On Mon, Oct 11, 2010 at 03:36:03AM +0530, Rabin Vincent wrote: > On Sat, Oct 09, 2010 at 08:37:57PM +0100, Russell King - ARM Linux wrote: > > On Sat, Oct 09, 2010 at 11:20:50PM +0530, Rabin Vincent wrote: > > > It's used just for the C entry functions for interrupts: asm_do_IRQ() > > > and the IPI and local timer functions. > > > > > > AFAICS __exception seems to be used only for is_exception_text(). If > > > that's the case, would it be OK to just place those functions in > > > __irq_entry if ftrace is built and have is_exception_text() check that > > > section too? > > > > No. is_exception_text() is used to detect those functions which have > > a specific stack layout - which is that there's a pt_regs struct on the > > stack. Grouping other functions into that violates the expectation. > > I'm not sure I follow. These functions (asm_do_IRQ(), do_IPI(), and > do_local_timer()) will be the only ones in __irq_entry. iow, __irq_entry > will contain nothing else except these functions. So we woudn't be > grouping other functions; it's just that some of the __exception > functions would be moved to the new section so that __exception and > __irq_entry combined will contain the functions with the specific stack > layout (and only those functions). And now to go back to the original question I asked: What is __irq_entry used for? If it's to identify those functions which can't be traced through because of the stack layout, that's true of all __exception marked functions - so we might as well make the linker symbols for irqentry alias the exception text symbols. I see nothing special of just the three functions you mention that warrant them being handled separately by ftrace. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
