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

The changes from commit 32832a407a ("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: Helge Deller <deller@gmx.de>
Reported-by: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
Fixes: 32832a407a ("io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area()")
Fixes: d808459b2e ("io_uring: Adjust mapping wrt architecture aliasing requirements")
Link: https://lore.kernel.org/r/ZNEyGV0jyI8kOOfz@p100
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Helge Deller 2023-08-07 20:04:09 +02:00 committed by Jens Axboe
parent 72dbde0f2a
commit 56675f8b9f
2 changed files with 8 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/parisc/kernel/sys_parisc.c
View File

@ -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 */

3
io_uring/io_uring.c
View File

@ -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