mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
2853d5fafb
- Atomic operations (lock prefixed instructions) which span two cache
lines have to acquire the global bus lock. This is at least 1k cycles
slower than an atomic operation within a cache line and disrupts
performance on other cores. Aside of performance disruption this is
a unpriviledged form of DoS.
Some newer CPUs have the capability to raise an #AC trap when such an
operation is attempted. The detection is by default enabled in warning
mode which will warn once when a user space application is caught. A
command line option allows to disable the detection or to select fatal
mode which will terminate offending applications with SIGBUS.
-----BEGIN PGP SIGNATURE-----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=D9x8
-----END PGP SIGNATURE-----
Merge tag 'x86-splitlock-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 splitlock updates from Thomas Gleixner:
"Support for 'split lock' detection:
Atomic operations (lock prefixed instructions) which span two cache
lines have to acquire the global bus lock. This is at least 1k cycles
slower than an atomic operation within a cache line and disrupts
performance on other cores. Aside of performance disruption this is a
unpriviledged form of DoS.
Some newer CPUs have the capability to raise an #AC trap when such an
operation is attempted. The detection is by default enabled in warning
mode which will warn once when a user space application is caught. A
command line option allows to disable the detection or to select fatal
mode which will terminate offending applications with SIGBUS"
* tag 'x86-splitlock-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR
x86/split_lock: Rework the initialization flow of split lock detection
x86/split_lock: Enable split lock detection by kernel
246 lines
8.2 KiB
C
246 lines
8.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/* thread_info.h: low-level thread information
|
|
*
|
|
* Copyright (C) 2002 David Howells (dhowells@redhat.com)
|
|
* - Incorporating suggestions made by Linus Torvalds and Dave Miller
|
|
*/
|
|
|
|
#ifndef _ASM_X86_THREAD_INFO_H
|
|
#define _ASM_X86_THREAD_INFO_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <asm/page.h>
|
|
#include <asm/percpu.h>
|
|
#include <asm/types.h>
|
|
|
|
/*
|
|
* TOP_OF_KERNEL_STACK_PADDING is a number of unused bytes that we
|
|
* reserve at the top of the kernel stack. We do it because of a nasty
|
|
* 32-bit corner case. On x86_32, the hardware stack frame is
|
|
* variable-length. Except for vm86 mode, struct pt_regs assumes a
|
|
* maximum-length frame. If we enter from CPL 0, the top 8 bytes of
|
|
* pt_regs don't actually exist. Ordinarily this doesn't matter, but it
|
|
* does in at least one case:
|
|
*
|
|
* If we take an NMI early enough in SYSENTER, then we can end up with
|
|
* pt_regs that extends above sp0. On the way out, in the espfix code,
|
|
* we can read the saved SS value, but that value will be above sp0.
|
|
* Without this offset, that can result in a page fault. (We are
|
|
* careful that, in this case, the value we read doesn't matter.)
|
|
*
|
|
* In vm86 mode, the hardware frame is much longer still, so add 16
|
|
* bytes to make room for the real-mode segments.
|
|
*
|
|
* x86_64 has a fixed-length stack frame.
|
|
*/
|
|
#ifdef CONFIG_X86_32
|
|
# ifdef CONFIG_VM86
|
|
# define TOP_OF_KERNEL_STACK_PADDING 16
|
|
# else
|
|
# define TOP_OF_KERNEL_STACK_PADDING 8
|
|
# endif
|
|
#else
|
|
# define TOP_OF_KERNEL_STACK_PADDING 0
|
|
#endif
|
|
|
|
/*
|
|
* low level task data that entry.S needs immediate access to
|
|
* - this struct should fit entirely inside of one cache line
|
|
* - this struct shares the supervisor stack pages
|
|
*/
|
|
#ifndef __ASSEMBLY__
|
|
struct task_struct;
|
|
#include <asm/cpufeature.h>
|
|
#include <linux/atomic.h>
|
|
|
|
struct thread_info {
|
|
unsigned long flags; /* low level flags */
|
|
u32 status; /* thread synchronous flags */
|
|
};
|
|
|
|
#define INIT_THREAD_INFO(tsk) \
|
|
{ \
|
|
.flags = 0, \
|
|
}
|
|
|
|
#else /* !__ASSEMBLY__ */
|
|
|
|
#include <asm/asm-offsets.h>
|
|
|
|
#endif
|
|
|
|
/*
|
|
* thread information flags
|
|
* - these are process state flags that various assembly files
|
|
* may need to access
|
|
*/
|
|
#define TIF_SYSCALL_TRACE 0 /* syscall trace active */
|
|
#define TIF_NOTIFY_RESUME 1 /* callback before returning to user */
|
|
#define TIF_SIGPENDING 2 /* signal pending */
|
|
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
|
|
#define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/
|
|
#define TIF_SSBD 5 /* Speculative store bypass disable */
|
|
#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
|
|
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
|
|
#define TIF_SECCOMP 8 /* secure computing */
|
|
#define TIF_SPEC_IB 9 /* Indirect branch speculation mitigation */
|
|
#define TIF_SPEC_FORCE_UPDATE 10 /* Force speculation MSR update in context switch */
|
|
#define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */
|
|
#define TIF_UPROBE 12 /* breakpointed or singlestepping */
|
|
#define TIF_PATCH_PENDING 13 /* pending live patching update */
|
|
#define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */
|
|
#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
|
|
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
|
|
#define TIF_IA32 17 /* IA32 compatibility process */
|
|
#define TIF_SLD 18 /* Restore split lock detection on context switch */
|
|
#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
|
|
#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
|
|
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
|
|
#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
|
|
#define TIF_BLOCKSTEP 25 /* set when we want DEBUGCTLMSR_BTF */
|
|
#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
|
|
#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
|
|
#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
|
|
#define TIF_X32 30 /* 32-bit native x86-64 binary */
|
|
#define TIF_FSCHECK 31 /* Check FS is USER_DS on return */
|
|
|
|
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
|
|
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
|
|
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
|
|
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
|
|
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
|
|
#define _TIF_SSBD (1 << TIF_SSBD)
|
|
#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
|
|
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
|
|
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
|
|
#define _TIF_SPEC_IB (1 << TIF_SPEC_IB)
|
|
#define _TIF_SPEC_FORCE_UPDATE (1 << TIF_SPEC_FORCE_UPDATE)
|
|
#define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY)
|
|
#define _TIF_UPROBE (1 << TIF_UPROBE)
|
|
#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
|
|
#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD)
|
|
#define _TIF_NOCPUID (1 << TIF_NOCPUID)
|
|
#define _TIF_NOTSC (1 << TIF_NOTSC)
|
|
#define _TIF_IA32 (1 << TIF_IA32)
|
|
#define _TIF_SLD (1 << TIF_SLD)
|
|
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
|
|
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
|
|
#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
|
|
#define _TIF_BLOCKSTEP (1 << TIF_BLOCKSTEP)
|
|
#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
|
|
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
|
|
#define _TIF_ADDR32 (1 << TIF_ADDR32)
|
|
#define _TIF_X32 (1 << TIF_X32)
|
|
#define _TIF_FSCHECK (1 << TIF_FSCHECK)
|
|
|
|
/* Work to do before invoking the actual syscall. */
|
|
#define _TIF_WORK_SYSCALL_ENTRY \
|
|
(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | _TIF_SYSCALL_AUDIT | \
|
|
_TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT)
|
|
|
|
/* flags to check in __switch_to() */
|
|
#define _TIF_WORK_CTXSW_BASE \
|
|
(_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \
|
|
_TIF_SSBD | _TIF_SPEC_FORCE_UPDATE | _TIF_SLD)
|
|
|
|
/*
|
|
* Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated.
|
|
*/
|
|
#ifdef CONFIG_SMP
|
|
# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE | _TIF_SPEC_IB)
|
|
#else
|
|
# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE)
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_IOPL_IOPERM
|
|
# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
|
|
_TIF_IO_BITMAP)
|
|
#else
|
|
# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY)
|
|
#endif
|
|
|
|
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
|
|
|
|
#define STACK_WARN (THREAD_SIZE/8)
|
|
|
|
/*
|
|
* macros/functions for gaining access to the thread information structure
|
|
*
|
|
* preempt_count needs to be 1 initially, until the scheduler is functional.
|
|
*/
|
|
#ifndef __ASSEMBLY__
|
|
|
|
/*
|
|
* Walks up the stack frames to make sure that the specified object is
|
|
* entirely contained by a single stack frame.
|
|
*
|
|
* Returns:
|
|
* GOOD_FRAME if within a frame
|
|
* BAD_STACK if placed across a frame boundary (or outside stack)
|
|
* NOT_STACK unable to determine (no frame pointers, etc)
|
|
*/
|
|
static inline int arch_within_stack_frames(const void * const stack,
|
|
const void * const stackend,
|
|
const void *obj, unsigned long len)
|
|
{
|
|
#if defined(CONFIG_FRAME_POINTER)
|
|
const void *frame = NULL;
|
|
const void *oldframe;
|
|
|
|
oldframe = __builtin_frame_address(1);
|
|
if (oldframe)
|
|
frame = __builtin_frame_address(2);
|
|
/*
|
|
* low ----------------------------------------------> high
|
|
* [saved bp][saved ip][args][local vars][saved bp][saved ip]
|
|
* ^----------------^
|
|
* allow copies only within here
|
|
*/
|
|
while (stack <= frame && frame < stackend) {
|
|
/*
|
|
* If obj + len extends past the last frame, this
|
|
* check won't pass and the next frame will be 0,
|
|
* causing us to bail out and correctly report
|
|
* the copy as invalid.
|
|
*/
|
|
if (obj + len <= frame)
|
|
return obj >= oldframe + 2 * sizeof(void *) ?
|
|
GOOD_FRAME : BAD_STACK;
|
|
oldframe = frame;
|
|
frame = *(const void * const *)frame;
|
|
}
|
|
return BAD_STACK;
|
|
#else
|
|
return NOT_STACK;
|
|
#endif
|
|
}
|
|
|
|
#else /* !__ASSEMBLY__ */
|
|
|
|
#ifdef CONFIG_X86_64
|
|
# define cpu_current_top_of_stack (cpu_tss_rw + TSS_sp1)
|
|
#endif
|
|
|
|
#endif
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
#define TS_I386_REGS_POKED 0x0004 /* regs poked by 32-bit ptracer */
|
|
#endif
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#ifdef CONFIG_X86_32
|
|
#define in_ia32_syscall() true
|
|
#else
|
|
#define in_ia32_syscall() (IS_ENABLED(CONFIG_IA32_EMULATION) && \
|
|
current_thread_info()->status & TS_COMPAT)
|
|
#endif
|
|
|
|
extern void arch_task_cache_init(void);
|
|
extern int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
|
|
extern void arch_release_task_struct(struct task_struct *tsk);
|
|
extern void arch_setup_new_exec(void);
|
|
#define arch_setup_new_exec arch_setup_new_exec
|
|
#endif /* !__ASSEMBLY__ */
|
|
|
|
#endif /* _ASM_X86_THREAD_INFO_H */
|