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target/arm: Enforce M-profile VMRS/VMSR register restrictions

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For M-profile before v8.1M, the only valid register for VMSR/VMRS is
the FPSCR.  We have a comment that states this, but the actual logic
to forbid accesses for any other register value is missing, so we
would end up with A-profile style behaviour.  Add the missing check.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20201119215617.29887-7-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2020-11-19 21:55:55 +00:00
parent 6e21a013fb
commit ede97c9d71
1 changed files with 4 additions and 1 deletions
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5
target/arm/translate-vfp.c.inc
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@ -622,7 +622,10 @@ static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a)
* Accesses to R15 are UNPREDICTABLE; we choose to undef.
* (FPSCR -> r15 is a special case which writes to the PSR flags.)
*/
if (a->rt == 15 && (!a->l || a->reg != ARM_VFP_FPSCR)) {
if (a->reg != ARM_VFP_FPSCR) {
return false;
}
if (a->rt == 15 && !a->l) {
return false;
}
}