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Linux x86 low-level debug register comment synchronization

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This commit updates comments in the low-level debug register code for
Linux x86, making GDB's and gdbserver's implementations identical.

gdb/ChangeLog:

	* x86-linux-nat.c (x86_linux_dr_get): Update comments.
	(x86_linux_dr_set): Likewise.
	(x86_linux_dr_get_addr): Likewise.
	(x86_linux_dr_get_control): Likewise.
	(x86_linux_dr_get_status): Likewise.
	(update_debug_registers_callback): Likewise.
	(x86_linux_dr_set_control): Likewise.
	(x86_linux_dr_set_addr): Likewise.
	(x86_linux_prepare_to_resume): Likewise.
	(x86_linux_new_thread): Likewise.

gdb/gdbserver/ChangeLog:

	* linux-x86-low.c (x86_linux_dr_get): Update comments.
	(x86_linux_dr_set): Likewise.
	(update_debug_registers_callback): Likewise.
	(x86_linux_dr_set_addr): Likewise.
	(x86_linux_dr_get_addr): Likewise.
	(x86_linux_dr_set_control): Likewise.
	(x86_linux_dr_get_control): Likewise.
	(x86_linux_dr_get_status): Likewise.
	(x86_linux_prepare_to_resume): Likewise.
This commit is contained in:
Gary Benson 2015-03-24 14:05:44 +00:00
parent 5dfe6ca8a8
commit 14b0bc68e8
4 changed files with 84 additions and 48 deletions
Download patch file Download diff file Expand all files Collapse all files

48
gdb/gdbserver/linux-x86-low.c
View file

@ -538,6 +538,8 @@ u_debugreg_offset (int regnum)
/* Support for debug registers. */
/* Get debug register REGNUM value from the LWP specified by PTID. */
static unsigned long
x86_linux_dr_get (ptid_t ptid, int regnum)
{
@ -555,6 +557,8 @@ x86_linux_dr_get (ptid_t ptid, int regnum)
return value;
}
/* Set debug register REGNUM to VALUE in the LWP specified by PTID. */
static void
x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
{
@ -569,27 +573,29 @@ x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
perror_with_name (_("Couldn't write debug register"));
}
/* Callback for iterate_over_lwps. Mark that our local mirror of
LWP's debug registers has been changed, and cause LWP to stop if
it isn't already. Values are written from our local mirror to
the actual debug registers immediately prior to LWP resuming. */
static int
update_debug_registers_callback (struct lwp_info *lwp, void *arg)
{
/* The actual update is done later just before resuming the lwp,
we just mark that the registers need updating. */
lwp_set_debug_registers_changed (lwp, 1);
/* If the lwp isn't stopped, force it to momentarily pause, so
we can update its debug registers. */
if (!lwp_is_stopped (lwp))
linux_stop_lwp (lwp);
/* Continue the iteration. */
return 0;
}
/* Update the inferior's debug register REGNUM from STATE. */
/* Store ADDR in debug register REGNUM of all LWPs of the current
inferior. */
static void
x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
{
/* Only update the threads of this process. */
ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (current_lwp_ptid ()));
gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
@ -597,7 +603,8 @@ x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
}
/* Return the inferior's debug register REGNUM. */
/* Return the address stored in the current inferior's debug register
REGNUM. */
static CORE_ADDR
x86_linux_dr_get_addr (int regnum)
@ -607,18 +614,19 @@ x86_linux_dr_get_addr (int regnum)
return x86_linux_dr_get (current_lwp_ptid (), regnum);
}
/* Update the inferior's DR7 debug control register from STATE. */
/* Store CONTROL in the debug control registers of all LWPs of the
current inferior. */
static void
x86_linux_dr_set_control (unsigned long control)
{
/* Only update the threads of this process. */
ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (current_lwp_ptid ()));
iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
}
/* Return the inferior's DR7 debug control register. */
/* Return the value stored in the current inferior's debug control
register. */
static unsigned long
x86_linux_dr_get_control (void)
@ -626,8 +634,8 @@ x86_linux_dr_get_control (void)
return x86_linux_dr_get (current_lwp_ptid (), DR_CONTROL);
}
/* Get the value of the DR6 debug status register from the inferior
and record it in STATE. */
/* Return the value stored in the current inferior's debug status
register. */
static unsigned long
x86_linux_dr_get_status (void)
@ -768,8 +776,8 @@ x86_debug_reg_state (pid_t pid)
return &proc->priv->arch_private->debug_reg_state;
}
/* Called when resuming a thread.
If the debug regs have changed, update the thread's copies. */
/* Called prior to resuming a thread. Updates the thread's debug
registers if the values in our local mirror have been changed. */
static void
x86_linux_prepare_to_resume (struct lwp_info *lwp)
@ -783,6 +791,12 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp)
= x86_debug_reg_state (ptid_get_pid (ptid));
int i;
/* Prior to Linux kernel 2.6.33 commit
72f674d203cd230426437cdcf7dd6f681dad8b0d, setting DR0-3 to
a value that did not match what was enabled in DR_CONTROL
resulted in EINVAL. To avoid this we zero DR_CONTROL before
writing address registers, only writing DR_CONTROL's actual
value once all the addresses are in place. */
x86_linux_dr_set (ptid, DR_CONTROL, 0);
ALL_DEBUG_ADDRESS_REGISTERS (i)
@ -791,12 +805,12 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp)
x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
/* If we're setting a watchpoint, any change the inferior
had done itself to the debug registers needs to be
discarded, otherwise, x86_dr_stopped_data_address can
get confused. */
has made to its debug registers needs to be discarded
to avoid x86_stopped_data_address getting confused. */
clear_status = 1;
}
/* If DR_CONTROL is supposed to be zero then it's already set. */
if (state->dr_control_mirror != 0)
x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);