From 52d4224dd26a601b13e41467703c784e1b14ad9d Mon Sep 17 00:00:00 2001 From: Szabolcs Nagy Date: Tue, 19 Apr 2022 15:18:56 +0100 Subject: cheri: fix posix timers We need to distinguish timerids that are small integers returned by the kernel and timerids that are pointers to struct timer. The existing pointer tagging does not work for CHERI because of the pointer shift. Simply use the top bit without shift to tag pointers. This still relies on the top byte ignore of aarch64 (the top byte does not affect the capability representation) and that pointers are not tagged for other reasons (like HWASAN). Note: this is morello specific and does not work for generic cheri. --- sysdeps/unix/sysv/linux/kernel-posix-timers.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/sysdeps/unix/sysv/linux/kernel-posix-timers.h b/sysdeps/unix/sysv/linux/kernel-posix-timers.h index 82ce92f2ae..371e328258 100644 --- a/sysdeps/unix/sysv/linux/kernel-posix-timers.h +++ b/sysdeps/unix/sysv/linux/kernel-posix-timers.h @@ -79,6 +79,25 @@ kernel_timer_to_timerid (kernel_timer_t ktimerid) return (timer_t) ((intptr_t) ktimerid); } +#ifdef __CHERI_PURE_CAPABILITY__ +static inline timer_t +timer_to_timerid (struct timer *ptr) +{ + return (timer_t) ((uintptr_t) ptr | ~(-1UL/2)); +} + +static inline bool +timer_is_sigev_thread (timer_t timerid) +{ + return ((uintptr_t) timerid & ~(-1UL/2)) != 0; +} + +static inline struct timer * +timerid_to_timer (timer_t timerid) +{ + return (struct timer *)((uintptr_t) timerid & (-1UL/2)); +} +#else static inline timer_t timer_to_timerid (struct timer *ptr) { @@ -96,6 +115,7 @@ timerid_to_timer (timer_t timerid) { return (struct timer *)((uintptr_t) timerid << 1); } +#endif static inline kernel_timer_t timerid_to_kernel_timer (timer_t timerid) -- cgit 1.4.1