On Mon, May 22, 2017 at 10:12:22AM +0800, Jin, Yao wrote: > Hi Peter, > > Maybe it's not very easy to move the skid checking to generic code > because we don't have a common kernel_ip() available to determine if > ip is a kernel address. > > I was trying to move kernel_ip() from arch/x86/events/perf_event.h > to generic code, but some difficulties I have: > > For example, in new kernel_ip(), we may use many > conditional-compilation for all arch, for example: > > #ifdef CONFIG_X86_32 > return ip > PAGE_OFFSET; > #endif > > #ifdef CONFIG_X86_64 > return (long)ip < 0; > #endif > > #ifdef CONFIG_ARM.... > ...... > #ifdef CONFIG_MIPS.... > ...... > > But the code is being ugly and hard to maintain. And frankly I don't > know kernel address space for all arch. > > Any idea? Could we just do at x86 side this time?
Can we not check user_mode(regs) for all architectures? !user_mode(regs) implies a kernel sample. Thanks, Mark.
