[PATCH] UML - Remove debugging code from page fault path

From: Jeff Dike (jdike_at_addtoit.com)
Date: 07/31/05

  • Next message: blaisorblade_at_yahoo.it: "[patch 1/1] UML Support - SYSEMU: slight cleanup and speedup" 
    To: akpm@osdl.org
Date:	Sun, 31 Jul 2005 13:13:41 -0400

    This eliminates the segfault info ring buffer, which added a system call to
    each page fault, and which hadn't been useful for debugging in ages.

    Signed-off-by: Jeff Dike <jdike@addtoit.com>

    Index: linux-2.6.12/arch/um/kernel/trap_kern.c
    ===================================================================
    --- linux-2.6.12.orig/arch/um/kernel/trap_kern.c 2005-07-31 12:54:35.000000000 -0400
    +++ linux-2.6.12/arch/um/kernel/trap_kern.c 2005-07-31 13:18:40.000000000 -0400
    @@ -200,30 +200,3 @@
     void trap_init(void)
     {
     }
    -
    -DEFINE_SPINLOCK(trap_lock);
    -
    -static int trap_index = 0;
    -
    -int next_trap_index(int limit)
    -{
    - int ret;
    -
    - spin_lock(&trap_lock);
    - ret = trap_index;
    - if(++trap_index == limit)
    - trap_index = 0;
    - spin_unlock(&trap_lock);
    - return(ret);
    -}
    -
    -/*
    - * Overrides for Emacs so that we follow Linus's tabbing style.
    - * Emacs will notice this stuff at the end of the file and automatically
    - * adjust the settings for this buffer only. This must remain at the end
    - * of the file.
    - * ---------------------------------------------------------------------------
    - * Local variables:
    - * c-file-style: "linux"
    - * End:
    - */
    Index: linux-2.6.12/arch/um/kernel/trap_user.c
    ===================================================================
    --- linux-2.6.12.orig/arch/um/kernel/trap_user.c 2005-07-31 12:54:35.000000000 -0400
    +++ linux-2.6.12/arch/um/kernel/trap_user.c 2005-07-31 13:18:02.000000000 -0400
    @@ -40,35 +40,14 @@
             } while(1);
     }
     
    -/* Unlocked - don't care if this is a bit off */
    -int nsegfaults = 0;
    -
    -struct {
    - unsigned long address;
    - int is_write;
    - int pid;
    - unsigned long sp;
    - int is_user;
    -} segfault_record[1024];
    -
     void segv_handler(int sig, union uml_pt_regs *regs)
     {
    - int index, max;
             struct faultinfo * fi = UPT_FAULTINFO(regs);
     
             if(UPT_IS_USER(regs) && !SEGV_IS_FIXABLE(fi)){
                     bad_segv(*fi, UPT_IP(regs));
                     return;
             }
    - max = sizeof(segfault_record)/sizeof(segfault_record[0]);
    - index = next_trap_index(max);
    -
    - nsegfaults++;
    - segfault_record[index].address = FAULT_ADDRESS(*fi);
    - segfault_record[index].pid = os_getpid();
    - segfault_record[index].is_write = FAULT_WRITE(*fi);
    - segfault_record[index].sp = UPT_SP(regs);
    - segfault_record[index].is_user = UPT_IS_USER(regs);
             segv(*fi, UPT_IP(regs), UPT_IS_USER(regs), regs);
     }
     

    -
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