| 1 | /*
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| 2 | * Copyright (C) 2006 Ondrej Palkovsky
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #include <syscall/syscall.h>
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| 30 | #include <arch/syscall.h>
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| 31 | #include <panic.h>
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| 32 | #include <arch/cpu.h>
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| 33 | #include <arch/pm.h>
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| 34 | #include <arch/asm.h>
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| 35 |
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| 36 | #include <print.h>
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| 37 |
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| 38 | extern void syscall_entry(void);
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| 39 |
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| 40 | /** Enable & setup support for SYSCALL/SYSRET */
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| 41 | void syscall_setup_cpu(void)
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| 42 | {
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| 43 | /* Enable SYSCALL/SYSRET */
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| 44 | set_efer_flag(AMD_SCE_FLAG);
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| 45 |
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| 46 | /* Setup syscall entry address */
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| 47 |
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| 48 | /* This is _mess_ - the 64-bit CS is argument+16,
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| 49 | * the SS is argument+8. The order is:
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| 50 | * +0(KDATA_DES), +8(UDATA_DES), +16(UTEXT_DES)
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| 51 | */
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| 52 | write_msr(AMD_MSR_STAR,
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| 53 | ((__u64)(gdtselector(KDATA_DES) | PL_USER)<<48) \
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| 54 | | ((__u64)(gdtselector(KTEXT_DES) | PL_KERNEL)<<32));
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| 55 | write_msr(AMD_MSR_LSTAR, (__u64)syscall_entry);
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| 56 | /* Mask RFLAGS on syscall
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| 57 | * - we do not care what is in the flags field
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| 58 | */
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| 59 | write_msr(AMD_MSR_SFMASK, 0);
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| 60 | }
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| 61 |
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| 62 | /** Dispatch system call */
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| 63 | __native syscall_handler(__native id, __native a1, __native a2, __native a3)
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| 64 | {
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| 65 | if (id < SYSCALL_END)
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| 66 | return syscall_table[id](a1,a2,a3);
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| 67 | else
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| 68 | panic("Undefined syscall %d", id);
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| 69 |
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| 70 | }
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