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

   1#include <stdint.h>
   2#include <assert.h>
   3
   4asm(".arch armv8.4-a");
   5
   6void do_test(uint64_t value)
   7{
   8    uint64_t salt1, salt2;
   9    uint64_t encode, decode;
  10
  11    /*
  12     * With TBI enabled and a 48-bit VA, there are 7 bits of auth,
  13     * and so a 1/128 chance of encode = pac(value,key,salt) producing
  14     * an auth for which leaves value unchanged.
  15     * Iterate until we find a salt for which encode != value.
  16     */
  17    for (salt1 = 1; ; salt1++) {
  18        asm volatile("pacda %0, %2" : "=r"(encode) : "0"(value), "r"(salt1));
  19        if (encode != value) {
  20            break;
  21        }
  22    }
  23
  24    /* A valid salt must produce a valid authorization.  */
  25    asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt1));
  26    assert(decode == value);
  27
  28    /*
  29     * An invalid salt usually fails authorization, but again there
  30     * is a chance of choosing another salt that works.
  31     * Iterate until we find another salt which does fail.
  32     */
  33    for (salt2 = salt1 + 1; ; salt2++) {
  34        asm volatile("autda %0, %2" : "=r"(decode) : "0"(encode), "r"(salt2));
  35        if (decode != value) {
  36            break;
  37        }
  38    }
  39
  40    /* The VA bits, bit 55, and the TBI bits, should be unchanged.  */
  41    assert(((decode ^ value) & 0xff80ffffffffffffull) == 0);
  42
  43    /*
  44     * Bits [54:53] are an error indicator based on the key used;
  45     * the DA key above is keynumber 0, so error == 0b01.  Otherwise
  46     * bit 55 of the original is sign-extended into the rest of the auth.
  47     */
  48    if ((value >> 55) & 1) {
  49        assert(((decode >> 48) & 0xff) == 0b10111111);
  50    } else {
  51        assert(((decode >> 48) & 0xff) == 0b00100000);
  52    }
  53}
  54
  55int main()
  56{
  57    do_test(0);
  58    do_test(-1);
  59    do_test(0xda004acedeadbeefull);
  60    return 0;
  61}
  62