Contributors: 102
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Thomas Gleixner |
1177 |
33.29% |
53 |
18.86% |
| Kyle Huey |
295 |
8.34% |
5 |
1.78% |
| Peter Zijlstra |
188 |
5.32% |
12 |
4.27% |
| Andi Kleen |
184 |
5.20% |
12 |
4.27% |
| Jeremy Fitzhardinge |
149 |
4.21% |
4 |
1.42% |
| Brian Gerst |
137 |
3.87% |
9 |
3.20% |
| Len Brown |
122 |
3.45% |
7 |
2.49% |
| Tim Chen |
96 |
2.71% |
2 |
0.71% |
| Andrew Lutomirski |
87 |
2.46% |
15 |
5.34% |
| Kirill A. Shutemov |
73 |
2.06% |
5 |
1.78% |
| Andrea Arcangeli |
70 |
1.98% |
2 |
0.71% |
| Chang S. Bae |
56 |
1.58% |
3 |
1.07% |
| Tom Lendacky |
55 |
1.56% |
3 |
1.07% |
| Wyes Karny |
52 |
1.47% |
2 |
0.71% |
| Eric W. Biedermann |
44 |
1.24% |
2 |
0.71% |
| Al Viro |
41 |
1.16% |
3 |
1.07% |
| Borislav Petkov |
39 |
1.10% |
5 |
1.78% |
| Linus Torvalds (pre-git) |
38 |
1.07% |
9 |
3.20% |
| Rick Edgecombe |
38 |
1.07% |
3 |
1.07% |
| Dave Hansen |
37 |
1.05% |
6 |
2.14% |
| Waiman Long |
34 |
0.96% |
1 |
0.36% |
| Ingo Molnar |
31 |
0.88% |
11 |
3.91% |
| Suresh B. Siddha |
29 |
0.82% |
3 |
1.07% |
| Arjan van de Ven |
29 |
0.82% |
3 |
1.07% |
| Stefan Metzmacher |
26 |
0.74% |
1 |
0.36% |
| Konrad Rzeszutek Wilk |
21 |
0.59% |
3 |
1.07% |
| Rusty Russell |
18 |
0.51% |
3 |
1.07% |
| Américo Wang |
16 |
0.45% |
1 |
0.36% |
| Tony Battersby |
15 |
0.42% |
1 |
0.36% |
| Yakui Zhao |
14 |
0.40% |
2 |
0.71% |
| Mike Galbraith |
13 |
0.37% |
1 |
0.36% |
| Ivan Vecera |
12 |
0.34% |
1 |
0.36% |
| Ashok Raj |
12 |
0.34% |
2 |
0.71% |
| Dave Jones |
12 |
0.34% |
2 |
0.71% |
| Glauber de Oliveira Costa |
11 |
0.31% |
5 |
1.78% |
| Joe Perches |
11 |
0.31% |
1 |
0.36% |
| Jiri Kosina |
10 |
0.28% |
1 |
0.36% |
| Kees Cook |
10 |
0.28% |
2 |
0.71% |
| Marcelo Tosatti |
10 |
0.28% |
1 |
0.36% |
| Josh Poimboeuf |
9 |
0.25% |
3 |
1.07% |
| Miguel Botón |
9 |
0.25% |
2 |
0.71% |
| Cyrill V. Gorcunov |
9 |
0.25% |
1 |
0.36% |
| Thomas Renninger |
9 |
0.25% |
1 |
0.36% |
| Roland McGrath |
8 |
0.23% |
2 |
0.71% |
| K.Prasad |
8 |
0.23% |
2 |
0.71% |
| Frédéric Weisbecker |
8 |
0.23% |
2 |
0.71% |
| Mario Limonciello |
8 |
0.23% |
1 |
0.36% |
| Oleg Nesterov |
7 |
0.20% |
2 |
0.71% |
| Erik Bosman |
7 |
0.20% |
1 |
0.36% |
| Yi Wang |
6 |
0.17% |
1 |
0.36% |
| Richard Weinberger |
6 |
0.17% |
1 |
0.36% |
| Linus Torvalds |
6 |
0.17% |
2 |
0.71% |
| Li RongQing |
5 |
0.14% |
1 |
0.36% |
| Grzegorz Andrejczuk |
5 |
0.14% |
1 |
0.36% |
| Mark Rutland |
5 |
0.14% |
1 |
0.36% |
| Josh Triplett |
5 |
0.14% |
1 |
0.36% |
| Harvey Harrison |
5 |
0.14% |
1 |
0.36% |
| Stephen Rothwell |
5 |
0.14% |
1 |
0.36% |
| Zwane Mwaikambo |
5 |
0.14% |
1 |
0.36% |
| Anthony Steinhauser |
5 |
0.14% |
1 |
0.36% |
| Jay Lang |
4 |
0.11% |
1 |
0.36% |
| Avi Kivity |
4 |
0.11% |
2 |
0.71% |
| Jiri Slaby |
4 |
0.11% |
1 |
0.36% |
| Qi Zheng |
3 |
0.08% |
1 |
0.36% |
| Kuppuswamy Sathyanarayanan |
3 |
0.08% |
1 |
0.36% |
| Jason A. Donenfeld |
3 |
0.08% |
2 |
0.71% |
| Anthony Liguori |
3 |
0.08% |
1 |
0.36% |
| Kyle McMartin |
3 |
0.08% |
1 |
0.36% |
| Yinghai Lu |
3 |
0.08% |
1 |
0.36% |
| Lai Jiangshan |
3 |
0.08% |
1 |
0.36% |
| Andrew Morton |
3 |
0.08% |
1 |
0.36% |
| Jan Beulich |
3 |
0.08% |
1 |
0.36% |
| Philippe Mathieu-Daudé |
3 |
0.08% |
1 |
0.36% |
| Don Zickus |
3 |
0.08% |
1 |
0.36% |
| Michael S. Tsirkin |
2 |
0.06% |
1 |
0.36% |
| Chris Metcalf |
2 |
0.06% |
1 |
0.36% |
| Tobias Klauser |
2 |
0.06% |
1 |
0.36% |
| Nadav Amit |
2 |
0.06% |
1 |
0.36% |
| Alex Nixon |
2 |
0.06% |
2 |
0.71% |
| Jaswinder Singh Rajput |
2 |
0.06% |
1 |
0.36% |
| Vineet Gupta |
2 |
0.06% |
1 |
0.36% |
| Alex Shi |
2 |
0.06% |
1 |
0.36% |
| David Woodhouse |
2 |
0.06% |
1 |
0.36% |
| Stéphane Eranian |
2 |
0.06% |
1 |
0.36% |
| Jason Cooper |
2 |
0.06% |
1 |
0.36% |
| Greg Kroah-Hartman |
1 |
0.03% |
1 |
0.36% |
| Jiapeng Chong |
1 |
0.03% |
1 |
0.36% |
| Dmitry Safonov |
1 |
0.03% |
1 |
0.36% |
| Paul Gortmaker |
1 |
0.03% |
1 |
0.36% |
| Juergen Gross |
1 |
0.03% |
1 |
0.36% |
| Christian Brauner |
1 |
0.03% |
1 |
0.36% |
| Andy Isaacson |
1 |
0.03% |
1 |
0.36% |
| Zachary Amsden |
1 |
0.03% |
1 |
0.36% |
| Björn Helgaas |
1 |
0.03% |
1 |
0.36% |
| Marc Dionne |
1 |
0.03% |
1 |
0.36% |
| Nick Desaulniers |
1 |
0.03% |
1 |
0.36% |
| Huang Rui |
1 |
0.03% |
1 |
0.36% |
| Tim Abbott |
1 |
0.03% |
1 |
0.36% |
| Pawan Gupta |
1 |
0.03% |
1 |
0.36% |
| Gabriel Krisman Bertazi |
1 |
0.03% |
1 |
0.36% |
| H. Peter Anvin |
1 |
0.03% |
1 |
0.36% |
| Alexander Duyck |
1 |
0.03% |
1 |
0.36% |
| Total |
3536 |
|
281 |
|
// SPDX-License-Identifier: GPL-2.0
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <linux/prctl.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/sched/idle.h>
#include <linux/sched/debug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/pm.h>
#include <linux/tick.h>
#include <linux/random.h>
#include <linux/user-return-notifier.h>
#include <linux/dmi.h>
#include <linux/utsname.h>
#include <linux/stackprotector.h>
#include <linux/cpuidle.h>
#include <linux/acpi.h>
#include <linux/elf-randomize.h>
#include <linux/static_call.h>
#include <trace/events/power.h>
#include <linux/hw_breakpoint.h>
#include <linux/entry-common.h>
#include <asm/cpu.h>
#include <asm/apic.h>
#include <linux/uaccess.h>
#include <asm/mwait.h>
#include <asm/fpu/api.h>
#include <asm/fpu/sched.h>
#include <asm/fpu/xstate.h>
#include <asm/debugreg.h>
#include <asm/nmi.h>
#include <asm/tlbflush.h>
#include <asm/mce.h>
#include <asm/vm86.h>
#include <asm/switch_to.h>
#include <asm/desc.h>
#include <asm/prctl.h>
#include <asm/spec-ctrl.h>
#include <asm/io_bitmap.h>
#include <asm/proto.h>
#include <asm/frame.h>
#include <asm/unwind.h>
#include <asm/tdx.h>
#include <asm/mmu_context.h>
#include <asm/shstk.h>
#include "process.h"
/*
* per-CPU TSS segments. Threads are completely 'soft' on Linux,
* no more per-task TSS's. The TSS size is kept cacheline-aligned
* so they are allowed to end up in the .data..cacheline_aligned
* section. Since TSS's are completely CPU-local, we want them
* on exact cacheline boundaries, to eliminate cacheline ping-pong.
*/
__visible DEFINE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw) = {
.x86_tss = {
/*
* .sp0 is only used when entering ring 0 from a lower
* privilege level. Since the init task never runs anything
* but ring 0 code, there is no need for a valid value here.
* Poison it.
*/
.sp0 = (1UL << (BITS_PER_LONG-1)) + 1,
#ifdef CONFIG_X86_32
.sp1 = TOP_OF_INIT_STACK,
.ss0 = __KERNEL_DS,
.ss1 = __KERNEL_CS,
#endif
.io_bitmap_base = IO_BITMAP_OFFSET_INVALID,
},
};
EXPORT_PER_CPU_SYMBOL(cpu_tss_rw);
DEFINE_PER_CPU(bool, __tss_limit_invalid);
EXPORT_PER_CPU_SYMBOL_GPL(__tss_limit_invalid);
/*
* this gets called so that we can store lazy state into memory and copy the
* current task into the new thread.
*/
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
memcpy(dst, src, arch_task_struct_size);
#ifdef CONFIG_VM86
dst->thread.vm86 = NULL;
#endif
/* Drop the copied pointer to current's fpstate */
dst->thread.fpu.fpstate = NULL;
return 0;
}
#ifdef CONFIG_X86_64
void arch_release_task_struct(struct task_struct *tsk)
{
if (fpu_state_size_dynamic())
fpstate_free(&tsk->thread.fpu);
}
#endif
/*
* Free thread data structures etc..
*/
void exit_thread(struct task_struct *tsk)
{
struct thread_struct *t = &tsk->thread;
struct fpu *fpu = &t->fpu;
if (test_thread_flag(TIF_IO_BITMAP))
io_bitmap_exit(tsk);
free_vm86(t);
shstk_free(tsk);
fpu__drop(fpu);
}
static int set_new_tls(struct task_struct *p, unsigned long tls)
{
struct user_desc __user *utls = (struct user_desc __user *)tls;
if (in_ia32_syscall())
return do_set_thread_area(p, -1, utls, 0);
else
return do_set_thread_area_64(p, ARCH_SET_FS, tls);
}
__visible void ret_from_fork(struct task_struct *prev, struct pt_regs *regs,
int (*fn)(void *), void *fn_arg)
{
schedule_tail(prev);
/* Is this a kernel thread? */
if (unlikely(fn)) {
fn(fn_arg);
/*
* A kernel thread is allowed to return here after successfully
* calling kernel_execve(). Exit to userspace to complete the
* execve() syscall.
*/
regs->ax = 0;
}
syscall_exit_to_user_mode(regs);
}
int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
unsigned long clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long tls = args->tls;
struct inactive_task_frame *frame;
struct fork_frame *fork_frame;
struct pt_regs *childregs;
unsigned long new_ssp;
int ret = 0;
childregs = task_pt_regs(p);
fork_frame = container_of(childregs, struct fork_frame, regs);
frame = &fork_frame->frame;
frame->bp = encode_frame_pointer(childregs);
frame->ret_addr = (unsigned long) ret_from_fork_asm;
p->thread.sp = (unsigned long) fork_frame;
p->thread.io_bitmap = NULL;
p->thread.iopl_warn = 0;
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
#ifdef CONFIG_X86_64
current_save_fsgs();
p->thread.fsindex = current->thread.fsindex;
p->thread.fsbase = current->thread.fsbase;
p->thread.gsindex = current->thread.gsindex;
p->thread.gsbase = current->thread.gsbase;
savesegment(es, p->thread.es);
savesegment(ds, p->thread.ds);
if (p->mm && (clone_flags & (CLONE_VM | CLONE_VFORK)) == CLONE_VM)
set_bit(MM_CONTEXT_LOCK_LAM, &p->mm->context.flags);
#else
p->thread.sp0 = (unsigned long) (childregs + 1);
savesegment(gs, p->thread.gs);
/*
* Clear all status flags including IF and set fixed bit. 64bit
* does not have this initialization as the frame does not contain
* flags. The flags consistency (especially vs. AC) is there
* ensured via objtool, which lacks 32bit support.
*/
frame->flags = X86_EFLAGS_FIXED;
#endif
/*
* Allocate a new shadow stack for thread if needed. If shadow stack,
* is disabled, new_ssp will remain 0, and fpu_clone() will know not to
* update it.
*/
new_ssp = shstk_alloc_thread_stack(p, clone_flags, args->stack_size);
if (IS_ERR_VALUE(new_ssp))
return PTR_ERR((void *)new_ssp);
fpu_clone(p, clone_flags, args->fn, new_ssp);
/* Kernel thread ? */
if (unlikely(p->flags & PF_KTHREAD)) {
p->thread.pkru = pkru_get_init_value();
memset(childregs, 0, sizeof(struct pt_regs));
kthread_frame_init(frame, args->fn, args->fn_arg);
return 0;
}
/*
* Clone current's PKRU value from hardware. tsk->thread.pkru
* is only valid when scheduled out.
*/
p->thread.pkru = read_pkru();
frame->bx = 0;
*childregs = *current_pt_regs();
childregs->ax = 0;
if (sp)
childregs->sp = sp;
if (unlikely(args->fn)) {
/*
* A user space thread, but it doesn't return to
* ret_after_fork().
*
* In order to indicate that to tools like gdb,
* we reset the stack and instruction pointers.
*
* It does the same kernel frame setup to return to a kernel
* function that a kernel thread does.
*/
childregs->sp = 0;
childregs->ip = 0;
kthread_frame_init(frame, args->fn, args->fn_arg);
return 0;
}
/* Set a new TLS for the child thread? */
if (clone_flags & CLONE_SETTLS)
ret = set_new_tls(p, tls);
if (!ret && unlikely(test_tsk_thread_flag(current, TIF_IO_BITMAP)))
io_bitmap_share(p);
return ret;
}
static void pkru_flush_thread(void)
{
/*
* If PKRU is enabled the default PKRU value has to be loaded into
* the hardware right here (similar to context switch).
*/
pkru_write_default();
}
void flush_thread(void)
{
struct task_struct *tsk = current;
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
fpu_flush_thread();
pkru_flush_thread();
}
void disable_TSC(void)
{
preempt_disable();
if (!test_and_set_thread_flag(TIF_NOTSC))
/*
* Must flip the CPU state synchronously with
* TIF_NOTSC in the current running context.
*/
cr4_set_bits(X86_CR4_TSD);
preempt_enable();
}
static void enable_TSC(void)
{
preempt_disable();
if (test_and_clear_thread_flag(TIF_NOTSC))
/*
* Must flip the CPU state synchronously with
* TIF_NOTSC in the current running context.
*/
cr4_clear_bits(X86_CR4_TSD);
preempt_enable();
}
int get_tsc_mode(unsigned long adr)
{
unsigned int val;
if (test_thread_flag(TIF_NOTSC))
val = PR_TSC_SIGSEGV;
else
val = PR_TSC_ENABLE;
return put_user(val, (unsigned int __user *)adr);
}
int set_tsc_mode(unsigned int val)
{
if (val == PR_TSC_SIGSEGV)
disable_TSC();
else if (val == PR_TSC_ENABLE)
enable_TSC();
else
return -EINVAL;
return 0;
}
DEFINE_PER_CPU(u64, msr_misc_features_shadow);
static void set_cpuid_faulting(bool on)
{
u64 msrval;
msrval = this_cpu_read(msr_misc_features_shadow);
msrval &= ~MSR_MISC_FEATURES_ENABLES_CPUID_FAULT;
msrval |= (on << MSR_MISC_FEATURES_ENABLES_CPUID_FAULT_BIT);
this_cpu_write(msr_misc_features_shadow, msrval);
wrmsrl(MSR_MISC_FEATURES_ENABLES, msrval);
}
static void disable_cpuid(void)
{
preempt_disable();
if (!test_and_set_thread_flag(TIF_NOCPUID)) {
/*
* Must flip the CPU state synchronously with
* TIF_NOCPUID in the current running context.
*/
set_cpuid_faulting(true);
}
preempt_enable();
}
static void enable_cpuid(void)
{
preempt_disable();
if (test_and_clear_thread_flag(TIF_NOCPUID)) {
/*
* Must flip the CPU state synchronously with
* TIF_NOCPUID in the current running context.
*/
set_cpuid_faulting(false);
}
preempt_enable();
}
static int get_cpuid_mode(void)
{
return !test_thread_flag(TIF_NOCPUID);
}
static int set_cpuid_mode(unsigned long cpuid_enabled)
{
if (!boot_cpu_has(X86_FEATURE_CPUID_FAULT))
return -ENODEV;
if (cpuid_enabled)
enable_cpuid();
else
disable_cpuid();
return 0;
}
/*
* Called immediately after a successful exec.
*/
void arch_setup_new_exec(void)
{
/* If cpuid was previously disabled for this task, re-enable it. */
if (test_thread_flag(TIF_NOCPUID))
enable_cpuid();
/*
* Don't inherit TIF_SSBD across exec boundary when
* PR_SPEC_DISABLE_NOEXEC is used.
*/
if (test_thread_flag(TIF_SSBD) &&
task_spec_ssb_noexec(current)) {
clear_thread_flag(TIF_SSBD);
task_clear_spec_ssb_disable(current);
task_clear_spec_ssb_noexec(current);
speculation_ctrl_update(read_thread_flags());
}
mm_reset_untag_mask(current->mm);
}
#ifdef CONFIG_X86_IOPL_IOPERM
static inline void switch_to_bitmap(unsigned long tifp)
{
/*
* Invalidate I/O bitmap if the previous task used it. This prevents
* any possible leakage of an active I/O bitmap.
*
* If the next task has an I/O bitmap it will handle it on exit to
* user mode.
*/
if (tifp & _TIF_IO_BITMAP)
tss_invalidate_io_bitmap();
}
static void tss_copy_io_bitmap(struct tss_struct *tss, struct io_bitmap *iobm)
{
/*
* Copy at least the byte range of the incoming tasks bitmap which
* covers the permitted I/O ports.
*
* If the previous task which used an I/O bitmap had more bits
* permitted, then the copy needs to cover those as well so they
* get turned off.
*/
memcpy(tss->io_bitmap.bitmap, iobm->bitmap,
max(tss->io_bitmap.prev_max, iobm->max));
/*
* Store the new max and the sequence number of this bitmap
* and a pointer to the bitmap itself.
*/
tss->io_bitmap.prev_max = iobm->max;
tss->io_bitmap.prev_sequence = iobm->sequence;
}
/**
* native_tss_update_io_bitmap - Update I/O bitmap before exiting to user mode
*/
void native_tss_update_io_bitmap(void)
{
struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
struct thread_struct *t = ¤t->thread;
u16 *base = &tss->x86_tss.io_bitmap_base;
if (!test_thread_flag(TIF_IO_BITMAP)) {
native_tss_invalidate_io_bitmap();
return;
}
if (IS_ENABLED(CONFIG_X86_IOPL_IOPERM) && t->iopl_emul == 3) {
*base = IO_BITMAP_OFFSET_VALID_ALL;
} else {
struct io_bitmap *iobm = t->io_bitmap;
/*
* Only copy bitmap data when the sequence number differs. The
* update time is accounted to the incoming task.
*/
if (tss->io_bitmap.prev_sequence != iobm->sequence)
tss_copy_io_bitmap(tss, iobm);
/* Enable the bitmap */
*base = IO_BITMAP_OFFSET_VALID_MAP;
}
/*
* Make sure that the TSS limit is covering the IO bitmap. It might have
* been cut down by a VMEXIT to 0x67 which would cause a subsequent I/O
* access from user space to trigger a #GP because the bitmap is outside
* the TSS limit.
*/
refresh_tss_limit();
}
#else /* CONFIG_X86_IOPL_IOPERM */
static inline void switch_to_bitmap(unsigned long tifp) { }
#endif
#ifdef CONFIG_SMP
struct ssb_state {
struct ssb_state *shared_state;
raw_spinlock_t lock;
unsigned int disable_state;
unsigned long local_state;
};
#define LSTATE_SSB 0
static DEFINE_PER_CPU(struct ssb_state, ssb_state);
void speculative_store_bypass_ht_init(void)
{
struct ssb_state *st = this_cpu_ptr(&ssb_state);
unsigned int this_cpu = smp_processor_id();
unsigned int cpu;
st->local_state = 0;
/*
* Shared state setup happens once on the first bringup
* of the CPU. It's not destroyed on CPU hotunplug.
*/
if (st->shared_state)
return;
raw_spin_lock_init(&st->lock);
/*
* Go over HT siblings and check whether one of them has set up the
* shared state pointer already.
*/
for_each_cpu(cpu, topology_sibling_cpumask(this_cpu)) {
if (cpu == this_cpu)
continue;
if (!per_cpu(ssb_state, cpu).shared_state)
continue;
/* Link it to the state of the sibling: */
st->shared_state = per_cpu(ssb_state, cpu).shared_state;
return;
}
/*
* First HT sibling to come up on the core. Link shared state of
* the first HT sibling to itself. The siblings on the same core
* which come up later will see the shared state pointer and link
* themselves to the state of this CPU.
*/
st->shared_state = st;
}
/*
* Logic is: First HT sibling enables SSBD for both siblings in the core
* and last sibling to disable it, disables it for the whole core. This how
* MSR_SPEC_CTRL works in "hardware":
*
* CORE_SPEC_CTRL = THREAD0_SPEC_CTRL | THREAD1_SPEC_CTRL
*/
static __always_inline void amd_set_core_ssb_state(unsigned long tifn)
{
struct ssb_state *st = this_cpu_ptr(&ssb_state);
u64 msr = x86_amd_ls_cfg_base;
if (!static_cpu_has(X86_FEATURE_ZEN)) {
msr |= ssbd_tif_to_amd_ls_cfg(tifn);
wrmsrl(MSR_AMD64_LS_CFG, msr);
return;
}
if (tifn & _TIF_SSBD) {
/*
* Since this can race with prctl(), block reentry on the
* same CPU.
*/
if (__test_and_set_bit(LSTATE_SSB, &st->local_state))
return;
msr |= x86_amd_ls_cfg_ssbd_mask;
raw_spin_lock(&st->shared_state->lock);
/* First sibling enables SSBD: */
if (!st->shared_state->disable_state)
wrmsrl(MSR_AMD64_LS_CFG, msr);
st->shared_state->disable_state++;
raw_spin_unlock(&st->shared_state->lock);
} else {
if (!__test_and_clear_bit(LSTATE_SSB, &st->local_state))
return;
raw_spin_lock(&st->shared_state->lock);
st->shared_state->disable_state--;
if (!st->shared_state->disable_state)
wrmsrl(MSR_AMD64_LS_CFG, msr);
raw_spin_unlock(&st->shared_state->lock);
}
}
#else
static __always_inline void amd_set_core_ssb_state(unsigned long tifn)
{
u64 msr = x86_amd_ls_cfg_base | ssbd_tif_to_amd_ls_cfg(tifn);
wrmsrl(MSR_AMD64_LS_CFG, msr);
}
#endif
static __always_inline void amd_set_ssb_virt_state(unsigned long tifn)
{
/*
* SSBD has the same definition in SPEC_CTRL and VIRT_SPEC_CTRL,
* so ssbd_tif_to_spec_ctrl() just works.
*/
wrmsrl(MSR_AMD64_VIRT_SPEC_CTRL, ssbd_tif_to_spec_ctrl(tifn));
}
/*
* Update the MSRs managing speculation control, during context switch.
*
* tifp: Previous task's thread flags
* tifn: Next task's thread flags
*/
static __always_inline void __speculation_ctrl_update(unsigned long tifp,
unsigned long tifn)
{
unsigned long tif_diff = tifp ^ tifn;
u64 msr = x86_spec_ctrl_base;
bool updmsr = false;
lockdep_assert_irqs_disabled();
/* Handle change of TIF_SSBD depending on the mitigation method. */
if (static_cpu_has(X86_FEATURE_VIRT_SSBD)) {
if (tif_diff & _TIF_SSBD)
amd_set_ssb_virt_state(tifn);
} else if (static_cpu_has(X86_FEATURE_LS_CFG_SSBD)) {
if (tif_diff & _TIF_SSBD)
amd_set_core_ssb_state(tifn);
} else if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD) ||
static_cpu_has(X86_FEATURE_AMD_SSBD)) {
updmsr |= !!(tif_diff & _TIF_SSBD);
msr |= ssbd_tif_to_spec_ctrl(tifn);
}
/* Only evaluate TIF_SPEC_IB if conditional STIBP is enabled. */
if (IS_ENABLED(CONFIG_SMP) &&
static_branch_unlikely(&switch_to_cond_stibp)) {
updmsr |= !!(tif_diff & _TIF_SPEC_IB);
msr |= stibp_tif_to_spec_ctrl(tifn);
}
if (updmsr)
update_spec_ctrl_cond(msr);
}
static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)
{
if (test_and_clear_tsk_thread_flag(tsk, TIF_SPEC_FORCE_UPDATE)) {
if (task_spec_ssb_disable(tsk))
set_tsk_thread_flag(tsk, TIF_SSBD);
else
clear_tsk_thread_flag(tsk, TIF_SSBD);
if (task_spec_ib_disable(tsk))
set_tsk_thread_flag(tsk, TIF_SPEC_IB);
else
clear_tsk_thread_flag(tsk, TIF_SPEC_IB);
}
/* Return the updated threadinfo flags*/
return read_task_thread_flags(tsk);
}
void speculation_ctrl_update(unsigned long tif)
{
unsigned long flags;
/* Forced update. Make sure all relevant TIF flags are different */
local_irq_save(flags);
__speculation_ctrl_update(~tif, tif);
local_irq_restore(flags);
}
/* Called from seccomp/prctl update */
void speculation_ctrl_update_current(void)
{
preempt_disable();
speculation_ctrl_update(speculation_ctrl_update_tif(current));
preempt_enable();
}
static inline void cr4_toggle_bits_irqsoff(unsigned long mask)
{
unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4);
newval = cr4 ^ mask;
if (newval != cr4) {
this_cpu_write(cpu_tlbstate.cr4, newval);
__write_cr4(newval);
}
}
void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
{
unsigned long tifp, tifn;
tifn = read_task_thread_flags(next_p);
tifp = read_task_thread_flags(prev_p);
switch_to_bitmap(tifp);
propagate_user_return_notify(prev_p, next_p);
if ((tifp & _TIF_BLOCKSTEP || tifn & _TIF_BLOCKSTEP) &&
arch_has_block_step()) {
unsigned long debugctl, msk;
rdmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
debugctl &= ~DEBUGCTLMSR_BTF;
msk = tifn & _TIF_BLOCKSTEP;
debugctl |= (msk >> TIF_BLOCKSTEP) << DEBUGCTLMSR_BTF_SHIFT;
wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
}
if ((tifp ^ tifn) & _TIF_NOTSC)
cr4_toggle_bits_irqsoff(X86_CR4_TSD);
if ((tifp ^ tifn) & _TIF_NOCPUID)
set_cpuid_faulting(!!(tifn & _TIF_NOCPUID));
if (likely(!((tifp | tifn) & _TIF_SPEC_FORCE_UPDATE))) {
__speculation_ctrl_update(tifp, tifn);
} else {
speculation_ctrl_update_tif(prev_p);
tifn = speculation_ctrl_update_tif(next_p);
/* Enforce MSR update to ensure consistent state */
__speculation_ctrl_update(~tifn, tifn);
}
}
/*
* Idle related variables and functions
*/
unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
EXPORT_SYMBOL(boot_option_idle_override);
/*
* We use this if we don't have any better idle routine..
*/
void __cpuidle default_idle(void)
{
raw_safe_halt();
raw_local_irq_disable();
}
#if defined(CONFIG_APM_MODULE) || defined(CONFIG_HALTPOLL_CPUIDLE_MODULE)
EXPORT_SYMBOL(default_idle);
#endif
DEFINE_STATIC_CALL_NULL(x86_idle, default_idle);
static bool x86_idle_set(void)
{
return !!static_call_query(x86_idle);
}
#ifndef CONFIG_SMP
static inline void __noreturn play_dead(void)
{
BUG();
}
#endif
void arch_cpu_idle_enter(void)
{
tsc_verify_tsc_adjust(false);
local_touch_nmi();
}
void __noreturn arch_cpu_idle_dead(void)
{
play_dead();
}
/*
* Called from the generic idle code.
*/
void __cpuidle arch_cpu_idle(void)
{
static_call(x86_idle)();
}
EXPORT_SYMBOL_GPL(arch_cpu_idle);
#ifdef CONFIG_XEN
bool xen_set_default_idle(void)
{
bool ret = x86_idle_set();
static_call_update(x86_idle, default_idle);
return ret;
}
#endif
struct cpumask cpus_stop_mask;
void __noreturn stop_this_cpu(void *dummy)
{
struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info);
unsigned int cpu = smp_processor_id();
local_irq_disable();
/*
* Remove this CPU from the online mask and disable it
* unconditionally. This might be redundant in case that the reboot
* vector was handled late and stop_other_cpus() sent an NMI.
*
* According to SDM and APM NMIs can be accepted even after soft
* disabling the local APIC.
*/
set_cpu_online(cpu, false);
disable_local_APIC();
mcheck_cpu_clear(c);
/*
* Use wbinvd on processors that support SME. This provides support
* for performing a successful kexec when going from SME inactive
* to SME active (or vice-versa). The cache must be cleared so that
* if there are entries with the same physical address, both with and
* without the encryption bit, they don't race each other when flushed
* and potentially end up with the wrong entry being committed to
* memory.
*
* Test the CPUID bit directly because the machine might've cleared
* X86_FEATURE_SME due to cmdline options.
*/
if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0)))
native_wbinvd();
/*
* This brings a cache line back and dirties it, but
* native_stop_other_cpus() will overwrite cpus_stop_mask after it
* observed that all CPUs reported stop. This write will invalidate
* the related cache line on this CPU.
*/
cpumask_clear_cpu(cpu, &cpus_stop_mask);
#ifdef CONFIG_SMP
if (smp_ops.stop_this_cpu) {
smp_ops.stop_this_cpu();
unreachable();
}
#endif
for (;;) {
/*
* Use native_halt() so that memory contents don't change
* (stack usage and variables) after possibly issuing the
* native_wbinvd() above.
*/
native_halt();
}
}
/*
* Prefer MWAIT over HALT if MWAIT is supported, MWAIT_CPUID leaf
* exists and whenever MONITOR/MWAIT extensions are present there is at
* least one C1 substate.
*
* Do not prefer MWAIT if MONITOR instruction has a bug or idle=nomwait
* is passed to kernel commandline parameter.
*/
static __init bool prefer_mwait_c1_over_halt(void)
{
const struct cpuinfo_x86 *c = &boot_cpu_data;
u32 eax, ebx, ecx, edx;
/* If override is enforced on the command line, fall back to HALT. */
if (boot_option_idle_override != IDLE_NO_OVERRIDE)
return false;
/* MWAIT is not supported on this platform. Fallback to HALT */
if (!cpu_has(c, X86_FEATURE_MWAIT))
return false;
/* Monitor has a bug or APIC stops in C1E. Fallback to HALT */
if (boot_cpu_has_bug(X86_BUG_MONITOR) || boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))
return false;
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
/*
* If MWAIT extensions are not available, it is safe to use MWAIT
* with EAX=0, ECX=0.
*/
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED))
return true;
/*
* If MWAIT extensions are available, there should be at least one
* MWAIT C1 substate present.
*/
return !!(edx & MWAIT_C1_SUBSTATE_MASK);
}
/*
* MONITOR/MWAIT with no hints, used for default C1 state. This invokes MWAIT
* with interrupts enabled and no flags, which is backwards compatible with the
* original MWAIT implementation.
*/
static __cpuidle void mwait_idle(void)
{
if (!current_set_polling_and_test()) {
if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
mb(); /* quirk */
clflush((void *)¤t_thread_info()->flags);
mb(); /* quirk */
}
__monitor((void *)¤t_thread_info()->flags, 0, 0);
if (!need_resched()) {
__sti_mwait(0, 0);
raw_local_irq_disable();
}
}
__current_clr_polling();
}
void __init select_idle_routine(void)
{
if (boot_option_idle_override == IDLE_POLL) {
if (IS_ENABLED(CONFIG_SMP) && __max_threads_per_core > 1)
pr_warn_once("WARNING: polling idle and HT enabled, performance may degrade\n");
return;
}
/* Required to guard against xen_set_default_idle() */
if (x86_idle_set())
return;
if (prefer_mwait_c1_over_halt()) {
pr_info("using mwait in idle threads\n");
static_call_update(x86_idle, mwait_idle);
} else if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) {
pr_info("using TDX aware idle routine\n");
static_call_update(x86_idle, tdx_safe_halt);
} else {
static_call_update(x86_idle, default_idle);
}
}
void amd_e400_c1e_apic_setup(void)
{
if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E)) {
pr_info("Switch to broadcast mode on CPU%d\n", smp_processor_id());
local_irq_disable();
tick_broadcast_force();
local_irq_enable();
}
}
void __init arch_post_acpi_subsys_init(void)
{
u32 lo, hi;
if (!boot_cpu_has_bug(X86_BUG_AMD_E400))
return;
/*
* AMD E400 detection needs to happen after ACPI has been enabled. If
* the machine is affected K8_INTP_C1E_ACTIVE_MASK bits are set in
* MSR_K8_INT_PENDING_MSG.
*/
rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
if (!(lo & K8_INTP_C1E_ACTIVE_MASK))
return;
boot_cpu_set_bug(X86_BUG_AMD_APIC_C1E);
if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
mark_tsc_unstable("TSC halt in AMD C1E");
if (IS_ENABLED(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST_IDLE))
static_branch_enable(&arch_needs_tick_broadcast);
pr_info("System has AMD C1E erratum E400. Workaround enabled.\n");
}
static int __init idle_setup(char *str)
{
if (!str)
return -EINVAL;
if (!strcmp(str, "poll")) {
pr_info("using polling idle threads\n");
boot_option_idle_override = IDLE_POLL;
cpu_idle_poll_ctrl(true);
} else if (!strcmp(str, "halt")) {
/* 'idle=halt' HALT for idle. C-states are disabled. */
boot_option_idle_override = IDLE_HALT;
} else if (!strcmp(str, "nomwait")) {
/* 'idle=nomwait' disables MWAIT for idle */
boot_option_idle_override = IDLE_NOMWAIT;
} else {
return -EINVAL;
}
return 0;
}
early_param("idle", idle_setup);
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
sp -= get_random_u32_below(8192);
return sp & ~0xf;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
if (mmap_is_ia32())
return randomize_page(mm->brk, SZ_32M);
return randomize_page(mm->brk, SZ_1G);
}
/*
* Called from fs/proc with a reference on @p to find the function
* which called into schedule(). This needs to be done carefully
* because the task might wake up and we might look at a stack
* changing under us.
*/
unsigned long __get_wchan(struct task_struct *p)
{
struct unwind_state state;
unsigned long addr = 0;
if (!try_get_task_stack(p))
return 0;
for (unwind_start(&state, p, NULL, NULL); !unwind_done(&state);
unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
if (!addr)
break;
if (in_sched_functions(addr))
continue;
break;
}
put_task_stack(p);
return addr;
}
long do_arch_prctl_common(int option, unsigned long arg2)
{
switch (option) {
case ARCH_GET_CPUID:
return get_cpuid_mode();
case ARCH_SET_CPUID:
return set_cpuid_mode(arg2);
case ARCH_GET_XCOMP_SUPP:
case ARCH_GET_XCOMP_PERM:
case ARCH_REQ_XCOMP_PERM:
case ARCH_GET_XCOMP_GUEST_PERM:
case ARCH_REQ_XCOMP_GUEST_PERM:
return fpu_xstate_prctl(option, arg2);
}
return -EINVAL;
}