Implement some limited flag handling

dc8511 · May 13, 2018 · 7a3a99a · 7a3a99a
1 parent 816ed11
commit 7a3a99a
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Showing 8 changed files with 85 additions and 57 deletions.
diff --git a/emu/cpu.h b/emu/cpu.h
@@ -78,10 +78,20 @@ struct cpu_state {
     // whether the true flag values are in the above struct, or computed from
     // the stored result and operands
     dword_t res, op1, op2;
-    bits pf_res:1;
-    bits zf_res:1;
-    bits sf_res:1;
-    bits af_ops:1;
+    union {
+        struct {
+            bits pf_res:1;
+            bits zf_res:1;
+            bits sf_res:1;
+            bits af_ops:1;
+        };
+        // for asm
+#define PF_RES (1 << 0)
+#define ZF_RES (1 << 1)
+#define SF_RES (1 << 2)
+#define AF_OPS (1 << 3)
+        byte_t flags_res;
+    };
 
     // fpu
     extFloat80_t fp[8];

diff --git a/emu/gadgets-x86/math.S b/emu/gadgets-x86/math.S
@@ -14,9 +14,22 @@
         movl %_tmp, \arg
     .else
         \op\()l \arg, %_tmp
+        .irp da_op, add,sub; .ifc \op,\da_op
+            seto CPU_of(%_cpu)
+            setc CPU_cf(%_cpu)
+            movl \arg, %r14d
+            movl %r14d, CPU_op1(%_cpu)
+            movl %_tmp, CPU_op2(%_cpu)
+            orl $AF_OPS, CPU_flags_res(%_cpu)
+        .endif; .endr
+        movl %_tmp, CPU_res(%_cpu)
+        orl $(PF_RES|ZF_RES|SF_RES), CPU_flags_res(%_cpu)
     .endif; .endif
 .endm
 
+.macro oc_flags
+.endm
+
 .irp op, load,store,add,and,sub,xor
     .macro x reg
         do_op \op, %\reg

diff --git a/emu/gadgets-x86/offsets.c b/emu/gadgets-x86/offsets.c
diff --git a/emu/gen.c b/emu/gen.c
@@ -75,7 +75,9 @@ static inline void gen_op(struct gen_state *state, gadget_t *gadgets, enum arg a
 
 #define load(thing) op(load, thing)
 #define store(thing) op(store, thing)
-#define oop(o, src, dst) load(dst); op(o, src); store(dst)
+// load-op-store
+#define los(o, src, dst) load(dst); op(o, src); store(dst)
+#define lo(o, src, dst) load(dst); op(o, src)
 
 #define DECLARE_LOCALS \
     dword_t addr_offset = 0;
@@ -97,14 +99,14 @@ static inline void gen_op(struct gen_state *state, gadget_t *gadgets, enum arg a
 #define MOVSX(src, dst,zs,zd) UNDEFINED
 #define XCHG(src, dst,z) UNDEFINED
 
-#define ADD(src, dst,z) oop(add, src, dst)
+#define ADD(src, dst,z) los(add, src, dst)
 #define OR(src, dst,z) UNDEFINED
 #define ADC(src, dst,z) UNDEFINED
 #define SBB(src, dst,z) UNDEFINED
-#define AND(src, dst,z) oop(and, src, dst)
-#define SUB(src, dst,z) oop(sub, src, dst)
-#define XOR(src, dst,z) oop(xor, src, dst)
-#define CMP(src, dst,z) UNDEFINED
+#define AND(src, dst,z) los(and, src, dst)
+#define SUB(src, dst,z) los(sub, src, dst)
+#define XOR(src, dst,z) los(xor, src, dst)
+#define CMP(src, dst,z) lo(sub, src, dst)
 #define TEST(src, dst,z) UNDEFINED
 #define NOT(val,z) UNDEFINED
 #define NEG(val,z) UNDEFINED

diff --git a/emu/offsets.c b/emu/offsets.c
@@ -2,29 +2,40 @@
 #include "emu/jit.h"
 
 void cpu() {
-    OFFSET(CPU_eax, struct cpu_state, eax);
-    OFFSET(CPU_ebx, struct cpu_state, ebx);
-    OFFSET(CPU_ecx, struct cpu_state, ecx);
-    OFFSET(CPU_edx, struct cpu_state, edx);
-    OFFSET(CPU_esi, struct cpu_state, esi);
-    OFFSET(CPU_edi, struct cpu_state, edi);
-    OFFSET(CPU_ebp, struct cpu_state, ebp);
-    OFFSET(CPU_esp, struct cpu_state, esp);
-    OFFSET(CPU_ax, struct cpu_state, ax);
-    OFFSET(CPU_bx, struct cpu_state, bx);
-    OFFSET(CPU_cx, struct cpu_state, cx);
-    OFFSET(CPU_dx, struct cpu_state, dx);
-    OFFSET(CPU_si, struct cpu_state, si);
-    OFFSET(CPU_di, struct cpu_state, di);
-    OFFSET(CPU_bp, struct cpu_state, bp);
-    OFFSET(CPU_sp, struct cpu_state, sp);
-    OFFSET(CPU_eip, struct cpu_state, eip);
+    OFFSET(CPU, cpu_state, eax);
+    OFFSET(CPU, cpu_state, ebx);
+    OFFSET(CPU, cpu_state, ecx);
+    OFFSET(CPU, cpu_state, edx);
+    OFFSET(CPU, cpu_state, esi);
+    OFFSET(CPU, cpu_state, edi);
+    OFFSET(CPU, cpu_state, ebp);
+    OFFSET(CPU, cpu_state, esp);
+    OFFSET(CPU, cpu_state, ax);
+    OFFSET(CPU, cpu_state, bx);
+    OFFSET(CPU, cpu_state, cx);
+    OFFSET(CPU, cpu_state, dx);
+    OFFSET(CPU, cpu_state, si);
+    OFFSET(CPU, cpu_state, di);
+    OFFSET(CPU, cpu_state, bp);
+    OFFSET(CPU, cpu_state, sp);
+    OFFSET(CPU, cpu_state, eip);
 
-    OFFSET(JIT_BLOCK_code, struct jit_block, code);
+    OFFSET(CPU, cpu_state, of);
+    OFFSET(CPU, cpu_state, cf);
+    OFFSET(CPU, cpu_state, res);
+    OFFSET(CPU, cpu_state, op1);
+    OFFSET(CPU, cpu_state, op2);
+    OFFSET(CPU, cpu_state, flags_res);
+    MACRO(PF_RES);
+    MACRO(ZF_RES);
+    MACRO(SF_RES);
+    MACRO(AF_OPS);
 
-    OFFSET(TLB_entries, struct tlb, entries);
-    OFFSET(TLB_dirty_page, struct tlb, dirty_page);
-    OFFSET(TLB_ENTRY_page, struct tlb_entry, page);
-    OFFSET(TLB_ENTRY_page_if_writable, struct tlb_entry, page_if_writable);
-    OFFSET(TLB_ENTRY_data_minus_addr, struct tlb_entry, data_minus_addr);
+    OFFSET(JIT_BLOCK, jit_block, code);
+
+    OFFSET(TLB, tlb, entries);
+    OFFSET(TLB, tlb, dirty_page);
+    OFFSET(TLB_ENTRY, tlb_entry, page);
+    OFFSET(TLB_ENTRY, tlb_entry, page_if_writable);
+    OFFSET(TLB_ENTRY, tlb_entry, data_minus_addr);
 }
diff --git a/ish-gdb.gdb b/ish-gdb.gdb
@@ -9,3 +9,12 @@ if subprocess.call('ninja') != 0:
     raise gdb.CommandError('compilation failed')
     end
 end
+
+define hook-stop
+    python
+if gdb.selected_frame().find_sal().symtab.filename.endswith('.S'):
+    gdb.execute('set disassemble-next-line on')
+else:
+    gdb.execute('set disassemble-next-line auto')
+    end
+end
diff --git a/tools/ptraceomatic.c b/tools/ptraceomatic.c
@@ -77,7 +77,6 @@ static int compare_cpus(struct cpu_state *cpu, struct tlb *tlb, int pid, int und
     CHECK_REG(rsp, esp);
     CHECK_REG(rbp, ebp);
     CHECK_REG(rip, eip);
-#if 0
     undefined_flags |= (1 << 8); // treat trap flag as undefined
     regs.eflags = (regs.eflags & ~undefined_flags) | (cpu->eflags & undefined_flags);
     // give a nice visual representation of the flags
@@ -91,7 +90,6 @@ static int compare_cpus(struct cpu_state *cpu, struct tlb *tlb, int pid, int und
         debugger;
         return -1;
     }
-#endif
 #define CHECK_XMMREG(i) \
     CHECK(*(uint64_t *) &fpregs.xmm_space[i * 2],   cpu->xmm[i].qw[0], "xmm" #i " low") \
     CHECK(*(uint64_t *) &fpregs.xmm_space[(i+1)*2], cpu->xmm[i].qw[1], "xmm" #i " high")

diff --git a/tools/staticdefine.h b/tools/staticdefine.h
@@ -1,11 +1,16 @@
 // credit goes to include/linux/kbuild.h
+#define _DEFINE(sym, val) \
+    asm volatile("\n.ascii \"->" sym " %0 " #val "\"" : : "i" (val))
 #define DEFINE(sym, val) \
-    asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
+    _DEFINE(#sym, val)
 
 #define BLANK() asm volatile("\n.ascii \"->\"" : : )
 
 #define OFFSET(sym, str, mem) \
-    DEFINE(sym, offsetof(str, mem))
+    DEFINE(sym##_##mem, offsetof(struct str, mem))
+
+#define MACRO(macro) \
+    _DEFINE(#macro, macro)
 
 #define COMMENT(x) \
     asm volatile("\n.ascii \"->#" x "\"")