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972410b023
Call arch_switch also in switch_to_skas, even if it's, for now, a no-op for that case (and mark this in the comment); this will change soon. Also, arch_switch for TT mode is actually useless when the PT proxy (a complicate debugging instrumentation for TT mode) is not enabled. In fact, it only calls update_debugregs, which checks debugregs_seq against seq (to check if the registers are up-to-date - seq here means a "version number" of the registers). If the ptrace proxy is not enabled, debugregs_seq always stays 0 and update_debugregs will be a no-op. So, optimize this out (the compiler can't do it). Also, I've been disappointed by the fact that it would make a lot of sense if, after calling a successful update_debugregs(current->thread.arch.debugregs_seq), current->thread.arch.debugregs_seq were updated with the new debugregs_seq. But this is not done. Is this a bug or a feature? For all purposes, it seems a bug (otherwise the whole mechanism does not make sense, which is also a possibility to check), which causes some performance only problems (not correctness), since we write_debugregs when not needed. Also, as suggested by Jeff, remove a redundant enabling of SIGVTALRM, comprised in the subsequent local_irq_enable(). I'm just a bit dubious if ordering matters there... Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
140 lines
3.2 KiB
C
140 lines
3.2 KiB
C
/*
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* Copyright (C) 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 <errno.h>
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#include <unistd.h>
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#include <linux/stddef.h>
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#include "ptrace_user.h"
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/* Grr, asm/user.h includes asm/ptrace.h, so has to follow ptrace_user.h */
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#include <asm/user.h>
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#include "kern_util.h"
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#include "sysdep/thread.h"
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#include "user.h"
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#include "os.h"
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#include "uml-config.h"
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int ptrace_getregs(long pid, unsigned long *regs_out)
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{
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if (ptrace(PTRACE_GETREGS, pid, 0, regs_out) < 0)
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return -errno;
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return 0;
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}
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int ptrace_setregs(long pid, unsigned long *regs)
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{
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if (ptrace(PTRACE_SETREGS, pid, 0, regs) < 0)
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return -errno;
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return 0;
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}
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int ptrace_getfpregs(long pid, unsigned long *regs)
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{
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if (ptrace(PTRACE_GETFPREGS, pid, 0, regs) < 0)
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return -errno;
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return 0;
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}
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int ptrace_setfpregs(long pid, unsigned long *regs)
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{
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if (ptrace(PTRACE_SETFPREGS, pid, 0, regs) < 0)
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return -errno;
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return 0;
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}
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/* All the below stuff is of interest for TT mode only */
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static void write_debugregs(int pid, unsigned long *regs)
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{
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struct user *dummy;
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int nregs, i;
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dummy = NULL;
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nregs = sizeof(dummy->u_debugreg)/sizeof(dummy->u_debugreg[0]);
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for(i = 0; i < nregs; i++){
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if((i == 4) || (i == 5)) continue;
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if(ptrace(PTRACE_POKEUSR, pid, &dummy->u_debugreg[i],
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regs[i]) < 0)
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printk("write_debugregs - ptrace failed on "
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"register %d, value = 0x%x, errno = %d\n", i,
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regs[i], errno);
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}
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}
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static void read_debugregs(int pid, unsigned long *regs)
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{
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struct user *dummy;
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int nregs, i;
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dummy = NULL;
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nregs = sizeof(dummy->u_debugreg)/sizeof(dummy->u_debugreg[0]);
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for(i = 0; i < nregs; i++){
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regs[i] = ptrace(PTRACE_PEEKUSR, pid,
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&dummy->u_debugreg[i], 0);
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}
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}
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/* Accessed only by the tracing thread */
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static unsigned long kernel_debugregs[8] = { [ 0 ... 7 ] = 0 };
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void arch_enter_kernel(void *task, int pid)
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{
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read_debugregs(pid, TASK_DEBUGREGS(task));
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write_debugregs(pid, kernel_debugregs);
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}
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void arch_leave_kernel(void *task, int pid)
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{
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read_debugregs(pid, kernel_debugregs);
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write_debugregs(pid, TASK_DEBUGREGS(task));
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}
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#ifdef UML_CONFIG_PT_PROXY
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/* Accessed only by the tracing thread */
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static int debugregs_seq;
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/* Only called by the ptrace proxy */
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void ptrace_pokeuser(unsigned long addr, unsigned long data)
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{
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if((addr < offsetof(struct user, u_debugreg[0])) ||
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(addr > offsetof(struct user, u_debugreg[7])))
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return;
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addr -= offsetof(struct user, u_debugreg[0]);
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addr = addr >> 2;
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if(kernel_debugregs[addr] == data) return;
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kernel_debugregs[addr] = data;
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debugregs_seq++;
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}
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static void update_debugregs_cb(void *arg)
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{
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int pid = *((int *) arg);
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write_debugregs(pid, kernel_debugregs);
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}
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/* Optimized out in its header when not defined */
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void update_debugregs(int seq)
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{
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int me;
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if(seq == debugregs_seq) return;
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me = os_getpid();
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initial_thread_cb(update_debugregs_cb, &me);
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}
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#endif
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/*
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* Overrides for Emacs so that we follow Linus's tabbing style.
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* Emacs will notice this stuff at the end of the file and automatically
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* adjust the settings for this buffer only. This must remain at the end
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* of the file.
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* ---------------------------------------------------------------------------
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* Local variables:
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* c-file-style: "linux"
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* End:
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*/
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