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-rw-r--r--sys/arch/amd64/cpu/mmu.c98
-rw-r--r--sys/inc/arch/amd64/vas.h39
-rw-r--r--sys/inc/mu/mmu.h54
-rw-r--r--sys/inc/vm/vm.h6
-rw-r--r--sys/kern/Makefile3
-rw-r--r--sys/kern/kern_init.c2
-rw-r--r--sys/mu/mmu_stub.c49
-rw-r--r--sys/vm/vm_init.c43
8 files changed, 293 insertions, 1 deletions
diff --git a/sys/arch/amd64/cpu/mmu.c b/sys/arch/amd64/cpu/mmu.c
new file mode 100644
index 0000000..65c4e46
--- /dev/null
+++ b/sys/arch/amd64/cpu/mmu.c
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <kern/panic.h>
+#include <mu/mmu.h>
+#include <vm/vm.h>
+#include <md/vas.h>
+
+/*
+ * See Intel SDM Vol 3A, Section 4.5, Table 4-19
+ */
+#define PTE_ADDR_MASK 0x000FFFFFFFFFF000
+#define PTE_P BIT(0) /* Present */
+#define PTE_RW BIT(1) /* Writable */
+#define PTE_US BIT(2) /* User r/w allowed */
+#define PTE_PWT BIT(3) /* Page-level write-through */
+#define PTE_PCD BIT(4) /* Page-level cache disable */
+#define PTE_ACC BIT(5) /* Accessed */
+#define PTE_DIRTY BIT(6) /* Dirty (written-to page) */
+#define PTE_PS BIT(7) /* Page size */
+#define PTE_GLOBAL BIT(8) /* Global / sticky map */
+#define PTE_NX BIT(63) /* Execute-disable */
+
+int
+mu_pmap_readvas(struct mmu_vas *vas)
+{
+ __asmv(
+ "mov %%cr3, %0"
+ : "=r" (vas->cr3)
+ :
+ : "memory"
+ );
+
+ vas->cr3 &= PTE_ADDR_MASK;
+ return 0;
+}
+
+int
+mu_pmap_writevas(struct mmu_vas *vas)
+{
+ __asmv(
+ "mov %0, %%cr3"
+ :
+ : "r" (vas->cr3)
+ : "memory"
+ );
+
+ return 0;
+}
+
+void
+mu_pmap_init(void)
+{
+ struct mmu_vas cur_vas;
+ uintptr_t *pml4;
+
+ /* Tear down the old lower half mappings */
+ mu_pmap_readvas(&cur_vas);
+ pml4 = PHYS_TO_VIRT(cur_vas.cr3);
+ for (uint16_t i = 0; i < 256; ++i) {
+ pml4[i] = 0;
+ }
+
+ /*
+ * The entries in the TLB may still refer to the old lower
+ * half mappings which are now stale... To avoid this biting
+ * us in the ass we should flush the *entire* TLB
+ */
+ mu_pmap_writevas(&cur_vas);
+}
diff --git a/sys/inc/arch/amd64/vas.h b/sys/inc/arch/amd64/vas.h
new file mode 100644
index 0000000..eeca5f7
--- /dev/null
+++ b/sys/inc/arch/amd64/vas.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MACHINE_VAS_H_
+#define _MACHINE_VAS_H_ 1
+
+#include <sys/types.h>
+
+struct mmu_vas {
+ uintptr_t cr3;
+};
+
+#endif /* !_MACHINE_VAS_H_ */
diff --git a/sys/inc/mu/mmu.h b/sys/inc/mu/mmu.h
new file mode 100644
index 0000000..85f4343
--- /dev/null
+++ b/sys/inc/mu/mmu.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _MU_PMAP_H_
+#define _MU_PMAP_H_ 1
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <md/vas.h> /* shared */
+
+/*
+ * Read the currently in-use virtual address space
+ * structure
+ */
+__weak int mu_pmap_readvas(struct mmu_vas *vas);
+
+/*
+ * Write a new virtual address structure to be put
+ * into use as the current address space
+ */
+__weak int mu_pmap_writevas(struct mmu_vas *vas);
+
+/*
+ * Initialize the platform memory management unit
+ */
+__weak void mu_pmap_init(void);
+
+#endif /* !_MU_PMAP_H_ */
diff --git a/sys/inc/vm/vm.h b/sys/inc/vm/vm.h
index e1866cb..4134005 100644
--- a/sys/inc/vm/vm.h
+++ b/sys/inc/vm/vm.h
@@ -40,4 +40,10 @@ extern volatile struct limine_hhdm_request hhdm_req;
#define PHYS_TO_VIRT(PHYS) PTR_OFFSET(PHYS, hhdm_req.response->offset)
#define VIRT_TO_PHYS(VIRT) (uintptr_t)PTR_NOFFET(VIRT, hhdm_req.response->offset)
+/*
+ * Initialize the virtual memory management
+ * subsystem
+ */
+void vm_init(void);
+
#endif /* !_VM_VM_H_ */
diff --git a/sys/kern/Makefile b/sys/kern/Makefile
index b04e252..718df06 100644
--- a/sys/kern/Makefile
+++ b/sys/kern/Makefile
@@ -6,6 +6,7 @@ CFILES += $(shell find ../lib -name "*.c")
CFILES += $(shell find ../os -name "*.c")
CFILES += $(shell find ../vm -name "*.c")
CFILES += $(shell find ../dev -name "*.c")
+CFILES += $(shell find ../mu -name "*.c")
OFILES = $(CFILES:.c=.o)
DFILES = $(CFILES:.c=.d)
CC =
@@ -17,4 +18,4 @@ all: $(OFILES)
-include $(DFILES)
%.o: %.c
$(PROMPT) " [CC] " $<
- $(CC) -c $< $(SYS_CFLAGS) -MMD -I../inc/ -I../inc/lib -o $@
+ $(CC) -c $< $(SYS_CFLAGS) -MMD -I../target/inc/ -I../inc/ -I../inc/lib -o $@
diff --git a/sys/kern/kern_init.c b/sys/kern/kern_init.c
index 74e17c4..68fb2fb 100644
--- a/sys/kern/kern_init.c
+++ b/sys/kern/kern_init.c
@@ -31,6 +31,7 @@
#include <dev/cons/cons.h>
#include <os/trace.h>
#include <vm/phys.h>
+#include <vm/vm.h>
struct console g_bootcons;
void kmain(void);
@@ -41,4 +42,5 @@ kmain(void)
console_reset(&g_bootcons);
trace("bootcons: console online\n");
vm_phys_init();
+ vm_init();
}
diff --git a/sys/mu/mmu_stub.c b/sys/mu/mmu_stub.c
new file mode 100644
index 0000000..4c2a3fa
--- /dev/null
+++ b/sys/mu/mmu_stub.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#include <mu/mmu.h>
+
+__strong void
+mu_pmap_init(void)
+{
+ (void)0;
+}
+
+__strong int
+mu_pmap_readvas(struct mmu_vas *vas)
+{
+ (void)vas;
+}
+
+__strong int
+mu_pmap_writevas(struct mmu_vas *vas)
+{
+ (void)vas;
+}
diff --git a/sys/vm/vm_init.c b/sys/vm/vm_init.c
new file mode 100644
index 0000000..8a08671
--- /dev/null
+++ b/sys/vm/vm_init.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPKERNE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LKERNS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * PKERNSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <os/trace.h>
+#include <vm/vm.h>
+#include <mu/mmu.h>
+
+#define dtrace(fmt, ...) trace("vm: " fmt, ##__VA_ARGS__)
+
+void
+vm_init(void)
+{
+ dtrace("bringing up mmu...\n");
+ mu_pmap_init();
+ dtrace("OK\n");
+}