From a0fc1436f1f4f84e93144480bf30e0c958d135b6 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Fri, 31 Jul 2020 12:38:05 -0700 Subject: xtensa: add missing exclusive access state management The result of the s32ex opcode is recorded in the ATOMCTL special register and must be retrieved with the getex opcode. Context switch between s32ex and getex may trash the ATOMCTL register and result in duplicate update or missing update of the atomic variable. Add atomctl8 field to the struct thread_info and use getex to swap ATOMCTL bit 8 as a part of context switch. Clear exclusive access monitor on kernel entry. Cc: stable@vger.kernel.org Fixes: f7c34874f04a ("xtensa: add exclusive atomics support") Signed-off-by: Max Filippov --- arch/xtensa/kernel/asm-offsets.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/xtensa/kernel/asm-offsets.c') diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c index 33a257b33723..dc5c83cad9be 100644 --- a/arch/xtensa/kernel/asm-offsets.c +++ b/arch/xtensa/kernel/asm-offsets.c @@ -93,6 +93,9 @@ int main(void) DEFINE(THREAD_RA, offsetof (struct task_struct, thread.ra)); DEFINE(THREAD_SP, offsetof (struct task_struct, thread.sp)); DEFINE(THREAD_CPENABLE, offsetof (struct thread_info, cpenable)); +#if XCHAL_HAVE_EXCLUSIVE + DEFINE(THREAD_ATOMCTL8, offsetof (struct thread_info, atomctl8)); +#endif #if XTENSA_HAVE_COPROCESSORS DEFINE(THREAD_XTREGS_CP0, offsetof(struct thread_info, xtregs_cp.cp0)); DEFINE(THREAD_XTREGS_CP1, offsetof(struct thread_info, xtregs_cp.cp1)); -- cgit v1.2.3