[PATCH 5.10 092/102] powerpc/sstep: Check instruction validity against ISA version before emulation

From: Greg Kroah-Hartman
Date: Fri Mar 05 2021 - 07:32:52 EST

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From: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxx>

commit 8813ff49607eab3caaf40fe8929b0ce7dc68e85f upstream.

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
[Dropped a few missing hunks for the backport to v5.10]
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/lib/sstep.c | 72 ++++++++++++++++++++++++++++++++++++++---------
1 file changed, 59 insertions(+), 13 deletions(-)

--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1241,9 +1241,11 @@ int analyse_instr(struct instruction_op
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
@@ -1347,7 +1349,7 @@ int analyse_instr(struct instruction_op
#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);
@@ -1381,7 +1383,7 @@ int analyse_instr(struct instruction_op
#ifdef __powerpc64__
case 4:
if (!cpu_has_feature(CPU_FTR_ARCH_300))
- return -1;
+ goto unknown_opcode;

switch (word & 0x3f) {
case 48: /* maddhd */
@@ -1467,6 +1469,8 @@ int analyse_instr(struct instruction_op
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;
@@ -1779,7 +1783,7 @@ int analyse_instr(struct instruction_op
#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
@@ -1789,7 +1793,7 @@ int analyse_instr(struct instruction_op

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;
@@ -1826,7 +1830,7 @@ int analyse_instr(struct instruction_op
#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 */
@@ -1848,14 +1852,14 @@ int analyse_instr(struct instruction_op
#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;
@@ -1932,14 +1936,14 @@ int analyse_instr(struct instruction_op
#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;
@@ -2049,7 +2053,7 @@ int analyse_instr(struct instruction_op
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];
@@ -2376,6 +2380,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2385,6 +2391,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2404,6 +2412,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2411,6 +2421,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2420,6 +2432,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2464,6 +2478,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2471,6 +2487,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2478,6 +2496,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2491,6 +2511,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2504,6 +2526,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2511,6 +2535,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2518,6 +2544,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2531,6 +2559,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2639,12 +2669,16 @@ int analyse_instr(struct instruction_op
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;
@@ -2681,6 +2715,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2691,6 +2727,8 @@ int analyse_instr(struct instruction_op

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);
@@ -2700,6 +2738,8 @@ int analyse_instr(struct instruction_op

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);
@@ -2708,6 +2748,8 @@ int analyse_instr(struct instruction_op
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;
@@ -2737,7 +2779,7 @@ int analyse_instr(struct instruction_op
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);
@@ -2872,6 +2914,10 @@ int analyse_instr(struct instruction_op

return 0;

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

Next message: Greg Kroah-Hartman: "[PATCH 5.10 091/102] swap: fix swapfile read/write offset"
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