| 1 | /*
|
|---|
| 2 | * Copyright (c) 2006 Ondrej Palkovsky
|
|---|
| 3 | * All rights reserved.
|
|---|
| 4 | *
|
|---|
| 5 | * Redistribution and use in source and binary forms, with or without
|
|---|
| 6 | * modification, are permitted provided that the following conditions
|
|---|
| 7 | * are met:
|
|---|
| 8 | *
|
|---|
| 9 | * - Redistributions of source code must retain the above copyright
|
|---|
| 10 | * notice, this list of conditions and the following disclaimer.
|
|---|
| 11 | * - Redistributions in binary form must reproduce the above copyright
|
|---|
| 12 | * notice, this list of conditions and the following disclaimer in the
|
|---|
| 13 | * documentation and/or other materials provided with the distribution.
|
|---|
| 14 | * - The name of the author may not be used to endorse or promote products
|
|---|
| 15 | * derived from this software without specific prior written permission.
|
|---|
| 16 | *
|
|---|
| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|---|
| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|---|
| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|---|
| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|---|
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|---|
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|---|
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|---|
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|---|
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|---|
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|---|
| 27 | */
|
|---|
| 28 |
|
|---|
| 29 | /** @addtogroup kernel_amd64
|
|---|
| 30 | * @{
|
|---|
| 31 | */
|
|---|
| 32 | /** @file
|
|---|
| 33 | */
|
|---|
| 34 |
|
|---|
| 35 | #include <syscall/syscall.h>
|
|---|
| 36 | #include <arch/syscall.h>
|
|---|
| 37 | #include <panic.h>
|
|---|
| 38 | #include <arch/cpu.h>
|
|---|
| 39 | #include <arch/pm.h>
|
|---|
| 40 | #include <arch/asm.h>
|
|---|
| 41 |
|
|---|
| 42 | #include <print.h>
|
|---|
| 43 |
|
|---|
| 44 | extern void syscall_entry(void);
|
|---|
| 45 |
|
|---|
| 46 | /** Enable & setup support for SYSCALL/SYSRET */
|
|---|
| 47 | void syscall_setup_cpu(void)
|
|---|
| 48 | {
|
|---|
| 49 | /* Enable SYSCALL/SYSRET */
|
|---|
| 50 | write_msr(AMD_MSR_EFER, read_msr(AMD_MSR_EFER) | AMD_SCE);
|
|---|
| 51 |
|
|---|
| 52 | /* Setup syscall entry address */
|
|---|
| 53 |
|
|---|
| 54 | /*
|
|---|
| 55 | * This is _mess_ - the 64-bit CS is argument + 16,
|
|---|
| 56 | * the SS is argument + 8. The order is:
|
|---|
| 57 | * +0(KDATA_DES), +8(UDATA_DES), +16(UTEXT_DES)
|
|---|
| 58 | */
|
|---|
| 59 | write_msr(AMD_MSR_STAR,
|
|---|
| 60 | ((uint64_t) (GDT_SELECTOR(KDATA_DES) | PL_USER) << 48) |
|
|---|
| 61 | ((uint64_t) (GDT_SELECTOR(KTEXT_DES) | PL_KERNEL) << 32));
|
|---|
| 62 | write_msr(AMD_MSR_LSTAR, (uint64_t)syscall_entry);
|
|---|
| 63 | /*
|
|---|
| 64 | * Mask RFLAGS on syscall
|
|---|
| 65 | * - disable interrupts, until we exchange the stack register
|
|---|
| 66 | * (mask the IF bit)
|
|---|
| 67 | * - clear DF so that the string instructions operate in
|
|---|
| 68 | * the right direction
|
|---|
| 69 | * - clear NT to prevent a #GP should the flag proliferate to an IRET
|
|---|
| 70 | * - clear TF to prevent an immediate #DB if TF is set
|
|---|
| 71 | */
|
|---|
| 72 | write_msr(AMD_MSR_SFMASK,
|
|---|
| 73 | RFLAGS_IF | RFLAGS_DF | RFLAGS_NT | RFLAGS_TF);
|
|---|
| 74 | }
|
|---|
| 75 |
|
|---|
| 76 | /** @}
|
|---|
| 77 | */
|
|---|
