From: "H. Peter Anvin (Intel)" <hpa@xxxxxxxxx> When using FRED, reserve space at the top of the stack frame, just like i386 does. A future version of FRED might have dynamic frame sizes, though, in which case it might be necessary to make TOP_OF_KERNEL_STACK_PADDING a variable instead of a constant. Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> Signed-off-by: Xin Li <xin3.li@xxxxxxxxx> --- arch/x86/include/asm/thread_info.h | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index f1cccba52eb9..998483078d5f 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -31,7 +31,9 @@ * In vm86 mode, the hardware frame is much longer still, so add 16 * bytes to make room for the real-mode segments. * - * x86_64 has a fixed-length stack frame. + * x86-64 has a fixed-length stack frame, but it depends on whether + * or not FRED is enabled. Future versions of FRED might make this + * dynamic, but for now it is always 2 words longer. */ #ifdef CONFIG_X86_32 # ifdef CONFIG_VM86 @@ -39,8 +41,12 @@ # else # define TOP_OF_KERNEL_STACK_PADDING 8 # endif -#else -# define TOP_OF_KERNEL_STACK_PADDING 0 +#else /* x86-64 */ +# ifdef CONFIG_X86_FRED +# define TOP_OF_KERNEL_STACK_PADDING (2*8) +# else +# define TOP_OF_KERNEL_STACK_PADDING 0 +# endif #endif /* -- 2.34.1
