Commit 63ff0ca9 authored by Richard Henderson's avatar Richard Henderson Committed by Peter Maydell
Browse files

target/arm: Implement pauth_addpac 



This is not really functional yet, because the crypto is not yet
implemented.  This, however follows the AddPAC pseudo function.

Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Message-id: 20190108223129.5570-27-richard.henderson@linaro.org
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent a7bfa086

target/arm/pauth_helper.c

+41 −1
Original line number Diff line number Diff line
@@ -35,7 +35,47 @@ static uint64_t pauth_computepac(uint64_t data, uint64_t modifier, 
static uint64_t pauth_addpac(CPUARMState *env, uint64_t ptr, uint64_t modifier,

                             ARMPACKey *key, bool data)

{

    g_assert_not_reached(); /* FIXME */

    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) {

        pac ^= MAKE_64BIT_MASK(top_bit - 1, 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)