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powerpc/sstep: Emulate prefixed instructions only when CPU_FTR_ARCH_31 is set

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[ Upstream commit ef6879f8c8053cc3b493f400a06d452d7fb13650 ]

Unconditional emulation of prefixed instructions will allow
emulation of them on Power10 predecessors which might cause
issues. Restrict that.

Fixes: 3920742b92f5 ("powerpc sstep: Add support for prefixed fixed-point arithmetic")
Fixes: 50b80a12e4cc ("powerpc sstep: Add support for prefixed load/stores")
Signed-off-by: Balamuruhan S <bala24@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201011050908.72173-2-ravi.bangoria@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Balamuruhan S 2020-10-11 10:39:04 +05:30 committed by Greg Kroah-Hartman
parent 62cd477bbd
commit bf608cf329
1 changed files with 6 additions and 0 deletions
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6
arch/powerpc/lib/sstep.c
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@ -1346,6 +1346,9 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
switch (opcode) {
#ifdef __powerpc64__
case 1:
if (!cpu_has_feature(CPU_FTR_ARCH_31))
return -1;
prefix_r = GET_PREFIX_R(word);
ra = GET_PREFIX_RA(suffix);
rd = (suffix >> 21) & 0x1f;
@ -2733,6 +2736,9 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
}
break;
case 1: /* Prefixed instructions */
if (!cpu_has_feature(CPU_FTR_ARCH_31))
return -1;
prefix_r = GET_PREFIX_R(word);
ra = GET_PREFIX_RA(suffix);
op->update_reg = ra;