diff options
Diffstat (limited to 'sys/arch/amd64')
| -rw-r--r-- | sys/arch/amd64/amd64/machdep.c | 12 | ||||
| -rw-r--r-- | sys/arch/amd64/amd64/tss.c | 177 |
2 files changed, 189 insertions, 0 deletions
diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c index 983a480..2fe71a9 100644 --- a/sys/arch/amd64/amd64/machdep.c +++ b/sys/arch/amd64/amd64/machdep.c @@ -30,6 +30,7 @@ #include <sys/types.h> #include <machine/cpu.h> #include <machine/gdt.h> +#include <machine/tss.h> #include <machine/idt.h> #include <machine/trap.h> #include <machine/asm.h> @@ -67,6 +68,16 @@ setup_vectors(void) idt_set_desc(0xE, IDT_TRAP_GATE, ISR(page_fault), 0); } +static inline void +init_tss(struct cpu_info *ci) +{ + struct tss_desc *desc; + + desc = (struct tss_desc *)&g_gdt_data[GDT_TSS]; + write_tss(ci, desc); + tss_load(); +} + static void try_mitigate_spectre(void) { @@ -95,6 +106,7 @@ cpu_startup(void) setup_vectors(); amd64_write_gs_base((uintptr_t)&g_bsp_ci); + init_tss(&g_bsp_ci); try_mitigate_spectre(); lapic_init(); diff --git a/sys/arch/amd64/amd64/tss.c b/sys/arch/amd64/amd64/tss.c new file mode 100644 index 0000000..5aab74a --- /dev/null +++ b/sys/arch/amd64/amd64/tss.c @@ -0,0 +1,177 @@ +/* + * Copyright (c) 2023-2024 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/param.h> +#include <sys/types.h> +#include <sys/errno.h> +#include <sys/panic.h> +#include <vm/dynalloc.h> +#include <vm/physmem.h> +#include <machine/tss.h> +#include <machine/cpu.h> +#include <assert.h> +#include <string.h> + +/* + * Allocates memory for TSS and kernel + * stack. + * + * XXX: Kernel stack is allocated from + * vm_alloc_frame() + */ +static void +alloc_resources(struct cpu_info *ci) +{ + const size_t STACK_SIZE = 0x1000; + struct tss_entry *tss; + static uintptr_t rsp0_base, rsp0; + + if (ci->tss == NULL) { + tss = dynalloc(sizeof(*tss)); + + if (tss == NULL) { + panic("Failed to alloc TSS\n"); + } + + memset(tss, 0, sizeof(*tss)); + rsp0_base = vm_alloc_frame(1); + + if (rsp0_base == 0) { + panic("Could not allocate RSP0 base\n"); + } + + rsp0 = rsp0_base + STACK_SIZE; + tss->rsp0_lo = rsp0 & 0xFFFFFFFF; + tss->rsp0_hi = (rsp0 >> 32) & 0xFFFFFFFF; + ci->tss = tss; + } +} + +/* + * Update interrupt stack table entry `istno' with `stack' + * + * @stack: Interrupt stack. + * @istno: IST number, must be 1-based. + * + * Returns 0 on success. + */ +int +tss_update_ist(struct cpu_info *ci, union tss_stack stack, uint8_t istno) +{ + volatile struct tss_entry *tss = ci->tss; + + __assert(tss != NULL); + + switch (istno) { + case 1: + tss->ist1_lo = stack.top_lo; + tss->ist1_hi = stack.top_hi; + break; + case 2: + tss->ist2_lo = stack.top_lo; + tss->ist2_hi = stack.top_hi; + break; + case 3: + tss->ist3_lo = stack.top_lo; + tss->ist3_hi = stack.top_hi; + break; + case 4: + tss->ist4_lo = stack.top_lo; + tss->ist4_hi = stack.top_hi; + break; + case 5: + tss->ist5_lo = stack.top_lo; + tss->ist5_hi = stack.top_hi; + break; + case 6: + tss->ist6_lo = stack.top_lo; + tss->ist6_hi = stack.top_hi; + break; + case 7: + tss->ist7_lo = stack.top_lo; + tss->ist7_hi = stack.top_hi; + break; + default: + return -EINVAL; + }; + + return 0; +} + +/* + * Allocates TSS stack. + * + * @entry_out: Pointer to location where allocated entry + * will be sent. + * + * Returns 0 on success. + */ +int +tss_alloc_stack(union tss_stack *entry_out, size_t size) +{ + uintptr_t base = (uintptr_t)dynalloc(size); + + if (base == 0) { + return -ENOMEM; + } + + entry_out->top = base + size; + return 0; +} + +void +write_tss(struct cpu_info *ci, struct tss_desc *desc) +{ + volatile struct tss_entry *tss; + uintptr_t tss_base; + + alloc_resources(ci); + tss_base = (uintptr_t)ci->tss; + + /* + * XXX: The AVL (Available for use by system software) + * bit is ignored by hardware and it is up to us + * to decide how to use it... As of now, it is useless + * to us and shall remain 0. + */ + desc->seglimit = sizeof(struct tss_entry); + desc->p = 1; /* Must be present to be valid! */ + desc->g = 0; /* Granularity -> 0 */ + desc->avl = 0; /* Not used */ + desc->dpl = 0; /* Descriptor Privilege Level -> 0 */ + desc->type = 0x9; /* For TSS -> 0x9 (0b1001) */ + + desc->base_lo16 = tss_base & 0xFFFF; + desc->base_mid8 = (tss_base >> 16) & 0xFF; + desc->base_hi_mid8 = (tss_base >> 24) & 0xFF; + desc->base_hi32 = (tss_base >> 32) & 0xFFFFFFFF; + + tss = ci->tss; + tss->io_base = 0xFF; /* Disallow ring 3 port I/O */ +} |