enum legacy_insn_status {
INSN_DEPRECATED,
INSN_OBSOLETE,
+ INSN_UNAVAILABLE,
};
struct insn_emulation {
const char *name;
- struct list_head node;
enum legacy_insn_status status;
- struct undef_hook *hooks;
+ bool (*try_emulate)(struct pt_regs *regs,
+ u32 insn);
int (*set_hw_mode)(bool enable);
+
int current_mode;
int min;
int max;
+
+ /*
+ * sysctl for this emulation + a sentinal entry.
+ */
+ struct ctl_table sysctl[2];
};
#define ARM_OPCODE_CONDTEST_FAIL 0
return ARM_OPCODE_CONDTEST_UNCOND;
}
+#ifdef CONFIG_SWP_EMULATION
/*
* Implement emulation of the SWP/SWPB instructions using load-exclusive and
* store-exclusive.
return 0;
}
-/*
- * Only emulate SWP/SWPB executed in ARM state/User mode.
- * The kernel must be SWP free and SWP{B} does not exist in Thumb.
- */
-static struct undef_hook swp_hooks[] = {
- {
- .instr_mask = 0x0fb00ff0,
- .instr_val = 0x01000090,
- .pstate_mask = PSR_AA32_MODE_MASK,
- .pstate_val = PSR_AA32_MODE_USR,
- .fn = swp_handler
- },
- { }
-};
+static bool try_emulate_swp(struct pt_regs *regs, u32 insn)
+{
+ /* SWP{B} only exists in ARM state and does not exist in Thumb */
+ if (!compat_user_mode(regs) || compat_thumb_mode(regs))
+ return false;
+
+ if ((insn & 0x0fb00ff0) != 0x01000090)
+ return false;
+
+ return swp_handler(regs, insn) == 0;
+}
static struct insn_emulation insn_swp = {
.name = "swp",
.status = INSN_OBSOLETE,
- .hooks = swp_hooks,
+ .try_emulate = try_emulate_swp,
.set_hw_mode = NULL,
};
+#endif /* CONFIG_SWP_EMULATION */
+#ifdef CONFIG_CP15_BARRIER_EMULATION
static int cp15barrier_handler(struct pt_regs *regs, u32 instr)
{
perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
return 0;
}
-static struct undef_hook cp15_barrier_hooks[] = {
- {
- .instr_mask = 0x0fff0fdf,
- .instr_val = 0x0e070f9a,
- .pstate_mask = PSR_AA32_MODE_MASK,
- .pstate_val = PSR_AA32_MODE_USR,
- .fn = cp15barrier_handler,
- },
- {
- .instr_mask = 0x0fff0fff,
- .instr_val = 0x0e070f95,
- .pstate_mask = PSR_AA32_MODE_MASK,
- .pstate_val = PSR_AA32_MODE_USR,
- .fn = cp15barrier_handler,
- },
- { }
-};
+static bool try_emulate_cp15_barrier(struct pt_regs *regs, u32 insn)
+{
+ if (!compat_user_mode(regs) || compat_thumb_mode(regs))
+ return false;
+
+ if ((insn & 0x0fff0fdf) == 0x0e070f9a)
+ return cp15barrier_handler(regs, insn) == 0;
+
+ if ((insn & 0x0fff0fff) == 0x0e070f95)
+ return cp15barrier_handler(regs, insn) == 0;
+
+ return false;
+}
static struct insn_emulation insn_cp15_barrier = {
.name = "cp15_barrier",
.status = INSN_DEPRECATED,
- .hooks = cp15_barrier_hooks,
+ .try_emulate = try_emulate_cp15_barrier,
.set_hw_mode = cp15_barrier_set_hw_mode,
};
+#endif /* CONFIG_CP15_BARRIER_EMULATION */
+#ifdef CONFIG_SETEND_EMULATION
static int setend_set_hw_mode(bool enable)
{
if (!cpu_supports_mixed_endian_el0())
return rc;
}
-static struct undef_hook setend_hooks[] = {
- {
- .instr_mask = 0xfffffdff,
- .instr_val = 0xf1010000,
- .pstate_mask = PSR_AA32_MODE_MASK,
- .pstate_val = PSR_AA32_MODE_USR,
- .fn = a32_setend_handler,
- },
- {
- /* Thumb mode */
- .instr_mask = 0xfffffff7,
- .instr_val = 0x0000b650,
- .pstate_mask = (PSR_AA32_T_BIT | PSR_AA32_MODE_MASK),
- .pstate_val = (PSR_AA32_T_BIT | PSR_AA32_MODE_USR),
- .fn = t16_setend_handler,
- },
- {}
-};
+static bool try_emulate_setend(struct pt_regs *regs, u32 insn)
+{
+ if (compat_thumb_mode(regs) &&
+ (insn & 0xfffffff7) == 0x0000b650)
+ return t16_setend_handler(regs, insn) == 0;
+
+ if (compat_user_mode(regs) &&
+ (insn & 0xfffffdff) == 0xf1010000)
+ return a32_setend_handler(regs, insn) == 0;
+
+ return false;
+}
static struct insn_emulation insn_setend = {
.name = "setend",
.status = INSN_DEPRECATED,
- .hooks = setend_hooks,
+ .try_emulate = try_emulate_setend,
.set_hw_mode = setend_set_hw_mode,
};
+#endif /* CONFIG_SETEND_EMULATION */
+
+static struct insn_emulation *insn_emulations[] = {
+#ifdef CONFIG_SWP_EMULATION
+ &insn_swp,
+#endif
+#ifdef CONFIG_CP15_BARRIER_EMULATION
+ &insn_cp15_barrier,
+#endif
+#ifdef CONFIG_SETEND_EMULATION
+ &insn_setend,
+#endif
+};
-static LIST_HEAD(insn_emulation);
-static int nr_insn_emulated __initdata;
-static DEFINE_RAW_SPINLOCK(insn_emulation_lock);
static DEFINE_MUTEX(insn_emulation_mutex);
-static void register_emulation_hooks(struct insn_emulation *insn)
-{
- struct undef_hook *hook;
-
- BUG_ON(!insn->hooks);
-
- for (hook = insn->hooks; hook->instr_mask; hook++)
- register_undef_hook(hook);
-
- pr_notice("Registered %s emulation handler\n", insn->name);
-}
-
-static void remove_emulation_hooks(struct insn_emulation *insn)
-{
- struct undef_hook *hook;
-
- BUG_ON(!insn->hooks);
-
- for (hook = insn->hooks; hook->instr_mask; hook++)
- unregister_undef_hook(hook);
-
- pr_notice("Removed %s emulation handler\n", insn->name);
-}
-
static void enable_insn_hw_mode(void *data)
{
struct insn_emulation *insn = (struct insn_emulation *)data;
{
int rc = 0;
unsigned long flags;
- struct insn_emulation *insn;
- raw_spin_lock_irqsave(&insn_emulation_lock, flags);
- list_for_each_entry(insn, &insn_emulation, node) {
- bool enable = (insn->current_mode == INSN_HW);
+ /*
+ * Disable IRQs to serialize against an IPI from
+ * run_all_cpu_set_hw_mode(), ensuring the HW is programmed to the most
+ * recent enablement state if the two race with one another.
+ */
+ local_irq_save(flags);
+ for (int i = 0; i < ARRAY_SIZE(insn_emulations); i++) {
+ struct insn_emulation *insn = insn_emulations[i];
+ bool enable = READ_ONCE(insn->current_mode) == INSN_HW;
if (insn->set_hw_mode && insn->set_hw_mode(enable)) {
pr_warn("CPU[%u] cannot support the emulation of %s",
cpu, insn->name);
rc = -EINVAL;
}
}
- raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
+ local_irq_restore(flags);
+
return rc;
}
case INSN_UNDEF: /* Nothing to be done */
break;
case INSN_EMULATE:
- remove_emulation_hooks(insn);
break;
case INSN_HW:
if (!run_all_cpu_set_hw_mode(insn, false))
case INSN_UNDEF:
break;
case INSN_EMULATE:
- register_emulation_hooks(insn);
break;
case INSN_HW:
ret = run_all_cpu_set_hw_mode(insn, true);
return ret;
}
-static void __init register_insn_emulation(struct insn_emulation *insn)
-{
- unsigned long flags;
-
- insn->min = INSN_UNDEF;
-
- switch (insn->status) {
- case INSN_DEPRECATED:
- insn->current_mode = INSN_EMULATE;
- /* Disable the HW mode if it was turned on at early boot time */
- run_all_cpu_set_hw_mode(insn, false);
- insn->max = INSN_HW;
- break;
- case INSN_OBSOLETE:
- insn->current_mode = INSN_UNDEF;
- insn->max = INSN_EMULATE;
- break;
- }
-
- raw_spin_lock_irqsave(&insn_emulation_lock, flags);
- list_add(&insn->node, &insn_emulation);
- nr_insn_emulated++;
- raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
-
- /* Register any handlers if required */
- update_insn_emulation_mode(insn, INSN_UNDEF);
-}
-
static int emulation_proc_handler(struct ctl_table *table, int write,
void *buffer, size_t *lenp,
loff_t *ppos)
ret = update_insn_emulation_mode(insn, prev_mode);
if (ret) {
/* Mode change failed, revert to previous mode. */
- insn->current_mode = prev_mode;
+ WRITE_ONCE(insn->current_mode, prev_mode);
update_insn_emulation_mode(insn, INSN_UNDEF);
}
ret:
return ret;
}
-static void __init register_insn_emulation_sysctl(void)
+static void __init register_insn_emulation(struct insn_emulation *insn)
{
- unsigned long flags;
- int i = 0;
- struct insn_emulation *insn;
- struct ctl_table *insns_sysctl, *sysctl;
+ struct ctl_table *sysctl;
- insns_sysctl = kcalloc(nr_insn_emulated + 1, sizeof(*sysctl),
- GFP_KERNEL);
- if (!insns_sysctl)
- return;
+ insn->min = INSN_UNDEF;
- raw_spin_lock_irqsave(&insn_emulation_lock, flags);
- list_for_each_entry(insn, &insn_emulation, node) {
- sysctl = &insns_sysctl[i];
+ switch (insn->status) {
+ case INSN_DEPRECATED:
+ insn->current_mode = INSN_EMULATE;
+ /* Disable the HW mode if it was turned on at early boot time */
+ run_all_cpu_set_hw_mode(insn, false);
+ insn->max = INSN_HW;
+ break;
+ case INSN_OBSOLETE:
+ insn->current_mode = INSN_UNDEF;
+ insn->max = INSN_EMULATE;
+ break;
+ case INSN_UNAVAILABLE:
+ insn->current_mode = INSN_UNDEF;
+ insn->max = INSN_UNDEF;
+ break;
+ }
+
+ /* Program the HW if required */
+ update_insn_emulation_mode(insn, INSN_UNDEF);
+
+ if (insn->status != INSN_UNAVAILABLE) {
+ sysctl = &insn->sysctl[0];
sysctl->mode = 0644;
sysctl->maxlen = sizeof(int);
sysctl->extra1 = &insn->min;
sysctl->extra2 = &insn->max;
sysctl->proc_handler = emulation_proc_handler;
- i++;
+
+ register_sysctl("abi", sysctl);
+ }
+}
+
+bool try_emulate_armv8_deprecated(struct pt_regs *regs, u32 insn)
+{
+ for (int i = 0; i < ARRAY_SIZE(insn_emulations); i++) {
+ struct insn_emulation *ie = insn_emulations[i];
+
+ if (ie->status == INSN_UNAVAILABLE)
+ continue;
+
+ /*
+ * A trap may race with the mode being changed
+ * INSN_EMULATE<->INSN_HW. Try to emulate the instruction to
+ * avoid a spurious UNDEF.
+ */
+ if (READ_ONCE(ie->current_mode) == INSN_UNDEF)
+ continue;
+
+ if (ie->try_emulate(regs, insn))
+ return true;
}
- raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
- register_sysctl("abi", insns_sysctl);
+ return false;
}
/*
*/
static int __init armv8_deprecated_init(void)
{
- if (IS_ENABLED(CONFIG_SWP_EMULATION))
- register_insn_emulation(&insn_swp);
+#ifdef CONFIG_SETEND_EMULATION
+ if (!system_supports_mixed_endian_el0()) {
+ insn_setend.status = INSN_UNAVAILABLE;
+ pr_info("setend instruction emulation is not supported on this system\n");
+ }
- if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION))
- register_insn_emulation(&insn_cp15_barrier);
+#endif
+ for (int i = 0; i < ARRAY_SIZE(insn_emulations); i++) {
+ struct insn_emulation *ie = insn_emulations[i];
- if (IS_ENABLED(CONFIG_SETEND_EMULATION)) {
- if (system_supports_mixed_endian_el0())
- register_insn_emulation(&insn_setend);
- else
- pr_info("setend instruction emulation is not supported on this system\n");
+ if (ie->status == INSN_UNAVAILABLE)
+ continue;
+
+ register_insn_emulation(ie);
}
cpuhp_setup_state_nocalls(CPUHP_AP_ARM64_ISNDEP_STARTING,
"arm64/isndep:starting",
run_all_insn_set_hw_mode, NULL);
- register_insn_emulation_sysctl();
-
return 0;
}
projects / users / hch / misc.git / commitdiff