[PATCH 5.11 392/775] powerpc/sstep: Check instruction validity against ISA version before emulation

From: Greg Kroah-Hartman
Date: Tue Mar 02 2021 - 00:06:59 EST

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From: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxx>

[ Upstream commit 8813ff49607eab3caaf40fe8929b0ce7dc68e85f ]

We currently unconditionally try to emulate newer instructions on older
Power versions that could cause issues. Gate it.

Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code")
Signed-off-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/161157995977.64773.13794501093457185080.stgit@thinktux.local
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/powerpc/lib/sstep.c | 78 +++++++++++++++++++++++++++++++---------
1 file changed, 62 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ede093e962347..5e725ed24d772 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1306,9 +1306,11 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
if ((word & 0xfe2) == 2)
op->type = SYSCALL;
else if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) &&
- (word & 0xfe3) == 1)
+ (word & 0xfe3) == 1) { /* scv */
op->type = SYSCALL_VECTORED_0;
- else
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
+ } else
op->type = UNKNOWN;
return 0;
#endif
@@ -1412,7 +1414,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#ifdef __powerpc64__
case 1:
if (!cpu_has_feature(CPU_FTR_ARCH_31))
- return -1;
+ goto unknown_opcode;

prefix_r = GET_PREFIX_R(word);
ra = GET_PREFIX_RA(suffix);
@@ -1446,7 +1448,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#ifdef __powerpc64__
case 4:
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;

switch (word & 0x3f) {
case 48: /* maddhd */
@@ -1532,6 +1534,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
case 19:
if (((word >> 1) & 0x1f) == 2) {
/* addpcis */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
imm = (short) (word & 0xffc1); /* d0 + d2 fields */
imm |= (word >> 15) & 0x3e; /* d1 field */
op->val = regs->nip + (imm << 16) + 4;
@@ -1844,7 +1848,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#ifdef __powerpc64__
case 265: /* modud */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
op->val = regs->gpr[ra] % regs->gpr[rb];
goto compute_done;
#endif
@@ -1854,7 +1858,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

case 267: /* moduw */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
op->val = (unsigned int) regs->gpr[ra] %
(unsigned int) regs->gpr[rb];
goto compute_done;
@@ -1891,7 +1895,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#endif
case 755: /* darn */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
switch (ra & 0x3) {
case 0:
/* 32-bit conditioned */
@@ -1913,14 +1917,14 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#ifdef __powerpc64__
case 777: /* modsd */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
op->val = (long int) regs->gpr[ra] %
(long int) regs->gpr[rb];
goto compute_done;
#endif
case 779: /* modsw */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
op->val = (int) regs->gpr[ra] %
(int) regs->gpr[rb];
goto compute_done;
@@ -1997,14 +2001,14 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#endif
case 538: /* cnttzw */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
val = (unsigned int) regs->gpr[rd];
op->val = (val ? __builtin_ctz(val) : 32);
goto logical_done;
#ifdef __powerpc64__
case 570: /* cnttzd */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
val = regs->gpr[rd];
op->val = (val ? __builtin_ctzl(val) : 64);
goto logical_done;
@@ -2114,7 +2118,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
case 890: /* extswsli with sh_5 = 0 */
case 891: /* extswsli with sh_5 = 1 */
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;
op->type = COMPUTE + SETREG;
sh = rb | ((word & 2) << 4);
val = (signed int) regs->gpr[rd];
@@ -2441,6 +2445,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 268: /* lxvx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 16);
op->element_size = 16;
@@ -2450,6 +2456,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
case 269: /* lxvl */
case 301: { /* lxvll */
int nb;
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->ea = ra ? regs->gpr[ra] : 0;
nb = regs->gpr[rb] & 0xff;
@@ -2470,13 +2478,15 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

case 333: /* lxvpx */
if (!cpu_has_feature(CPU_FTR_ARCH_31))
- return -1;
+ goto unknown_opcode;
op->reg = VSX_REGISTER_XTP(rd);
op->type = MKOP(LOAD_VSX, 0, 32);
op->element_size = 32;
break;

case 364: /* lxvwsx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 4);
op->element_size = 4;
@@ -2484,6 +2494,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 396: /* stxvx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(STORE_VSX, 0, 16);
op->element_size = 16;
@@ -2493,6 +2505,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
case 397: /* stxvl */
case 429: { /* stxvll */
int nb;
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->ea = ra ? regs->gpr[ra] : 0;
nb = regs->gpr[rb] & 0xff;
@@ -2506,7 +2520,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
}
case 461: /* stxvpx */
if (!cpu_has_feature(CPU_FTR_ARCH_31))
- return -1;
+ goto unknown_opcode;
op->reg = VSX_REGISTER_XTP(rd);
op->type = MKOP(STORE_VSX, 0, 32);
op->element_size = 32;
@@ -2544,6 +2558,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 781: /* lxsibzx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 1);
op->element_size = 8;
@@ -2551,6 +2567,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 812: /* lxvh8x */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 16);
op->element_size = 2;
@@ -2558,6 +2576,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 813: /* lxsihzx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 2);
op->element_size = 8;
@@ -2571,6 +2591,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 876: /* lxvb16x */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(LOAD_VSX, 0, 16);
op->element_size = 1;
@@ -2584,6 +2606,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 909: /* stxsibx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(STORE_VSX, 0, 1);
op->element_size = 8;
@@ -2591,6 +2615,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 940: /* stxvh8x */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(STORE_VSX, 0, 16);
op->element_size = 2;
@@ -2598,6 +2624,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 941: /* stxsihx */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(STORE_VSX, 0, 2);
op->element_size = 8;
@@ -2611,6 +2639,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 1004: /* stxvb16x */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd | ((word & 1) << 5);
op->type = MKOP(STORE_VSX, 0, 16);
op->element_size = 1;
@@ -2719,12 +2749,16 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
op->type = MKOP(LOAD_FP, 0, 16);
break;
case 2: /* lxsd */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd + 32;
op->type = MKOP(LOAD_VSX, 0, 8);
op->element_size = 8;
op->vsx_flags = VSX_CHECK_VEC;
break;
case 3: /* lxssp */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->reg = rd + 32;
op->type = MKOP(LOAD_VSX, 0, 4);
op->element_size = 8;
@@ -2754,7 +2788,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
#ifdef CONFIG_VSX
case 6:
if (!cpu_has_feature(CPU_FTR_ARCH_31))
- return -1;
+ goto unknown_opcode;
op->ea = dqform_ea(word, regs);
op->reg = VSX_REGISTER_XTP(rd);
op->element_size = 32;
@@ -2777,6 +2811,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 1: /* lxv */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->ea = dqform_ea(word, regs);
if (word & 8)
op->reg = rd + 32;
@@ -2787,6 +2823,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

case 2: /* stxsd with LSB of DS field = 0 */
case 6: /* stxsd with LSB of DS field = 1 */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->ea = dsform_ea(word, regs);
op->reg = rd + 32;
op->type = MKOP(STORE_VSX, 0, 8);
@@ -2796,6 +2834,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

case 3: /* stxssp with LSB of DS field = 0 */
case 7: /* stxssp with LSB of DS field = 1 */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->ea = dsform_ea(word, regs);
op->reg = rd + 32;
op->type = MKOP(STORE_VSX, 0, 4);
@@ -2804,6 +2844,8 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
break;

case 5: /* stxv */
+ if (!cpu_has_feature(CPU_FTR_ARCH_300))
+ goto unknown_opcode;
op->ea = dqform_ea(word, regs);
if (word & 8)
op->reg = rd + 32;
@@ -2833,7 +2875,7 @@ 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;
+ goto unknown_opcode;

prefix_r = GET_PREFIX_R(word);
ra = GET_PREFIX_RA(suffix);
@@ -2982,6 +3024,10 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

return 0;

+ unknown_opcode:
+ op->type = UNKNOWN;
+ return 0;
+
logical_done:
if (word & 1)
set_cr0(regs, op);
--
2.27.0

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