ppc: Fix the range check in the LSWI instruction
There are two issues: First, the number of registers that are used has to be calculated with "(nb + 3) / 4" (i.e. round always up, not down). Second, the "start <= ra && (start + nr - 32) > ra" condition for the wrap-around case is wrong: It has to be tested with "||" instead of "&&". Since we can reuse this check later for the LSWX instruction, let's place the fixed code into a helper function, too. Signed-off-by: Thomas Huth <thuth@redhat.com> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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@ -2415,6 +2415,16 @@ static inline bool msr_is_64bit(CPUPPCState *env, target_ulong msr)
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return msr & (1ULL << MSR_SF);
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}
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/**
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* Check whether register rx is in the range between start and
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* start + nregs (as needed by the LSWX and LSWI instructions)
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*/
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static inline bool lsw_reg_in_range(int start, int nregs, int rx)
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{
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return (start + nregs <= 32 && rx >= start && rx < start + nregs) ||
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(start + nregs > 32 && (rx >= start || rx < start + nregs - 32));
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}
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extern void (*cpu_ppc_hypercall)(PowerPCCPU *);
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#include "exec/exec-all.h"
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@ -3227,10 +3227,8 @@ static void gen_lswi(DisasContext *ctx)
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if (nb == 0)
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nb = 32;
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nr = nb / 4;
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if (unlikely(((start + nr) > 32 &&
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start <= ra && (start + nr - 32) > ra) ||
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((start + nr) <= 32 && start <= ra && (start + nr) > ra))) {
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nr = (nb + 3) / 4;
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if (unlikely(lsw_reg_in_range(start, nr, ra))) {
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gen_inval_exception(ctx, POWERPC_EXCP_INVAL_LSWX);
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return;
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}
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