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Diffstat (limited to 'arch/arm64/kernel/armv8_deprecated.c')
-rw-r--r--arch/arm64/kernel/armv8_deprecated.c662
1 files changed, 662 insertions, 0 deletions
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
new file mode 100644
index 000000000..7922c2e71
--- /dev/null
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -0,0 +1,662 @@
+/*
+ * Copyright (C) 2014 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpu.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/perf_event.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+
+#include <asm/insn.h>
+#include <asm/opcodes.h>
+#include <asm/system_misc.h>
+#include <asm/traps.h>
+#include <asm/uaccess.h>
+#include <asm/cpufeature.h>
+
+#define CREATE_TRACE_POINTS
+#include "trace-events-emulation.h"
+
+/*
+ * The runtime support for deprecated instruction support can be in one of
+ * following three states -
+ *
+ * 0 = undef
+ * 1 = emulate (software emulation)
+ * 2 = hw (supported in hardware)
+ */
+enum insn_emulation_mode {
+ INSN_UNDEF,
+ INSN_EMULATE,
+ INSN_HW,
+};
+
+enum legacy_insn_status {
+ INSN_DEPRECATED,
+ INSN_OBSOLETE,
+};
+
+struct insn_emulation_ops {
+ const char *name;
+ enum legacy_insn_status status;
+ struct undef_hook *hooks;
+ int (*set_hw_mode)(bool enable);
+};
+
+struct insn_emulation {
+ struct list_head node;
+ struct insn_emulation_ops *ops;
+ int current_mode;
+ int min;
+ int max;
+};
+
+static LIST_HEAD(insn_emulation);
+static int nr_insn_emulated;
+static DEFINE_RAW_SPINLOCK(insn_emulation_lock);
+
+static void register_emulation_hooks(struct insn_emulation_ops *ops)
+{
+ struct undef_hook *hook;
+
+ BUG_ON(!ops->hooks);
+
+ for (hook = ops->hooks; hook->instr_mask; hook++)
+ register_undef_hook(hook);
+
+ pr_notice("Registered %s emulation handler\n", ops->name);
+}
+
+static void remove_emulation_hooks(struct insn_emulation_ops *ops)
+{
+ struct undef_hook *hook;
+
+ BUG_ON(!ops->hooks);
+
+ for (hook = ops->hooks; hook->instr_mask; hook++)
+ unregister_undef_hook(hook);
+
+ pr_notice("Removed %s emulation handler\n", ops->name);
+}
+
+static void enable_insn_hw_mode(void *data)
+{
+ struct insn_emulation *insn = (struct insn_emulation *)data;
+ if (insn->ops->set_hw_mode)
+ insn->ops->set_hw_mode(true);
+}
+
+static void disable_insn_hw_mode(void *data)
+{
+ struct insn_emulation *insn = (struct insn_emulation *)data;
+ if (insn->ops->set_hw_mode)
+ insn->ops->set_hw_mode(false);
+}
+
+/* Run set_hw_mode(mode) on all active CPUs */
+static int run_all_cpu_set_hw_mode(struct insn_emulation *insn, bool enable)
+{
+ if (!insn->ops->set_hw_mode)
+ return -EINVAL;
+ if (enable)
+ on_each_cpu(enable_insn_hw_mode, (void *)insn, true);
+ else
+ on_each_cpu(disable_insn_hw_mode, (void *)insn, true);
+ return 0;
+}
+
+/*
+ * Run set_hw_mode for all insns on a starting CPU.
+ * Returns:
+ * 0 - If all the hooks ran successfully.
+ * -EINVAL - At least one hook is not supported by the CPU.
+ */
+static int run_all_insn_set_hw_mode(unsigned long cpu)
+{
+ 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);
+ if (insn->ops->set_hw_mode && insn->ops->set_hw_mode(enable)) {
+ pr_warn("CPU[%ld] cannot support the emulation of %s",
+ cpu, insn->ops->name);
+ rc = -EINVAL;
+ }
+ }
+ raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
+ return rc;
+}
+
+static int update_insn_emulation_mode(struct insn_emulation *insn,
+ enum insn_emulation_mode prev)
+{
+ int ret = 0;
+
+ switch (prev) {
+ case INSN_UNDEF: /* Nothing to be done */
+ break;
+ case INSN_EMULATE:
+ remove_emulation_hooks(insn->ops);
+ break;
+ case INSN_HW:
+ if (!run_all_cpu_set_hw_mode(insn, false))
+ pr_notice("Disabled %s support\n", insn->ops->name);
+ break;
+ }
+
+ switch (insn->current_mode) {
+ case INSN_UNDEF:
+ break;
+ case INSN_EMULATE:
+ register_emulation_hooks(insn->ops);
+ break;
+ case INSN_HW:
+ ret = run_all_cpu_set_hw_mode(insn, true);
+ if (!ret)
+ pr_notice("Enabled %s support\n", insn->ops->name);
+ break;
+ }
+
+ return ret;
+}
+
+static void register_insn_emulation(struct insn_emulation_ops *ops)
+{
+ unsigned long flags;
+ struct insn_emulation *insn;
+
+ insn = kzalloc(sizeof(*insn), GFP_KERNEL);
+ insn->ops = ops;
+ insn->min = INSN_UNDEF;
+
+ switch (ops->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 __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret = 0;
+ struct insn_emulation *insn = (struct insn_emulation *) table->data;
+ enum insn_emulation_mode prev_mode = insn->current_mode;
+
+ table->data = &insn->current_mode;
+ ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+
+ if (ret || !write || prev_mode == insn->current_mode)
+ goto ret;
+
+ ret = update_insn_emulation_mode(insn, prev_mode);
+ if (ret) {
+ /* Mode change failed, revert to previous mode. */
+ insn->current_mode = prev_mode;
+ update_insn_emulation_mode(insn, INSN_UNDEF);
+ }
+ret:
+ table->data = insn;
+ return ret;
+}
+
+static struct ctl_table ctl_abi[] = {
+ {
+ .procname = "abi",
+ .mode = 0555,
+ },
+ { }
+};
+
+static void register_insn_emulation_sysctl(struct ctl_table *table)
+{
+ unsigned long flags;
+ int i = 0;
+ struct insn_emulation *insn;
+ struct ctl_table *insns_sysctl, *sysctl;
+
+ insns_sysctl = kzalloc(sizeof(*sysctl) * (nr_insn_emulated + 1),
+ GFP_KERNEL);
+
+ raw_spin_lock_irqsave(&insn_emulation_lock, flags);
+ list_for_each_entry(insn, &insn_emulation, node) {
+ sysctl = &insns_sysctl[i];
+
+ sysctl->mode = 0644;
+ sysctl->maxlen = sizeof(int);
+
+ sysctl->procname = insn->ops->name;
+ sysctl->data = insn;
+ sysctl->extra1 = &insn->min;
+ sysctl->extra2 = &insn->max;
+ sysctl->proc_handler = emulation_proc_handler;
+ i++;
+ }
+ raw_spin_unlock_irqrestore(&insn_emulation_lock, flags);
+
+ table->child = insns_sysctl;
+ register_sysctl_table(table);
+}
+
+/*
+ * Implement emulation of the SWP/SWPB instructions using load-exclusive and
+ * store-exclusive.
+ *
+ * Syntax of SWP{B} instruction: SWP{B}<c> <Rt>, <Rt2>, [<Rn>]
+ * Where: Rt = destination
+ * Rt2 = source
+ * Rn = address
+ */
+
+/*
+ * Error-checking SWP macros implemented using ldxr{b}/stxr{b}
+ */
+#define __user_swpX_asm(data, addr, res, temp, B) \
+ __asm__ __volatile__( \
+ " mov %w2, %w1\n" \
+ "0: ldxr"B" %w1, [%3]\n" \
+ "1: stxr"B" %w0, %w2, [%3]\n" \
+ " cbz %w0, 2f\n" \
+ " mov %w0, %w4\n" \
+ "2:\n" \
+ " .pushsection .fixup,\"ax\"\n" \
+ " .align 2\n" \
+ "3: mov %w0, %w5\n" \
+ " b 2b\n" \
+ " .popsection" \
+ " .pushsection __ex_table,\"a\"\n" \
+ " .align 3\n" \
+ " .quad 0b, 3b\n" \
+ " .quad 1b, 3b\n" \
+ " .popsection" \
+ : "=&r" (res), "+r" (data), "=&r" (temp) \
+ : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \
+ : "memory")
+
+#define __user_swp_asm(data, addr, res, temp) \
+ __user_swpX_asm(data, addr, res, temp, "")
+#define __user_swpb_asm(data, addr, res, temp) \
+ __user_swpX_asm(data, addr, res, temp, "b")
+
+/*
+ * Bit 22 of the instruction encoding distinguishes between
+ * the SWP and SWPB variants (bit set means SWPB).
+ */
+#define TYPE_SWPB (1 << 22)
+
+/*
+ * Set up process info to signal segmentation fault - called on access error.
+ */
+static void set_segfault(struct pt_regs *regs, unsigned long addr)
+{
+ siginfo_t info;
+
+ down_read(&current->mm->mmap_sem);
+ if (find_vma(current->mm, addr) == NULL)
+ info.si_code = SEGV_MAPERR;
+ else
+ info.si_code = SEGV_ACCERR;
+ up_read(&current->mm->mmap_sem);
+
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ info.si_addr = (void *) instruction_pointer(regs);
+
+ pr_debug("SWP{B} emulation: access caused memory abort!\n");
+ arm64_notify_die("Illegal memory access", regs, &info, 0);
+}
+
+static int emulate_swpX(unsigned int address, unsigned int *data,
+ unsigned int type)
+{
+ unsigned int res = 0;
+
+ if ((type != TYPE_SWPB) && (address & 0x3)) {
+ /* SWP to unaligned address not permitted */
+ pr_debug("SWP instruction on unaligned pointer!\n");
+ return -EFAULT;
+ }
+
+ while (1) {
+ unsigned long temp;
+
+ if (type == TYPE_SWPB)
+ __user_swpb_asm(*data, address, res, temp);
+ else
+ __user_swp_asm(*data, address, res, temp);
+
+ if (likely(res != -EAGAIN) || signal_pending(current))
+ break;
+
+ cond_resched();
+ }
+
+ return res;
+}
+
+/*
+ * swp_handler logs the id of calling process, dissects the instruction, sanity
+ * checks the memory location, calls emulate_swpX for the actual operation and
+ * deals with fixup/error handling before returning
+ */
+static int swp_handler(struct pt_regs *regs, u32 instr)
+{
+ u32 destreg, data, type, address = 0;
+ int rn, rt2, res = 0;
+
+ perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
+
+ type = instr & TYPE_SWPB;
+
+ switch (arm_check_condition(instr, regs->pstate)) {
+ case ARM_OPCODE_CONDTEST_PASS:
+ break;
+ case ARM_OPCODE_CONDTEST_FAIL:
+ /* Condition failed - return to next instruction */
+ goto ret;
+ case ARM_OPCODE_CONDTEST_UNCOND:
+ /* If unconditional encoding - not a SWP, undef */
+ return -EFAULT;
+ default:
+ return -EINVAL;
+ }
+
+ rn = aarch32_insn_extract_reg_num(instr, A32_RN_OFFSET);
+ rt2 = aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET);
+
+ address = (u32)regs->user_regs.regs[rn];
+ data = (u32)regs->user_regs.regs[rt2];
+ destreg = aarch32_insn_extract_reg_num(instr, A32_RT_OFFSET);
+
+ pr_debug("addr in r%d->0x%08x, dest is r%d, source in r%d->0x%08x)\n",
+ rn, address, destreg,
+ aarch32_insn_extract_reg_num(instr, A32_RT2_OFFSET), data);
+
+ /* Check access in reasonable access range for both SWP and SWPB */
+ if (!access_ok(VERIFY_WRITE, (address & ~3), 4)) {
+ pr_debug("SWP{B} emulation: access to 0x%08x not allowed!\n",
+ address);
+ goto fault;
+ }
+
+ res = emulate_swpX(address, &data, type);
+ if (res == -EFAULT)
+ goto fault;
+ else if (res == 0)
+ regs->user_regs.regs[destreg] = data;
+
+ret:
+ if (type == TYPE_SWPB)
+ trace_instruction_emulation("swpb", regs->pc);
+ else
+ trace_instruction_emulation("swp", regs->pc);
+
+ pr_warn_ratelimited("\"%s\" (%ld) uses obsolete SWP{B} instruction at 0x%llx\n",
+ current->comm, (unsigned long)current->pid, regs->pc);
+
+ regs->pc += 4;
+ return 0;
+
+fault:
+ set_segfault(regs, address);
+
+ 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 = COMPAT_PSR_MODE_MASK,
+ .pstate_val = COMPAT_PSR_MODE_USR,
+ .fn = swp_handler
+ },
+ { }
+};
+
+static struct insn_emulation_ops swp_ops = {
+ .name = "swp",
+ .status = INSN_OBSOLETE,
+ .hooks = swp_hooks,
+ .set_hw_mode = NULL,
+};
+
+static int cp15barrier_handler(struct pt_regs *regs, u32 instr)
+{
+ perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
+
+ switch (arm_check_condition(instr, regs->pstate)) {
+ case ARM_OPCODE_CONDTEST_PASS:
+ break;
+ case ARM_OPCODE_CONDTEST_FAIL:
+ /* Condition failed - return to next instruction */
+ goto ret;
+ case ARM_OPCODE_CONDTEST_UNCOND:
+ /* If unconditional encoding - not a barrier instruction */
+ return -EFAULT;
+ default:
+ return -EINVAL;
+ }
+
+ switch (aarch32_insn_mcr_extract_crm(instr)) {
+ case 10:
+ /*
+ * dmb - mcr p15, 0, Rt, c7, c10, 5
+ * dsb - mcr p15, 0, Rt, c7, c10, 4
+ */
+ if (aarch32_insn_mcr_extract_opc2(instr) == 5) {
+ dmb(sy);
+ trace_instruction_emulation(
+ "mcr p15, 0, Rt, c7, c10, 5 ; dmb", regs->pc);
+ } else {
+ dsb(sy);
+ trace_instruction_emulation(
+ "mcr p15, 0, Rt, c7, c10, 4 ; dsb", regs->pc);
+ }
+ break;
+ case 5:
+ /*
+ * isb - mcr p15, 0, Rt, c7, c5, 4
+ *
+ * Taking an exception or returning from one acts as an
+ * instruction barrier. So no explicit barrier needed here.
+ */
+ trace_instruction_emulation(
+ "mcr p15, 0, Rt, c7, c5, 4 ; isb", regs->pc);
+ break;
+ }
+
+ret:
+ pr_warn_ratelimited("\"%s\" (%ld) uses deprecated CP15 Barrier instruction at 0x%llx\n",
+ current->comm, (unsigned long)current->pid, regs->pc);
+
+ regs->pc += 4;
+ return 0;
+}
+
+static inline void config_sctlr_el1(u32 clear, u32 set)
+{
+ u32 val;
+
+ asm volatile("mrs %0, sctlr_el1" : "=r" (val));
+ val &= ~clear;
+ val |= set;
+ asm volatile("msr sctlr_el1, %0" : : "r" (val));
+}
+
+static int cp15_barrier_set_hw_mode(bool enable)
+{
+ if (enable)
+ config_sctlr_el1(0, SCTLR_EL1_CP15BEN);
+ else
+ config_sctlr_el1(SCTLR_EL1_CP15BEN, 0);
+ return 0;
+}
+
+static struct undef_hook cp15_barrier_hooks[] = {
+ {
+ .instr_mask = 0x0fff0fdf,
+ .instr_val = 0x0e070f9a,
+ .pstate_mask = COMPAT_PSR_MODE_MASK,
+ .pstate_val = COMPAT_PSR_MODE_USR,
+ .fn = cp15barrier_handler,
+ },
+ {
+ .instr_mask = 0x0fff0fff,
+ .instr_val = 0x0e070f95,
+ .pstate_mask = COMPAT_PSR_MODE_MASK,
+ .pstate_val = COMPAT_PSR_MODE_USR,
+ .fn = cp15barrier_handler,
+ },
+ { }
+};
+
+static struct insn_emulation_ops cp15_barrier_ops = {
+ .name = "cp15_barrier",
+ .status = INSN_DEPRECATED,
+ .hooks = cp15_barrier_hooks,
+ .set_hw_mode = cp15_barrier_set_hw_mode,
+};
+
+static int setend_set_hw_mode(bool enable)
+{
+ if (!cpu_supports_mixed_endian_el0())
+ return -EINVAL;
+
+ if (enable)
+ config_sctlr_el1(SCTLR_EL1_SED, 0);
+ else
+ config_sctlr_el1(0, SCTLR_EL1_SED);
+ return 0;
+}
+
+static int compat_setend_handler(struct pt_regs *regs, u32 big_endian)
+{
+ char *insn;
+
+ perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, regs->pc);
+
+ if (big_endian) {
+ insn = "setend be";
+ regs->pstate |= COMPAT_PSR_E_BIT;
+ } else {
+ insn = "setend le";
+ regs->pstate &= ~COMPAT_PSR_E_BIT;
+ }
+
+ trace_instruction_emulation(insn, regs->pc);
+ pr_warn_ratelimited("\"%s\" (%ld) uses deprecated setend instruction at 0x%llx\n",
+ current->comm, (unsigned long)current->pid, regs->pc);
+
+ return 0;
+}
+
+static int a32_setend_handler(struct pt_regs *regs, u32 instr)
+{
+ int rc = compat_setend_handler(regs, (instr >> 9) & 1);
+ regs->pc += 4;
+ return rc;
+}
+
+static int t16_setend_handler(struct pt_regs *regs, u32 instr)
+{
+ int rc = compat_setend_handler(regs, (instr >> 3) & 1);
+ regs->pc += 2;
+ return rc;
+}
+
+static struct undef_hook setend_hooks[] = {
+ {
+ .instr_mask = 0xfffffdff,
+ .instr_val = 0xf1010000,
+ .pstate_mask = COMPAT_PSR_MODE_MASK,
+ .pstate_val = COMPAT_PSR_MODE_USR,
+ .fn = a32_setend_handler,
+ },
+ {
+ /* Thumb mode */
+ .instr_mask = 0x0000fff7,
+ .instr_val = 0x0000b650,
+ .pstate_mask = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_MASK),
+ .pstate_val = (COMPAT_PSR_T_BIT | COMPAT_PSR_MODE_USR),
+ .fn = t16_setend_handler,
+ },
+ {}
+};
+
+static struct insn_emulation_ops setend_ops = {
+ .name = "setend",
+ .status = INSN_DEPRECATED,
+ .hooks = setend_hooks,
+ .set_hw_mode = setend_set_hw_mode,
+};
+
+static int insn_cpu_hotplug_notify(struct notifier_block *b,
+ unsigned long action, void *hcpu)
+{
+ int rc = 0;
+ if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)
+ rc = run_all_insn_set_hw_mode((unsigned long)hcpu);
+
+ return notifier_from_errno(rc);
+}
+
+static struct notifier_block insn_cpu_hotplug_notifier = {
+ .notifier_call = insn_cpu_hotplug_notify,
+};
+
+/*
+ * Invoked as late_initcall, since not needed before init spawned.
+ */
+static int __init armv8_deprecated_init(void)
+{
+ if (IS_ENABLED(CONFIG_SWP_EMULATION))
+ register_insn_emulation(&swp_ops);
+
+ if (IS_ENABLED(CONFIG_CP15_BARRIER_EMULATION))
+ register_insn_emulation(&cp15_barrier_ops);
+
+ if (IS_ENABLED(CONFIG_SETEND_EMULATION)) {
+ if(system_supports_mixed_endian_el0())
+ register_insn_emulation(&setend_ops);
+ else
+ pr_info("setend instruction emulation is not supported on the system");
+ }
+
+ register_cpu_notifier(&insn_cpu_hotplug_notifier);
+ register_insn_emulation_sysctl(ctl_abi);
+
+ return 0;
+}
+
+late_initcall(armv8_deprecated_init);
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-18 23:55:16 +0000