On Tue, Mar 10, 2015 at 8:22 PM, Denys Vlasenko <[email protected]> wrote: > On 03/10/2015 07:05 PM, Andy Lutomirski wrote: >> x86_32, unlike x86_64, pads the top of the kernel stack. Document >> this padding and give it a name. >> >> This should make no change whatsoever to the compiled kernel image. >> It also doesn't fix any of the current bugs in this area. >> >> Signed-off-by: Andy Lutomirski <[email protected]> >> --- >> arch/x86/include/asm/processor.h | 3 ++- >> arch/x86/include/asm/thread_info.h | 30 ++++++++++++++++++++++++++++++ >> 2 files changed, 32 insertions(+), 1 deletion(-) >> >> diff --git a/arch/x86/include/asm/processor.h >> b/arch/x86/include/asm/processor.h >> index 48a61c1c626e..88d9aa745898 100644 >> --- a/arch/x86/include/asm/processor.h >> +++ b/arch/x86/include/asm/processor.h >> @@ -849,7 +849,8 @@ extern unsigned long thread_saved_pc(struct task_struct >> *tsk); >> #define task_pt_regs(task) \ >> ({ \ >> struct pt_regs *__regs__; \ >> - __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task))-8); \ >> + __regs__ = (struct pt_regs *)(KSTK_TOP(task_stack_page(task)) - \ >> + TOP_OF_KERNEL_STACK_PADDING); \ >> __regs__ - 1; \ >> })
While we are at it, this macro can be simplified further. It uses KSTK_TOP, and it's the only use of that macro. In turn, KSTK_TOP uses THREAD_SIZE_LONGS, and it is the only use of that macro too! (And to nitpick, this macro is whitespace-damaged. Seven space indent). I'll send a patch based on your current git. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
