde_t newpte = pa | perm | PTE_P;
// if this entry has already been mapped, we're in trouble
if (IS_PRESENT(*pte)) {
- if (*pte != entry) {
+ if (*pte != newpte) {
#if TRACING_VM
- cio_puts(" ALREADY MAPPED?");
- cio_printf(" PDIX 0x%x PTIX 0x%x\n", PDIX(addr), PTIX(addr));
+ cio_printf(
+ "vm_map: va %08x pa %08x pte %08x *pte %08x entry %08x\n",
+ (uint32_t)va, pa, (uint32_t)pte, (uint32_t)*pte, newpte);
+ cio_printf(" addr %08x PDIX 0x%x PTIX 0x%x\n", (uint32_t)addr,
+ PDIX(addr), PTIX(addr));
// dump the directory
- ptdump(pdir, true, 0, N_PDE);
+ ptdump(pdir, true, PDIX(addr), 4);
// find the relevant PDE entry
uint32_t ix = PDIX(va);
@@ -617,16 +653,15 @@ int vm_map(pde_t *pdir, void *va, uint32_t pa, uint32_t size, int perm)
// round the PMT index down
uint32_t ix2 = PTIX(va) & MOD4_MASK;
// dump the PMT for the relevant directory entry
- ptdump((void *)P2V(PDE_ADDR(entry)), false, ix2, 8);
+ ptdump((void *)P2V(PDE_ADDR(entry)), false, ix2, 4);
}
#endif
-
PANIC(0, "mapping an already-mapped address");
}
}
// ok, set the PTE as requested
- *pte = entry;
+ *pte = newpte;
// nope - move to the next page
addr += SZ_PAGE;
@@ -647,17 +682,21 @@ int vm_map(pde_t *pdir, void *va, uint32_t pa, uint32_t size, int perm)
** now have two sets of page tables that refer to the same physical
** frames in memory.
**
-** @param old Existing page directory
** @param new New page directory
+** @param old Existing page directory
**
** @return status of the duplication attempt
*/
-int vm_uvmdup(pde_t *old, pde_t *new)
+int vm_uvmdup(pde_t *new, pde_t *old)
{
if (old == NULL || new == NULL) {
return E_BAD_PARAM;
}
+#if TRACING_VM
+ cio_printf("vmdup: old %08x new %08x\n", (uint32_t)old, (uint32_t)new);
+#endif
+
// we only want to deal with the "user" half of the address space
for (int i = 0; i < (N_PDE >> 1); ++i) {
// the entry to copy
diff --git a/kernel/vmtables.c b/kernel/vmtables.c
index 4dfce43..113fd8b 100644
--- a/kernel/vmtables.c
+++ b/kernel/vmtables.c
@@ -365,7 +365,7 @@ const pte_t id_map[N_PTE] = {
};
#endif /* MAKE_IDENTITY_MAP */
-extern int _end;
+extern char _end[];
/*
** Kernel address mappings, present in every page table
@@ -375,7 +375,7 @@ const mapping_t kmap[] = {
{ KERN_BASE, 0, EXT_BASE, PDE_RW },
{ KERN_VLINK, KERN_PLINK, V2P(_data), PDE_RW },
// { (uint32_t) _data, V2P(_data), V2P(_end), PDE_RW },
- { (uint32_t)_data, V2P(_data), PHYS_TOP, PDE_RW },
- { DEV_BASE, DEV_BASE, 0, PDE_RW }
+ { (uint32_t)_data, V2P(_data), PHYS_TOP, PDE_RW }
+ // { DEV_BASE, DEV_BASE, 0, PDE_RW }
};
const uint_t n_kmap = sizeof(kmap) / sizeof(kmap[0]);