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x86 setup: sizeof() is unsigned, unbreak comparisons 

We use signed values for limit checking since the values can go
negative under certain circumstances.  However, sizeof() is unsigned
and forces the comparison to be unsigned, so move the comparison into
the heap_free() macros so we can ensure it is a signed comparison.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2007-10-25 16:09:38 -07:00
parent 6b6815c6d5
commit e6e1ace990
4 changed files with 5 additions and 5 deletions
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4
arch/x86/boot/boot.h
View File

@ -216,9 +216,9 @@ static inline char *__get_heap(size_t s, size_t a, size_t n)
#define GET_HEAP(type, n) \ #define GET_HEAP(type, n) \
((type *)__get_heap(sizeof(type),__alignof__(type),(n))) ((type *)__get_heap(sizeof(type),__alignof__(type),(n)))
static inline int heap_free(void) static inline bool heap_free(size_t n)
{ {
return heap_end-HEAP; return (int)(heap_end-HEAP) >= (int)n;
} }
/* copy.S */ /* copy.S */

2
arch/x86/boot/video-bios.c
View File

@ -79,7 +79,7 @@ static int bios_probe(void)
video_bios.modes = GET_HEAP(struct mode_info, 0); video_bios.modes = GET_HEAP(struct mode_info, 0);
for (mode = 0x14; mode <= 0x7f; mode++) { for (mode = 0x14; mode <= 0x7f; mode++) {
if (heap_free() < sizeof(struct mode_info)) if (!heap_free(sizeof(struct mode_info)))
break; break;
if (mode_defined(VIDEO_FIRST_BIOS+mode)) if (mode_defined(VIDEO_FIRST_BIOS+mode))

2
arch/x86/boot/video-vesa.c
View File

@ -57,7 +57,7 @@ static int vesa_probe(void)
while ((mode = rdfs16(mode_ptr)) != 0xffff) { while ((mode = rdfs16(mode_ptr)) != 0xffff) {
mode_ptr += 2; mode_ptr += 2;
if (heap_free() < sizeof(struct mode_info)) if (!heap_free(sizeof(struct mode_info)))
break; /* Heap full, can't save mode info */ break; /* Heap full, can't save mode info */
if (mode & ~0x1ff) if (mode & ~0x1ff)

2
arch/x86/boot/video.c
View File

@ -371,7 +371,7 @@ static void save_screen(void)
saved.curx = boot_params.screen_info.orig_x; saved.curx = boot_params.screen_info.orig_x;
saved.cury = boot_params.screen_info.orig_y; saved.cury = boot_params.screen_info.orig_y;
if (heap_free() < saved.x*saved.y*sizeof(u16)+512) if (!heap_free(saved.x*saved.y*sizeof(u16)+512))
return; /* Not enough heap to save the screen */ return; /* Not enough heap to save the screen */
saved.data = GET_HEAP(u16, saved.x*saved.y); saved.data = GET_HEAP(u16, saved.x*saved.y);