Commit 5d8544e2 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

RISC-V: Generic library routines and assembly



This patch contains code that is more specific to the RISC-V ISA than it
is to Linux.  It contains string and math operations, C wrappers for
various assembly instructions, stack walking code, and uaccess.
Signed-off-by: default avatarPalmer Dabbelt <palmer@dabbelt.com>
parent fab957c1
/*
* Copyright (C) 2015 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_ASM_H
#define _ASM_RISCV_ASM_H
#ifdef __ASSEMBLY__
#define __ASM_STR(x) x
#else
#define __ASM_STR(x) #x
#endif
#if __riscv_xlen == 64
#define __REG_SEL(a, b) __ASM_STR(a)
#elif __riscv_xlen == 32
#define __REG_SEL(a, b) __ASM_STR(b)
#else
#error "Unexpected __riscv_xlen"
#endif
#define REG_L __REG_SEL(ld, lw)
#define REG_S __REG_SEL(sd, sw)
#define SZREG __REG_SEL(8, 4)
#define LGREG __REG_SEL(3, 2)
#if __SIZEOF_POINTER__ == 8
#ifdef __ASSEMBLY__
#define RISCV_PTR .dword
#define RISCV_SZPTR 8
#define RISCV_LGPTR 3
#else
#define RISCV_PTR ".dword"
#define RISCV_SZPTR "8"
#define RISCV_LGPTR "3"
#endif
#elif __SIZEOF_POINTER__ == 4
#ifdef __ASSEMBLY__
#define RISCV_PTR .word
#define RISCV_SZPTR 4
#define RISCV_LGPTR 2
#else
#define RISCV_PTR ".word"
#define RISCV_SZPTR "4"
#define RISCV_LGPTR "2"
#endif
#else
#error "Unexpected __SIZEOF_POINTER__"
#endif
#if (__SIZEOF_INT__ == 4)
#define INT __ASM_STR(.word)
#define SZINT __ASM_STR(4)
#define LGINT __ASM_STR(2)
#else
#error "Unexpected __SIZEOF_INT__"
#endif
#if (__SIZEOF_SHORT__ == 2)
#define SHORT __ASM_STR(.half)
#define SZSHORT __ASM_STR(2)
#define LGSHORT __ASM_STR(1)
#else
#error "Unexpected __SIZEOF_SHORT__"
#endif
#endif /* _ASM_RISCV_ASM_H */
/*
* Copyright (C) 2015 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_CSR_H
#define _ASM_RISCV_CSR_H
#include <linux/const.h>
/* Status register flags */
#define SR_IE _AC(0x00000002, UL) /* Interrupt Enable */
#define SR_PIE _AC(0x00000020, UL) /* Previous IE */
#define SR_PS _AC(0x00000100, UL) /* Previously Supervisor */
#define SR_SUM _AC(0x00040000, UL) /* Supervisor may access User Memory */
#define SR_FS _AC(0x00006000, UL) /* Floating-point Status */
#define SR_FS_OFF _AC(0x00000000, UL)
#define SR_FS_INITIAL _AC(0x00002000, UL)
#define SR_FS_CLEAN _AC(0x00004000, UL)
#define SR_FS_DIRTY _AC(0x00006000, UL)
#define SR_XS _AC(0x00018000, UL) /* Extension Status */
#define SR_XS_OFF _AC(0x00000000, UL)
#define SR_XS_INITIAL _AC(0x00008000, UL)
#define SR_XS_CLEAN _AC(0x00010000, UL)
#define SR_XS_DIRTY _AC(0x00018000, UL)
#ifndef CONFIG_64BIT
#define SR_SD _AC(0x80000000, UL) /* FS/XS dirty */
#else
#define SR_SD _AC(0x8000000000000000, UL) /* FS/XS dirty */
#endif
/* SPTBR flags */
#if __riscv_xlen == 32
#define SPTBR_PPN _AC(0x003FFFFF, UL)
#define SPTBR_MODE_32 _AC(0x80000000, UL)
#define SPTBR_MODE SPTBR_MODE_32
#else
#define SPTBR_PPN _AC(0x00000FFFFFFFFFFF, UL)
#define SPTBR_MODE_39 _AC(0x8000000000000000, UL)
#define SPTBR_MODE SPTBR_MODE_39
#endif
/* Interrupt Enable and Interrupt Pending flags */
#define SIE_SSIE _AC(0x00000002, UL) /* Software Interrupt Enable */
#define SIE_STIE _AC(0x00000020, UL) /* Timer Interrupt Enable */
#define EXC_INST_MISALIGNED 0
#define EXC_INST_ACCESS 1
#define EXC_BREAKPOINT 3
#define EXC_LOAD_ACCESS 5
#define EXC_STORE_ACCESS 7
#define EXC_SYSCALL 8
#define EXC_INST_PAGE_FAULT 12
#define EXC_LOAD_PAGE_FAULT 13
#define EXC_STORE_PAGE_FAULT 15
#ifndef __ASSEMBLY__
#define csr_swap(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrw %0, " #csr ", %1" \
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_read(csr) \
({ \
register unsigned long __v; \
__asm__ __volatile__ ("csrr %0, " #csr \
: "=r" (__v) : \
: "memory"); \
__v; \
})
#define csr_write(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrw " #csr ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#define csr_read_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrs %0, " #csr ", %1" \
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_set(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrs " #csr ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#define csr_read_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrrc %0, " #csr ", %1" \
: "=r" (__v) : "rK" (__v) \
: "memory"); \
__v; \
})
#define csr_clear(csr, val) \
({ \
unsigned long __v = (unsigned long)(val); \
__asm__ __volatile__ ("csrc " #csr ", %0" \
: : "rK" (__v) \
: "memory"); \
})
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_CSR_H */
/*
* Copyright (C) 2015 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_LINKAGE_H
#define _ASM_RISCV_LINKAGE_H
#define __ALIGN .balign 4
#define __ALIGN_STR ".balign 4"
#endif /* _ASM_RISCV_LINKAGE_H */
/*
* Copyright (C) 2013 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _ASM_RISCV_STRING_H
#define _ASM_RISCV_STRING_H
#include <linux/types.h>
#include <linux/linkage.h>
#define __HAVE_ARCH_MEMSET
extern asmlinkage void *memset(void *, int, size_t);
#define __HAVE_ARCH_MEMCPY
extern asmlinkage void *memcpy(void *, const void *, size_t);
#endif /* _ASM_RISCV_STRING_H */
/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* This file was copied from include/asm-generic/uaccess.h
*/
#ifndef _ASM_RISCV_UACCESS_H
#define _ASM_RISCV_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/errno.h>
#include <linux/compiler.h>
#include <linux/thread_info.h>
#include <asm/byteorder.h>
#include <asm/asm.h>
#define __enable_user_access() \
__asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory")
#define __disable_user_access() \
__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
/*
* The fs value determines whether argument validity checking should be
* performed or not. If get_fs() == USER_DS, checking is performed, with
* get_fs() == KERNEL_DS, checking is bypassed.
*
* For historical reasons, these macros are grossly misnamed.
*/
#define KERNEL_DS (~0UL)
#define USER_DS (TASK_SIZE)
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
}
#define segment_eq(a, b) ((a) == (b))
#define user_addr_max() (get_fs())
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/**
* access_ok: - Checks if a user space pointer is valid
* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
* to write to a block, it is always safe to read from it.
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep.
*
* Checks if a pointer to a block of memory in user space is valid.
*
* Returns true (nonzero) if the memory block may be valid, false (zero)
* if it is definitely invalid.
*
* Note that, depending on architecture, this function probably just
* checks that the pointer is in the user space range - after calling
* this function, memory access functions may still return -EFAULT.
*/
#define access_ok(type, addr, size) ({ \
__chk_user_ptr(addr); \
likely(__access_ok((unsigned long __force)(addr), (size))); \
})
/*
* Ensure that the range [addr, addr+size) is within the process's
* address space
*/
static inline int __access_ok(unsigned long addr, unsigned long size)
{
const mm_segment_t fs = get_fs();
return (size <= fs) && (addr <= (fs - size));
}
/*
* The exception table consists of pairs of addresses: the first is the
* address of an instruction that is allowed to fault, and the second is
* the address at which the program should continue. No registers are
* modified, so it is entirely up to the continuation code to figure out
* what to do.
*
* All the routines below use bits of fixup code that are out of line
* with the main instruction path. This means when everything is well,
* we don't even have to jump over them. Further, they do not intrude
* on our cache or tlb entries.
*/
struct exception_table_entry {
unsigned long insn, fixup;
};
extern int fixup_exception(struct pt_regs *state);
#if defined(__LITTLE_ENDIAN)
#define __MSW 1
#define __LSW 0
#elif defined(__BIG_ENDIAN)
#define __MSW 0
#define __LSW 1
#else
#error "Unknown endianness"
#endif
/*
* The "__xxx" versions of the user access functions do not verify the address
* space - it must have been done previously with a separate "access_ok()"
* call.
*/
#ifdef CONFIG_MMU
#define __get_user_asm(insn, x, ptr, err) \
do { \
uintptr_t __tmp; \
__typeof__(x) __x; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" " insn " %1, %3\n" \
"2:\n" \
" .section .fixup,\"ax\"\n" \
" .balign 4\n" \
"3:\n" \
" li %0, %4\n" \
" li %1, 0\n" \
" jump 2b, %2\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .balign " RISCV_SZPTR "\n" \
" " RISCV_PTR " 1b, 3b\n" \
" .previous" \
: "+r" (err), "=&r" (__x), "=r" (__tmp) \
: "m" (*(ptr)), "i" (-EFAULT)); \
__disable_user_access(); \
(x) = __x; \
} while (0)
#endif /* CONFIG_MMU */
#ifdef CONFIG_64BIT
#define __get_user_8(x, ptr, err) \
__get_user_asm("ld", x, ptr, err)
#else /* !CONFIG_64BIT */
#ifdef CONFIG_MMU
#define __get_user_8(x, ptr, err) \
do { \
u32 __user *__ptr = (u32 __user *)(ptr); \
u32 __lo, __hi; \
uintptr_t __tmp; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" lw %1, %4\n" \
"2:\n" \
" lw %2, %5\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .balign 4\n" \
"4:\n" \
" li %0, %6\n" \
" li %1, 0\n" \
" li %2, 0\n" \
" jump 3b, %3\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .balign " RISCV_SZPTR "\n" \
" " RISCV_PTR " 1b, 4b\n" \
" " RISCV_PTR " 2b, 4b\n" \
" .previous" \
: "+r" (err), "=&r" (__lo), "=r" (__hi), \
"=r" (__tmp) \
: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
"i" (-EFAULT)); \
__disable_user_access(); \
(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
(((u64)__hi << 32) | __lo))); \
} while (0)
#endif /* CONFIG_MMU */
#endif /* CONFIG_64BIT */
/**
* __get_user: - Get a simple variable from user space, with less checking.
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and the result of
* dereferencing @ptr must be assignable to @x without a cast.
*
* Caller must check the pointer with access_ok() before calling this
* function.
*
* Returns zero on success, or -EFAULT on error.
* On error, the variable @x is set to zero.
*/
#define __get_user(x, ptr) \
({ \
register long __gu_err = 0; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
__chk_user_ptr(__gu_ptr); \
switch (sizeof(*__gu_ptr)) { \
case 1: \
__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
break; \
case 2: \
__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
break; \
case 4: \
__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
break; \
case 8: \
__get_user_8((x), __gu_ptr, __gu_err); \
break; \
default: \
BUILD_BUG(); \
} \
__gu_err; \
})
/**
* get_user: - Get a simple variable from user space.
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and the result of
* dereferencing @ptr must be assignable to @x without a cast.
*
* Returns zero on success, or -EFAULT on error.
* On error, the variable @x is set to zero.
*/
#define get_user(x, ptr) \
({ \
const __typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
__get_user((x), __p) : \
((x) = 0, -EFAULT); \
})
#ifdef CONFIG_MMU
#define __put_user_asm(insn, x, ptr, err) \
do { \
uintptr_t __tmp; \
__typeof__(*(ptr)) __x = x; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" " insn " %z3, %2\n" \
"2:\n" \
" .section .fixup,\"ax\"\n" \
" .balign 4\n" \
"3:\n" \
" li %0, %4\n" \
" jump 2b, %1\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .balign " RISCV_SZPTR "\n" \
" " RISCV_PTR " 1b, 3b\n" \
" .previous" \
: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
: "rJ" (__x), "i" (-EFAULT)); \
__disable_user_access(); \
} while (0)
#endif /* CONFIG_MMU */
#ifdef CONFIG_64BIT
#define __put_user_8(x, ptr, err) \
__put_user_asm("sd", x, ptr, err)
#else /* !CONFIG_64BIT */
#ifdef CONFIG_MMU
#define __put_user_8(x, ptr, err) \
do { \
u32 __user *__ptr = (u32 __user *)(ptr); \
u64 __x = (__typeof__((x)-(x)))(x); \
uintptr_t __tmp; \
__enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" sw %z4, %2\n" \
"2:\n" \
" sw %z5, %3\n" \
"3:\n" \
" .section .fixup,\"ax\"\n" \
" .balign 4\n" \
"4:\n" \
" li %0, %6\n" \
" jump 2b, %1\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .balign " RISCV_SZPTR "\n" \
" " RISCV_PTR " 1b, 4b\n" \
" " RISCV_PTR " 2b, 4b\n" \
" .previous" \
: "+r" (err), "=r" (__tmp), \
"=m" (__ptr[__LSW]), \
"=m" (__ptr[__MSW]) \
: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
__disable_user_access(); \
} while (0)
#endif /* CONFIG_MMU */
#endif /* CONFIG_64BIT */
/**
* __put_user: - Write a simple value into user space, with less checking.
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and @x must be assignable
* to the result of dereferencing @ptr.
*
* Caller must check the pointer with access_ok() before calling this
* function.
*
* Returns zero on success, or -EFAULT on error.
*/
#define __put_user(x, ptr) \
({ \
register long __pu_err = 0; \
__typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
__chk_user_ptr(__gu_ptr); \
switch (sizeof(*__gu_ptr)) { \
case 1: \
__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
break; \
case 2: \
__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
break; \
case 4: \
__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
break; \
case 8: \
__put_user_8((x), __gu_ptr, __pu_err); \
break; \
default: \
BUILD_BUG(); \
} \
__pu_err; \
})
/**
* put_user: - Write a simple value into user space.