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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_SPECIAL_INSNS_H
#define _ASM_X86_SPECIAL_INSNS_H
#ifdef __KERNEL__
#include <asm/nops.h>
#include <asm/processor-flags.h>
#include <linux/irqflags.h>
#include <linux/jump_label.h>
/*
* The compiler should not reorder volatile asm statements with respect to each
* other: they should execute in program order. However GCC 4.9.x and 5.x have
* a bug (which was fixed in 8.1, 7.3 and 6.5) where they might reorder
* volatile asm. The write functions are not affected since they have memory
* clobbers preventing reordering. To prevent reads from being reordered with
* respect to writes, use a dummy memory operand.
*/
#define __FORCE_ORDER "m"(*(unsigned int *)0x1000UL)
void native_write_cr0(unsigned long val);
static inline unsigned long native_read_cr0(void)
{
unsigned long val;
asm volatile("mov %%cr0,%0\n\t" : "=r" (val) : __FORCE_ORDER);
return val;
}
static __always_inline unsigned long native_read_cr2(void)
{
unsigned long val;
asm volatile("mov %%cr2,%0\n\t" : "=r" (val) : __FORCE_ORDER);
return val;
}
static __always_inline void native_write_cr2(unsigned long val)
{
asm volatile("mov %0,%%cr2": : "r" (val) : "memory");
}
static inline unsigned long __native_read_cr3(void)
{
unsigned long val;
asm volatile("mov %%cr3,%0\n\t" : "=r" (val) : __FORCE_ORDER);
return val;
}
static inline void native_write_cr3(unsigned long val)
{
asm volatile("mov %0,%%cr3": : "r" (val) : "memory");
}
static inline unsigned long native_read_cr4(void)
{
unsigned long val;
#ifdef CONFIG_X86_32
/*
* This could fault if CR4 does not exist. Non-existent CR4
* is functionally equivalent to CR4 == 0. Keep it simple and pretend
* that CR4 == 0 on CPUs that don't have CR4.
*/
asm volatile("1: mov %%cr4, %0\n"
"2:\n"
_ASM_EXTABLE(1b, 2b)
: "=r" (val) : "0" (0), __FORCE_ORDER);
#else
/* CR4 always exists on x86_64. */
asm volatile("mov %%cr4,%0\n\t" : "=r" (val) : __FORCE_ORDER);
#endif
return val;
}
void native_write_cr4(unsigned long val);
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
static inline u32 rdpkru(void)
{
u32 ecx = 0;
u32 edx, pkru;
/*
* "rdpkru" instruction. Places PKRU contents in to EAX,
* clears EDX and requires that ecx=0.
*/
asm volatile(".byte 0x0f,0x01,0xee\n\t"
: "=a" (pkru), "=d" (edx)
: "c" (ecx));
return pkru;
}
static inline void wrpkru(u32 pkru)
{
u32 ecx = 0, edx = 0;
/*
* "wrpkru" instruction. Loads contents in EAX to PKRU,
* requires that ecx = edx = 0.
*/
asm volatile(".byte 0x0f,0x01,0xef\n\t"
: : "a" (pkru), "c"(ecx), "d"(edx));
}
static inline void __write_pkru(u32 pkru)
{
/*
* WRPKRU is relatively expensive compared to RDPKRU.
* Avoid WRPKRU when it would not change the value.
*/
if (pkru == rdpkru())
return;
wrpkru(pkru);
}
#else
static inline u32 rdpkru(void)
{
return 0;
}
static inline void __write_pkru(u32 pkru)
{
}
#endif
static inline void native_wbinvd(void)
{
asm volatile("wbinvd": : :"memory");
}
extern asmlinkage void asm_load_gs_index(unsigned int selector);
static inline void native_load_gs_index(unsigned int selector)
{
unsigned long flags;
local_irq_save(flags);
asm_load_gs_index(selector);
local_irq_restore(flags);
}
static inline unsigned long __read_cr4(void)
{
return native_read_cr4();
}
#ifdef CONFIG_PARAVIRT_XXL
#include <asm/paravirt.h>
#else
static inline unsigned long read_cr0(void)
{
return native_read_cr0();
}
static inline void write_cr0(unsigned long x)
{
native_write_cr0(x);
}
static __always_inline unsigned long read_cr2(void)
{
return native_read_cr2();
}
static __always_inline void write_cr2(unsigned long x)
{
native_write_cr2(x);
}
/*
* Careful! CR3 contains more than just an address. You probably want
* read_cr3_pa() instead.
*/
static inline unsigned long __read_cr3(void)
{
return __native_read_cr3();
}
static inline void write_cr3(unsigned long x)
{
native_write_cr3(x);
}
static inline void __write_cr4(unsigned long x)
{
native_write_cr4(x);
}
static inline void wbinvd(void)
{
native_wbinvd();
}
#ifdef CONFIG_X86_64
static inline void load_gs_index(unsigned int selector)
{
native_load_gs_index(selector);
}
#endif
#endif /* CONFIG_PARAVIRT_XXL */
static inline void clflush(volatile void *__p)
{
asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p));
}
static inline void clflushopt(volatile void *__p)
{
alternative_io(".byte 0x3e; clflush %P0",
".byte 0x66; clflush %P0",
X86_FEATURE_CLFLUSHOPT,
"+m" (*(volatile char __force *)__p));
}
static inline void clwb(volatile void *__p)
{
volatile struct { char x[64]; } *p = __p;
asm volatile(ALTERNATIVE_2(
".byte 0x3e; clflush (%[pax])",
".byte 0x66; clflush (%[pax])", /* clflushopt (%%rax) */
X86_FEATURE_CLFLUSHOPT,
".byte 0x66, 0x0f, 0xae, 0x30", /* clwb (%%rax) */
X86_FEATURE_CLWB)
: [p] "+m" (*p)
: [pax] "a" (p));
}
#define nop() asm volatile ("nop")
static inline void serialize(void)
{
/* Instruction opcode for SERIALIZE; supported in binutils >= 2.35. */
asm volatile(".byte 0xf, 0x1, 0xe8" ::: "memory");
}
/* The dst parameter must be 64-bytes aligned */
static inline void movdir64b(void __iomem *dst, const void *src)
{
const struct { char _[64]; } *__src = src;
struct { char _[64]; } __iomem *__dst = dst;
/*
* MOVDIR64B %(rdx), rax.
*
* Both __src and __dst must be memory constraints in order to tell the
* compiler that no other memory accesses should be reordered around
* this one.
*
* Also, both must be supplied as lvalues because this tells
* the compiler what the object is (its size) the instruction accesses.
* I.e., not the pointers but what they point to, thus the deref'ing '*'.
*/
asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
: "+m" (*__dst)
: "m" (*__src), "a" (__dst), "d" (__src));
}
/**
* enqcmds - Enqueue a command in supervisor (CPL0) mode
* @dst: destination, in MMIO space (must be 512-bit aligned)
* @src: 512 bits memory operand
*
* The ENQCMDS instruction allows software to write a 512-bit command to
* a 512-bit-aligned special MMIO region that supports the instruction.
* A return status is loaded into the ZF flag in the RFLAGS register.
* ZF = 0 equates to success, and ZF = 1 indicates retry or error.
*
* This function issues the ENQCMDS instruction to submit data from
* kernel space to MMIO space, in a unit of 512 bits. Order of data access
* is not guaranteed, nor is a memory barrier performed afterwards. It
* returns 0 on success and -EAGAIN on failure.
*
* Warning: Do not use this helper unless your driver has checked that the
* ENQCMDS instruction is supported on the platform and the device accepts
* ENQCMDS.
*/
static inline int enqcmds(void __iomem *dst, const void *src)
{
const struct { char _[64]; } *__src = src;
struct { char _[64]; } __iomem *__dst = dst;
bool zf;
/*
* ENQCMDS %(rdx), rax
*
* See movdir64b()'s comment on operand specification.
*/
asm volatile(".byte 0xf3, 0x0f, 0x38, 0xf8, 0x02, 0x66, 0x90"
CC_SET(z)
: CC_OUT(z) (zf), "+m" (*__dst)
: "m" (*__src), "a" (__dst), "d" (__src));
/* Submission failure is indicated via EFLAGS.ZF=1 */
if (zf)
return -EAGAIN;
return 0;
}
#endif /* __KERNEL__ */
#endif /* _ASM_X86_SPECIAL_INSNS_H */
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