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![Roland McGrath](/assets/img/avatar_default.png)
This renames ptrace_32.c back to ptrace.c, in preparation for merging the 32/64 versions of these files. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
484 lines
12 KiB
C
484 lines
12 KiB
C
/* By Ross Biro 1/23/92 */
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/*
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* Pentium III FXSR, SSE support
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/errno.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/security.h>
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#include <linux/audit.h>
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#include <linux/seccomp.h>
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#include <linux/signal.h>
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#include <asm/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/debugreg.h>
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#include <asm/ldt.h>
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#include <asm/desc.h>
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/*
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* does not yet catch signals sent when the child dies.
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* in exit.c or in signal.c.
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*/
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/*
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* Determines which flags the user has access to [1 = access, 0 = no access].
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* Prohibits changing ID(21), VIP(20), VIF(19), VM(17), NT(14), IOPL(12-13), IF(9).
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* Also masks reserved bits (31-22, 15, 5, 3, 1).
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*/
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#define FLAG_MASK 0x00050dd5
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static long *pt_regs_access(struct pt_regs *regs, unsigned long regno)
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{
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BUILD_BUG_ON(offsetof(struct pt_regs, bx) != 0);
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if (regno > FS)
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--regno;
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return ®s->bx + regno;
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}
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static int putreg(struct task_struct *child,
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unsigned long regno, unsigned long value)
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{
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struct pt_regs *regs = task_pt_regs(child);
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regno >>= 2;
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switch (regno) {
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case GS:
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if (value && (value & 3) != 3)
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return -EIO;
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child->thread.gs = value;
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if (child == current)
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/*
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* The user-mode %gs is not affected by
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* kernel entry, so we must update the CPU.
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*/
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loadsegment(gs, value);
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return 0;
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case DS:
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case ES:
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case FS:
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if (value && (value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case SS:
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case CS:
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if ((value & 3) != 3)
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return -EIO;
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value &= 0xffff;
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break;
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case EFL:
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value &= FLAG_MASK;
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/*
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* If the user value contains TF, mark that
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* it was not "us" (the debugger) that set it.
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* If not, make sure it stays set if we had.
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*/
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if (value & X86_EFLAGS_TF)
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clear_tsk_thread_flag(child, TIF_FORCED_TF);
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else if (test_tsk_thread_flag(child, TIF_FORCED_TF))
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value |= X86_EFLAGS_TF;
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value |= regs->flags & ~FLAG_MASK;
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break;
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}
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*pt_regs_access(regs, regno) = value;
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return 0;
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}
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static unsigned long getreg(struct task_struct *child, unsigned long regno)
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{
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struct pt_regs *regs = task_pt_regs(child);
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unsigned long retval = ~0UL;
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regno >>= 2;
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switch (regno) {
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case EFL:
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/*
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* If the debugger set TF, hide it from the readout.
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*/
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retval = regs->flags;
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if (test_tsk_thread_flag(child, TIF_FORCED_TF))
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retval &= ~X86_EFLAGS_TF;
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break;
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case GS:
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retval = child->thread.gs;
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if (child == current)
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savesegment(gs, retval);
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break;
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case DS:
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case ES:
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case FS:
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case SS:
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case CS:
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retval = 0xffff;
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/* fall through */
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default:
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retval &= *pt_regs_access(regs, regno);
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}
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return retval;
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}
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/*
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* This function is trivial and will be inlined by the compiler.
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* Having it separates the implementation details of debug
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* registers from the interface details of ptrace.
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*/
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static unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
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{
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switch (n) {
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case 0: return child->thread.debugreg0;
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case 1: return child->thread.debugreg1;
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case 2: return child->thread.debugreg2;
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case 3: return child->thread.debugreg3;
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case 6: return child->thread.debugreg6;
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case 7: return child->thread.debugreg7;
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}
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return 0;
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}
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static int ptrace_set_debugreg(struct task_struct *child,
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int n, unsigned long data)
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{
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int i;
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if (unlikely(n == 4 || n == 5))
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return -EIO;
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if (n < 4 && unlikely(data >= TASK_SIZE - 3))
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return -EIO;
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switch (n) {
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case 0: child->thread.debugreg0 = data; break;
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case 1: child->thread.debugreg1 = data; break;
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case 2: child->thread.debugreg2 = data; break;
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case 3: child->thread.debugreg3 = data; break;
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case 6:
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child->thread.debugreg6 = data;
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break;
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case 7:
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/*
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* Sanity-check data. Take one half-byte at once with
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* check = (val >> (16 + 4*i)) & 0xf. It contains the
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* R/Wi and LENi bits; bits 0 and 1 are R/Wi, and bits
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* 2 and 3 are LENi. Given a list of invalid values,
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* we do mask |= 1 << invalid_value, so that
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* (mask >> check) & 1 is a correct test for invalid
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* values.
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*
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* R/Wi contains the type of the breakpoint /
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* watchpoint, LENi contains the length of the watched
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* data in the watchpoint case.
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*
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* The invalid values are:
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* - LENi == 0x10 (undefined), so mask |= 0x0f00.
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* - R/Wi == 0x10 (break on I/O reads or writes), so
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* mask |= 0x4444.
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* - R/Wi == 0x00 && LENi != 0x00, so we have mask |=
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* 0x1110.
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*
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* Finally, mask = 0x0f00 | 0x4444 | 0x1110 == 0x5f54.
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*
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* See the Intel Manual "System Programming Guide",
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* 15.2.4
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*
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* Note that LENi == 0x10 is defined on x86_64 in long
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* mode (i.e. even for 32-bit userspace software, but
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* 64-bit kernel), so the x86_64 mask value is 0x5454.
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* See the AMD manual no. 24593 (AMD64 System Programming)
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*/
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data &= ~DR_CONTROL_RESERVED;
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for (i = 0; i < 4; i++)
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if ((0x5f54 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
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return -EIO;
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child->thread.debugreg7 = data;
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if (data)
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set_tsk_thread_flag(child, TIF_DEBUG);
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else
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clear_tsk_thread_flag(child, TIF_DEBUG);
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break;
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}
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return 0;
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}
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/*
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* Called by kernel/ptrace.c when detaching..
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*
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* Make sure the single step bit is not set.
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*/
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void ptrace_disable(struct task_struct *child)
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{
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user_disable_single_step(child);
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clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
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}
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long arch_ptrace(struct task_struct *child, long request, long addr, long data)
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{
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struct user * dummy = NULL;
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int i, ret;
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unsigned long __user *datap = (unsigned long __user *)data;
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switch (request) {
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/* when I and D space are separate, these will need to be fixed. */
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case PTRACE_PEEKTEXT: /* read word at location addr. */
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case PTRACE_PEEKDATA:
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ret = generic_ptrace_peekdata(child, addr, data);
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break;
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/* read the word at location addr in the USER area. */
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case PTRACE_PEEKUSR: {
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unsigned long tmp;
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ret = -EIO;
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if ((addr & 3) || addr < 0 ||
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addr > sizeof(struct user) - 3)
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break;
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tmp = 0; /* Default return condition */
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if(addr < FRAME_SIZE*sizeof(long))
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tmp = getreg(child, addr);
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if(addr >= (long) &dummy->u_debugreg[0] &&
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addr <= (long) &dummy->u_debugreg[7]){
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addr -= (long) &dummy->u_debugreg[0];
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addr = addr >> 2;
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tmp = ptrace_get_debugreg(child, addr);
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}
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ret = put_user(tmp, datap);
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break;
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}
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/* when I and D space are separate, this will have to be fixed. */
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case PTRACE_POKETEXT: /* write the word at location addr. */
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case PTRACE_POKEDATA:
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ret = generic_ptrace_pokedata(child, addr, data);
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break;
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case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
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ret = -EIO;
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if ((addr & 3) || addr < 0 ||
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addr > sizeof(struct user) - 3)
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break;
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if (addr < FRAME_SIZE*sizeof(long)) {
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ret = putreg(child, addr, data);
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break;
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}
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/* We need to be very careful here. We implicitly
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want to modify a portion of the task_struct, and we
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have to be selective about what portions we allow someone
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to modify. */
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ret = -EIO;
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if(addr >= (long) &dummy->u_debugreg[0] &&
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addr <= (long) &dummy->u_debugreg[7]){
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addr -= (long) &dummy->u_debugreg;
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addr = addr >> 2;
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ret = ptrace_set_debugreg(child, addr, data);
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}
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break;
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case PTRACE_GETREGS: { /* Get all gp regs from the child. */
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if (!access_ok(VERIFY_WRITE, datap, FRAME_SIZE*sizeof(long))) {
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ret = -EIO;
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break;
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}
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for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
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__put_user(getreg(child, i), datap);
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datap++;
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}
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ret = 0;
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break;
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}
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case PTRACE_SETREGS: { /* Set all gp regs in the child. */
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unsigned long tmp;
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if (!access_ok(VERIFY_READ, datap, FRAME_SIZE*sizeof(long))) {
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ret = -EIO;
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break;
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}
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for ( i = 0; i < FRAME_SIZE*sizeof(long); i += sizeof(long) ) {
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__get_user(tmp, datap);
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putreg(child, i, tmp);
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datap++;
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}
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ret = 0;
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break;
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}
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case PTRACE_GETFPREGS: { /* Get the child FPU state. */
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if (!access_ok(VERIFY_WRITE, datap,
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sizeof(struct user_i387_struct))) {
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ret = -EIO;
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break;
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}
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ret = 0;
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if (!tsk_used_math(child))
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init_fpu(child);
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get_fpregs((struct user_i387_struct __user *)data, child);
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break;
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}
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case PTRACE_SETFPREGS: { /* Set the child FPU state. */
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if (!access_ok(VERIFY_READ, datap,
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sizeof(struct user_i387_struct))) {
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ret = -EIO;
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break;
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}
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set_stopped_child_used_math(child);
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set_fpregs(child, (struct user_i387_struct __user *)data);
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ret = 0;
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break;
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}
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case PTRACE_GETFPXREGS: { /* Get the child extended FPU state. */
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if (!access_ok(VERIFY_WRITE, datap,
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sizeof(struct user_fxsr_struct))) {
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ret = -EIO;
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break;
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}
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if (!tsk_used_math(child))
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init_fpu(child);
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ret = get_fpxregs((struct user_fxsr_struct __user *)data, child);
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break;
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}
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case PTRACE_SETFPXREGS: { /* Set the child extended FPU state. */
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if (!access_ok(VERIFY_READ, datap,
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sizeof(struct user_fxsr_struct))) {
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ret = -EIO;
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break;
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}
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set_stopped_child_used_math(child);
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ret = set_fpxregs(child, (struct user_fxsr_struct __user *)data);
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break;
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}
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case PTRACE_GET_THREAD_AREA:
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if (addr < 0)
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return -EIO;
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ret = do_get_thread_area(child, addr,
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(struct user_desc __user *) data);
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break;
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case PTRACE_SET_THREAD_AREA:
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if (addr < 0)
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return -EIO;
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ret = do_set_thread_area(child, addr,
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(struct user_desc __user *) data, 0);
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break;
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default:
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ret = ptrace_request(child, request, addr, data);
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break;
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}
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return ret;
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}
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void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
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{
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struct siginfo info;
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tsk->thread.trap_no = 1;
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tsk->thread.error_code = error_code;
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memset(&info, 0, sizeof(info));
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info.si_signo = SIGTRAP;
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info.si_code = TRAP_BRKPT;
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/* User-mode ip? */
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info.si_addr = user_mode_vm(regs) ? (void __user *) regs->ip : NULL;
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/* Send us the fake SIGTRAP */
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force_sig_info(SIGTRAP, &info, tsk);
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}
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/* notification of system call entry/exit
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* - triggered by current->work.syscall_trace
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*/
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__attribute__((regparm(3)))
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int do_syscall_trace(struct pt_regs *regs, int entryexit)
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{
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int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU);
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/*
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* With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
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* interception
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*/
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int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
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int ret = 0;
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/* do the secure computing check first */
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if (!entryexit)
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secure_computing(regs->orig_ax);
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if (unlikely(current->audit_context)) {
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if (entryexit)
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audit_syscall_exit(AUDITSC_RESULT(regs->ax),
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regs->ax);
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/* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
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* on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
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* not used, entry.S will call us only on syscall exit, not
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* entry; so when TIF_SYSCALL_AUDIT is used we must avoid
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* calling send_sigtrap() on syscall entry.
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*
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* Note that when PTRACE_SYSEMU_SINGLESTEP is used,
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* is_singlestep is false, despite his name, so we will still do
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* the correct thing.
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*/
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else if (is_singlestep)
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goto out;
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}
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if (!(current->ptrace & PT_PTRACED))
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goto out;
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/* If a process stops on the 1st tracepoint with SYSCALL_TRACE
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* and then is resumed with SYSEMU_SINGLESTEP, it will come in
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* here. We have to check this and return */
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if (is_sysemu && entryexit)
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return 0;
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/* Fake a debug trap */
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if (is_singlestep)
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send_sigtrap(current, regs, 0);
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if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
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goto out;
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/* the 0x80 provides a way for the tracing parent to distinguish
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between a syscall stop and SIGTRAP delivery */
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/* Note that the debugger could change the result of test_thread_flag!*/
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ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80:0));
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/*
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* this isn't the same as continuing with a signal, but it will do
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* for normal use. strace only continues with a signal if the
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* stopping signal is not SIGTRAP. -brl
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*/
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if (current->exit_code) {
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send_sig(current->exit_code, current, 1);
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current->exit_code = 0;
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}
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ret = is_sysemu;
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out:
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if (unlikely(current->audit_context) && !entryexit)
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audit_syscall_entry(AUDIT_ARCH_I386, regs->orig_ax,
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regs->bx, regs->cx, regs->dx, regs->si);
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if (ret == 0)
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return 0;
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regs->orig_ax = -1; /* force skip of syscall restarting */
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if (unlikely(current->audit_context))
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audit_syscall_exit(AUDITSC_RESULT(regs->ax), regs->ax);
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return 1;
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}
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