From fbfb872f5f417cea48760c535e0ff027c88b507a Mon Sep 17 00:00:00 2001 From: Nathan Lynch Date: Thu, 11 Sep 2014 02:49:08 +0100 Subject: ARM: 8148/1: flush TLS and thumbee register state during exec The TPIDRURO and TPIDRURW registers need to be flushed during exec; otherwise TLS information is potentially leaked. TPIDRURO in particular needs careful treatment. Since flush_thread basically needs the same code used to set the TLS in arm_syscall, pull that into a common set_tls helper in tls.h and use it in both places. Similarly, TEEHBR needs to be cleared during exec as well. Clearing its save slot in thread_info isn't right as there is no guarantee that a thread switch will occur before the new program runs. Just setting the register directly is sufficient. Signed-off-by: Nathan Lynch Acked-by: Will Deacon Cc: Signed-off-by: Russell King --- arch/arm/kernel/traps.c | 17 +---------------- 1 file changed, 1 insertion(+), 16 deletions(-) (limited to 'arch/arm/kernel/traps.c') diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index c8e4bb714944..a964c9f40f87 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -581,7 +581,6 @@ do_cache_op(unsigned long start, unsigned long end, int flags) #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE) asmlinkage int arm_syscall(int no, struct pt_regs *regs) { - struct thread_info *thread = current_thread_info(); siginfo_t info; if ((no >> 16) != (__ARM_NR_BASE>> 16)) @@ -632,21 +631,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) return regs->ARM_r0; case NR(set_tls): - thread->tp_value[0] = regs->ARM_r0; - if (tls_emu) - return 0; - if (has_tls_reg) { - asm ("mcr p15, 0, %0, c13, c0, 3" - : : "r" (regs->ARM_r0)); - } else { - /* - * User space must never try to access this directly. - * Expect your app to break eventually if you do so. - * The user helper at 0xffff0fe0 must be used instead. - * (see entry-armv.S for details) - */ - *((unsigned int *)0xffff0ff0) = regs->ARM_r0; - } + set_tls(regs->ARM_r0); return 0; #ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG -- cgit v1.2.3