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l1shift.c
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l1shift.c
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/*
* Copyright (c) 2023 Peter J. Philipp
* 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. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*
*/
/*
* This program is a calculator for trying to make human sense of the
* locore.S program in OpenBSD/riscv64 it is dated sept. 7 2023
*
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/tree.h>
#include <machine/pmap.h>
#include <uvm/uvm_extern.h>
#include <uvm/uvm_page.h>
#include <stdio.h>
#include <stdlib.h>
#define PTE_D (1 << 7) /* Dirty */
#define PTE_A (1 << 6) /* Accessed */
#define PTE_G (1 << 5) /* Global */
#define PTE_X (1 << 3) /* execute */
#define PTE_W (1 << 2) /* Write */
#define PTE_R (1 << 1) /* Read */
#define PTE_V (1 << 0) /* Valid */
#define OLD_PTE_KERN (PTE_R | PTE_W | PTE_A | PTE_D | PTE_V)
#define PTE_KERN (PTE_A | PTE_D | PTE_W)
#define KERNBASE 0xffffffc000000000UL
#define PTE_PPN0_S 10
#define PTE_PPN1_S 19
#define PTE_PPN2_S 28
#define PTE_PPN3_S 37
#define PTE_SIZE 8
int
main(void)
{
uint64_t i = 0x40000000;
uint64_t ib, ib0, ib1, p1, p2, pd;
i = i / 4096;
#if 0
printf("sizeof struct vm_page %lu (%lx)\n", sizeof(struct vm_page), sizeof(struct vm_page));
printf("working PTE_KERN\n");
printf("PTE_KERN = %d (%x) %s\n", PTE_KERN, PTE_KERN, (PTE_KERN % 8) ? "n" : "y");
printf("%lld (%llx) %s\n", i, i, (i % 8) ? "n" : "y");
printf("%lld (%llx) %s\n", PTE_KERN | (i << 10), PTE_KERN | (i << 10),
(PTE_KERN | (i << 10)) % 8 ? "n" : "y");
printf("old PTE_KERN\n");
printf("OLD_PTE_KERN = %d (%x) %s\n", OLD_PTE_KERN, OLD_PTE_KERN, (OLD_PTE_KERN % 8) ? "n" : "y");
printf("%lld (%llx) %s\n", i, i, (i % 8) ? "n" : "y");
printf("%lld (%llx) %s\n", OLD_PTE_KERN | (i << 10), OLD_PTE_KERN | (i << 10),
(OLD_PTE_KERN | (i << 10)) % 8 ? "n" : "y");
printf("%lld (%llx)\n", (1ULL << 9), (1ULL << 9));
#endif
/*
745: ffffffc00100b000 0 NOTYPE LOCAL DEFAULT 4 pagetable_l1
746: ffffffc00100c000 0 NOTYPE LOCAL DEFAULT 4 pagetable_l2
747: ffffffc00100d000 0 NOTYPE LOCAL DEFAULT 4 pagetable_l2_devmap
*/
ib = 0xffffffc001101f20;
printf("_end is at %llu (%llx)\n", ib, ib);
ib = 0xffffffc00100b000;
p1 = ib;
printf("pagetable_l1 (this is s1) = %llu (%llx)\n", ib, ib);
ib += 4096;
p2 = ib;
printf("pagetable_l2 = (this is s2) = = %llu (%llx)\n", ib, ib);
printf("add L1 entry =========================\n");
ib >>= 12;
p2 = ib;
printf("pagetable_l2 >> PAGE_SHIFT(12) = %llu (%llx)\n", ib, ib);
ib = KERNBASE;
printf("KERNBASE = %lu (%lx)\n", KERNBASE, KERNBASE);
ib >>= 30;
printf("KERNBASE >> 30 = %llu (%llx)\n", (ib), (ib));
ib &= 0x1ff;
printf("(KERNBASE >> 30) & 0x1ff %llu (%llx)\n", (ib), (ib));
ib = p2;
ib <<= PTE_PPN0_S;
printf("pagetable_l2 << PTE_PPN0_S: %llu (%llx)\n", (ib), (ib));
ib |= PTE_V;
ib0 = ib;
printf("above (this is t6)| PTE_V: %llu (%llx)\n", (ib), (ib));
ib = ((KERNBASE >> 30) & 0x1ff) * 8;
printf("((KERNBASE >> 30) & 0x1ff) * 8(PTE_SIZE): %llu (%llx)\n", (ib), (ib));
printf("((KERNBASE >> 30) & 0x1ff) * 8(PTE_SIZE): %llu (%llx)\\\n"
"(2048) + s1(becomes t0) == %llu (%llx)\n", (ib), (ib),
(ib + p1), (ib + p1));
ib += p1;
printf("store t6(%llu [%llx] into t0(%llu [%llx])\n", ib0, ib0,
ib, ib);
printf("============================\nL2 megapages (511 * 2 MB)\n");
printf(" ^^^^^^^^^^^^^^^\n");
printf("the comments and code are wrong, there is on 511 * 2 MB megapages (9 bits)\n");
printf("$ dc\n");
printf("2o\n");
printf("512 p\n");
printf("1000000000\n");
printf("511 p\n");
printf("111111111\n\n");
pd = 0xffffffc00100d000;
printf("let pd = pagetable_l2_devmap == %llu (%llx)\n", pd, pd);
pd >>= 12;
printf("right shift this pd by 12 (PAGE_SHIFT) %llu (%llx)\n", pd, pd);
ib = 0x4000000;
printf("let physmem BASE(0x40000000) >> 21 (divide 2MB, L2_SHIFT) == %llu (%llx)\n",
(ib >> 21), (ib >> 21));
ib >>= 21;
ib0 = ib;
ib += 512;
printf("add (512) == %llu (%llx)\n", (ib), (ib));
ib0 <<= PTE_PPN1_S;
printf("base physmem pagecount (%llu [%llx]) << PTE_PPN1_S\n",
ib0, ib0);
ib0 |= (PTE_KERN | PTE_X);
printf("OR with (PTE_KERN | PTE_X) %llu (%llx) and write to pagetable2"
"at %llu (%llx)\n", ib0, ib0, p2, p2);
ib1 = p2;
ib1 += 8;
printf("add PAGE_SIZE(8) to pagetable2 == %llu (%llx)\n", ib1, ib1);
ib1 += 1;
printf("add 1 it is now %llu (%llx)\n", ib1, ib1);
printf("li a5, (VM_MAX_KERNEL_ADDRESS - L2_SIZE)\n");
#define PJP_VM_MAX_KERNEL_ADDRESS (0xffffffc800000000UL)
printf(" VM_MAX_KERNEL_ADDRESS - 2MB == %llu (%llx)\n",
(PJP_VM_MAX_KERNEL_ADDRESS - (1ULL << 21)),
(PJP_VM_MAX_KERNEL_ADDRESS - (1ULL << 21)));
ib = (PJP_VM_MAX_KERNEL_ADDRESS - (1ULL << 21));
ib >>= 30;
printf("right shift this by 30 (L1_SHIFT) %llu (%llx)\n",
ib, ib);
ib &= 0x1ff;
printf("and it by 0x1ff == %llu (%llx)\n",
ib, ib);
ib |= 1;
printf ("and OR it by 1 (PTE_V) == %llu (%llx)\n", ib, ib);
pd <<= 10;
printf("leftshift pagetable_devmap (pd) by PTE_PPN0_S == %llu (%llx)\n",
pd, pd);
printf("more to come.. \n");
}