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freebsd/lib/libsys/x86/pkru.c
2024-02-05 20:34:55 +00:00

135 lines
3.5 KiB
C

/*-
* Copyright (c) 2019 The FreeBSD Foundation
*
* Portions of this software were developed by Konstantin Belousov
* under sponsorship from the FreeBSD Foundation.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <machine/cpufunc.h>
#include <machine/specialreg.h>
#include <machine/sysarch.h>
#include <x86/ifunc.h>
#include <errno.h>
#include <string.h>
#define MAX_PKRU_IDX 0xf
#ifdef __i386__
#define X86_SET_PKRU I386_SET_PKRU
#define X86_CLEAR_PKRU I386_CLEAR_PKRU
#else
#define X86_SET_PKRU AMD64_SET_PKRU
#define X86_CLEAR_PKRU AMD64_CLEAR_PKRU
#endif
static int
x86_pkru_get_perm_unsup(u_int keyidx, int *access, int *modify)
{
errno = EOPNOTSUPP;
return (-1);
}
static int
x86_pkru_get_perm_hw(u_int keyidx, int *access, int *modify)
{
uint32_t pkru;
if (keyidx > MAX_PKRU_IDX) {
errno = EINVAL;
return (-1);
}
keyidx *= 2;
pkru = rdpkru();
*access = (pkru & (1 << keyidx)) == 0;
*modify = (pkru & (2 << keyidx)) == 0;
return (0);
}
DEFINE_UIFUNC(, int, x86_pkru_get_perm, (u_int, int *, int *))
{
return ((cpu_stdext_feature2 & CPUID_STDEXT2_OSPKE) == 0 ?
x86_pkru_get_perm_unsup : x86_pkru_get_perm_hw);
}
static int
x86_pkru_set_perm_unsup(u_int keyidx, int access, int modify)
{
errno = EOPNOTSUPP;
return (-1);
}
static int
x86_pkru_set_perm_hw(u_int keyidx, int access, int modify)
{
uint32_t pkru;
if (keyidx > MAX_PKRU_IDX) {
errno = EINVAL;
return (-1);
}
keyidx *= 2;
pkru = rdpkru();
pkru &= ~(3 << keyidx);
if (!access)
pkru |= 1 << keyidx;
if (!modify)
pkru |= 2 << keyidx;
wrpkru(pkru);
return (0);
}
DEFINE_UIFUNC(, int, x86_pkru_set_perm, (u_int, int, int))
{
return ((cpu_stdext_feature2 & CPUID_STDEXT2_OSPKE) == 0 ?
x86_pkru_set_perm_unsup : x86_pkru_set_perm_hw);
}
int
x86_pkru_protect_range(void *addr, unsigned long len, u_int keyidx, int flags)
{
struct amd64_set_pkru a64pkru;
memset(&a64pkru, 0, sizeof(a64pkru));
a64pkru.addr = addr;
a64pkru.len = len;
a64pkru.keyidx = keyidx;
a64pkru.flags = flags;
return (sysarch(X86_SET_PKRU, &a64pkru));
}
int
x86_pkru_unprotect_range(void *addr, unsigned long len)
{
struct amd64_set_pkru a64pkru;
memset(&a64pkru, 0, sizeof(a64pkru));
a64pkru.addr = addr;
a64pkru.len = len;
return (sysarch(X86_CLEAR_PKRU, &a64pkru));
}