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From: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
To: mpe@ellerman.id.au
Cc: ravi.bangoria@linux.ibm.com, jniethe5@gmail.com,
	bala24@linux.ibm.com, paulus@samba.org, sandipan@linux.ibm.com,
	naveen.n.rao@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v5 1/5] powerpc/sstep: Emulate prefixed instructions only when CPU_FTR_ARCH_31 is set
Date: Sun, 11 Oct 2020 10:39:04 +0530
Message-ID: <20201011050908.72173-2-ravi.bangoria@linux.ibm.com> (raw)
In-Reply-To: <20201011050908.72173-1-ravi.bangoria@linux.ibm.com>

From: Balamuruhan S <bala24@linux.ibm.com>

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>
---
 arch/powerpc/lib/sstep.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index e9dcaba9a4f8..e6242744c71b 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -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;
-- 
2.26.2


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-11  5:09 [PATCH v5 0/5] powerpc/sstep: VSX 32-byte vector paired load/store instructions Ravi Bangoria
2020-10-11  5:09 ` Ravi Bangoria [this message]
2020-10-11 15:06   ` [PATCH v5 1/5] powerpc/sstep: Emulate prefixed instructions only when CPU_FTR_ARCH_31 is set Sandipan Das
2020-10-12  1:51   ` Daniel Axtens
2020-10-12 11:07     ` Ravi Bangoria
2020-10-12 12:55       ` Daniel Axtens
2020-10-12 13:44   ` Daniel Axtens
2020-10-14  7:34     ` Ravi Bangoria
2020-10-11  5:09 ` [PATCH v5 2/5] powerpc/sstep: Cover new VSX instructions under CONFIG_VSX Ravi Bangoria
2020-10-11  5:09 ` [PATCH v5 3/5] powerpc/sstep: Support VSX vector paired storage access instructions Ravi Bangoria
2020-10-11  5:09 ` [PATCH v5 4/5] powerpc/ppc-opcode: Add encoding macros for VSX vector paired instructions Ravi Bangoria
2020-10-11  5:09 ` [PATCH v5 5/5] powerpc/sstep: Add testcases for VSX vector paired load/store instructions Ravi Bangoria
2020-12-15 10:49 ` [PATCH v5 0/5] powerpc/sstep: VSX 32-byte " Michael Ellerman

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