LXR qemu/tests/tcg/aarch64/pauth-2.c

   1#include <stdint.h>
   2#include <assert.h>
   3
   4void do_test(uint64_t value)
   5{
   6    uint64_t salt1, salt2;
   7    uint64_t encode, decode;
   8
   9    /*
  10     * With TBI enabled and a 48-bit VA, there are 7 bits of auth,
  11     * and so a 1/128 chance of encode = pac(value,key,salt) producing
  12     * an auth for which leaves value unchanged.
  13     * Iterate until we find a salt for which encode != value.
  14     */
  15    for (salt1 = 1; ; salt1++) {
  16        asm volatile("pacda %0, %2" : "=r"(encode) : "0"(value), "r"(salt1));
  17        if (encode != value) {
  18            break;
  19        }
  20    }
  21
  22    /* A valid salt must produce a valid authorization.  */
  23    asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt1));
  24    assert(decode == value);
  25
  26    /*
  27     * An invalid salt usually fails authorization, but again there
  28     * is a chance of choosing another salt that works.
  29     * Iterate until we find another salt which does fail.
  30     */
  31    for (salt2 = salt1 + 1; ; salt2++) {
  32        asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt2));
  33        if (decode != value) {
  34            break;
  35        }
  36    }
  37
  38    /* The VA bits, bit 55, and the TBI bits, should be unchanged.  */
  39    assert(((decode ^ value) & 0xff80ffffffffffffull) == 0);
  40
  41    /*
  42     * Bits [54:53] are an error indicator based on the key used;
  43     * the DA key above is keynumber 0, so error == 0b01.  Otherwise
  44     * bit 55 of the original is sign-extended into the rest of the auth.
  45     */
  46    if ((value >> 55) & 1) {
  47        assert(((decode >> 48) & 0xff) == 0b10111111);
  48    } else {
  49        assert(((decode >> 48) & 0xff) == 0b00100000);
  50    }
  51}
  52
  53int main()
  54{
  55    do_test(0);
  56    do_test(0xda004acedeadbeefull);
  57    return 0;
  58}
  59