[PATCH v4 1/2] [PATCH] powerpc/sstep: Check instruction validity against ISA version before emulation
Ananth N Mavinakayanahalli
ananth at linux.ibm.com
Tue Jan 26 00:06:22 AEDT 2021
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 at linux.ibm.com>
---
[v4] Based on feedback from Paul Mackerras, Naveen Rao and Michael Ellerman,
changed return code to 0, after setting opcode type to UNKNOWN
[v3] Addressed Naveen's comments on scv and addpcis
[v2] Fixed description
---
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 bf7a7d62ae8b..f859cbbb6375 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1304,9 +1304,11 @@ 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
@@ -1410,7 +1412,7 @@ 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);
@@ -1444,7 +1446,7 @@ 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 */
@@ -1530,6 +1532,8 @@ 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;
@@ -1842,7 +1846,7 @@ 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
@@ -1852,7 +1856,7 @@ 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;
@@ -1889,7 +1893,7 @@ 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 */
@@ -1911,14 +1915,14 @@ 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;
@@ -1995,14 +1999,14 @@ 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;
@@ -2112,7 +2116,7 @@ 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];
@@ -2439,6 +2443,8 @@ 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;
@@ -2448,6 +2454,8 @@ 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;
@@ -2468,13 +2476,15 @@ 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;
@@ -2482,6 +2492,8 @@ 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;
@@ -2491,6 +2503,8 @@ 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;
@@ -2504,7 +2518,7 @@ 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;
@@ -2542,6 +2556,8 @@ 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;
@@ -2549,6 +2565,8 @@ 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;
@@ -2556,6 +2574,8 @@ 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;
@@ -2569,6 +2589,8 @@ 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;
@@ -2582,6 +2604,8 @@ 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;
@@ -2589,6 +2613,8 @@ 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;
@@ -2596,6 +2622,8 @@ 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;
@@ -2609,6 +2637,8 @@ 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;
@@ -2717,12 +2747,16 @@ 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;
@@ -2752,7 +2786,7 @@ 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;
@@ -2775,6 +2809,8 @@ 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;
@@ -2785,6 +2821,8 @@ 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);
@@ -2794,6 +2832,8 @@ 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);
@@ -2802,6 +2842,8 @@ 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;
@@ -2831,7 +2873,7 @@ 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);
@@ -2980,6 +3022,10 @@ 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);
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