Commit 56675f8b authored by Helge Deller's avatar Helge Deller Committed by Jens Axboe
Browse files

io_uring/parisc: Adjust pgoff in io_uring mmap() for parisc 



The changes from commit 32832a40 ("io_uring: Fix io_uring mmap() by
using architecture-provided get_unmapped_area()") to the parisc
implementation of get_unmapped_area() broke glibc's locale-gen
executable when running on parisc.

This patch reverts those architecture-specific changes, and instead
adjusts in io_uring_mmu_get_unmapped_area() the pgoff offset which is
then given to parisc's get_unmapped_area() function.  This is much
cleaner than the previous approach, and we still will get a coherent
addresss.

This patch has no effect on other architectures (SHM_COLOUR is only
defined on parisc), and the liburing testcase stil passes on parisc.

Cc: stable@vger.kernel.org # 6.4
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Reported-by: default avatarChristoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: 32832a40 ("io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area()")
Fixes: d808459b ("io_uring: Adjust mapping wrt architecture aliasing requirements")
Link: https://lore.kernel.org/r/ZNEyGV0jyI8kOOfz@p100


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 72dbde0f

arch/parisc/kernel/sys_parisc.c

+5 −10
Original line number Diff line number Diff line
@@ -27,17 +27,12 @@ 
#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)
@@ -117,7 +112,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp, 
	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 */

io_uring/io_uring.c

+3 −0
Original line number Diff line number Diff line
@@ -3470,6 +3470,8 @@ static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp, 
	 * - 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.

	 */
@@ -3478,6 +3480,7 @@ static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp, 
	pgoff = 0;	/* has been translated to ptr above */

#ifdef SHM_COLOUR

	addr = (uintptr_t) ptr;

	pgoff = addr >> PAGE_SHIFT;

#else

	addr = 0UL;

#endif