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target/arm: Implement pauth_addpac

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

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20190108223129.5570-27-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Richard Henderson 2019-01-21 10:23:13 +00:00 committed by Peter Maydell
parent a7bfa086c9
commit 63ff0ca94c
1 changed files with 41 additions and 1 deletions
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42
target/arm/pauth_helper.c
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@ -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)