[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH for-5.0] target/arm: PSTATE.PAN should not clear exec bits
From: |
Peter Maydell |
Subject: |
[PATCH for-5.0] target/arm: PSTATE.PAN should not clear exec bits |
Date: |
Mon, 30 Mar 2020 18:06:51 +0100 |
Our implementation of the PSTATE.PAN bit incorrectly cleared all
access permission bits for privileged access to memory which is
user-accessible. It should only affect the privileged read and write
permissions; execute permission is dealt with via XN/PXN instead.
Fixes: 81636b70c226dc27d7ebc8d
Signed-off-by: Peter Maydell <address@hidden>
---
Compare the pseudocode AArch64.CheckPermission().
---
target/arm/helper.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 163c91a1ccd..ed7eb8ab54e 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -10025,9 +10025,11 @@ static int get_S1prot(CPUARMState *env, ARMMMUIdx
mmu_idx, bool is_aa64,
prot_rw = user_rw;
} else {
if (user_rw && regime_is_pan(env, mmu_idx)) {
- return 0;
+ /* PAN forbids data accesses but doesn't affect insn fetch */
+ prot_rw = 0;
+ } else {
+ prot_rw = simple_ap_to_rw_prot_is_user(ap, false);
}
- prot_rw = simple_ap_to_rw_prot_is_user(ap, false);
}
if (ns && arm_is_secure(env) && (env->cp15.scr_el3 & SCR_SIF)) {
--
2.20.1
- [PATCH for-5.0] target/arm: PSTATE.PAN should not clear exec bits,
Peter Maydell <=