[Qemu-devel] [PATCH 20/26] target/arm: Implement pauth_auth

[Richard Henderson]

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

Signed-off-by: Richard Henderson <address@hidden>
---
 target/arm/helper-a64.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c
index 8860704720..2c14a71f03 100644
--- a/target/arm/helper-a64.c
+++ b/target/arm/helper-a64.c
@@ -1081,7 +1081,26 @@ static uint64_t pauth_original_ptr(uint64_t ptr, 
ARMVAParameters param)
 static uint64_t pauth_auth(CPUARMState *env, uint64_t ptr, uint64_t modifier,
                            uint64_t *key, bool data, int keynumber)
 {
-    g_assert_not_reached(); /* FIXME */
+    ARMMMUIdx mmu_idx = arm_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(orig_ptr, modifier, key[1], key[0]);
+    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(ptr, 53, 2, error_code);
+        } else {
+            return deposit64(ptr, 61, 2, error_code);
+        }
+    }
+    return orig_ptr;
 }
 
 static uint64_t pauth_strip(CPUARMState *env, uint64_t ptr, bool data)
-- 
2.17.2