On Fri, Feb 25, 2011 at 03:04:12PM +0000, Peter Maydell wrote:
> 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.mayd...@linaro.org>
> ---
> This patch stands alone as a fix to target-arm; it's a prerequisite
> for Adam's VA->PA translation patch, because otherwise attempting a
> user-read translation will get you a WFI instead...
>
> target-arm/translate.c | 35 ++++++++++++++++++++++++++++++-----
> 1 files changed, 30 insertions(+), 5 deletions(-)
Thanks, applied.
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index dbd958b..baa1256 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))
> --
> 1.7.1
>
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
