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Commit b3685465 authored by Andy Whitcroft's avatar Andy Whitcroft Committed by Kleber Sacilotto de Souza
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Revert "x86/spec_ctrl: Add sysctl knobs to enable/disable SPEC_CTRL feature" 

CVE-2017-5753 (revert embargoed)
CVE-2017-5715 (revert embargoed)

This reverts commit 5e7fa023.
Signed-off-by: default avatarAndy Whitcroft <apw@canonical.com>
Signed-off-by: default avatarKleber Sacilotto de Souza <kleber.souza@canonical.com>
parent 1089af8d
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Showing with 19 additions and 4895 deletions
Documentation/admin-guide/kernel-parameters.txt deleted 100644 → 0
View file @ 1089af8d
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arch/x86/include/asm/mwait.h
View file @ b3685465
......@@ -106,14 +106,14 @@ static inline void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
mb();
}
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
__monitor((void *)&current_thread_info()->flags, 0, 0);
if (!need_resched())
__mwait(eax, ecx);
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
}
current_clr_polling();
......
arch/x86/include/asm/spec_ctrl.h
View file @ b3685465
......@@ -8,9 +8,6 @@
#ifdef __ASSEMBLY__
.extern use_ibrs
.extern use_ibpb
#define __ASM_ENABLE_IBRS \
pushq %rax; \
pushq %rcx; \
......@@ -107,30 +104,15 @@
add $(32*8), %rsp;
.macro ENABLE_IBRS
testl $1, use_ibrs
jz 10f
__ASM_ENABLE_IBRS
jmp 20f
10:
lfence
20:
ALTERNATIVE "", __stringify(__ASM_ENABLE_IBRS), X86_FEATURE_SPEC_CTRL
.endm
.macro ENABLE_IBRS_CLOBBER
testl $1, use_ibrs
jz 11f
__ASM_ENABLE_IBRS_CLOBBER
jmp 21f
11:
lfence
21:
ALTERNATIVE "", __stringify(__ASM_ENABLE_IBRS_CLOBBER), X86_FEATURE_SPEC_CTRL
.endm
.macro DISABLE_IBRS
testl $1, use_ibrs
jz 9f
__ASM_DISABLE_IBRS
9:
ALTERNATIVE "", __stringify(__ASM_DISABLE_IBRS), X86_FEATURE_SPEC_CTRL
.endm
.macro STUFF_RSB
......
arch/x86/kernel/cpu/intel.c
View file @ b3685465
......@@ -529,17 +529,10 @@ static void init_intel(struct cpuinfo_x86 *c)
init_intel_energy_perf(c);
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL)) {
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
printk_once(KERN_INFO "FEATURE SPEC_CTRL Present\n");
set_ibrs_supported();
set_ibpb_supported();
if (ibrs_inuse)
sysctl_ibrs_enabled = 1;
if (ibpb_inuse)
sysctl_ibpb_enabled = 1;
} else {
else
printk_once(KERN_INFO "FEATURE SPEC_CTRL Not Present\n");
}
}
#ifdef CONFIG_X86_32
......
arch/x86/kernel/cpu/microcode/core.c
View file @ b3685465
......@@ -419,17 +419,6 @@ static ssize_t reload_store(struct device *dev,
}
if (!ret)
perf_check_microcode();
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL)) {
printk_once(KERN_INFO "FEATURE SPEC_CTRL Present\n");
set_ibrs_supported();
set_ibpb_supported();
if (ibrs_inuse)
sysctl_ibrs_enabled = 1;
if (ibpb_inuse)
sysctl_ibpb_enabled = 1;
}
mutex_unlock(&microcode_mutex);
put_online_cpus();
......
arch/x86/kernel/process.c
View file @ b3685465
......@@ -424,16 +424,16 @@ static void mwait_idle(void)
smp_mb(); /* quirk */
}
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
__monitor((void *)&current_thread_info()->flags, 0, 0);
if (!need_resched()) {
__sti_mwait(0, 0);
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
} else {
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
local_irq_enable();
}
......
arch/x86/kernel/smpboot.c
View file @ b3685465
......@@ -1657,14 +1657,14 @@ void native_play_dead(void)
play_dead_common();
tboot_shutdown(TB_SHUTDOWN_WFS);
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
mwait_play_dead(); /* Only returns on failure */
if (cpuidle_play_dead())
hlt_play_dead();
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
}
......
arch/x86/kvm/vmx.c
View file @ b3685465
......@@ -2050,7 +2050,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
if (per_cpu(current_vmcs, cpu) != vmx->loaded_vmcs->vmcs) {
per_cpu(current_vmcs, cpu) = vmx->loaded_vmcs->vmcs;
vmcs_load(vmx->loaded_vmcs->vmcs);
if (ibpb_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
native_wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
}
......@@ -8600,7 +8600,7 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu)
atomic_switch_perf_msrs(vmx);
if (ibrs_inuse)
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
add_atomic_switch_msr(vmx, MSR_IA32_SPEC_CTRL,
vcpu->arch.spec_ctrl, FEATURE_ENABLE_IBRS);
......
arch/x86/lib/delay.c
View file @ b3685465
......@@ -100,7 +100,8 @@ static void delay_mwaitx(unsigned long __loops)
for (;;) {
delay = min_t(u64, MWAITX_MAX_LOOPS, loops);
if (ibrs_inuse && (delay > IBRS_DISABLE_THRESHOLD))
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) &&
(delay > IBRS_DISABLE_THRESHOLD))
native_wrmsrl(MSR_IA32_SPEC_CTRL, 0);
/*
......@@ -116,7 +117,8 @@ static void delay_mwaitx(unsigned long __loops)
*/
__mwaitx(MWAITX_DISABLE_CSTATES, delay, MWAITX_ECX_TIMER_ENABLE);
if (ibrs_inuse && (delay > IBRS_DISABLE_THRESHOLD))
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) &&
(delay > IBRS_DISABLE_THRESHOLD))
native_wrmsrl(MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
end = rdtsc_ordered();
......
arch/x86/mm/tlb.c
View file @ b3685465
......@@ -142,7 +142,7 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next,
cpumask_clear_cpu(cpu, mm_cpumask(prev));
/* Null tsk means switching to kernel, so that's safe */
if (ibpb_inuse && tsk &&
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL) && tsk &&
___ptrace_may_access(tsk, current, PTRACE_MODE_IBPB))
native_wrmsrl(MSR_IA32_PRED_CMD, FEATURE_SET_IBPB);
......
include/linux/smp.h
View file @ b3685465
......@@ -50,93 +50,6 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
int smp_call_function_single_async(int cpu, struct call_single_data *csd);
#ifdef CONFIG_X86
/* indicate usage of IBRS to control execution speculation */
extern int use_ibrs;
extern u32 sysctl_ibrs_enabled;
extern struct mutex spec_ctrl_mutex;
#define ibrs_supported (use_ibrs & 0x2)
#define ibrs_disabled (use_ibrs & 0x4)
static inline void set_ibrs_inuse(void)
{
if (ibrs_supported)
use_ibrs |= 0x1;
}
static inline void clear_ibrs_inuse(void)
{
use_ibrs &= ~0x1;
}
static inline int check_ibrs_inuse(void)
{
if (use_ibrs & 0x1)
return 1;
else
/* rmb to prevent wrong speculation for security */
rmb();
return 0;
}
static inline void set_ibrs_supported(void)
{
use_ibrs |= 0x2;
if (!ibrs_disabled)
set_ibrs_inuse();
}
static inline void set_ibrs_disabled(void)
{
use_ibrs |= 0x4;
if (check_ibrs_inuse())
clear_ibrs_inuse();
}
static inline void clear_ibrs_disabled(void)
{
use_ibrs &= ~0x4;
set_ibrs_inuse();
}
#define ibrs_inuse (check_ibrs_inuse())
/* indicate usage of IBPB to control execution speculation */
extern int use_ibpb;
extern u32 sysctl_ibpb_enabled;
#define ibpb_supported (use_ibpb & 0x2)
#define ibpb_disabled (use_ibpb & 0x4)
static inline void set_ibpb_inuse(void)
{
if (ibpb_supported)
use_ibpb |= 0x1;
}
static inline void clear_ibpb_inuse(void)
{
use_ibpb &= ~0x1;
}
static inline int check_ibpb_inuse(void)
{
if (use_ibpb & 0x1)
return 1;
else
/* rmb to prevent wrong speculation for security */
rmb();
return 0;
}
static inline void set_ibpb_supported(void)
{
use_ibpb |= 0x2;
if (!ibpb_disabled)
set_ibpb_inuse();
}
static inline void set_ibpb_disabled(void)
{
use_ibpb |= 0x4;
if (check_ibpb_inuse())
clear_ibpb_inuse();
}
static inline void clear_ibpb_disabled(void)
{
use_ibpb &= ~0x4;
set_ibpb_inuse();
}
#define ibpb_inuse (check_ibpb_inuse())
#endif
#ifdef CONFIG_SMP
#include <linux/preempt.h>
......
kernel/smp.c
View file @ b3685465
......@@ -499,26 +499,6 @@ EXPORT_SYMBOL(smp_call_function);
unsigned int setup_max_cpus = NR_CPUS;
EXPORT_SYMBOL(setup_max_cpus);
#ifdef CONFIG_X86
/*
* use IBRS
* bit 0 = indicate if ibrs is currently in use
* bit 1 = indicate if system supports ibrs
* bit 2 = indicate if admin disables ibrs
*/
int use_ibrs;
EXPORT_SYMBOL(use_ibrs);
/*
* use IBRS
* bit 0 = indicate if ibpb is currently in use
* bit 1 = indicate if system supports ibpb
* bit 2 = indicate if admin disables ibpb
*/
int use_ibpb;
EXPORT_SYMBOL(use_ibpb);
#endif
/*
* Setup routine for controlling SMP activation
......@@ -543,27 +523,6 @@ static int __init nosmp(char *str)
early_param("nosmp", nosmp);
#ifdef CONFIG_X86
static int __init noibrs(char *str)
{
set_ibrs_disabled();
return 0;
}
early_param("noibrs", noibrs);
static int __init noibpb(char *str)
{
set_ibpb_disabled();
return 0;
}
early_param("noibpb", noibpb);
#endif
/* this is hard limit */
static int __init nrcpus(char *str)
{
......
kernel/sysctl.c
View file @ b3685465
......@@ -72,7 +72,6 @@
#include <asm/processor.h>
#ifdef CONFIG_X86
#include <asm/msr.h>
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/io.h>
......@@ -199,15 +198,6 @@ static int proc_dostring_coredump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
#endif
#ifdef CONFIG_X86
int proc_dointvec_ibrs_ctrl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
int proc_dointvec_ibpb_ctrl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
int proc_dointvec_ibrs_dump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos);
#endif
#ifdef CONFIG_MAGIC_SYSRQ
/* Note: sysrq code uses it's own private copy */
static int __sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE;
......@@ -244,12 +234,6 @@ extern struct ctl_table epoll_table[];
int sysctl_legacy_va_layout;
#endif
u32 sysctl_ibrs_dump = 0;
u32 sysctl_ibrs_enabled = 0;
EXPORT_SYMBOL(sysctl_ibrs_enabled);
u32 sysctl_ibpb_enabled = 0;
EXPORT_SYMBOL(sysctl_ibpb_enabled);
/* The default sysctl tables: */
static struct ctl_table sysctl_base_table[] = {
......@@ -1233,35 +1217,6 @@ static struct ctl_table kern_table[] = {
.extra1 = &one,
.extra2 = &one,
},
#endif
#ifdef CONFIG_X86
{
.procname = "ibrs_enabled",
.data = &sysctl_ibrs_enabled,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_ibrs_ctrl,
.extra1 = &zero,
.extra2 = &two,
},
{
.procname = "ibpb_enabled",
.data = &sysctl_ibpb_enabled,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_ibpb_ctrl,
.extra1 = &zero,
.extra2 = &one,
},
{
.procname = "ibrs_dump",
.data = &sysctl_ibrs_dump,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = proc_dointvec_ibrs_dump,
.extra1 = &zero,
.extra2 = &one,
},
#endif
{ }
};
......@@ -2420,85 +2375,6 @@ int proc_dointvec_minmax(struct ctl_table *table, int write,
do_proc_dointvec_minmax_conv, &param);
}
#ifdef CONFIG_X86
int proc_dointvec_ibrs_dump(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
unsigned int cpu;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
printk("sysctl_ibrs_enabled = %u, sysctl_ibpb_enabled = %u\n", sysctl_ibrs_enabled, sysctl_ibpb_enabled);
printk("use_ibrs = %d, use_ibpb = %d\n", use_ibrs, use_ibpb);
for_each_online_cpu(cpu) {
u64 val;
if (boot_cpu_has(X86_FEATURE_SPEC_CTRL))
rdmsrl_on_cpu(cpu, MSR_IA32_SPEC_CTRL, &val);
else
val = 0;
printk("read cpu %d ibrs val %lu\n", cpu, (unsigned long) val);
}
return ret;
}
int proc_dointvec_ibrs_ctrl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
unsigned int cpu;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
pr_debug("sysctl_ibrs_enabled = %u, sysctl_ibpb_enabled = %u\n", sysctl_ibrs_enabled, sysctl_ibpb_enabled);
pr_debug("before:use_ibrs = %d, use_ibpb = %d\n", use_ibrs, use_ibpb);
if (sysctl_ibrs_enabled == 0) {
/* always set IBRS off */
set_ibrs_disabled();
if (ibrs_supported) {
for_each_online_cpu(cpu)
wrmsrl_on_cpu(cpu, MSR_IA32_SPEC_CTRL, 0x0);
}
} else if (sysctl_ibrs_enabled == 2) {
/* always set IBRS on, even in user space */
clear_ibrs_disabled();
if (ibrs_supported) {
for_each_online_cpu(cpu)
wrmsrl_on_cpu(cpu, MSR_IA32_SPEC_CTRL, FEATURE_ENABLE_IBRS);
} else {
sysctl_ibrs_enabled = 0;
}
} else if (sysctl_ibrs_enabled == 1) {
/* use IBRS in kernel */
clear_ibrs_disabled();
if (!ibrs_inuse)
/* platform don't support ibrs */
sysctl_ibrs_enabled = 0;
}
pr_debug("after:use_ibrs = %d, use_ibpb = %d\n", use_ibrs, use_ibpb);
return ret;
}
int proc_dointvec_ibpb_ctrl(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
pr_debug("sysctl_ibrs_enabled = %u, sysctl_ibpb_enabled = %u\n", sysctl_ibrs_enabled, sysctl_ibpb_enabled);
pr_debug("before:use_ibrs = %d, use_ibpb = %d\n", use_ibrs, use_ibpb);
if (sysctl_ibpb_enabled == 0)
set_ibpb_disabled();
else if (sysctl_ibpb_enabled == 1) {
clear_ibpb_disabled();
if (!ibpb_inuse)
/* platform don't support ibpb */
sysctl_ibpb_enabled = 0;
}
pr_debug("after:use_ibrs = %d, use_ibpb = %d\n", use_ibrs, use_ibpb);
return ret;
}
#endif
static void validate_coredump_safety(void)
{
#ifdef CONFIG_COREDUMP
......
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