#include <linux/mm.h>
#include <linux/ptrace.h>
-#ifdef CONFIG_X86_32
-static
-#endif
-unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs)
+unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs)
{
unsigned long addr, seg;
-#ifdef CONFIG_X86_64
- addr = regs->rip;
+ addr = regs->ip;
seg = regs->cs & 0xffff;
-#else
- addr = regs->eip;
- seg = regs->xcs & 0xffff;
- if (regs->eflags & X86_EFLAGS_VM) {
+ if (v8086_mode(regs)) {
addr = (addr & 0xffff) + (seg << 4);
return addr;
}
-#endif
/*
* We'll assume that the code segments in the GDT
{
int i, copied;
unsigned char opcode[15];
- unsigned long addr = convert_rip_to_linear(child, regs);
+ unsigned long addr = convert_ip_to_linear(child, regs);
copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
for (i = 0; i < copied; i++) {
return 0;
}
-void user_enable_single_step(struct task_struct *child)
+/*
+ * Enable single-stepping. Return nonzero if user mode is not using TF itself.
+ */
+static int enable_single_step(struct task_struct *child)
{
struct pt_regs *regs = task_pt_regs(child);
/*
* If TF was already set, don't do anything else
*/
- if (regs->eflags & X86_EFLAGS_TF)
- return;
+ if (regs->flags & X86_EFLAGS_TF)
+ return 0;
/* Set TF on the kernel stack.. */
- regs->eflags |= X86_EFLAGS_TF;
+ regs->flags |= X86_EFLAGS_TF;
/*
* ..but if TF is changed by the instruction we will trace,
* won't clear it by hand later.
*/
if (is_setting_trap_flag(child, regs))
+ return 0;
+
+ set_tsk_thread_flag(child, TIF_FORCED_TF);
+
+ return 1;
+}
+
+/*
+ * Install this value in MSR_IA32_DEBUGCTLMSR whenever child is running.
+ */
+static void write_debugctlmsr(struct task_struct *child, unsigned long val)
+{
+ if (child->thread.debugctlmsr == val)
return;
- child->ptrace |= PT_DTRACE;
+ child->thread.debugctlmsr = val;
+
+ if (child != current)
+ return;
+
+ wrmsrl(MSR_IA32_DEBUGCTLMSR, val);
+}
+
+/*
+ * Enable single or block step.
+ */
+static void enable_step(struct task_struct *child, bool block)
+{
+ /*
+ * Make sure block stepping (BTF) is not enabled unless it should be.
+ * Note that we don't try to worry about any is_setting_trap_flag()
+ * instructions after the first when using block stepping.
+ * So noone should try to use debugger block stepping in a program
+ * that uses user-mode single stepping itself.
+ */
+ if (enable_single_step(child) && block) {
+ set_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+ write_debugctlmsr(child,
+ child->thread.debugctlmsr | DEBUGCTLMSR_BTF);
+ } else {
+ write_debugctlmsr(child,
+ child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
+
+ if (!child->thread.debugctlmsr)
+ clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+ }
+}
+
+void user_enable_single_step(struct task_struct *child)
+{
+ enable_step(child, 0);
+}
+
+void user_enable_block_step(struct task_struct *child)
+{
+ enable_step(child, 1);
}
void user_disable_single_step(struct task_struct *child)
{
+ /*
+ * Make sure block stepping (BTF) is disabled.
+ */
+ write_debugctlmsr(child,
+ child->thread.debugctlmsr & ~DEBUGCTLMSR_BTF);
+
+ if (!child->thread.debugctlmsr)
+ clear_tsk_thread_flag(child, TIF_DEBUGCTLMSR);
+
/* Always clear TIF_SINGLESTEP... */
clear_tsk_thread_flag(child, TIF_SINGLESTEP);
/* But touch TF only if it was set by us.. */
- if (child->ptrace & PT_DTRACE) {
- struct pt_regs *regs = task_pt_regs(child);
- regs->eflags &= ~X86_EFLAGS_TF;
- child->ptrace &= ~PT_DTRACE;
- }
+ if (test_and_clear_tsk_thread_flag(child, TIF_FORCED_TF))
+ task_pt_regs(child)->flags &= ~X86_EFLAGS_TF;
}