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Revision eb35bdd7bca29a13c8ecd44e6fd747a84ce675db authored by Will Deacon on 11 September 2014, 13:38:16 UTC, committed by Will Deacon on 11 September 2014, 17:34:58 UTC 
arm64: flush TLS registers during exec
 
Nathan reports that we leak TLS information from the parent context
during an exec, as we don't clear the TLS registers when flushing the
thread state.

This patch updates the flushing code so that we:

  (1) Unconditionally zero the tpidr_el0 register (since this is fully
      context switched for native tasks and zeroed for compat tasks)

  (2) Zero the tp_value state in thread_info before clearing the
      tpidrr0_el0 register for compat tasks (since this is only writable
      by the set_tls compat syscall and therefore not fully switched).

A missing compiler barrier is also added to the compat set_tls syscall.

Cc: <stable@vger.kernel.org>
Acked-by: Nathan Lynch <Nathan_Lynch@mentor.com>
Reported-by: Nathan Lynch <Nathan_Lynch@mentor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
1 parent 3d8afe3
Raw File
do_mounts.h 
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/major.h>
#include <linux/root_dev.h>

void  change_floppy(char *fmt, ...);
void  mount_block_root(char *name, int flags);
void  mount_root(void);
extern int root_mountflags;

static inline int create_dev(char *name, dev_t dev)
{
	sys_unlink(name);
	return sys_mknod(name, S_IFBLK|0600, new_encode_dev(dev));
}

#if BITS_PER_LONG == 32
static inline u32 bstat(char *name)
{
	struct stat64 stat;
	if (sys_stat64(name, &stat) != 0)
		return 0;
	if (!S_ISBLK(stat.st_mode))
		return 0;
	if (stat.st_rdev != (u32)stat.st_rdev)
		return 0;
	return stat.st_rdev;
}
#else
static inline u32 bstat(char *name)
{
	struct stat stat;
	if (sys_newstat(name, &stat) != 0)
		return 0;
	if (!S_ISBLK(stat.st_mode))
		return 0;
	return stat.st_rdev;
}
#endif

#ifdef CONFIG_BLK_DEV_RAM

int __init rd_load_disk(int n);
int __init rd_load_image(char *from);

#else

static inline int rd_load_disk(int n) { return 0; }
static inline int rd_load_image(char *from) { return 0; }

#endif

#ifdef CONFIG_BLK_DEV_INITRD

int __init initrd_load(void);

#else

static inline int initrd_load(void) { return 0; }

#endif

#ifdef CONFIG_BLK_DEV_MD

void md_run_setup(void);

#else

static inline void md_run_setup(void) {}

#endif
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