Quelle  security.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
//
// Security related flags and so on.
//
// Copyright 2018, Michael Ellerman, IBM Corporation.

#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/memblock.h>
#include <linux/nospec.h>
#include <linux/prctl.h>
#include <linux/seq_buf.h>
#include <linux/debugfs.h>

#include <asm/asm-prototypes.h>
#include <asm/text-patching.h>
#include <asm/security_features.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/inst.h>

#include "setup.h"

u64 powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;

enum branch_cache_flush_type {
 BRANCH_CACHE_FLUSH_NONE = 0x1,
 BRANCH_CACHE_FLUSH_SW = 0x2,
 BRANCH_CACHE_FLUSH_HW = 0x4,
};
static enum branch_cache_flush_type count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;
static enum branch_cache_flush_type link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;

bool barrier_nospec_enabled;
static bool no_nospec;
static bool btb_flush_enabled;
#if defined(CONFIG_PPC_E500) || defined(CONFIG_PPC_BOOK3S_64)
static bool no_spectrev2;
#endif

static void enable_barrier_nospec(bool enable)
{
 barrier_nospec_enabled = enable;
 do_barrier_nospec_fixups(enable);
}

void __init setup_barrier_nospec(void)
{
 bool enable;

 /*
 * It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well.
 * But there's a good reason not to. The two flags we check below are
 * both are enabled by default in the kernel, so if the hcall is not
 * functional they will be enabled.
 * On a system where the host firmware has been updated (so the ori
 * functions as a barrier), but on which the hypervisor (KVM/Qemu) has
 * not been updated, we would like to enable the barrier. Dropping the
 * check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is
 * we potentially enable the barrier on systems where the host firmware
 * is not updated, but that's harmless as it's a no-op.
 */
 enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
   security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);

 if (!no_nospec && !cpu_mitigations_off())
  enable_barrier_nospec(enable);
}

static int __init handle_nospectre_v1(char *p)
{
 no_nospec = true;

 return 0;
}
early_param("nospectre_v1", handle_nospectre_v1);

#ifdef CONFIG_DEBUG_FS
static int barrier_nospec_set(void *data, u64 val)
{
 switch (val) {
 case 0:
 case 1:
  break;
 default:
  return -EINVAL;
 }

 if (!!val == !!barrier_nospec_enabled)
  return 0;

 enable_barrier_nospec(!!val);

 return 0;
}

static int barrier_nospec_get(void *data, u64 *val)
{
 *val = barrier_nospec_enabled ? 1 : 0;
 return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(fops_barrier_nospec, barrier_nospec_get,
    barrier_nospec_set, "%llu\n");

static __init int barrier_nospec_debugfs_init(void)
{
 debugfs_create_file_unsafe("barrier_nospec", 0600,
       arch_debugfs_dir, NULL,
       &fops_barrier_nospec);
 return 0;
}
device_initcall(barrier_nospec_debugfs_init);

static __init int security_feature_debugfs_init(void)
{
 debugfs_create_x64("security_features", 0400, arch_debugfs_dir,
      &powerpc_security_features);
 return 0;
}
device_initcall(security_feature_debugfs_init);
#endif /* CONFIG_DEBUG_FS */

#if defined(CONFIG_PPC_E500) || defined(CONFIG_PPC_BOOK3S_64)
static int __init handle_nospectre_v2(char *p)
{
 no_spectrev2 = true;

 return 0;
}
early_param("nospectre_v2", handle_nospectre_v2);
#endif /* CONFIG_PPC_E500 || CONFIG_PPC_BOOK3S_64 */

#ifdef CONFIG_PPC_E500
void __init setup_spectre_v2(void)
{
 if (no_spectrev2 || cpu_mitigations_off())
  do_btb_flush_fixups();
 else
  btb_flush_enabled = true;
}
#endif /* CONFIG_PPC_E500 */

#ifdef CONFIG_PPC_BOOK3S_64
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
{
 bool thread_priv;

 thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);

 if (rfi_flush) {
  struct seq_buf s;
  seq_buf_init(&s, buf, PAGE_SIZE - 1);

  seq_buf_printf(&s, "Mitigation: RFI Flush");
  if (thread_priv)
   seq_buf_printf(&s, ", L1D private per thread");

  seq_buf_printf(&s, "\n");

  return s.len;
 }

 if (thread_priv)
  return sprintf(buf, "Vulnerable: L1D private per thread\n");

 if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
     !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
  return sprintf(buf, "Not affected\n");

 return sprintf(buf, "Vulnerable\n");
}

ssize_t cpu_show_l1tf(struct device *dev, struct device_attribute *attr, char *buf)
{
 return cpu_show_meltdown(dev, attr, buf);
}
#endif

ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
{
 struct seq_buf s;

 seq_buf_init(&s, buf, PAGE_SIZE - 1);

 if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
  if (barrier_nospec_enabled)
   seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
  else
   seq_buf_printf(&s, "Vulnerable");

  if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
   seq_buf_printf(&s, ", ori31 speculation barrier enabled");

  seq_buf_printf(&s, "\n");
 } else
  seq_buf_printf(&s, "Not affected\n");

 return s.len;
}

ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
{
 struct seq_buf s;
 bool bcs, ccd;

 seq_buf_init(&s, buf, PAGE_SIZE - 1);

 bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
 ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);

 if (bcs || ccd) {
  seq_buf_printf(&s, "Mitigation: ");

  if (bcs)
   seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");

  if (bcs && ccd)
   seq_buf_printf(&s, ", ");

  if (ccd)
   seq_buf_printf(&s, "Indirect branch cache disabled");

 } else if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
  seq_buf_printf(&s, "Mitigation: Software count cache flush");

  if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW)
   seq_buf_printf(&s, " (hardware accelerated)");

 } else if (btb_flush_enabled) {
  seq_buf_printf(&s, "Mitigation: Branch predictor state flush");
 } else {
  seq_buf_printf(&s, "Vulnerable");
 }

 if (bcs || ccd || count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE) {
  if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
   seq_buf_printf(&s, ", Software link stack flush");
  if (link_stack_flush_type == BRANCH_CACHE_FLUSH_HW)
   seq_buf_printf(&s, " (hardware accelerated)");
 }

 seq_buf_printf(&s, "\n");

 return s.len;
}

#ifdef CONFIG_PPC_BOOK3S_64
/*
 * Store-forwarding barrier support.
 */

static enum stf_barrier_type stf_enabled_flush_types;
static bool no_stf_barrier;
static bool stf_barrier;

static int __init handle_no_stf_barrier(char *p)
{
 pr_info("stf-barrier: disabled on command line.");
 no_stf_barrier = true;
 return 0;
}

early_param("no_stf_barrier", handle_no_stf_barrier);

enum stf_barrier_type stf_barrier_type_get(void)
{
 return stf_enabled_flush_types;
}

/* This is the generic flag used by other architectures */
static int __init handle_ssbd(char *p)
{
 if (!p || strncmp(p, "auto", 5) == 0 || strncmp(p, "on", 2) == 0 ) {
  /* Until firmware tells us, we have the barrier with auto */
  return 0;
 } else if (strncmp(p, "off", 3) == 0) {
  handle_no_stf_barrier(NULL);
  return 0;
 } else
  return 1;

 return 0;
}
early_param("spec_store_bypass_disable", handle_ssbd);

/* This is the generic flag used by other architectures */
static int __init handle_no_ssbd(char *p)
{
 handle_no_stf_barrier(NULL);
 return 0;
}
early_param("nospec_store_bypass_disable", handle_no_ssbd);

static void stf_barrier_enable(bool enable)
{
 if (enable)
  do_stf_barrier_fixups(stf_enabled_flush_types);
 else
  do_stf_barrier_fixups(STF_BARRIER_NONE);

 stf_barrier = enable;
}

void setup_stf_barrier(void)
{
 enum stf_barrier_type type;
 bool enable;

 /* Default to fallback in case fw-features are not available */
 if (cpu_has_feature(CPU_FTR_ARCH_300))
  type = STF_BARRIER_EIEIO;
 else if (cpu_has_feature(CPU_FTR_ARCH_207S))
  type = STF_BARRIER_SYNC_ORI;
 else if (cpu_has_feature(CPU_FTR_ARCH_206))
  type = STF_BARRIER_FALLBACK;
 else
  type = STF_BARRIER_NONE;

 enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
   security_ftr_enabled(SEC_FTR_STF_BARRIER);

 if (type == STF_BARRIER_FALLBACK) {
  pr_info("stf-barrier: fallback barrier available\n");
 } else if (type == STF_BARRIER_SYNC_ORI) {
  pr_info("stf-barrier: hwsync barrier available\n");
 } else if (type == STF_BARRIER_EIEIO) {
  pr_info("stf-barrier: eieio barrier available\n");
 }

 stf_enabled_flush_types = type;

 if (!no_stf_barrier && !cpu_mitigations_off())
  stf_barrier_enable(enable);
}

ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
{
 if (stf_barrier && stf_enabled_flush_types != STF_BARRIER_NONE) {
  const char *type;
  switch (stf_enabled_flush_types) {
  case STF_BARRIER_EIEIO:
   type = "eieio";
   break;
  case STF_BARRIER_SYNC_ORI:
   type = "hwsync";
   break;
  case STF_BARRIER_FALLBACK:
   type = "fallback";
   break;
  default:
   type = "unknown";
  }
  return sprintf(buf, "Mitigation: Kernel entry/exit barrier (%s)\n", type);
 }

 if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
     !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
  return sprintf(buf, "Not affected\n");

 return sprintf(buf, "Vulnerable\n");
}

static int ssb_prctl_get(struct task_struct *task)
{
 /*
 * The STF_BARRIER feature is on by default, so if it's off that means
 * firmware has explicitly said the CPU is not vulnerable via either
 * the hypercall or device tree.
 */
 if (!security_ftr_enabled(SEC_FTR_STF_BARRIER))
  return PR_SPEC_NOT_AFFECTED;

 /*
 * If the system's CPU has no known barrier (see setup_stf_barrier())
 * then assume that the CPU is not vulnerable.
 */
 if (stf_enabled_flush_types == STF_BARRIER_NONE)
  return PR_SPEC_NOT_AFFECTED;

 /*
 * Otherwise the CPU is vulnerable. The barrier is not a global or
 * per-process mitigation, so the only value that can be reported here
 * is PR_SPEC_ENABLE, which appears as "vulnerable" in /proc.
 */
 return PR_SPEC_ENABLE;
}

int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which)
{
 switch (which) {
 case PR_SPEC_STORE_BYPASS:
  return ssb_prctl_get(task);
 default:
  return -ENODEV;
 }
}

#ifdef CONFIG_DEBUG_FS
static int stf_barrier_set(void *data, u64 val)
{
 bool enable;

 if (val == 1)
  enable = true;
 else if (val == 0)
  enable = false;
 else
  return -EINVAL;

 /* Only do anything if we're changing state */
 if (enable != stf_barrier)
  stf_barrier_enable(enable);

 return 0;
}

static int stf_barrier_get(void *data, u64 *val)
{
 *val = stf_barrier ? 1 : 0;
 return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set,
    "%llu\n");

static __init int stf_barrier_debugfs_init(void)
{
 debugfs_create_file_unsafe("stf_barrier", 0600, arch_debugfs_dir,
       NULL, &fops_stf_barrier);
 return 0;
}
device_initcall(stf_barrier_debugfs_init);
#endif /* CONFIG_DEBUG_FS */

static void update_branch_cache_flush(void)
{
 u32 *site, __maybe_unused *site2;

#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 site = &patch__call_kvm_flush_link_stack;
 site2 = &patch__call_kvm_flush_link_stack_p9;
 // This controls the branch from guest_exit_cont to kvm_flush_link_stack
 if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
  patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
  patch_instruction_site(site2, ppc_inst(PPC_RAW_NOP()));
 } else {
  // Could use HW flush, but that could also flush count cache
  patch_branch_site(site, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
  patch_branch_site(site2, (u64)&kvm_flush_link_stack, BRANCH_SET_LINK);
 }
#endif

 // Patch out the bcctr first, then nop the rest
 site = &patch__call_flush_branch_caches3;
 patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
 site = &patch__call_flush_branch_caches2;
 patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));
 site = &patch__call_flush_branch_caches1;
 patch_instruction_site(site, ppc_inst(PPC_RAW_NOP()));

 // This controls the branch from _switch to flush_branch_caches
 if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE &&
     link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE) {
  // Nothing to be done

 } else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW &&
     link_stack_flush_type == BRANCH_CACHE_FLUSH_HW) {
  // Patch in the bcctr last
  site = &patch__call_flush_branch_caches1;
  patch_instruction_site(site, ppc_inst(0x39207fff)); // li r9,0x7fff
  site = &patch__call_flush_branch_caches2;
  patch_instruction_site(site, ppc_inst(0x7d2903a6)); // mtctr r9
  site = &patch__call_flush_branch_caches3;
  patch_instruction_site(site, ppc_inst(PPC_INST_BCCTR_FLUSH));

 } else {
  patch_branch_site(site, (u64)&flush_branch_caches, BRANCH_SET_LINK);

  // If we just need to flush the link stack, early return
  if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE) {
   patch_instruction_site(&patch__flush_link_stack_return,
            ppc_inst(PPC_RAW_BLR()));

  // If we have flush instruction, early return
  } else if (count_cache_flush_type == BRANCH_CACHE_FLUSH_HW) {
   patch_instruction_site(&patch__flush_count_cache_return,
            ppc_inst(PPC_RAW_BLR()));
  }
 }
}

static void toggle_branch_cache_flush(bool enable)
{
 if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
  if (count_cache_flush_type != BRANCH_CACHE_FLUSH_NONE)
   count_cache_flush_type = BRANCH_CACHE_FLUSH_NONE;

  pr_info("count-cache-flush: flush disabled.\n");
 } else {
  if (security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
   count_cache_flush_type = BRANCH_CACHE_FLUSH_HW;
   pr_info("count-cache-flush: hardware flush enabled.\n");
  } else {
   count_cache_flush_type = BRANCH_CACHE_FLUSH_SW;
   pr_info("count-cache-flush: software flush enabled.\n");
  }
 }

 if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_LINK_STACK)) {
  if (link_stack_flush_type != BRANCH_CACHE_FLUSH_NONE)
   link_stack_flush_type = BRANCH_CACHE_FLUSH_NONE;

  pr_info("link-stack-flush: flush disabled.\n");
 } else {
  if (security_ftr_enabled(SEC_FTR_BCCTR_LINK_FLUSH_ASSIST)) {
   link_stack_flush_type = BRANCH_CACHE_FLUSH_HW;
   pr_info("link-stack-flush: hardware flush enabled.\n");
  } else {
   link_stack_flush_type = BRANCH_CACHE_FLUSH_SW;
   pr_info("link-stack-flush: software flush enabled.\n");
  }
 }

 update_branch_cache_flush();
}

void setup_count_cache_flush(void)
{
 bool enable = true;

 if (no_spectrev2 || cpu_mitigations_off()) {
  if (security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED) ||
      security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED))
   pr_warn("Spectre v2 mitigations not fully under software control, can't disable\n");

  enable = false;
 }

 /*
 * There's no firmware feature flag/hypervisor bit to tell us we need to
 * flush the link stack on context switch. So we set it here if we see
 * either of the Spectre v2 mitigations that aim to protect userspace.
 */
 if (security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED) ||
     security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE))
  security_ftr_set(SEC_FTR_FLUSH_LINK_STACK);

 toggle_branch_cache_flush(enable);
}

static enum l1d_flush_type enabled_flush_types;
static void *l1d_flush_fallback_area;
static bool no_rfi_flush;
static bool no_entry_flush;
static bool no_uaccess_flush;
bool rfi_flush;
static bool entry_flush;
static bool uaccess_flush;
DEFINE_STATIC_KEY_FALSE(uaccess_flush_key);
EXPORT_SYMBOL(uaccess_flush_key);

static int __init handle_no_rfi_flush(char *p)
{
 pr_info("rfi-flush: disabled on command line.");
 no_rfi_flush = true;
 return 0;
}
early_param("no_rfi_flush", handle_no_rfi_flush);

static int __init handle_no_entry_flush(char *p)
{
 pr_info("entry-flush: disabled on command line.");
 no_entry_flush = true;
 return 0;
}
early_param("no_entry_flush", handle_no_entry_flush);

static int __init handle_no_uaccess_flush(char *p)
{
 pr_info("uaccess-flush: disabled on command line.");
 no_uaccess_flush = true;
 return 0;
}
early_param("no_uaccess_flush", handle_no_uaccess_flush);

/*
 * The RFI flush is not KPTI, but because users will see doco that says to use
 * nopti we hijack that option here to also disable the RFI flush.
 */
static int __init handle_no_pti(char *p)
{
 pr_info("rfi-flush: disabling due to 'nopti' on command line.\n");
 handle_no_rfi_flush(NULL);
 return 0;
}
early_param("nopti", handle_no_pti);

static void do_nothing(void *unused)
{
 /*
 * We don't need to do the flush explicitly, just enter+exit kernel is
 * sufficient, the RFI exit handlers will do the right thing.
 */
}

void rfi_flush_enable(bool enable)
{
 if (enable) {
  do_rfi_flush_fixups(enabled_flush_types);
  on_each_cpu(do_nothing, NULL, 1);
 } else
  do_rfi_flush_fixups(L1D_FLUSH_NONE);

 rfi_flush = enable;
}

static void entry_flush_enable(bool enable)
{
 if (enable) {
  do_entry_flush_fixups(enabled_flush_types);
  on_each_cpu(do_nothing, NULL, 1);
 } else {
  do_entry_flush_fixups(L1D_FLUSH_NONE);
 }

 entry_flush = enable;
}

static void uaccess_flush_enable(bool enable)
{
 if (enable) {
  do_uaccess_flush_fixups(enabled_flush_types);
  static_branch_enable(&uaccess_flush_key);
  on_each_cpu(do_nothing, NULL, 1);
 } else {
  static_branch_disable(&uaccess_flush_key);
  do_uaccess_flush_fixups(L1D_FLUSH_NONE);
 }

 uaccess_flush = enable;
}

static void __ref init_fallback_flush(void)
{
 u64 l1d_size, limit;
 int cpu;

 /* Only allocate the fallback flush area once (at boot time). */
 if (l1d_flush_fallback_area)
  return;

 l1d_size = ppc64_caches.l1d.size;

 /*
 * If there is no d-cache-size property in the device tree, l1d_size
 * could be zero. That leads to the loop in the asm wrapping around to
 * 2^64-1, and then walking off the end of the fallback area and
 * eventually causing a page fault which is fatal. Just default to
 * something vaguely sane.
 */
 if (!l1d_size)
  l1d_size = (64 * 1024);

 limit = min(ppc64_bolted_size(), ppc64_rma_size);

 /*
 * Align to L1d size, and size it at 2x L1d size, to catch possible
 * hardware prefetch runoff. We don't have a recipe for load patterns to
 * reliably avoid the prefetcher.
 */
 l1d_flush_fallback_area = memblock_alloc_try_nid(l1d_size * 2,
      l1d_size, MEMBLOCK_LOW_LIMIT,
      limit, NUMA_NO_NODE);
 if (!l1d_flush_fallback_area)
  panic("%s: Failed to allocate %llu bytes align=0x%llx max_addr=%pa\n",
        __func__, l1d_size * 2, l1d_size, &limit);


 for_each_possible_cpu(cpu) {
  struct paca_struct *paca = paca_ptrs[cpu];
  paca->rfi_flush_fallback_area = l1d_flush_fallback_area;
  paca->l1d_flush_size = l1d_size;
 }
}

void setup_rfi_flush(enum l1d_flush_type types, bool enable)
{
 if (types & L1D_FLUSH_FALLBACK) {
  pr_info("rfi-flush: fallback displacement flush available\n");
  init_fallback_flush();
 }

 if (types & L1D_FLUSH_ORI)
  pr_info("rfi-flush: ori type flush available\n");

 if (types & L1D_FLUSH_MTTRIG)
  pr_info("rfi-flush: mttrig type flush available\n");

 enabled_flush_types = types;

 if (!cpu_mitigations_off() && !no_rfi_flush)
  rfi_flush_enable(enable);
}

void setup_entry_flush(bool enable)
{
 if (cpu_mitigations_off())
  return;

 if (!no_entry_flush)
  entry_flush_enable(enable);
}

void setup_uaccess_flush(bool enable)
{
 if (cpu_mitigations_off())
  return;

 if (!no_uaccess_flush)
  uaccess_flush_enable(enable);
}

#ifdef CONFIG_DEBUG_FS
static int count_cache_flush_set(void *data, u64 val)
{
 bool enable;

 if (val == 1)
  enable = true;
 else if (val == 0)
  enable = false;
 else
  return -EINVAL;

 toggle_branch_cache_flush(enable);

 return 0;
}

static int count_cache_flush_get(void *data, u64 *val)
{
 if (count_cache_flush_type == BRANCH_CACHE_FLUSH_NONE)
  *val = 0;
 else
  *val = 1;

 return 0;
}

static int link_stack_flush_get(void *data, u64 *val)
{
 if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE)
  *val = 0;
 else
  *val = 1;

 return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
    count_cache_flush_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_link_stack_flush, link_stack_flush_get,
    count_cache_flush_set, "%llu\n");

static __init int count_cache_flush_debugfs_init(void)
{
 debugfs_create_file_unsafe("count_cache_flush", 0600,
       arch_debugfs_dir, NULL,
       &fops_count_cache_flush);
 debugfs_create_file_unsafe("link_stack_flush", 0600,
       arch_debugfs_dir, NULL,
       &fops_link_stack_flush);
 return 0;
}
device_initcall(count_cache_flush_debugfs_init);

static int rfi_flush_set(void *data, u64 val)
{
 bool enable;

 if (val == 1)
  enable = true;
 else if (val == 0)
  enable = false;
 else
  return -EINVAL;

 /* Only do anything if we're changing state */
 if (enable != rfi_flush)
  rfi_flush_enable(enable);

 return 0;
}

static int rfi_flush_get(void *data, u64 *val)
{
 *val = rfi_flush ? 1 : 0;
 return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_rfi_flush, rfi_flush_get, rfi_flush_set, "%llu\n");

static int entry_flush_set(void *data, u64 val)
{
 bool enable;

 if (val == 1)
  enable = true;
 else if (val == 0)
  enable = false;
 else
  return -EINVAL;

 /* Only do anything if we're changing state */
 if (enable != entry_flush)
  entry_flush_enable(enable);

 return 0;
}

static int entry_flush_get(void *data, u64 *val)
{
 *val = entry_flush ? 1 : 0;
 return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_entry_flush, entry_flush_get, entry_flush_set, "%llu\n");

static int uaccess_flush_set(void *data, u64 val)
{
 bool enable;

 if (val == 1)
  enable = true;
 else if (val == 0)
  enable = false;
 else
  return -EINVAL;

 /* Only do anything if we're changing state */
 if (enable != uaccess_flush)
  uaccess_flush_enable(enable);

 return 0;
}

static int uaccess_flush_get(void *data, u64 *val)
{
 *val = uaccess_flush ? 1 : 0;
 return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(fops_uaccess_flush, uaccess_flush_get, uaccess_flush_set, "%llu\n");

static __init int rfi_flush_debugfs_init(void)
{
 debugfs_create_file("rfi_flush", 0600, arch_debugfs_dir, NULL, &fops_rfi_flush);
 debugfs_create_file("entry_flush", 0600, arch_debugfs_dir, NULL, &fops_entry_flush);
 debugfs_create_file("uaccess_flush", 0600, arch_debugfs_dir, NULL, &fops_uaccess_flush);
 return 0;
}
device_initcall(rfi_flush_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
#endif /* CONFIG_PPC_BOOK3S_64 */