We cannot overwrite a register which is not saved (ESI) because this
will lead to a corruption in JIT code. The proper solution is
to copy the call arguments.
Signed-off-by: Tomek Grabiec <tgrab...@gmail.com>
---
arch/x86/emit-code.c | 37 +++++++++++++++++++++++++++++++------
include/jit/compiler.h | 3 ++-
include/jit/emit-code.h | 3 ++-
jit/trampoline.c | 7 ++++---
4 files changed, 39 insertions(+), 11 deletions(-)
diff --git a/arch/x86/emit-code.c b/arch/x86/emit-code.c
index 236ba0e..c4ba179 100644
--- a/arch/x86/emit-code.c
+++ b/arch/x86/emit-code.c
@@ -1389,21 +1389,46 @@ void emit_trampoline(struct compilation_unit *cu,
}
void emit_jni_trampoline(struct buffer *buf, struct vm_jni_env *jni_env,
- void *target)
+ void *target, struct vm_method *method)
{
+ unsigned long args_size;
+
jit_text_lock();
buf->buf = jit_text_ptr();
- /* save return address into caller-saved register */
- __emit_pop_reg(buf, REG_ESI);
+ __emit_push_reg(buf, REG_ESI);
+ __emit_push_reg(buf, REG_EDI);
+ __emit_push_reg(buf, REG_ECX);
+
+ /*
+ * Make a copy of call arguments
+ */
+ __emit_mov_reg_reg(buf, REG_ESP, REG_ESI);
+ __emit_add_imm_reg(buf, (3 + 1) * sizeof(unsigned long), REG_ESI);
+
+ args_size = sizeof(unsigned long) + (method->args_count + 1);
+
+ __emit_add_imm_reg(buf, -args_size, REG_ESP);
+ __emit_mov_reg_reg(buf, REG_ESP, REG_EDI);
+
+ __emit_mov_imm_reg(buf, method->args_count + 1, REG_ECX);
+
+ /* CLD */
+ emit(buf, 0xfc);
+
+ /* REP MOVSD */
+ emit(buf, 0xf3);
+ emit(buf, 0xa5);
__emit_push_imm(buf, (unsigned long) jni_env);
__emit_call(buf, target);
- __emit_add_imm_reg(buf, 4, REG_ESP);
+ __emit_add_imm_reg(buf, args_size + sizeof(unsigned long), REG_ESP);
+
+ __emit_pop_reg(buf, REG_ECX);
+ __emit_pop_reg(buf, REG_EDI);
+ __emit_pop_reg(buf, REG_ESI);
- /* return to caller*/
- __emit_push_reg(buf, REG_ESI);
emit_ret(buf);
jit_text_reserve(buffer_offset(buf));
diff --git a/include/jit/compiler.h b/include/jit/compiler.h
index 8584954..e2609ef 100644
--- a/include/jit/compiler.h
+++ b/include/jit/compiler.h
@@ -14,6 +14,7 @@ struct compilation_unit;
struct expression;
struct statement;
struct buffer;
+struct vm_method;
struct fixup_site {
/* Compilation unit to which relcall_insn belongs */
@@ -62,7 +63,7 @@ void *jit_magic_trampoline(struct compilation_unit *);
struct jit_trampoline *alloc_jit_trampoline(void);
struct jni_trampoline *alloc_jni_trampoline(void);
struct jit_trampoline *build_jit_trampoline(struct compilation_unit *);
-struct jni_trampoline *build_jni_trampoline(void *);
+struct jni_trampoline *build_jni_trampoline(struct vm_method *, void *);
void free_jit_trampoline(struct jit_trampoline *);
void free_jni_trampoline(struct jni_trampoline *);
diff --git a/include/jit/emit-code.h b/include/jit/emit-code.h
index 07c41bf..291955f 100644
--- a/include/jit/emit-code.h
+++ b/include/jit/emit-code.h
@@ -8,6 +8,7 @@ struct buffer;
struct insn;
struct vm_object;
struct vm_jni_env;
+struct vm_method;
enum emitter_type {
NO_OPERANDS = 1,
@@ -39,6 +40,6 @@ extern void emit_body(struct basic_block *, struct buffer *);
extern void backpatch_branch_target(struct buffer *buf, struct insn *insn,
unsigned long target_offset);
extern void emit_jni_trampoline(struct buffer *buf, struct vm_jni_env *jni_env,
- void *target);
+ void *target, struct vm_method *method);
#endif /* JATO_EMIT_CODE_H */
diff --git a/jit/trampoline.c b/jit/trampoline.c
index 0de2db5..42f3afa 100644
--- a/jit/trampoline.c
+++ b/jit/trampoline.c
@@ -65,7 +65,8 @@ static void *jit_native_trampoline(struct compilation_unit
*cu)
add_cu_mapping((unsigned long)ret, cu);
if (!method->jni_trampoline)
- method->jni_trampoline = build_jni_trampoline(ret);
+ method->jni_trampoline =
+ build_jni_trampoline(method, ret);
return buffer_ptr(method->jni_trampoline->objcode);
}
@@ -151,13 +152,13 @@ struct jit_trampoline *build_jit_trampoline(struct
compilation_unit *cu)
return trampoline;
}
-struct jni_trampoline *build_jni_trampoline(void *target)
+struct jni_trampoline *build_jni_trampoline(struct vm_method *vmm, void
*target)
{
struct jni_trampoline *trampoline;
trampoline = alloc_jni_trampoline();
if (trampoline)
emit_jni_trampoline(trampoline->objcode, vm_jni_get_jni_env(),
- target);
+ target, vmm);
return trampoline;
}
--
1.6.0.6
------------------------------------------------------------------------------
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