Unicorn 2: Support ARM Advanced SIMD Instructions

[quangnh89]

I have a firmware that working on ARMv7 architecture. I try to emulate the firmware and I have found a problem with the support for SIMD instructions, for example: VPUSH instruction.

Source environment

I built unicorn on the dev branch at sha 6c1cbef6ac505d355033aef1176b684d02e1eb3a. This has been tested on Windows system on Intel hardware

Failure

The failure appears if I try to execute any Advanced SIMD Instruction.

Following the documentation, SIMD instructions are supported from ARMv7 and later. https://developer.arm.com/documentation/ddi0406/cb/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/VPUSH

https://developer.arm.com/documentation/100076/0200/a32-t32-instruction-set-reference/advanced-simd-instructions--32-bit-

Test code

Test code which exhibits this problem here:

diff --git "a/tests/unit/test_arm.c" "b/tests/unit/test_arm.c"
index 1efd5682..ca4e973d 100644
--- "a/tests/unit/test_arm.c"
+++ "b/tests/unit/test_arm.c"
@@ -751,6 +751,25 @@ static void test_armeb_ldrb(void)
     OK(uc_close(uc));
 }
 
+static void test_arm_vpush(void)
+{
+    uc_engine *uc;
+    const char test_code[] = "\x08\x0B\x2D\xED"; // VPUSH {D0-D3}
+    uint64_t stack_address = 0x800000;
+	uint64_t stack_size = 2 * 1024 * 1024;
+    int sp = stack_size / 2;
+
+    uc_common_setup(&uc, UC_ARCH_ARM, UC_MODE_ARM,
+                    test_code, sizeof(test_code)-1, UC_CPU_ARM_CORTEX_A7);
+
+    OK(uc_mem_map(uc, stack_address, stack_size, UC_PROT_ALL));
+    OK(uc_reg_write(uc, UC_ARM_REG_SP, &sp));
+
+    OK(uc_emu_start(uc, code_start, code_start + sizeof(test_code) - 1, 0, 0));
+
+    OK(uc_close(uc));
+}
+
 TEST_LIST = {{"test_arm_nop", test_arm_nop},
              {"test_arm_thumb_sub", test_arm_thumb_sub},
              {"test_armeb_sub", test_armeb_sub},
@@ -773,4 +792,5 @@ TEST_LIST = {{"test_arm_nop", test_arm_nop},
              {"test_arm_be_cpsr_sctlr", test_arm_be_cpsr_sctlr},
              {"test_arm_switch_endian", test_arm_switch_endian},
              {"test_armeb_ldrb", test_armeb_ldrb},
+             {"test_arm_vpush", test_arm_vpush},
              {NULL, NULL}};
\ No newline at end of file

Failing output (Unicorn 2)

Test test_arm_nop...                            [ OK ]
Test test_arm_thumb_sub...                      [ OK ]
Test test_armeb_sub...                          [ OK ]
Test test_armeb_be8_sub...                      [ OK ]
Test test_arm_thumbeb_sub...                    [ OK ]
Test test_arm_thumb_ite...                      [ OK ]
Test test_arm_m_thumb_mrs...                    [ OK ]
Test test_arm_m_control...                      [ OK ]
Test test_arm_m_exc_return...                   [ OK ]
Test test_arm_und32_to_svc32...                 [ OK ]
Test test_arm_usr32_to_svc32...                 [ OK ]
Test test_arm_v8...                             [ OK ]
Test test_arm_thumb_smlabb...                   [ OK ]
Test test_arm_not_allow_privilege_escalation... [ OK ]
Test test_arm_mrc...                            [ OK ]
Test test_arm_hflags_rebuilt...                 [ OK ]
Test test_arm_mem_access_abort...               [ OK ]
Test test_arm_read_sctlr...                     [ OK ]
Test test_arm_be_cpsr_sctlr...                  [ OK ]
Test test_arm_switch_endian...                  [ OK ]
Test test_armeb_ldrb...                         [ OK ]
Test test_arm_vpush...                          [ FAILED ]
  test_arm.c:768: Check __err == UC_ERR_OK... failed
    Invalid instruction (UC_ERR_INSN_INVALID)
FAILED: 1 of 22 unit tests has failed.

Expect

Test test_arm_nop...                            [ OK ]
Test test_arm_thumb_sub...                      [ OK ]
Test test_armeb_sub...                          [ OK ]
Test test_armeb_be8_sub...                      [ OK ]
Test test_arm_thumbeb_sub...                    [ OK ]
Test test_arm_thumb_ite...                      [ OK ]
Test test_arm_m_thumb_mrs...                    [ OK ]
Test test_arm_m_control...                      [ OK ]
Test test_arm_m_exc_return...                   [ OK ]
Test test_arm_und32_to_svc32...                 [ OK ]
Test test_arm_usr32_to_svc32...                 [ OK ]
Test test_arm_v8...                             [ OK ]
Test test_arm_thumb_smlabb...                   [ OK ]
Test test_arm_not_allow_privilege_escalation... [ OK ]
Test test_arm_mrc...                            [ OK ]
Test test_arm_hflags_rebuilt...                 [ OK ]
Test test_arm_mem_access_abort...               [ OK ]
Test test_arm_read_sctlr...                     [ OK ]
Test test_arm_be_cpsr_sctlr...                  [ OK ]
Test test_arm_switch_endian...                  [ OK ]
Test test_armeb_ldrb...                         [ OK ]
Test test_arm_vpush...                          [ OK ]