linux/arch/um/sys-i386/ptrace_user.c

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/*
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <linux/stddef.h>
#include "ptrace_user.h"
/* Grr, asm/user.h includes asm/ptrace.h, so has to follow ptrace_user.h */
#include <asm/user.h>
#include "kern_util.h"
#include "sysdep/thread.h"
#include "user.h"
#include "os.h"
[PATCH] uml: clean arch_switch usage 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>
2006-03-31 18:30:21 +08:00
#include "uml-config.h"
int ptrace_getregs(long pid, unsigned long *regs_out)
{
if (ptrace(PTRACE_GETREGS, pid, 0, regs_out) < 0)
return -errno;
return 0;
}
int ptrace_setregs(long pid, unsigned long *regs)
{
if (ptrace(PTRACE_SETREGS, pid, 0, regs) < 0)
return -errno;
return 0;
}
int ptrace_getfpregs(long pid, unsigned long *regs)
{
if (ptrace(PTRACE_GETFPREGS, pid, 0, regs) < 0)
return -errno;
return 0;
}
int ptrace_setfpregs(long pid, unsigned long *regs)
{
if (ptrace(PTRACE_SETFPREGS, pid, 0, regs) < 0)
return -errno;
return 0;
}
[PATCH] uml: clean arch_switch usage 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>
2006-03-31 18:30:21 +08:00
/* All the below stuff is of interest for TT mode only */
static void write_debugregs(int pid, unsigned long *regs)
{
struct user *dummy;
int nregs, i;
dummy = NULL;
nregs = sizeof(dummy->u_debugreg)/sizeof(dummy->u_debugreg[0]);
for(i = 0; i < nregs; i++){
if((i == 4) || (i == 5)) continue;
if(ptrace(PTRACE_POKEUSR, pid, &dummy->u_debugreg[i],
regs[i]) < 0)
printk("write_debugregs - ptrace failed on "
"register %d, value = 0x%lx, errno = %d\n", i,
regs[i], errno);
}
}
static void read_debugregs(int pid, unsigned long *regs)
{
struct user *dummy;
int nregs, i;
dummy = NULL;
nregs = sizeof(dummy->u_debugreg)/sizeof(dummy->u_debugreg[0]);
for(i = 0; i < nregs; i++){
regs[i] = ptrace(PTRACE_PEEKUSR, pid,
&dummy->u_debugreg[i], 0);
}
}
/* Accessed only by the tracing thread */
static unsigned long kernel_debugregs[8] = { [ 0 ... 7 ] = 0 };
void arch_enter_kernel(void *task, int pid)
{
read_debugregs(pid, TASK_DEBUGREGS(task));
write_debugregs(pid, kernel_debugregs);
}
void arch_leave_kernel(void *task, int pid)
{
read_debugregs(pid, kernel_debugregs);
write_debugregs(pid, TASK_DEBUGREGS(task));
}
[PATCH] uml: clean arch_switch usage 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>
2006-03-31 18:30:21 +08:00
#ifdef UML_CONFIG_PT_PROXY
/* Accessed only by the tracing thread */
static int debugregs_seq;
/* Only called by the ptrace proxy */
void ptrace_pokeuser(unsigned long addr, unsigned long data)
{
if((addr < offsetof(struct user, u_debugreg[0])) ||
(addr > offsetof(struct user, u_debugreg[7])))
return;
addr -= offsetof(struct user, u_debugreg[0]);
addr = addr >> 2;
if(kernel_debugregs[addr] == data) return;
kernel_debugregs[addr] = data;
debugregs_seq++;
}
static void update_debugregs_cb(void *arg)
{
int pid = *((int *) arg);
write_debugregs(pid, kernel_debugregs);
}
[PATCH] uml: clean arch_switch usage 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>
2006-03-31 18:30:21 +08:00
/* Optimized out in its header when not defined */
void update_debugregs(int seq)
{
int me;
if(seq == debugregs_seq) return;
me = os_getpid();
initial_thread_cb(update_debugregs_cb, &me);
}
[PATCH] uml: clean arch_switch usage 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>
2006-03-31 18:30:21 +08:00
#endif
/*
* 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:
*/