diff options
Diffstat (limited to 'gdb/i386-linux-nat.c')
| -rw-r--r-- | gdb/i386-linux-nat.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c index f4d8d5f..1ee7503 100644 --- a/gdb/i386-linux-nat.c +++ b/gdb/i386-linux-nat.c @@ -732,7 +732,7 @@ update_debug_registers_callback (struct lwp_info *lwp, void *arg) return 0; } -/* Set DR_CONTROL to ADDR in all LWPs of the current inferior. */ +/* Set DR_CONTROL to CONTROL in all LWPs of the current inferior. */ static void x86_linux_dr_set_control (unsigned long control) @@ -775,9 +775,16 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp) = i386_debug_reg_state (ptid_get_pid (lwp->ptid)); int i; - /* See amd64_linux_prepare_to_resume for Linux kernel note on - i386_linux_dr_set calls ordering. */ + /* On Linux kernel before 2.6.33 commit + 72f674d203cd230426437cdcf7dd6f681dad8b0d + if you enable a breakpoint by the DR_CONTROL bits you need to have + already written the corresponding DR_FIRSTADDR...DR_LASTADDR registers. + Ensure DR_CONTROL gets written as the very last register here. */ + + /* Clear DR_CONTROL first. In some cases, setting DR0-3 to a + value that doesn't match what is enabled in DR_CONTROL + results in EINVAL. */ x86_linux_dr_set (lwp->ptid, DR_CONTROL, 0); for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++) @@ -792,6 +799,8 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp) clear_status = 1; } + /* If DR_CONTROL is supposed to be zero, we've already set it + above. */ if (state->dr_control_mirror != 0) x86_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror); |