Add segfault_was_write to cpu_state

saiminhtet · Dec 21, 2020 · 1e06d8d · 1e06d8d
1 parent f2976b7
commit 1e06d8d
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Showing 4 changed files with 8 additions and 0 deletions.
diff --git a/emu/cpu.h b/emu/cpu.h
@@ -159,6 +159,7 @@ struct cpu_state {
 
     // for the page fault handler
     addr_t segfault_addr;
+    bool segfault_was_write;
 
     dword_t trapno;
 };

diff --git a/jit/gadgets-x86_64/entry.S b/jit/gadgets-x86_64/entry.S
@@ -52,6 +52,7 @@ jit_exit:
     movl (%_ip), %_tmp
     movl 8(%_ip), %_eip
     movl %_eip, CPU_segfault_addr(%_cpu)
+    movb $0, CPU_segfault_was_write(%_cpu)
     jmp jit_exit
 
 .gadget exit

diff --git a/jit/gadgets-x86_64/memory.S b/jit/gadgets-x86_64/memory.S
@@ -79,6 +79,11 @@
 
 segfault_\type:
     movl %_addr, CPU_segfault_addr(%_cpu)
+    .ifc \type,read
+        movb $0, CPU_segfault_was_write(%_cpu)
+    .else
+        movb $1, CPU_segfault_was_write(%_cpu)
+    .endif
     movl (%_ip), %_eip
     movl $INT_GPF, %_tmp
     jmp jit_exit

diff --git a/jit/offsets.c b/jit/offsets.c
@@ -50,6 +50,7 @@ void cpu() {
     OFFSET(LOCAL, jit_frame, last_block);
     OFFSET(LOCAL, jit_frame, ret_cache);
     OFFSET(CPU, cpu_state, segfault_addr);
+    OFFSET(CPU, cpu_state, segfault_was_write);
     MACRO(MEM_READ);
     MACRO(MEM_WRITE);