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// Code to access multiple segments within gcc.
//
// Copyright (C) 2008,2009 Kevin O'Connor <kevin@koconnor.net>
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#ifndef __FARPTR_H
#define __FARPTR_H
#include "ioport.h" // insb
// Dummy definitions used to make sure gcc understands dependencies
// between SET_SEG and GET/READ/WRITE_SEG macros.
extern u16 __segment_ES, __segment_CS, __segment_DS, __segment_SS;
extern u16 __segment_FS, __segment_GS;
// Low level macros for reading/writing memory via a segment selector.
#define READ8_SEG(prefix, SEG, value, var) \
__asm__(prefix "movb %%" #SEG ":%1, %b0" : "=Qi"(value) \
: "m"(var), "m"(__segment_ ## SEG))
#define READ16_SEG(prefix, SEG, value, var) \
__asm__(prefix "movw %%" #SEG ":%1, %w0" : "=ri"(value) \
: "m"(var), "m"(__segment_ ## SEG))
#define READ32_SEG(prefix, SEG, value, var) \
__asm__(prefix "movl %%" #SEG ":%1, %0" : "=ri"(value) \
: "m"(var), "m"(__segment_ ## SEG))
#define READ64_SEG(prefix, SEG, value, var) do { \
union u64_u32_u __value; \
union u64_u32_u *__r64_ptr = (union u64_u32_u *)&(var); \
READ32_SEG(prefix, SEG, __value.hi, __r64_ptr->hi); \
READ32_SEG(prefix, SEG, __value.lo, __r64_ptr->lo); \
*(u64*)&(value) = __value.val; \
} while (0)
#define WRITE8_SEG(prefix, SEG, var, value) \
__asm__(prefix "movb %b1, %%" #SEG ":%0" : "=m"(var) \
: "Q"(value), "m"(__segment_ ## SEG))
#define WRITE16_SEG(prefix, SEG, var, value) \
__asm__(prefix "movw %w1, %%" #SEG ":%0" : "=m"(var) \
: "r"(value), "m"(__segment_ ## SEG))
#define WRITE32_SEG(prefix, SEG, var, value) \
__asm__(prefix "movl %1, %%" #SEG ":%0" : "=m"(var) \
: "r"(value), "m"(__segment_ ## SEG))
#define WRITE64_SEG(prefix, SEG, var, value) do { \
union u64_u32_u __value; \
union u64_u32_u *__w64_ptr = (union u64_u32_u *)&(var); \
typeof(var) __value_tmp = (value); \
__value.val = *(u64*)&__value_tmp; \
WRITE32_SEG(prefix, SEG, __w64_ptr->hi, __value.hi); \
WRITE32_SEG(prefix, SEG, __w64_ptr->lo, __value.lo); \
} while (0)
// Macros for automatically choosing the appropriate memory size
// access method.
extern void __force_link_error__unknown_type(void);
#define __GET_VAR(prefix, seg, var) ({ \
typeof(var) __val; \
if (sizeof(__val) == 1) \
READ8_SEG(prefix, seg, __val, var); \
else if (sizeof(__val) == 2) \
READ16_SEG(prefix, seg, __val, var); \
else if (sizeof(__val) == 4) \
READ32_SEG(prefix, seg, __val, var); \
else if (sizeof(__val) == 8) \
READ64_SEG(prefix, seg, __val, var); \
else \
__force_link_error__unknown_type(); \
__val; })
#define __SET_VAR(prefix, seg, var, val) do { \
if (sizeof(var) == 1) \
WRITE8_SEG(prefix, seg, var, (val)); \
else if (sizeof(var) == 2) \
WRITE16_SEG(prefix, seg, var, (val)); \
else if (sizeof(var) == 4) \
WRITE32_SEG(prefix, seg, var, (val)); \
else if (sizeof(var) == 8) \
WRITE64_SEG(prefix, seg, var, (val)); \
else \
__force_link_error__unknown_type(); \
} while (0)
#define DECL_SEGFUNCS(SEG) \
static inline void __set_seg_##SEG(u16 seg) { \
__asm__("movw %w1, %%" #SEG : "=m"(__segment_##SEG) \
: "rm"(seg)); \
} \
static inline u16 __get_seg_##SEG(void) { \
u16 res; \
__asm__("movw %%" #SEG ", %w0" : "=rm"(res) \
: "m"(__segment_##SEG)); \
return res; \
}
DECL_SEGFUNCS(CS)
DECL_SEGFUNCS(DS)
DECL_SEGFUNCS(ES)
DECL_SEGFUNCS(FS)
DECL_SEGFUNCS(GS)
DECL_SEGFUNCS(SS)
// Low level macros for getting/setting a segment register.
#define __SET_SEG(SEG, value) \
__set_seg_##SEG(value)
#define __GET_SEG(SEG) \
__get_seg_##SEG()
// Macros for accessing a variable in another segment. (They
// automatically update the %es segment and then make the appropriate
// access.)
#define __GET_FARVAR(seg, var) ({ \
SET_SEG(ES, (seg)); \
GET_VAR(ES, (var)); })
#define __SET_FARVAR(seg, var, val) do { \
typeof(var) __sfv_val = (val); \
SET_SEG(ES, (seg)); \
SET_VAR(ES, (var), __sfv_val); \
} while (0)
// Macros for accesssing a 32bit flat mode pointer from 16bit real
// mode. (They automatically update the %es segment, break the
// pointer into segment/offset, and then make the access.)
#define __GET_FLATPTR(ptr) ({ \
typeof(&(ptr)) __ptr = &(ptr); \
GET_FARVAR(FLATPTR_TO_SEG(__ptr) \
, *(typeof(__ptr))FLATPTR_TO_OFFSET(__ptr)); })
#define __SET_FLATPTR(ptr, val) do { \
typeof (&(ptr)) __ptr = &(ptr); \
SET_FARVAR(FLATPTR_TO_SEG(__ptr) \
, *(typeof(__ptr))FLATPTR_TO_OFFSET(__ptr) \
, (val)); \
} while (0)
// Macros for converting to/from 32bit flat mode pointers to their
// equivalent 16bit segment/offset values.
#define FLATPTR_TO_SEG(p) (((u32)(p)) >> 4)
#define FLATPTR_TO_OFFSET(p) (((u32)(p)) & 0xf)
#define MAKE_FLATPTR(seg,off) ((void*)(((u32)(seg)<<4)+(u32)(off)))
#if MODESEGMENT == 1
// Definitions when using segmented mode.
#define GET_FARVAR(seg, var) __GET_FARVAR((seg), (var))
#define SET_FARVAR(seg, var, val) __SET_FARVAR((seg), (var), (val))
#define GET_VAR(seg, var) __GET_VAR("", seg, (var))
#define SET_VAR(seg, var, val) __SET_VAR("", seg, (var), (val))
#define SET_SEG(SEG, value) __SET_SEG(SEG, (value))
#define GET_SEG(SEG) __GET_SEG(SEG)
#define GET_FLATPTR(ptr) __GET_FLATPTR(ptr)
#define SET_FLATPTR(ptr, val) __SET_FLATPTR((ptr), (val))
static inline void insb_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
insb(port, (u8*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
static inline void insw_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
insw(port, (u16*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
static inline void insl_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
insl(port, (u32*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
static inline void outsb_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
outsb(port, (u8*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
static inline void outsw_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
outsw(port, (u16*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
static inline void outsl_fl(u16 port, void *ptr_fl, u16 count) {
SET_SEG(ES, FLATPTR_TO_SEG(ptr_fl));
outsl(port, (u32*)FLATPTR_TO_OFFSET(ptr_fl), count);
}
#else
// In 32-bit flat mode there is no need to mess with the segments.
#define GET_FARVAR(seg, var) \
(*((typeof(&(var)))MAKE_FLATPTR((seg), &(var))))
#define SET_FARVAR(seg, var, val) \
do { GET_FARVAR((seg), (var)) = (val); } while (0)
#define GET_VAR(seg, var) (var)
#define SET_VAR(seg, var, val) do { (var) = (val); } while (0)
#define SET_SEG(SEG, value) ((void)(value))
#define GET_SEG(SEG) 0
#define GET_FLATPTR(ptr) (ptr)
#define SET_FLATPTR(ptr, val) do { (ptr) = (val); } while (0)
#define insb_fl(port, ptr_fl, count) insb(port, ptr_fl, count)
#define insw_fl(port, ptr_fl, count) insw(port, ptr_fl, count)
#define insl_fl(port, ptr_fl, count) insl(port, ptr_fl, count)
#define outsb_fl(port, ptr_fl, count) outsb(port, ptr_fl, count)
#define outsw_fl(port, ptr_fl, count) outsw(port, ptr_fl, count)
#define outsl_fl(port, ptr_fl, count) outsl(port, ptr_fl, count)
#endif
// Definition for common 16bit segment/offset pointers.
struct segoff_s {
union {
struct {
u16 offset;
u16 seg;
};
u32 segoff;
};
};
#define SEGOFF(s,o) ({struct segoff_s __so; __so.offset=(o); __so.seg=(s); __so;})
static inline struct segoff_s FLATPTR_TO_SEGOFF(void *p) {
return SEGOFF(FLATPTR_TO_SEG(p), FLATPTR_TO_OFFSET(p));
}
static inline void *SEGOFF_TO_FLATPTR(struct segoff_s so) {
return MAKE_FLATPTR(so.seg, so.offset);
}
#endif // farptr.h