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qemu/target/arm/pauth_helper.c
Chetan Pant 50f57e09fd arm tcg cpus: Fix Lesser GPL version number 
There is no "version 2" of the "Lesser" General Public License.
It is either "GPL version 2.0" or "Lesser GPL version 2.1".
This patch replaces all occurrences of "Lesser GPL version 2" with
"Lesser GPL version 2.1" in comment section.

Signed-off-by: Chetan Pant <chetan4windows@gmail.com>
Message-Id: <20201023122913.19561-1-chetan4windows@gmail.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2020-11-15 16:42:14 +01:00

499 lines
14 KiB
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/*
* ARM v8.3-PAuth Operations
*
* Copyright (c) 2019 Linaro, Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "internals.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#include "exec/helper-proto.h"
#include "tcg/tcg-gvec-desc.h"
static uint64_t pac_cell_shuffle(uint64_t i)
{
uint64_t o = 0;
o |= extract64(i, 52, 4);
o |= extract64(i, 24, 4) << 4;
o |= extract64(i, 44, 4) << 8;
o |= extract64(i, 0, 4) << 12;
o |= extract64(i, 28, 4) << 16;
o |= extract64(i, 48, 4) << 20;
o |= extract64(i, 4, 4) << 24;
o |= extract64(i, 40, 4) << 28;
o |= extract64(i, 32, 4) << 32;
o |= extract64(i, 12, 4) << 36;
o |= extract64(i, 56, 4) << 40;
o |= extract64(i, 20, 4) << 44;
o |= extract64(i, 8, 4) << 48;
o |= extract64(i, 36, 4) << 52;
o |= extract64(i, 16, 4) << 56;
o |= extract64(i, 60, 4) << 60;
return o;
}
static uint64_t pac_cell_inv_shuffle(uint64_t i)
{
uint64_t o = 0;
o |= extract64(i, 12, 4);
o |= extract64(i, 24, 4) << 4;
o |= extract64(i, 48, 4) << 8;
o |= extract64(i, 36, 4) << 12;
o |= extract64(i, 56, 4) << 16;
o |= extract64(i, 44, 4) << 20;
o |= extract64(i, 4, 4) << 24;
o |= extract64(i, 16, 4) << 28;
o |= i & MAKE_64BIT_MASK(32, 4);
o |= extract64(i, 52, 4) << 36;
o |= extract64(i, 28, 4) << 40;
o |= extract64(i, 8, 4) << 44;
o |= extract64(i, 20, 4) << 48;
o |= extract64(i, 0, 4) << 52;
o |= extract64(i, 40, 4) << 56;
o |= i & MAKE_64BIT_MASK(60, 4);
return o;
}
static uint64_t pac_sub(uint64_t i)
{
static const uint8_t sub[16] = {
0xb, 0x6, 0x8, 0xf, 0xc, 0x0, 0x9, 0xe,
0x3, 0x7, 0x4, 0x5, 0xd, 0x2, 0x1, 0xa,
};
uint64_t o = 0;
int b;
for (b = 0; b < 64; b += 4) {
o |= (uint64_t)sub[(i >> b) & 0xf] << b;
}
return o;
}
static uint64_t pac_inv_sub(uint64_t i)
{
static const uint8_t inv_sub[16] = {
0x5, 0xe, 0xd, 0x8, 0xa, 0xb, 0x1, 0x9,
0x2, 0x6, 0xf, 0x0, 0x4, 0xc, 0x7, 0x3,
};
uint64_t o = 0;
int b;
for (b = 0; b < 64; b += 4) {
o |= (uint64_t)inv_sub[(i >> b) & 0xf] << b;
}
return o;
}
static int rot_cell(int cell, int n)
{
/* 4-bit rotate left by n. */
cell |= cell << 4;
return extract32(cell, 4 - n, 4);
}
static uint64_t pac_mult(uint64_t i)
{
uint64_t o = 0;
int b;
for (b = 0; b < 4 * 4; b += 4) {
int i0, i4, i8, ic, t0, t1, t2, t3;
i0 = extract64(i, b, 4);
i4 = extract64(i, b + 4 * 4, 4);
i8 = extract64(i, b + 8 * 4, 4);
ic = extract64(i, b + 12 * 4, 4);
t0 = rot_cell(i8, 1) ^ rot_cell(i4, 2) ^ rot_cell(i0, 1);
t1 = rot_cell(ic, 1) ^ rot_cell(i4, 1) ^ rot_cell(i0, 2);
t2 = rot_cell(ic, 2) ^ rot_cell(i8, 1) ^ rot_cell(i0, 1);
t3 = rot_cell(ic, 1) ^ rot_cell(i8, 2) ^ rot_cell(i4, 1);
o |= (uint64_t)t3 << b;
o |= (uint64_t)t2 << (b + 4 * 4);
o |= (uint64_t)t1 << (b + 8 * 4);
o |= (uint64_t)t0 << (b + 12 * 4);
}
return o;
}
static uint64_t tweak_cell_rot(uint64_t cell)
{
return (cell >> 1) | (((cell ^ (cell >> 1)) & 1) << 3);
}
static uint64_t tweak_shuffle(uint64_t i)
{
uint64_t o = 0;
o |= extract64(i, 16, 4) << 0;
o |= extract64(i, 20, 4) << 4;
o |= tweak_cell_rot(extract64(i, 24, 4)) << 8;
o |= extract64(i, 28, 4) << 12;
o |= tweak_cell_rot(extract64(i, 44, 4)) << 16;
o |= extract64(i, 8, 4) << 20;
o |= extract64(i, 12, 4) << 24;
o |= tweak_cell_rot(extract64(i, 32, 4)) << 28;
o |= extract64(i, 48, 4) << 32;
o |= extract64(i, 52, 4) << 36;
o |= extract64(i, 56, 4) << 40;
o |= tweak_cell_rot(extract64(i, 60, 4)) << 44;
o |= tweak_cell_rot(extract64(i, 0, 4)) << 48;
o |= extract64(i, 4, 4) << 52;
o |= tweak_cell_rot(extract64(i, 40, 4)) << 56;
o |= tweak_cell_rot(extract64(i, 36, 4)) << 60;
return o;
}
static uint64_t tweak_cell_inv_rot(uint64_t cell)
{
return ((cell << 1) & 0xf) | ((cell & 1) ^ (cell >> 3));
}
static uint64_t tweak_inv_shuffle(uint64_t i)
{
uint64_t o = 0;
o |= tweak_cell_inv_rot(extract64(i, 48, 4));
o |= extract64(i, 52, 4) << 4;
o |= extract64(i, 20, 4) << 8;
o |= extract64(i, 24, 4) << 12;
o |= extract64(i, 0, 4) << 16;
o |= extract64(i, 4, 4) << 20;
o |= tweak_cell_inv_rot(extract64(i, 8, 4)) << 24;
o |= extract64(i, 12, 4) << 28;
o |= tweak_cell_inv_rot(extract64(i, 28, 4)) << 32;
o |= tweak_cell_inv_rot(extract64(i, 60, 4)) << 36;
o |= tweak_cell_inv_rot(extract64(i, 56, 4)) << 40;
o |= tweak_cell_inv_rot(extract64(i, 16, 4)) << 44;
o |= extract64(i, 32, 4) << 48;
o |= extract64(i, 36, 4) << 52;
o |= extract64(i, 40, 4) << 56;
o |= tweak_cell_inv_rot(extract64(i, 44, 4)) << 60;
return o;
}
static uint64_t pauth_computepac(uint64_t data, uint64_t modifier,
ARMPACKey key)
{
static const uint64_t RC[5] = {
0x0000000000000000ull,
0x13198A2E03707344ull,
0xA4093822299F31D0ull,
0x082EFA98EC4E6C89ull,
0x452821E638D01377ull,
};
const uint64_t alpha = 0xC0AC29B7C97C50DDull;
/*
* Note that in the ARM pseudocode, key0 contains bits <127:64>
* and key1 contains bits <63:0> of the 128-bit key.
*/
uint64_t key0 = key.hi, key1 = key.lo;
uint64_t workingval, runningmod, roundkey, modk0;
int i;
modk0 = (key0 << 63) | ((key0 >> 1) ^ (key0 >> 63));
runningmod = modifier;
workingval = data ^ key0;
for (i = 0; i <= 4; ++i) {
roundkey = key1 ^ runningmod;
workingval ^= roundkey;
workingval ^= RC[i];
if (i > 0) {
workingval = pac_cell_shuffle(workingval);
workingval = pac_mult(workingval);
}
workingval = pac_sub(workingval);
runningmod = tweak_shuffle(runningmod);
}
roundkey = modk0 ^ runningmod;
workingval ^= roundkey;
workingval = pac_cell_shuffle(workingval);
workingval = pac_mult(workingval);
workingval = pac_sub(workingval);
workingval = pac_cell_shuffle(workingval);
workingval = pac_mult(workingval);
workingval ^= key1;
workingval = pac_cell_inv_shuffle(workingval);
workingval = pac_inv_sub(workingval);
workingval = pac_mult(workingval);
workingval = pac_cell_inv_shuffle(workingval);
workingval ^= key0;
workingval ^= runningmod;
for (i = 0; i <= 4; ++i) {
workingval = pac_inv_sub(workingval);
if (i < 4) {
workingval = pac_mult(workingval);
workingval = pac_cell_inv_shuffle(workingval);
}
runningmod = tweak_inv_shuffle(runningmod);
roundkey = key1 ^ runningmod;
workingval ^= RC[4 - i];
workingval ^= roundkey;
workingval ^= alpha;
}
workingval ^= modk0;
return workingval;
}
static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,
ARMPACKey *key, bool data)
{
ARMMMUIdx mmu_idx = arm_stage1_mmu_idx(env);
ARMVAParameters param = aa64_va_parameters(env, ptr, mmu_idx, data);
uint64_t pac, ext_ptr, ext, test;
int bot_bit, top_bit;
/* If tagged pointers are in use, use ptr<55>, otherwise ptr<63>. */
if (param.tbi) {
ext = sextract64(ptr, 55, 1);
} else {
ext = sextract64(ptr, 63, 1);
}
/* Build a pointer with known good extension bits. */
top_bit = 64 - 8 * param.tbi;
bot_bit = 64 - param.tsz;
ext_ptr = deposit64(ptr, bot_bit, top_bit - bot_bit, ext);
pac = pauth_computepac(ext_ptr, modifier, *key);
/*
* Check if the ptr has good extension bits and corrupt the
* pointer authentication code if not.
*/
test = sextract64(ptr, bot_bit, top_bit - bot_bit);
if (test != 0 && test != -1) {
/*
* Note that our top_bit is one greater than the pseudocode's
* version, hence "- 2" here.
*/
pac ^= MAKE_64BIT_MASK(top_bit - 2, 1);
}
/*
* Preserve the determination between upper and lower at bit 55,
* and insert pointer authentication code.
*/
if (param.tbi) {
ptr &= ~MAKE_64BIT_MASK(bot_bit, 55 - bot_bit + 1);
pac &= MAKE_64BIT_MASK(bot_bit, 54 - bot_bit + 1);
} else {
ptr &= MAKE_64BIT_MASK(0, bot_bit);
pac &= ~(MAKE_64BIT_MASK(55, 1) | MAKE_64BIT_MASK(0, bot_bit));
}
ext &= MAKE_64BIT_MASK(55, 1);
return pac | ext | ptr;
}
static uint64_t pauth_original_ptr(uint64_t ptr, ARMVAParameters param)
{
/* Note that bit 55 is used whether or not the regime has 2 ranges. */
uint64_t extfield = sextract64(ptr, 55, 1);
int bot_pac_bit = 64 - param.tsz;
int top_pac_bit = 64 - 8 * param.tbi;
return deposit64(ptr, bot_pac_bit, top_pac_bit - bot_pac_bit, extfield);
}
static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
ARMPACKey *key, bool data, int keynumber)
{
ARMMMUIdx mmu_idx = arm_stage1_mmu_idx(env);
ARMVAParameters param = aa64_va_parameters(env, ptr, mmu_idx, data);
int bot_bit, top_bit;
uint64_t pac, orig_ptr, test;
orig_ptr = pauth_original_ptr(ptr, param);
pac = pauth_computepac(orig_ptr, modifier, *key);
bot_bit = 64 - param.tsz;
top_bit = 64 - 8 * param.tbi;
test = (pac ^ ptr) & ~MAKE_64BIT_MASK(55, 1);
if (unlikely(extract64(test, bot_bit, top_bit - bot_bit))) {
int error_code = (keynumber << 1) | (keynumber ^ 1);
if (param.tbi) {
return deposit64(orig_ptr, 53, 2, error_code);
} else {
return deposit64(orig_ptr, 61, 2, error_code);
}
}
return orig_ptr;
}
static uint64_t pauth_strip(CPUARMState *env, uint64_t ptr, bool data)
{
ARMMMUIdx mmu_idx = arm_stage1_mmu_idx(env);
ARMVAParameters param = aa64_va_parameters(env, ptr, mmu_idx, data);
return pauth_original_ptr(ptr, param);
}
static void QEMU_NORETURN pauth_trap(CPUARMState *env, int target_el,
uintptr_t ra)
{
raise_exception_ra(env, EXCP_UDEF, syn_pactrap(), target_el, ra);
}
static void pauth_check_trap(CPUARMState *env, int el, uintptr_t ra)
{
if (el < 2 && arm_feature(env, ARM_FEATURE_EL2)) {
uint64_t hcr = arm_hcr_el2_eff(env);
bool trap = !(hcr & HCR_API);
if (el == 0) {
/* Trap only applies to EL1&0 regime. */
trap &= (hcr & (HCR_E2H | HCR_TGE)) != (HCR_E2H | HCR_TGE);
}
/* FIXME: ARMv8.3-NV: HCR_NV trap takes precedence for ERETA[AB]. */
if (trap) {
pauth_trap(env, 2, ra);
}
}
if (el < 3 && arm_feature(env, ARM_FEATURE_EL3)) {
if (!(env->cp15.scr_el3 & SCR_API)) {
pauth_trap(env, 3, ra);
}
}
}
static bool pauth_key_enabled(CPUARMState *env, int el, uint32_t bit)
{
return (arm_sctlr(env, el) & bit) != 0;
}
uint64_t HELPER(pacia)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnIA)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_addpac(env, x, y, &env->keys.apia, false);
}
uint64_t HELPER(pacib)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnIB)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_addpac(env, x, y, &env->keys.apib, false);
}
uint64_t HELPER(pacda)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnDA)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_addpac(env, x, y, &env->keys.apda, true);
}
uint64_t HELPER(pacdb)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnDB)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_addpac(env, x, y, &env->keys.apdb, true);
}
uint64_t HELPER(pacga)(CPUARMState *env, uint64_t x, uint64_t y)
{
uint64_t pac;
pauth_check_trap(env, arm_current_el(env), GETPC());
pac = pauth_computepac(x, y, env->keys.apga);
return pac & 0xffffffff00000000ull;
}
uint64_t HELPER(autia)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnIA)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_auth(env, x, y, &env->keys.apia, false, 0);
}
uint64_t HELPER(autib)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnIB)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_auth(env, x, y, &env->keys.apib, false, 1);
}
uint64_t HELPER(autda)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnDA)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_auth(env, x, y, &env->keys.apda, true, 0);
}
uint64_t HELPER(autdb)(CPUARMState *env, uint64_t x, uint64_t y)
{
int el = arm_current_el(env);
if (!pauth_key_enabled(env, el, SCTLR_EnDB)) {
return x;
}
pauth_check_trap(env, el, GETPC());
return pauth_auth(env, x, y, &env->keys.apdb, true, 1);
}
uint64_t HELPER(xpaci)(CPUARMState *env, uint64_t a)
{
return pauth_strip(env, a, false);
}
uint64_t HELPER(xpacd)(CPUARMState *env, uint64_t a)
{
return pauth_strip(env, a, true);
}
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