kernel_optimize_test/arch/s390/include/asm/mmu.h
Vasily Gorbik d1befa6582 s390/vdso: avoid 64-bit vdso mapping for compat tasks
vdso_fault used is_compat_task function (on s390 it tests "current"
thread_info flags) to distinguish compat tasks and map 31-bit vdso
pages. But "current" task might not correspond to mm context.

When 31-bit compat inferior is executed under gdb, gdb does
PTRACE_PEEKTEXT on vdso page, causing vdso_fault with "current" being
64-bit gdb process. So, 31-bit inferior ends up with 64-bit vdso mapped.

To avoid this problem a new compat_mm flag has been introduced into
mm context. This flag is used in vdso_fault and vdso_mremap instead
of is_compat_task.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-09-20 13:20:29 +02:00

59 lines
1.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __MMU_H
#define __MMU_H
#include <linux/cpumask.h>
#include <linux/errno.h>
typedef struct {
spinlock_t lock;
cpumask_t cpu_attach_mask;
atomic_t flush_count;
unsigned int flush_mm;
struct list_head pgtable_list;
struct list_head gmap_list;
unsigned long gmap_asce;
unsigned long asce;
unsigned long asce_limit;
unsigned long vdso_base;
/*
* The following bitfields need a down_write on the mm
* semaphore when they are written to. As they are only
* written once, they can be read without a lock.
*
* The mmu context allocates 4K page tables.
*/
unsigned int alloc_pgste:1;
/* The mmu context uses extended page tables. */
unsigned int has_pgste:1;
/* The mmu context uses storage keys. */
unsigned int uses_skeys:1;
/* The mmu context uses CMM. */
unsigned int uses_cmm:1;
/* The gmaps associated with this context are allowed to use huge pages. */
unsigned int allow_gmap_hpage_1m:1;
/* The mmu context is for compat task */
unsigned int compat_mm:1;
} mm_context_t;
#define INIT_MM_CONTEXT(name) \
.context.lock = __SPIN_LOCK_UNLOCKED(name.context.lock), \
.context.pgtable_list = LIST_HEAD_INIT(name.context.pgtable_list), \
.context.gmap_list = LIST_HEAD_INIT(name.context.gmap_list),
static inline int tprot(unsigned long addr)
{
int rc = -EFAULT;
asm volatile(
" tprot 0(%1),0\n"
"0: ipm %0\n"
" srl %0,28\n"
"1:\n"
EX_TABLE(0b,1b)
: "+d" (rc) : "a" (addr) : "cc");
return rc;
}
#endif