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target/arm: Implement v8M VLLDM and VLSTM

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For v8M the instructions VLLDM and VLSTM support lazy saving
and restoring of the secure floating-point registers. Even
if the floating point extension is not implemented, these
instructions must act as NOPs in Secure state, so they can
be used as part of the secure-to-nonsecure call sequence.

Fixes: https://bugs.launchpad.net/qemu/+bug/1768295
Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20180503105730.5958-1-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2018-05-04 18:05:51 +01:00
parent a82929a251
commit b1e5336a98
1 changed files with 16 additions and 1 deletions
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17
target/arm/translate.c
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@ -10795,8 +10795,23 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
/* Coprocessor. */
if (arm_dc_feature(s, ARM_FEATURE_M)) {
/* We don't currently implement M profile FP support,
* so this entire space should give a NOCP fault.
* so this entire space should give a NOCP fault, with
* the exception of the v8M VLLDM and VLSTM insns, which
* must be NOPs in Secure state and UNDEF in Nonsecure state.
*/
if (arm_dc_feature(s, ARM_FEATURE_V8) &&
(insn & 0xffa00f00) == 0xec200a00) {
/* 0b1110_1100_0x1x_xxxx_xxxx_1010_xxxx_xxxx
* - VLLDM, VLSTM
* We choose to UNDEF if the RAZ bits are non-zero.
*/
if (!s->v8m_secure || (insn & 0x0040f0ff)) {
goto illegal_op;
}
/* Just NOP since FP support is not implemented */
break;
}
/* All other insns: NOCP */
gen_exception_insn(s, 4, EXCP_NOCP, syn_uncategorized(),
default_exception_el(s));
break;