#include <linux/elf-randomize.h>
/*
- * Construct an artificial page offset for the mapping based on the virtual
+ * Construct an artificial page offset for the mapping based on the physical
* address of the kernel file mapping variable.
- * If filp is zero the calculated pgoff value aliases the memory of the given
- * address. This is useful for io_uring where the mapping shall alias a kernel
- * address and a userspace adress where both the kernel and the userspace
- * access the same memory region.
*/
-#define GET_FILP_PGOFF(filp, addr) \
- ((filp ? (((unsigned long) filp->f_mapping) >> 8) \
- & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL) \
- + (addr >> PAGE_SHIFT))
+#define GET_FILP_PGOFF(filp) \
+ (filp ? (((unsigned long) filp->f_mapping) >> 8) \
+ & ((SHM_COLOUR-1) >> PAGE_SHIFT) : 0UL)
static unsigned long shared_align_offset(unsigned long filp_pgoff,
unsigned long pgoff)
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
- filp_pgoff = GET_FILP_PGOFF(filp, addr);
+ filp_pgoff = GET_FILP_PGOFF(filp);
if (flags & MAP_FIXED) {
/* Even MAP_FIXED mappings must reside within TASK_SIZE */
* - use the kernel virtual address of the shared io_uring context
* (instead of the userspace-provided address, which has to be 0UL
* anyway).
+ * - use the same pgoff which the get_unmapped_area() uses to
+ * calculate the page colouring.
* For architectures without such aliasing requirements, the
* architecture will return any suitable mapping because addr is 0.
*/
pgoff = 0; /* has been translated to ptr above */
#ifdef SHM_COLOUR
addr = (uintptr_t) ptr;
+ pgoff = addr >> PAGE_SHIFT;
#else
addr = 0UL;
#endif