* [Qemu-devel] [PULL for-2.0] tcg-arm: Avoid ldrd/strd for user-only emulation
2014-03-28 13:16 [Qemu-devel] [PULL for-2.0] tcg-arm update Richard Henderson
@ 2014-03-28 13:16 ` Richard Henderson
2014-03-28 15:31 ` [Qemu-devel] [PULL for-2.0] tcg-arm update Peter Maydell
1 sibling, 0 replies; 3+ messages in thread
From: Richard Henderson @ 2014-03-28 13:16 UTC (permalink / raw)
To: qemu-devel; +Cc: peter.maydell
The arm ldrd/strd insns must cause alignment traps, whereas
at least for armv7 ldr/str must handle unaligned operations.
While this is hardly the only problem facing user-only emu,
this solves one problem for i386 on armv7 emulation.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reported-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
tcg/arm/tcg-target.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
index c8884b3..a65fc65 100644
--- a/tcg/arm/tcg-target.c
+++ b/tcg/arm/tcg-target.c
@@ -60,6 +60,13 @@ static int arm_arch = __ARM_ARCH;
bool use_idiv_instructions;
#endif
+/* ??? Ought to think about changing CONFIG_SOFTMMU to always defined. */
+#ifdef CONFIG_SOFTMMU
+# define USING_SOFTMMU 1
+#else
+# define USING_SOFTMMU 0
+#endif
+
#ifndef NDEBUG
static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
"%r0",
@@ -1404,7 +1411,9 @@ static inline void tcg_out_qemu_ld_index(TCGContext *s, TCGMemOp opc,
TCGReg dl = (bswap ? datahi : datalo);
TCGReg dh = (bswap ? datalo : datahi);
- if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {
+ /* Avoid ldrd for user-only emulation, to handle unaligned. */
+ if (USING_SOFTMMU && use_armv6_instructions
+ && (dl & 1) == 0 && dh == dl + 1) {
tcg_out_ldrd_r(s, COND_AL, dl, addrlo, addend);
} else if (dl != addend) {
tcg_out_ld32_rwb(s, COND_AL, dl, addend, addrlo);
@@ -1463,7 +1472,9 @@ static inline void tcg_out_qemu_ld_direct(TCGContext *s, TCGMemOp opc,
TCGReg dl = (bswap ? datahi : datalo);
TCGReg dh = (bswap ? datalo : datahi);
- if (use_armv6_instructions && (dl & 1) == 0 && dh == dl + 1) {
+ /* Avoid ldrd for user-only emulation, to handle unaligned. */
+ if (USING_SOFTMMU && use_armv6_instructions
+ && (dl & 1) == 0 && dh == dl + 1) {
tcg_out_ldrd_8(s, COND_AL, dl, addrlo, 0);
} else if (dl == addrlo) {
tcg_out_ld32_12(s, COND_AL, dh, addrlo, bswap ? 0 : 4);
@@ -1548,12 +1559,13 @@ static inline void tcg_out_qemu_st_index(TCGContext *s, int cond, TCGMemOp opc,
}
break;
case MO_64:
+ /* Avoid strd for user-only emulation, to handle unaligned. */
if (bswap) {
tcg_out_bswap32(s, cond, TCG_REG_R0, datahi);
tcg_out_st32_rwb(s, cond, TCG_REG_R0, addend, addrlo);
tcg_out_bswap32(s, cond, TCG_REG_R0, datalo);
tcg_out_st32_12(s, cond, TCG_REG_R0, addend, 4);
- } else if (use_armv6_instructions
+ } else if (USING_SOFTMMU && use_armv6_instructions
&& (datalo & 1) == 0 && datahi == datalo + 1) {
tcg_out_strd_r(s, cond, datalo, addrlo, addend);
} else {
@@ -1592,12 +1604,13 @@ static inline void tcg_out_qemu_st_direct(TCGContext *s, TCGMemOp opc,
}
break;
case MO_64:
+ /* Avoid strd for user-only emulation, to handle unaligned. */
if (bswap) {
tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datahi);
tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 0);
tcg_out_bswap32(s, COND_AL, TCG_REG_R0, datalo);
tcg_out_st32_12(s, COND_AL, TCG_REG_R0, addrlo, 4);
- } else if (use_armv6_instructions
+ } else if (USING_SOFTMMU && use_armv6_instructions
&& (datalo & 1) == 0 && datahi == datalo + 1) {
tcg_out_strd_8(s, COND_AL, datalo, addrlo, 0);
} else {
--
1.8.3.1
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