1d7173baf2
This patch implements soft interrupts. Interrupt enabling and disabling no
longer map to sigprocmask. Rather, a flag is set indicating whether
interrupts may be handled. If a signal comes in and interrupts are marked as
OK, then it is handled normally. If interrupts are marked as off, then the
signal handler simply returns after noting that a signal needs handling. When
interrupts are enabled later on, this pending signals flag is checked, and the
IRQ handlers are called at that point.
The point of this is to reduce the cost of local_irq_save et al, since they
are very much more common than the signals that they are enabling and
disabling. Soft interrupts produce a speed-up of ~25% on a kernel build.
Subtleties -
UML uses sigsetjmp/siglongjmp to switch contexts. sigsetjmp has been
wrapped in a save_flags-like macro which remembers the interrupt state at
setjmp time, and restores it when it is longjmp-ed back to.
The enable_signals function has to loop because the IRQ handler
disables interrupts before returning. enable_signals has to return with
signals enabled, and signals may come in between the disabling and the
return to enable_signals. So, it loops for as long as there are pending
signals, ensuring that signals are enabled when it finally returns, and
that there are no pending signals that need to be dealt with.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
117 lines
2.4 KiB
C
117 lines
2.4 KiB
C
/*
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* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <limits.h>
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#include <setjmp.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/utsname.h>
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#include <sys/param.h>
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#include <sys/time.h>
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#include "asm/types.h"
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#include <ctype.h>
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#include <signal.h>
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#include <wait.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <sched.h>
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#include <termios.h>
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#include <string.h>
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#include "user_util.h"
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#include "kern_util.h"
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#include "user.h"
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#include "mem_user.h"
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#include "init.h"
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#include "ptrace_user.h"
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#include "uml-config.h"
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#include "os.h"
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#include "longjmp.h"
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void stack_protections(unsigned long address)
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{
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int prot = PROT_READ | PROT_WRITE | PROT_EXEC;
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if(mprotect((void *) address, page_size(), prot) < 0)
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panic("protecting stack failed, errno = %d", errno);
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}
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void task_protections(unsigned long address)
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{
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unsigned long guard = address + page_size();
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unsigned long stack = guard + page_size();
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int prot = 0, pages;
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#ifdef notdef
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if(mprotect((void *) stack, page_size(), prot) < 0)
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panic("protecting guard page failed, errno = %d", errno);
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#endif
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pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER) - 2;
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prot = PROT_READ | PROT_WRITE | PROT_EXEC;
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if(mprotect((void *) stack, pages * page_size(), prot) < 0)
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panic("protecting stack failed, errno = %d", errno);
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}
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int raw(int fd)
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{
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struct termios tt;
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int err;
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CATCH_EINTR(err = tcgetattr(fd, &tt));
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if(err < 0)
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return -errno;
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cfmakeraw(&tt);
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CATCH_EINTR(err = tcsetattr(fd, TCSADRAIN, &tt));
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if(err < 0)
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return -errno;
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/* XXX tcsetattr could have applied only some changes
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* (and cfmakeraw() is a set of changes) */
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return(0);
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}
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void setup_machinename(char *machine_out)
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{
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struct utsname host;
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uname(&host);
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#if defined(UML_CONFIG_UML_X86) && !defined(UML_CONFIG_64BIT)
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if (!strcmp(host.machine, "x86_64")) {
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strcpy(machine_out, "i686");
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return;
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}
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#endif
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strcpy(machine_out, host.machine);
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}
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char host_info[(_UTSNAME_LENGTH + 1) * 4 + _UTSNAME_NODENAME_LENGTH + 1];
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void setup_hostinfo(void)
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{
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struct utsname host;
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uname(&host);
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sprintf(host_info, "%s %s %s %s %s", host.sysname, host.nodename,
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host.release, host.version, host.machine);
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}
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int setjmp_wrapper(void (*proc)(void *, void *), ...)
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{
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va_list args;
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sigjmp_buf buf;
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int n;
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n = sigsetjmp(buf, 1);
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if(n == 0){
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va_start(args, proc);
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(*proc)(&buf, &args);
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}
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va_end(args);
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return(n);
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}
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