On Wed, Jun 05, 2002 at 11:53:10AM -0700, Linus Torvalds wrote:
> All of the flags should be "sticky one-bits", so just oring them should do
> the right thing.
>
> That way we don't have to add nasty BUG checks to the code, and since
> we're already dirtying both cache-lines the extra overhead should
> literally be just the cost of doing one locked "orl".
This patch on top of the others should do that. I've placed a full
diff from 2.5.20 to the current code at
http://www.kvack.org/~blah/stack-v2.5.20-A2.diff .
-ben
-- "You will be reincarnated as a toad; and you will be much happier.":r ~/patches/v2.5.20/v2.5.20-smallstack-A0-A1.diff diff -urN stackcheck-v2.5.20-A1/arch/i386/kernel/entry.S stack-2.5.20.diff/arch/i386/kernel/entry.S --- stackcheck-v2.5.20-A1/arch/i386/kernel/entry.S Wed Jun 5 15:59:12 2002 +++ stack-2.5.20.diff/arch/i386/kernel/entry.S Wed Jun 5 15:55:09 2002 @@ -365,26 +365,34 @@ movl TI_IRQ_STACK(%ebx),%ecx movl TI_TASK(%ebx),%edx movl %esp,%eax - leal (THREAD_SIZE-4)(%ecx),%ebx + leal (THREAD_SIZE-4)(%ecx),%esi testl %ecx,%ecx # is there a valid irq_stack? # switch to the irq stack #ifdef CONFIG_X86_HAVE_CMOV - cmovnz %ebx,%esp -#warning using cmov + cmovnz %esi,%esp #else -#warning cannot use cmov jnz 1f - mov %ebx,%esp + mov %esi,%esp 1: #endif # update the task pointer in the irq stack - GET_THREAD_INFO(%ebx) - movl %edx,TI_TASK(%ebx) + GET_THREAD_INFO(%esi) + movl %edx,TI_TASK(%esi) call do_IRQ + movl %eax,%esp # potentially restore non-irq stack + + # copy flags from the irq stack back into the task's thread_info + # %esi is saved over the do_IRQ call and contains the irq stack + # thread_info pointer + # %ebx contains the original thread_info pointer + movl TI_FLAGS(%esi),%eax + movl $0,TI_FLAGS(%esi) + LOCK orl %eax,TI_FLAGS(%ebx) + jmp ret_from_intr #define BUILD_INTERRUPT(name, nr) \ diff -urN stackcheck-v2.5.20-A1/arch/i386/kernel/smpboot.c stack-2.5.20.diff/arch/i386/kernel/smpboot.c --- stackcheck-v2.5.20-A1/arch/i386/kernel/smpboot.c Wed Jun 5 15:59:08 2002 +++ stack-2.5.20.diff/arch/i386/kernel/smpboot.c Wed Jun 5 15:12:36 2002 @@ -875,7 +875,13 @@ /* So we see what's up */ printk("Booting processor %d/%d eip %lx\n", cpu, apicid, start_eip); - stack_start.esp = (void *) (THREAD_SIZE + (char *)idle->thread_info); + + /* The -4 is to correct for the fact that the stack pointer + * is used to find the location of the thread_info structure + * by masking off several of the LSBs. Without the -4, esp + * is pointing to the page after the one the stack is on. + */ + stack_start.esp = (void *)(THREAD_SIZE - 4 + (char *)idle->thread_info); /* * This grunge runs the startup process for diff -urN stackcheck-v2.5.20-A1/include/asm-i386/thread_info.h stack-2.5.20.diff/include/asm-i386/thread_info.h --- stackcheck-v2.5.20-A1/include/asm-i386/thread_info.h Wed Jun 5 15:59:08 2002 +++ stack-2.5.20.diff/include/asm-i386/thread_info.h Wed Jun 5 14:55:04 2002 @@ -57,6 +57,7 @@ * macros/functions for gaining access to the thread information structure */ #define THREAD_ORDER 0 +#define INIT_THREAD_SIZE THREAD_SIZE #ifndef __ASSEMBLY__ #define init_thread_info (init_thread_union.thread_info) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Jun 07 2002 - 22:00:26 EST