diff options
Diffstat (limited to 'ANDROID_3.4.5/arch/x86/kernel/step.c')
| -rw-r--r-- | ANDROID_3.4.5/arch/x86/kernel/step.c | 216 |
1 files changed, 0 insertions, 216 deletions
diff --git a/ANDROID_3.4.5/arch/x86/kernel/step.c b/ANDROID_3.4.5/arch/x86/kernel/step.c deleted file mode 100644 index c346d116..00000000 --- a/ANDROID_3.4.5/arch/x86/kernel/step.c +++ /dev/null @@ -1,216 +0,0 @@ -/* - * x86 single-step support code, common to 32-bit and 64-bit. - */ -#include <linux/sched.h> -#include <linux/mm.h> -#include <linux/ptrace.h> -#include <asm/desc.h> - -unsigned long convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs) -{ - unsigned long addr, seg; - - addr = regs->ip; - seg = regs->cs & 0xffff; - if (v8086_mode(regs)) { - addr = (addr & 0xffff) + (seg << 4); - return addr; - } - - /* - * We'll assume that the code segments in the GDT - * are all zero-based. That is largely true: the - * TLS segments are used for data, and the PNPBIOS - * and APM bios ones we just ignore here. - */ - if ((seg & SEGMENT_TI_MASK) == SEGMENT_LDT) { - struct desc_struct *desc; - unsigned long base; - - seg &= ~7UL; - - mutex_lock(&child->mm->context.lock); - if (unlikely((seg >> 3) >= child->mm->context.size)) - addr = -1L; /* bogus selector, access would fault */ - else { - desc = child->mm->context.ldt + seg; - base = get_desc_base(desc); - - /* 16-bit code segment? */ - if (!desc->d) - addr &= 0xffff; - addr += base; - } - mutex_unlock(&child->mm->context.lock); - } - - return addr; -} - -static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) -{ - int i, copied; - unsigned char opcode[15]; - 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++) { - switch (opcode[i]) { - /* popf and iret */ - case 0x9d: case 0xcf: - return 1; - - /* CHECKME: 64 65 */ - - /* opcode and address size prefixes */ - case 0x66: case 0x67: - continue; - /* irrelevant prefixes (segment overrides and repeats) */ - case 0x26: case 0x2e: - case 0x36: case 0x3e: - case 0x64: case 0x65: - case 0xf0: case 0xf2: case 0xf3: - continue; - -#ifdef CONFIG_X86_64 - case 0x40 ... 0x4f: - if (!user_64bit_mode(regs)) - /* 32-bit mode: register increment */ - return 0; - /* 64-bit mode: REX prefix */ - continue; -#endif - - /* CHECKME: f2, f3 */ - - /* - * pushf: NOTE! We should probably not let - * the user see the TF bit being set. But - * it's more pain than it's worth to avoid - * it, and a debugger could emulate this - * all in user space if it _really_ cares. - */ - case 0x9c: - default: - return 0; - } - } - return 0; -} - -/* - * 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); - unsigned long oflags; - - /* - * If we stepped into a sysenter/syscall insn, it trapped in - * kernel mode; do_debug() cleared TF and set TIF_SINGLESTEP. - * If user-mode had set TF itself, then it's still clear from - * do_debug() and we need to set it again to restore the user - * state so we don't wrongly set TIF_FORCED_TF below. - * If enable_single_step() was used last and that is what - * set TIF_SINGLESTEP, then both TF and TIF_FORCED_TF are - * already set and our bookkeeping is fine. - */ - if (unlikely(test_tsk_thread_flag(child, TIF_SINGLESTEP))) - regs->flags |= X86_EFLAGS_TF; - - /* - * Always set TIF_SINGLESTEP - this guarantees that - * we single-step system calls etc.. This will also - * cause us to set TF when returning to user mode. - */ - set_tsk_thread_flag(child, TIF_SINGLESTEP); - - oflags = regs->flags; - - /* Set TF on the kernel stack.. */ - regs->flags |= X86_EFLAGS_TF; - - /* - * ..but if TF is changed by the instruction we will trace, - * don't mark it as being "us" that set it, so that we - * won't clear it by hand later. - * - * Note that if we don't actually execute the popf because - * of a signal arriving right now or suchlike, we will lose - * track of the fact that it really was "us" that set it. - */ - if (is_setting_trap_flag(child, regs)) { - clear_tsk_thread_flag(child, TIF_FORCED_TF); - return 0; - } - - /* - * If TF was already set, check whether it was us who set it. - * If not, we should never attempt a block step. - */ - if (oflags & X86_EFLAGS_TF) - return test_tsk_thread_flag(child, TIF_FORCED_TF); - - set_tsk_thread_flag(child, TIF_FORCED_TF); - - return 1; -} - -/* - * 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 no one should try to use debugger block stepping in a program - * that uses user-mode single stepping itself. - */ - if (enable_single_step(child) && block) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl |= DEBUGCTLMSR_BTF; - update_debugctlmsr(debugctl); - set_tsk_thread_flag(child, TIF_BLOCKSTEP); - } else if (test_tsk_thread_flag(child, TIF_BLOCKSTEP)) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl &= ~DEBUGCTLMSR_BTF; - update_debugctlmsr(debugctl); - clear_tsk_thread_flag(child, TIF_BLOCKSTEP); - } -} - -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. - */ - if (test_tsk_thread_flag(child, TIF_BLOCKSTEP)) { - unsigned long debugctl = get_debugctlmsr(); - - debugctl &= ~DEBUGCTLMSR_BTF; - update_debugctlmsr(debugctl); - clear_tsk_thread_flag(child, TIF_BLOCKSTEP); - } - - /* Always clear TIF_SINGLESTEP... */ - clear_tsk_thread_flag(child, TIF_SINGLESTEP); - - /* But touch TF only if it was set by us.. */ - if (test_and_clear_tsk_thread_flag(child, TIF_FORCED_TF)) - task_pt_regs(child)->flags &= ~X86_EFLAGS_TF; -} |