qemu

pauth_helper.c (14969B)

---

 /*
  * 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"
 #include "qemu/xxhash.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_architected(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_computepac_impdef(uint64_t data, uint64_t modifier,
                                         ARMPACKey key)
 {
     return qemu_xxhash64_4(data, modifier, key.lo, key.hi);
 }
 
 static uint64_t pauth_computepac(CPUARMState *env, uint64_t data,
                                  uint64_t modifier, ARMPACKey key)
 {
     if (cpu_isar_feature(aa64_pauth_arch, env_archcpu(env))) {
         return pauth_computepac_architected(data, modifier, key);
     } else {
         return pauth_computepac_impdef(data, modifier, key);
     }
 }
 
 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(env, 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(env, 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 G_NORETURN
 void 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_is_el2_enabled(env)) {
         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(env, 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);
 }