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authorPeter Maydell <peter.maydell@linaro.org>2011-02-25 15:04:12 +0000
committerAurelien Jarno <aurelien@aurel32.net>2011-03-06 20:20:19 +0100
commitcc68890166c2c1c5003e3eeb8535e1872e239a95 (patch)
treea89d9319c9bdc44df541f73da3a388eebdc1717f
parent96c94b298f99d6edf4e49d03cc8458f5b6e9d5f0 (diff)
target-arm: Don't decode old cp15 WFI instructions on v7 cores
In v7 of the ARM architecture, WFI (wait for interrupt) is a first-class instruction, but in previous versions this functionality was provided via a cp15 coprocessor register. Add correct feature checks to the decoding of the cp15 WFI instructions so that they behave correctly for newer cores. In particular, the old 0,c7,c8,2 encoding used on ARM940 has been reused for VA-to-PA translation in v6 and v7. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Adam Lackorzynski <adam@os.inf.tu-dresden.de> Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
-rw-r--r--target-arm/translate.c35
1 files changed, 30 insertions, 5 deletions
diff --git a/target-arm/translate.c b/target-arm/translate.c
index dbd958be78..baa12563e7 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -2538,13 +2538,38 @@ static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn)
if (IS_USER(s) && !cp15_user_ok(insn)) {
return 1;
}
- if ((insn & 0x0fff0fff) == 0x0e070f90
- || (insn & 0x0fff0fff) == 0x0e070f58) {
- /* Wait for interrupt. */
- gen_set_pc_im(s->pc);
- s->is_jmp = DISAS_WFI;
+
+ /* Pre-v7 versions of the architecture implemented WFI via coprocessor
+ * instructions rather than a separate instruction.
+ */
+ if ((insn & 0x0fff0fff) == 0x0e070f90) {
+ /* 0,c7,c0,4: Standard v6 WFI (also used in some pre-v6 cores).
+ * In v7, this must NOP.
+ */
+ if (!arm_feature(env, ARM_FEATURE_V7)) {
+ /* Wait for interrupt. */
+ gen_set_pc_im(s->pc);
+ s->is_jmp = DISAS_WFI;
+ }
return 0;
}
+
+ if ((insn & 0x0fff0fff) == 0x0e070f58) {
+ /* 0,c7,c8,2: Not all pre-v6 cores implemented this WFI,
+ * so this is slightly over-broad.
+ */
+ if (!arm_feature(env, ARM_FEATURE_V6)) {
+ /* Wait for interrupt. */
+ gen_set_pc_im(s->pc);
+ s->is_jmp = DISAS_WFI;
+ return 0;
+ }
+ /* Otherwise fall through to handle via helper function.
+ * In particular, on v7 and some v6 cores this is one of
+ * the VA-PA registers.
+ */
+ }
+
rd = (insn >> 12) & 0xf;
if (cp15_tls_load_store(env, s, insn, rd))