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freebsd-dev/sys/amd64/include/pcpu.h
Konstantin Belousov 319117fd57 IBRS support, AKA Spectre hardware mitigation. 
It is coded according to the Intel document 336996-001, reading of the
patches posted on lkml, and some additional consultations with Intel.

For existing processors, you need a microcode update which adds IBRS
CPU features, and to manually enable it by setting the tunable/sysctl
hw.ibrs_disable to 0.  Current status can be checked in sysctl
hw.ibrs_active.  The mitigation might be inactive if the CPU feature
is not patched in, or if CPU reports that IBRS use is not required, by
IA32_ARCH_CAP_IBRS_ALL bit.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D14029
2018-01-31 14:36:27 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) Peter Wemm <peter@netplex.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _MACHINE_PCPU_H_
#define _MACHINE_PCPU_H_
#ifndef _SYS_CDEFS_H_
#error "sys/cdefs.h is a prerequisite for this file"
#endif
#define PC_PTI_STACK_SZ 16
/*
* The SMP parts are setup in pmap.c and locore.s for the BSP, and
* mp_machdep.c sets up the data for the AP's to "see" when they awake.
* The reason for doing it via a struct is so that an array of pointers
* to each CPU's data can be set up for things like "check curproc on all
* other processors"
*/
#define PCPU_MD_FIELDS \
char pc_monitorbuf[128] __aligned(128); /* cache line */ \
struct pcpu *pc_prvspace; /* Self-reference */ \
struct pmap *pc_curpmap; \
struct amd64tss *pc_tssp; /* TSS segment active on CPU */ \
struct amd64tss *pc_commontssp;/* Common TSS for the CPU */ \
uint64_t pc_kcr3; \
uint64_t pc_ucr3; \
uint64_t pc_saved_ucr3; \
register_t pc_rsp0; \
register_t pc_scratch_rsp; /* User %rsp in syscall */ \
register_t pc_scratch_rax; \
u_int pc_apic_id; \
u_int pc_acpi_id; /* ACPI CPU id */ \
/* Pointer to the CPU %fs descriptor */ \
struct user_segment_descriptor *pc_fs32p; \
/* Pointer to the CPU %gs descriptor */ \
struct user_segment_descriptor *pc_gs32p; \
/* Pointer to the CPU LDT descriptor */ \
struct system_segment_descriptor *pc_ldt; \
/* Pointer to the CPU TSS descriptor */ \
struct system_segment_descriptor *pc_tss; \
uint64_t pc_pm_save_cnt; \
u_int pc_cmci_mask; /* MCx banks for CMCI */ \
uint64_t pc_dbreg[16]; /* ddb debugging regs */ \
uint64_t pc_pti_stack[PC_PTI_STACK_SZ]; \
int pc_dbreg_cmd; /* ddb debugging reg cmd */ \
u_int pc_vcpu_id; /* Xen vCPU ID */ \
uint32_t pc_pcid_next; \
uint32_t pc_pcid_gen; \
uint32_t pc_smp_tlb_done; /* TLB op acknowledgement */ \
uint32_t pc_ibpb_set; \
char __pad[216] /* be divisor of PAGE_SIZE \
after cache alignment */
#define PC_DBREG_CMD_NONE 0
#define PC_DBREG_CMD_LOAD 1
#ifdef _KERNEL
#if defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE___TYPEOF)
/*
* Evaluates to the byte offset of the per-cpu variable name.
*/
#define __pcpu_offset(name) \
__offsetof(struct pcpu, name)
/*
* Evaluates to the type of the per-cpu variable name.
*/
#define __pcpu_type(name) \
__typeof(((struct pcpu *)0)->name)
/*
* Evaluates to the address of the per-cpu variable name.
*/
#define __PCPU_PTR(name) __extension__ ({ \
__pcpu_type(name) *__p; \
\
__asm __volatile("movq %%gs:%1,%0; addq %2,%0" \
: "=r" (__p) \
: "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace))), \
"i" (__pcpu_offset(name))); \
\
__p; \
})
/*
* Evaluates to the value of the per-cpu variable name.
*/
#define __PCPU_GET(name) __extension__ ({ \
__pcpu_type(name) __res; \
struct __s { \
u_char __b[MIN(sizeof(__pcpu_type(name)), 8)]; \
} __s; \
\
if (sizeof(__res) == 1 || sizeof(__res) == 2 || \
sizeof(__res) == 4 || sizeof(__res) == 8) { \
__asm __volatile("mov %%gs:%1,%0" \
: "=r" (__s) \
: "m" (*(struct __s *)(__pcpu_offset(name)))); \
*(struct __s *)(void *)&__res = __s; \
} else { \
__res = *__PCPU_PTR(name); \
} \
__res; \
})
/*
* Adds the value to the per-cpu counter name. The implementation
* must be atomic with respect to interrupts.
*/
#define __PCPU_ADD(name, val) do { \
__pcpu_type(name) __val; \
struct __s { \
u_char __b[MIN(sizeof(__pcpu_type(name)), 8)]; \
} __s; \
\
__val = (val); \
if (sizeof(__val) == 1 || sizeof(__val) == 2 || \
sizeof(__val) == 4 || sizeof(__val) == 8) { \
__s = *(struct __s *)(void *)&__val; \
__asm __volatile("add %1,%%gs:%0" \
: "=m" (*(struct __s *)(__pcpu_offset(name))) \
: "r" (__s)); \
} else \
*__PCPU_PTR(name) += __val; \
} while (0)
/*
* Increments the value of the per-cpu counter name. The implementation
* must be atomic with respect to interrupts.
*/
#define __PCPU_INC(name) do { \
CTASSERT(sizeof(__pcpu_type(name)) == 1 || \
sizeof(__pcpu_type(name)) == 2 || \
sizeof(__pcpu_type(name)) == 4 || \
sizeof(__pcpu_type(name)) == 8); \
if (sizeof(__pcpu_type(name)) == 1) { \
__asm __volatile("incb %%gs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} else if (sizeof(__pcpu_type(name)) == 2) { \
__asm __volatile("incw %%gs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} else if (sizeof(__pcpu_type(name)) == 4) { \
__asm __volatile("incl %%gs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} else if (sizeof(__pcpu_type(name)) == 8) { \
__asm __volatile("incq %%gs:%0" \
: "=m" (*(__pcpu_type(name) *)(__pcpu_offset(name)))\
: "m" (*(__pcpu_type(name) *)(__pcpu_offset(name))));\
} \
} while (0)
/*
* Sets the value of the per-cpu variable name to value val.
*/
#define __PCPU_SET(name, val) { \
__pcpu_type(name) __val; \
struct __s { \
u_char __b[MIN(sizeof(__pcpu_type(name)), 8)]; \
} __s; \
\
__val = (val); \
if (sizeof(__val) == 1 || sizeof(__val) == 2 || \
sizeof(__val) == 4 || sizeof(__val) == 8) { \
__s = *(struct __s *)(void *)&__val; \
__asm __volatile("mov %1,%%gs:%0" \
: "=m" (*(struct __s *)(__pcpu_offset(name))) \
: "r" (__s)); \
} else { \
*__PCPU_PTR(name) = __val; \
} \
}
#define get_pcpu() __extension__ ({ \
struct pcpu *__pc; \
\
__asm __volatile("movq %%gs:%1,%0" \
: "=r" (__pc) \
: "m" (*(struct pcpu *)(__pcpu_offset(pc_prvspace)))); \
__pc; \
})
#define PCPU_GET(member) __PCPU_GET(pc_ ## member)
#define PCPU_ADD(member, val) __PCPU_ADD(pc_ ## member, val)
#define PCPU_INC(member) __PCPU_INC(pc_ ## member)
#define PCPU_PTR(member) __PCPU_PTR(pc_ ## member)
#define PCPU_SET(member, val) __PCPU_SET(pc_ ## member, val)
#define OFFSETOF_CURTHREAD 0
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wnull-dereference"
#endif
static __inline __pure2 struct thread *
__curthread(void)
{
struct thread *td;
__asm("movq %%gs:%1,%0" : "=r" (td)
: "m" (*(char *)OFFSETOF_CURTHREAD));
return (td);
}
#ifdef __clang__
#pragma clang diagnostic pop
#endif
#define curthread (__curthread())
#define OFFSETOF_CURPCB 32
static __inline __pure2 struct pcb *
__curpcb(void)
{
struct pcb *pcb;
__asm("movq %%gs:%1,%0" : "=r" (pcb) : "m" (*(char *)OFFSETOF_CURPCB));
return (pcb);
}
#define curpcb (__curpcb())
#define IS_BSP() (PCPU_GET(cpuid) == 0)
#else /* !__GNUCLIKE_ASM || !__GNUCLIKE___TYPEOF */
#error "this file needs to be ported to your compiler"
#endif /* __GNUCLIKE_ASM && __GNUCLIKE___TYPEOF */
#endif /* _KERNEL */
#endif /* !_MACHINE_PCPU_H_ */
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