H.J. Lu <hjl.to...@gmail.com> writes: > On Tue, Sep 15, 2015 at 2:45 PM, Matthew Fortune > <matthew.fort...@imgtec.com> wrote: > > H.J. Lu <hjl.to...@gmail.com> writes: > >> On Thu, Sep 3, 2015 at 10:37 AM, H.J. Lu <hjl.to...@gmail.com> wrote: > >> > The interrupt and exception handlers are called by x86 processors. X86 > >> > hardware puts information on stack and calls the handler. The > >> > requirements are > >> > > >> > 1. Both interrupt and exception handlers must use the 'IRET' instruction, > >> > instead of the 'RET' instruction, to return from the handlers. > >> > 2. All registers are callee-saved in interrupt and exception handlers. > >> > 3. The difference between interrupt and exception handlers is the > >> > exception handler must pop 'ERROR_CODE' off the stack before the 'IRET' > >> > instruction. > >> > > >> > The design goals of interrupt and exception handlers for x86 processors > >> > are: > >> > > >> > 1. No new calling convention in compiler. > >> > 2. Support both 32-bit and 64-bit modes. > >> > 3. Flexible for compilers to optimize. > >> > 4. Easy to use by programmers. > >> > > >> > To implement interrupt and exception handlers for x86 processors, a > >> > compiler should support: > >> > > >> > 1. void * __builtin_ia32_interrupt_data (void) > >> > >> I got a feedback on the name of this builtin function. Since > >> it also works for 64-bit, we should avoid ia32 in its name. > >> We'd like to change it to > >> > >> void * __builtin_interrupt_data (void) > >> > >> Any comments? > > > > For what it's worth, this seems like a good plan to me. I don't know x86 > > but how many variations of interrupt and exception handling mechanisms > > are there? If there are lots then you may want to make it clear which > > subset of them you intend to support. I just added a few more variations > > of interrupt handlers to MIPS and it got complicated quite quickly. > > > > I think I remember someone asking about interrupt handler support for > > x86 some time ago and the answer then was that there were too many > > variants to make it useful. > > In my proposal, there are only 2 handlers: interrupt and exception. > __builtin_interrupt_data is provided to programmers to implement > different variants of those handlers.
Yes, I realised that but was just curious how many hardware interrupt handling schemes there are for x86. I.e. How the handlers are glued into an interrupt vector/how they get routed. Is there a generic piece of code that could at least hook up/install an exception handler on most x86 variants? Matthew
