From a82582b1af6a4a57ca53bcfad9f71428cb5f9a54 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Sat, 2 May 2020 15:26:10 +0100 Subject: [PATCH] xen/x86: atomic: Don't allow to write atomically in a pointer to const At the moment, write_atomic() will happily write to a pointer to const. While there are no use in Xen, it would be best to catch them at compilation time. Signed-off-by: Julien Grall Acked-by: Jan Beulich --- xen/include/asm-x86/atomic.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/xen/include/asm-x86/atomic.h b/xen/include/asm-x86/atomic.h index 6b40f9c9f8..27aad43aaa 100644 --- a/xen/include/asm-x86/atomic.h +++ b/xen/include/asm-x86/atomic.h @@ -63,6 +63,8 @@ void __bad_atomic_size(void); #define write_atomic(p, x) ({ \ typeof(*(p)) __x = (x); \ + /* Check that the pointer is not a const type */ \ + void *__maybe_unused p_ = &__x; \ unsigned long x_ = (unsigned long)__x; \ switch ( sizeof(*(p)) ) { \ case 1: write_u8_atomic((uint8_t *)(p), x_); break; \ -- 2.30.2