arm: basic support for ARMv4/ARMv4T emulation
Currently target-arm/ assumes at least ARMv5 core. Add support for
handling also ARMv4/ARMv4T. This changes the following instructions:
BX(v4T and later)
BKPT, BLX, CDP2, CLZ, LDC2, LDRD, MCRR, MCRR2, MRRC, MCRR, MRC2, MRRC,
MRRC2, PLD QADD, QDADD, QDSUB, QSUB, STRD, SMLAxy, SMLALxy, SMLAWxy,
SMULxy, SMULWxy, STC2 (v5 and later)
All instructions that are "v5TE and later" are also bound to just v5, as
that's how it was before.
This patch doesn _not_ include disabling of cp15 access and base-updated
data abort model (that will be required to emulate chips based on a
ARM7TDMI), because:
* no ARM7TDMI chips are currently emulated (or planned)
* those features aren't strictly necessary for my purposes (SA-1 core
emulation).
All v5 models are handled as they are v5T. Internally we still have a
check if the model is a v5(T) or v5TE, but as all emulated cores are
v5TE, those two cases are simply aliased (for now).
Patch is heavily based on patch by Filip Navara <filip.navara@gmail.com>
which in turn is based on work by Ulrich Hecht <uli@suse.de> and Vincent
Sanders <vince@kyllikki.org>.
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/target-arm/translate.c b/target-arm/translate.c
index 55d524b..998cfd5 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -34,6 +34,10 @@
#define GEN_HELPER 1
#include "helpers.h"
+#define ENABLE_ARCH_4T arm_feature(env, ARM_FEATURE_V4T)
+#define ENABLE_ARCH_5 arm_feature(env, ARM_FEATURE_V5)
+/* currently all emulated v5 cores are also v5TE, so don't bother */
+#define ENABLE_ARCH_5TE arm_feature(env, ARM_FEATURE_V5)
#define ENABLE_ARCH_5J 0
#define ENABLE_ARCH_6 arm_feature(env, ARM_FEATURE_V6)
#define ENABLE_ARCH_6K arm_feature(env, ARM_FEATURE_V6K)
@@ -750,6 +754,20 @@
}
}
+/* Variant of store_reg which uses branch&exchange logic when storing
+ * to r15 in ARM architecture v5T and above. This is used for storing
+ * the results of a LDR/LDM/POP into r15, and corresponds to the cases
+ * in the ARM ARM which use the LoadWritePC() pseudocode function. */
+static inline void store_reg_from_load(CPUState *env, DisasContext *s,
+ int reg, TCGv var)
+{
+ if (reg == 15 && ENABLE_ARCH_5) {
+ gen_bx(s, var);
+ } else {
+ store_reg(s, reg, var);
+ }
+}
+
static inline TCGv gen_ld8s(TCGv addr, int index)
{
TCGv tmp = tcg_temp_new_i32();
@@ -3436,6 +3454,10 @@
/* Mask out undefined bits. */
mask &= ~CPSR_RESERVED;
+ if (!arm_feature(env, ARM_FEATURE_V4T))
+ mask &= ~CPSR_T;
+ if (!arm_feature(env, ARM_FEATURE_V5))
+ mask &= ~CPSR_Q; /* V5TE in reality*/
if (!arm_feature(env, ARM_FEATURE_V6))
mask &= ~(CPSR_E | CPSR_GE);
if (!arm_feature(env, ARM_FEATURE_THUMB2))
@@ -6127,6 +6149,12 @@
goto illegal_op;
cond = insn >> 28;
if (cond == 0xf){
+ /* In ARMv3 and v4 the NV condition is UNPREDICTABLE; we
+ * choose to UNDEF. In ARMv5 and above the space is used
+ * for miscellaneous unconditional instructions.
+ */
+ ARCH(5);
+
/* Unconditional instructions. */
if (((insn >> 25) & 7) == 1) {
/* NEON Data processing. */
@@ -6155,6 +6183,7 @@
}
}
/* Otherwise PLD; v5TE+ */
+ ARCH(5TE);
return;
}
if (((insn & 0x0f70f000) == 0x0450f000) ||
@@ -6291,6 +6320,7 @@
val += (offset << 2) | ((insn >> 23) & 2) | 1;
/* pipeline offset */
val += 4;
+ /* protected by ARCH(5); above, near the start of uncond block */
gen_bx_im(s, val);
return;
} else if ((insn & 0x0e000f00) == 0x0c000100) {
@@ -6302,6 +6332,7 @@
}
} else if ((insn & 0x0fe00000) == 0x0c400000) {
/* Coprocessor double register transfer. */
+ ARCH(5TE);
} else if ((insn & 0x0f000010) == 0x0e000010) {
/* Additional coprocessor register transfer. */
} else if ((insn & 0x0ff10020) == 0x01000000) {
@@ -6402,10 +6433,12 @@
case 0x1:
if (op1 == 1) {
/* branch/exchange thumb (bx). */
+ ARCH(4T);
tmp = load_reg(s, rm);
gen_bx(s, tmp);
} else if (op1 == 3) {
/* clz */
+ ARCH(5);
rd = (insn >> 12) & 0xf;
tmp = load_reg(s, rm);
gen_helper_clz(tmp, tmp);
@@ -6428,6 +6461,7 @@
if (op1 != 1)
goto illegal_op;
+ ARCH(5);
/* branch link/exchange thumb (blx) */
tmp = load_reg(s, rm);
tmp2 = tcg_temp_new_i32();
@@ -6436,6 +6470,7 @@
gen_bx(s, tmp);
break;
case 0x5: /* saturating add/subtract */
+ ARCH(5TE);
rd = (insn >> 12) & 0xf;
rn = (insn >> 16) & 0xf;
tmp = load_reg(s, rm);
@@ -6457,12 +6492,14 @@
goto illegal_op;
}
/* bkpt */
+ ARCH(5);
gen_exception_insn(s, 4, EXCP_BKPT);
break;
case 0x8: /* signed multiply */
case 0xa:
case 0xc:
case 0xe:
+ ARCH(5TE);
rs = (insn >> 8) & 0xf;
rn = (insn >> 12) & 0xf;
rd = (insn >> 16) & 0xf;
@@ -6858,6 +6895,7 @@
}
load = 1;
} else if (sh & 2) {
+ ARCH(5TE);
/* doubleword */
if (sh & 1) {
/* store */
@@ -7198,10 +7236,7 @@
}
if (insn & (1 << 20)) {
/* Complete the load. */
- if (rd == 15)
- gen_bx(s, tmp);
- else
- store_reg(s, rd, tmp);
+ store_reg_from_load(env, s, rd, tmp);
}
break;
case 0x08:
@@ -7254,9 +7289,7 @@
if (insn & (1 << 20)) {
/* load */
tmp = gen_ld32(addr, IS_USER(s));
- if (i == 15) {
- gen_bx(s, tmp);
- } else if (user) {
+ if (user) {
tmp2 = tcg_const_i32(i);
gen_helper_set_user_reg(tmp2, tmp);
tcg_temp_free_i32(tmp2);
@@ -7265,7 +7298,7 @@
loaded_var = tmp;
loaded_base = 1;
} else {
- store_reg(s, i, tmp);
+ store_reg_from_load(env, s, i, tmp);
}
} else {
/* store */
@@ -7465,6 +7498,7 @@
16-bit instructions to get correct prefetch abort behavior. */
insn = insn_hw1;
if ((insn & (1 << 12)) == 0) {
+ ARCH(5);
/* Second half of blx. */
offset = ((insn & 0x7ff) << 1);
tmp = load_reg(s, 14);
@@ -8061,6 +8095,7 @@
} else {
/* blx */
offset &= ~(uint32_t)2;
+ /* thumb2 bx, no need to check */
gen_bx_im(s, offset);
}
} else if (((insn >> 23) & 7) == 7) {
@@ -8642,11 +8677,13 @@
case 3:/* branch [and link] exchange thumb register */
tmp = load_reg(s, rm);
if (insn & (1 << 7)) {
+ ARCH(5);
val = (uint32_t)s->pc | 1;
tmp2 = tcg_temp_new_i32();
tcg_gen_movi_i32(tmp2, val);
store_reg(s, 14, tmp2);
}
+ /* already thumb, no need to check */
gen_bx(s, tmp);
break;
}
@@ -9006,8 +9043,9 @@
/* write back the new stack pointer */
store_reg(s, 13, addr);
/* set the new PC value */
- if ((insn & 0x0900) == 0x0900)
- gen_bx(s, tmp);
+ if ((insn & 0x0900) == 0x0900) {
+ store_reg_from_load(env, s, 15, tmp);
+ }
break;
case 1: case 3: case 9: case 11: /* czb */
@@ -9038,6 +9076,7 @@
break;
case 0xe: /* bkpt */
+ ARCH(5);
gen_exception_insn(s, 2, EXCP_BKPT);
break;
