diff options
| author | André Hentschel <nerv@dawncrow.de> | 2013-06-18 23:23:26 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2013-06-24 15:21:59 +0100 |
| commit | a4780adeefd042482f624f5e0d577bf9cdcbb760 (patch) | |
| tree | ead0e79b4f797a26cc30fc1596ada6fd6da5daf6 /arch/arm/kernel/traps.c | |
| parent | 4a1b573346ee0d64d95beb78d49a5bbb574e6c6a (diff) | |
| download | blackbird-obmc-linux-a4780adeefd042482f624f5e0d577bf9cdcbb760.tar.gz blackbird-obmc-linux-a4780adeefd042482f624f5e0d577bf9cdcbb760.zip | |
ARM: 7735/2: Preserve the user r/w register TPIDRURW on context switch and fork
Since commit 6a1c53124aa1 the user writeable TLS register was zeroed to
prevent it from being used as a covert channel between two tasks.
There are more and more applications coming to Windows RT,
Wine could support them, but mostly they expect to have
the thread environment block (TEB) in TPIDRURW.
This patch preserves that register per thread instead of clearing it.
Unlike the TPIDRURO, which is already switched, the TPIDRURW
can be updated from userspace so needs careful treatment in the case that we
modify TPIDRURW and call fork(). To avoid this we must always read
TPIDRURW in copy_thread.
Signed-off-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Jonathan Austin <jonathan.austin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/traps.c')
| -rw-r--r-- | arch/arm/kernel/traps.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 18b32e8e4497..517bfd4da1c9 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -581,7 +581,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) return regs->ARM_r0; case NR(set_tls): - thread->tp_value = regs->ARM_r0; + thread->tp_value[0] = regs->ARM_r0; if (tls_emu) return 0; if (has_tls_reg) { @@ -699,7 +699,7 @@ static int get_tp_trap(struct pt_regs *regs, unsigned int instr) int reg = (instr >> 12) & 15; if (reg == 15) return 1; - regs->uregs[reg] = current_thread_info()->tp_value; + regs->uregs[reg] = current_thread_info()->tp_value[0]; regs->ARM_pc += 4; return 0; } |
