#ifndef LIBKIR_H
#define LIBKIR_H
#include "realmode.h"
#ifndef ASSEMBLY
/*
* Full API documentation for these functions is in realmode.h.
*
*/
/* Access to variables in .data16 and .text16 in a way compatible with librm */
#define __data16( variable ) variable
#define __data16_array( variable, array ) variable array
#define __bss16( variable ) variable
#define __bss16_array( variable, array ) variable array
#define __text16( variable ) variable
#define __text16_array( variable,array ) variable array
#define __use_data16( variable ) variable
#define __use_text16( variable ) variable
#define __from_data16( pointer ) pointer
#define __from_text16( pointer ) pointer
/* Real-mode data and code segments */
static inline __attribute__ (( always_inline )) unsigned int _rm_cs ( void ) {
uint16_t cs;
__asm__ __volatile__ ( "movw %%cs, %w0" : "=r" ( cs ) );
return cs;
}
static inline __attribute__ (( always_inline )) unsigned int _rm_ds ( void ) {
uint16_t ds;
__asm__ __volatile__ ( "movw %%ds, %w0" : "=r" ( ds ) );
return ds;
}
#define rm_cs ( _rm_cs() )
#define rm_ds ( _rm_ds() )
/* Copy to/from base memory */
static inline void copy_to_real_libkir ( unsigned int dest_seg,
unsigned int dest_off,
const void *src, size_t n ) {
unsigned int discard_D, discard_S, discard_c;
__asm__ __volatile__ ( "pushw %%es\n\t"
"movw %3, %%es\n\t"
"rep movsb\n\t"
"popw %%es\n\t"
: "=D" ( discard_D ), "=S" ( discard_S ),
"=c" ( discard_c )
: "r" ( dest_seg ), "D" ( dest_off ),
"S" ( src ),
"c" ( n )
: "memory" );
}
static inline void copy_from_real_libkir ( void *dest,
unsigned int src_seg,
unsigned int src_off,
size_t n ) {
unsigned int discard_D, discard_S, discard_c;
__asm__ __volatile__ ( "pushw %%ds\n\t"
"movw %4, %%ds\n\t"
"rep movsb\n\t"
"popw %%ds\n\t"
: "=D" ( discard_D ), "=S" ( discard_S ),
"=c" ( discard_c )
: "D" ( dest ),
"r" ( src_seg ), "S" ( src_off ),
"c" ( n )
: "memory" );
}
#define copy_to_real copy_to_real_libkir
#define copy_from_real copy_from_real_libkir
/*
* Transfer individual values to/from base memory. There may well be
* a neater way to do this. We have two versions: one for constant
* offsets (where the mov instruction must be of the form "mov
* %es:123, %xx") and one for non-constant offsets (where the mov
* instruction must be of the form "mov %es:(%xx), %yx". If it's
* possible to incorporate both forms into one __asm__ instruction, I
* don't know how to do it.
*
* Ideally, the mov instruction should be "mov%z0"; the "%z0" is meant
* to expand to either "b", "w" or "l" depending on the size of
* operand 0. This would remove the (minor) ambiguity in the mov
* instruction. However, gcc on at least my system barfs with an
* "internal compiler error" when confronted with %z0.
*
*/
#define put_real_kir_const_off( var, seg, off ) \
__asm__ ( "movw %w1, %%es\n\t" \
"mov %0, %%es:%c2\n\t" \
"pushw %%ds\n\t" /* restore %es */ \
"popw %%es\n\t" \
: \
: "r,r" ( var ), "rm,rm" ( seg ), "i,!r" ( off ) \
)
#define put_real_kir_nonconst_off( var, seg, off ) \
__asm__ ( "movw %w1, %%es\n\t" \
"mov %0, %%es:(%2)\n\t" \
"pushw %%ds\n\t" /* restore %es */ \
"popw %%es\n\t" \
: \
: "r" ( var ), "rm" ( seg ), "r" ( off ) \
)
#define put_real_kir( var, seg, off ) \
do { \
if ( __builtin_constant_p ( off ) ) \
put_real_kir_const_off ( var, seg, off ); \
else \
put_real_kir_nonconst_off ( var, seg, off ); \
} while ( 0 )
#define get_real_kir_const_off( var, seg, off ) \
__asm__ ( "movw %w1, %%es\n\t" \
"mov %%es:%c2, %0\n\t" \
"pushw %%ds\n\t" /* restore %es */ \
"popw %%es\n\t" \
: "=r,r" ( var ) \
: "rm,rm" ( seg ), "i,!r" ( off ) \
)
#define get_real_kir_nonconst_off( var, seg, off ) \
__asm__ ( "movw %w1, %%es\n\t" \
"mov %%es:(%2), %0\n\t" \
"pushw %%ds\n\t" /* restore %es */ \
"popw %%es\n\t" \
: "=r" ( var ) \
: "rm" ( seg ), "r" ( off ) \
)
#define get_real_kir( var, seg, off ) \
do { \
if ( __builtin_constant_p ( off ) ) \
get_real_kir_const_off ( var, seg, off ); \
else \
get_real_kir_nonconst_off ( var, seg, off ); \
} while ( 0 )
#define put_real put_real_kir
#define get_real get_real_kir
/**
* A pointer to a user buffer
*
* This is actually a struct segoff, but encoded as a uint32_t to
* ensure that gcc passes it around efficiently.
*/
typedef uint32_t userptr_t;
/**
* Copy data to user buffer
*
* @v buffer User buffer
* @v offset Offset within user buffer
* @v src Source
* @v len Length
*/
static inline __attribute__ (( always_inline )) void
copy_to_user ( userptr_t buffer, off_t offset, const void *src, size_t len ) {
copy_to_real ( ( buffer >> 16 ), ( ( buffer & 0xffff ) + offset ),
src, len );
}
/**
* Copy data from user buffer
*
* @v dest Destination
* @v buffer User buffer
* @v offset Offset within user buffer
* @v len Length
*/
static inline __attribute__ (( always_inline )) void
copy_from_user ( void *dest, userptr_t buffer, off_t offset, size_t len ) {
copy_from_real ( dest, ( buffer >> 16 ),
( ( buffer & 0xffff ) + offset ), len );
}
/**
* Convert segment:offset address to user buffer
*
* @v segment Real-mode segment
* @v offset Real-mode offset
* @ret buffer User buffer
*/
static inline __attribute__ (( always_inline )) userptr_t
real_to_user ( unsigned int segment, unsigned int offset ) {
return ( ( segment << 16 ) | offset );
}
/**
* Convert virtual address to user buffer
*
* @v virtual Virtual address
* @ret buffer User buffer
*
* This constructs a user buffer from an ordinary pointer. Use it
* when you need to pass a pointer to an internal buffer to a function
* that expects a @c userptr_t.
*/
static inline __attribute__ (( always_inline )) userptr_t
virt_to_user ( void * virtual ) {
return real_to_user ( rm_ds, ( intptr_t ) virtual );
}
/* TEXT16_CODE: declare a fragment of code that resides in .text16 */
#define TEXT16_CODE( asm_code_str ) \
".section \".text16\", \"ax\", @progbits\n\t" \
".code16\n\t" \
".arch i386\n\t" \
asm_code_str "\n\t" \
".code16gcc\n\t" \
".previous\n\t"
/* REAL_CODE: declare a fragment of code that executes in real mode */
#define REAL_CODE( asm_code_str ) \
".code16\n\t" \
asm_code_str "\n\t" \
".code16gcc\n\t"
#endif /* ASSEMBLY */
#endif /* LIBKIR_H */
