443 lines
10 KiB
C
443 lines
10 KiB
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/seq_buf.h>
|
|
|
|
#include <asm/asm-prototypes.h>
|
|
#include <asm/code-patching.h>
|
|
#include <asm/debugfs.h>
|
|
#include <asm/security_features.h>
|
|
#include <asm/setup.h>
|
|
|
|
|
|
unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
|
|
|
|
enum count_cache_flush_type {
|
|
COUNT_CACHE_FLUSH_NONE = 0x1,
|
|
COUNT_CACHE_FLUSH_SW = 0x2,
|
|
COUNT_CACHE_FLUSH_HW = 0x4,
|
|
};
|
|
static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
|
|
|
|
bool barrier_nospec_enabled;
|
|
static bool no_nospec;
|
|
static bool btb_flush_enabled;
|
|
#ifdef CONFIG_PPC_FSL_BOOK3E
|
|
static bool no_spectrev2;
|
|
#endif
|
|
|
|
static void enable_barrier_nospec(bool enable)
|
|
{
|
|
barrier_nospec_enabled = enable;
|
|
do_barrier_nospec_fixups(enable);
|
|
}
|
|
|
|
void 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)
|
|
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_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
|
|
barrier_nospec_get, barrier_nospec_set, "%llu\n");
|
|
|
|
static __init int barrier_nospec_debugfs_init(void)
|
|
{
|
|
debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
|
|
&fops_barrier_nospec);
|
|
return 0;
|
|
}
|
|
device_initcall(barrier_nospec_debugfs_init);
|
|
#endif /* CONFIG_DEBUG_FS */
|
|
|
|
#ifdef CONFIG_PPC_FSL_BOOK3E
|
|
static int __init handle_nospectre_v2(char *p)
|
|
{
|
|
no_spectrev2 = true;
|
|
|
|
return 0;
|
|
}
|
|
early_param("nospectre_v2", handle_nospectre_v2);
|
|
void setup_spectre_v2(void)
|
|
{
|
|
if (no_spectrev2)
|
|
do_btb_flush_fixups();
|
|
else
|
|
btb_flush_enabled = true;
|
|
}
|
|
#endif /* CONFIG_PPC_FSL_BOOK3E */
|
|
|
|
#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 || thread_priv) {
|
|
struct seq_buf s;
|
|
seq_buf_init(&s, buf, PAGE_SIZE - 1);
|
|
|
|
seq_buf_printf(&s, "Mitigation: ");
|
|
|
|
if (rfi_flush)
|
|
seq_buf_printf(&s, "RFI Flush");
|
|
|
|
if (rfi_flush && thread_priv)
|
|
seq_buf_printf(&s, ", ");
|
|
|
|
if (thread_priv)
|
|
seq_buf_printf(&s, "L1D private per thread");
|
|
|
|
seq_buf_printf(&s, "\n");
|
|
|
|
return s.len;
|
|
}
|
|
|
|
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");
|
|
}
|
|
#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 || count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
|
|
bool comma = false;
|
|
seq_buf_printf(&s, "Mitigation: ");
|
|
|
|
if (bcs) {
|
|
seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
|
|
comma = true;
|
|
}
|
|
|
|
if (ccd) {
|
|
if (comma)
|
|
seq_buf_printf(&s, ", ");
|
|
seq_buf_printf(&s, "Indirect branch cache disabled");
|
|
comma = true;
|
|
}
|
|
|
|
if (comma)
|
|
seq_buf_printf(&s, ", ");
|
|
|
|
seq_buf_printf(&s, "Software count cache flush");
|
|
|
|
if (count_cache_flush_type == COUNT_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");
|
|
}
|
|
|
|
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;
|
|
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);
|
|
|
|
/* 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, hv;
|
|
|
|
hv = cpu_has_feature(CPU_FTR_HVMODE);
|
|
|
|
/* 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_L1D_FLUSH_PR) ||
|
|
(security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) && hv));
|
|
|
|
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)
|
|
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");
|
|
}
|
|
|
|
#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_SIMPLE_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set, "%llu\n");
|
|
|
|
static __init int stf_barrier_debugfs_init(void)
|
|
{
|
|
debugfs_create_file("stf_barrier", 0600, powerpc_debugfs_root, NULL, &fops_stf_barrier);
|
|
return 0;
|
|
}
|
|
device_initcall(stf_barrier_debugfs_init);
|
|
#endif /* CONFIG_DEBUG_FS */
|
|
|
|
static void toggle_count_cache_flush(bool enable)
|
|
{
|
|
if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
|
|
patch_instruction_site(&patch__call_flush_count_cache, PPC_INST_NOP);
|
|
count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
|
|
pr_info("count-cache-flush: software flush disabled.\n");
|
|
return;
|
|
}
|
|
|
|
patch_branch_site(&patch__call_flush_count_cache,
|
|
(u64)&flush_count_cache, BRANCH_SET_LINK);
|
|
|
|
if (!security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
|
|
count_cache_flush_type = COUNT_CACHE_FLUSH_SW;
|
|
pr_info("count-cache-flush: full software flush sequence enabled.\n");
|
|
return;
|
|
}
|
|
|
|
patch_instruction_site(&patch__flush_count_cache_return, PPC_INST_BLR);
|
|
count_cache_flush_type = COUNT_CACHE_FLUSH_HW;
|
|
pr_info("count-cache-flush: hardware assisted flush sequence enabled\n");
|
|
}
|
|
|
|
void setup_count_cache_flush(void)
|
|
{
|
|
toggle_count_cache_flush(true);
|
|
}
|
|
|
|
#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_count_cache_flush(enable);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int count_cache_flush_get(void *data, u64 *val)
|
|
{
|
|
if (count_cache_flush_type == COUNT_CACHE_FLUSH_NONE)
|
|
*val = 0;
|
|
else
|
|
*val = 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
DEFINE_SIMPLE_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
|
|
count_cache_flush_set, "%llu\n");
|
|
|
|
static __init int count_cache_flush_debugfs_init(void)
|
|
{
|
|
debugfs_create_file("count_cache_flush", 0600, powerpc_debugfs_root,
|
|
NULL, &fops_count_cache_flush);
|
|
return 0;
|
|
}
|
|
device_initcall(count_cache_flush_debugfs_init);
|
|
#endif /* CONFIG_DEBUG_FS */
|
|
#endif /* CONFIG_PPC_BOOK3S_64 */
|