From 2498814fcb3068f19b82b1519b4038721f61af43 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 23 Apr 2012 15:38:28 +0100 Subject: ARM: 7399/1: vfp: move user vfp state save/restore code out of signal.c The user VFP state must be preserved (subject to ucontext modifications) across invocation of a signal handler and this is currently handled by vfp_{preserve,restore}_context in signal.c Since this code requires intimate low-level knowledge of the VFP state, this patch moves it into vfpmodule.c. Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/include/asm/thread_info.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index d4c24d412a8d..0f04d84582e1 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -118,6 +118,13 @@ extern void iwmmxt_task_switch(struct thread_info *); extern void vfp_sync_hwstate(struct thread_info *); extern void vfp_flush_hwstate(struct thread_info *); +struct user_vfp; +struct user_vfp_exc; + +extern int vfp_preserve_user_clear_hwstate(struct user_vfp __user *, + struct user_vfp_exc __user *); +extern int vfp_restore_user_hwstate(struct user_vfp __user *, + struct user_vfp_exc __user *); #endif /* -- cgit v1.2.1 From 6a1c53124aa161eb624ce7b1e40ade728186d34c Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 27 Apr 2012 12:45:07 +0100 Subject: ARM: 7403/1: tls: remove covert channel via TPIDRURW TPIDRURW is a user read/write register forming part of the group of thread registers in more recent versions of the ARM architecture (~v6+). Currently, the kernel does not touch this register, which allows tasks to communicate covertly by reading and writing to the register without context-switching affecting its contents. This patch clears TPIDRURW when TPIDRURO is updated via the set_tls macro, which is called directly from __switch_to. Since the current behaviour makes the register useless to userspace as far as thread pointers are concerned, simply clearing the register (rather than saving and restoring it) will not cause any problems to userspace. Cc: stable@vger.kernel.org Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/include/asm/tls.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/include') diff --git a/arch/arm/include/asm/tls.h b/arch/arm/include/asm/tls.h index 60843eb0f61c..73409e6c0251 100644 --- a/arch/arm/include/asm/tls.h +++ b/arch/arm/include/asm/tls.h @@ -7,6 +7,8 @@ .macro set_tls_v6k, tp, tmp1, tmp2 mcr p15, 0, \tp, c13, c0, 3 @ set TLS register + mov \tmp1, #0 + mcr p15, 0, \tmp1, c13, c0, 2 @ clear user r/w TLS register .endm .macro set_tls_v6, tp, tmp1, tmp2 @@ -15,6 +17,8 @@ mov \tmp2, #0xffff0fff tst \tmp1, #HWCAP_TLS @ hardware TLS available? mcrne p15, 0, \tp, c13, c0, 3 @ yes, set TLS register + movne \tmp1, #0 + mcrne p15, 0, \tmp1, c13, c0, 2 @ clear user r/w TLS register streq \tp, [\tmp2, #-15] @ set TLS value at 0xffff0ff0 .endm -- cgit v1.2.1