Merge pull request ish-app#1667 from kmeisthax/unaligned_cmpxchg8b_fault

Sekedo664 · Jan 4, 2022 · b74ec82 · b74ec82
2 parents 1c1be5c + 971d4f3
commit b74ec82
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diff --git a/jit/gadgets-aarch64/memory.S b/jit/gadgets-aarch64/memory.S
@@ -83,6 +83,7 @@ NAME(si_gadgets):
         mov _xaddr, x19
         ret
 
+.global segfault_\type
 segfault_\type:
     ldr _addr, [_tlb, -TLB_entries+TLB_segfault_addr]
     str _addr, [_cpu, CPU_segfault_addr]

diff --git a/jit/gadgets-aarch64/misc.S b/jit/gadgets-aarch64/misc.S
@@ -87,7 +87,14 @@
 .gadget_array cmpxchg
 .gadget_array atomic_cmpxchg
 
+.extern segfault_write
+
 .gadget atomic_cmpxchg8b
+    #Test for alignment.
+    tst _addr, 0x7
+    b.ne 2f
+
+    #cmpxchg8b via aligned exclusive 8b load
     write_prep 64, atomic_cmpxchg8b
     mov w9, eax
     bfi x9, xdx, 32, 32
@@ -115,6 +122,10 @@
     gret 1
     write_bullshit 64, atomic_cmpxchg8b
 
+2:  #All unaligned paths
+    b segfault_write
+
+
 .gadget cmpxchg8b
     write_prep 64, cmpxchg8b
     mov w9, eax