Fixed MTP to work with TWRP

arch/parisc/kernel/ptrace.c

@@ -0,0 +1,305 @@
+/*
+ * Kernel support for the ptrace() and syscall tracing interfaces.
+ *
+ * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
+ * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
+ * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
+ * Copyright (C) 2008 Helge Deller <deller@gmx.de>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/tracehook.h>
+#include <linux/user.h>
+#include <linux/personality.h>
+#include <linux/security.h>
+#include <linux/seccomp.h>
+#include <linux/compat.h>
+#include <linux/signal.h>
+#include <linux/audit.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/processor.h>
+#include <asm/asm-offsets.h>
+
+/* PSW bits we allow the debugger to modify */
+#define USER_PSW_BITS	(PSW_N | PSW_B | PSW_V | PSW_CB)
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure single step bits etc are not set.
+ */
+void ptrace_disable(struct task_struct *task)
+{
+	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
+
+	/* make sure the trap bits are not set */
+	pa_psw(task)->r = 0;
+	pa_psw(task)->t = 0;
+	pa_psw(task)->h = 0;
+	pa_psw(task)->l = 0;
+}
+
+/*
+ * The following functions are called by ptrace_resume() when
+ * enabling or disabling single/block tracing.
+ */
+void user_disable_single_step(struct task_struct *task)
+{
+	ptrace_disable(task);
+}
+
+void user_enable_single_step(struct task_struct *task)
+{
+	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
+	set_tsk_thread_flag(task, TIF_SINGLESTEP);
+
+	if (pa_psw(task)->n) {
+		struct siginfo si;
+
+		/* Nullified, just crank over the queue. */
+		task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
+		task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
+		task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
+		pa_psw(task)->n = 0;
+		pa_psw(task)->x = 0;
+		pa_psw(task)->y = 0;
+		pa_psw(task)->z = 0;
+		pa_psw(task)->b = 0;
+		ptrace_disable(task);
+		/* Don't wake up the task, but let the
+		   parent know something happened. */
+		si.si_code = TRAP_TRACE;
+		si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
+		si.si_signo = SIGTRAP;
+		si.si_errno = 0;
+		force_sig_info(SIGTRAP, &si, task);
+		/* notify_parent(task, SIGCHLD); */
+		return;
+	}
+
+	/* Enable recovery counter traps.  The recovery counter
+	 * itself will be set to zero on a task switch.  If the
+	 * task is suspended on a syscall then the syscall return
+	 * path will overwrite the recovery counter with a suitable
+	 * value such that it traps once back in user space.  We
+	 * disable interrupts in the tasks PSW here also, to avoid
+	 * interrupts while the recovery counter is decrementing.
+	 */
+	pa_psw(task)->r = 1;
+	pa_psw(task)->t = 0;
+	pa_psw(task)->h = 0;
+	pa_psw(task)->l = 0;
+}
+
+void user_enable_block_step(struct task_struct *task)
+{
+	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
+	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
+
+	/* Enable taken branch trap. */
+	pa_psw(task)->r = 0;
+	pa_psw(task)->t = 1;
+	pa_psw(task)->h = 0;
+	pa_psw(task)->l = 0;
+}
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	unsigned long tmp;
+	long ret = -EIO;
+
+	switch (request) {
+
+	/* Read the word at location addr in the USER area.  For ptraced
+	   processes, the kernel saves all regs on a syscall. */
+	case PTRACE_PEEKUSR:
+		if ((addr & (sizeof(unsigned long)-1)) ||
+		     addr >= sizeof(struct pt_regs))
+			break;
+		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
+		ret = put_user(tmp, (unsigned long __user *) data);
+		break;
+
+	/* Write the word at location addr in the USER area.  This will need
+	   to change when the kernel no longer saves all regs on a syscall.
+	   FIXME.  There is a problem at the moment in that r3-r18 are only
+	   saved if the process is ptraced on syscall entry, and even then
+	   those values are overwritten by actual register values on syscall
+	   exit. */
+	case PTRACE_POKEUSR:
+		/* Some register values written here may be ignored in
+		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
+		 * r31/r31+4, and not with the values in pt_regs.
+		 */
+		if (addr == PT_PSW) {
+			/* Allow writing to Nullify, Divide-step-correction,
+			 * and carry/borrow bits.
+			 * BEWARE, if you set N, and then single step, it won't
+			 * stop on the nullified instruction.
+			 */
+			data &= USER_PSW_BITS;
+			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
+			task_regs(child)->gr[0] |= data;
+			ret = 0;
+			break;
+		}
+
+		if ((addr & (sizeof(unsigned long)-1)) ||
+		     addr >= sizeof(struct pt_regs))
+			break;
+		if ((addr >= PT_GR1 && addr <= PT_GR31) ||
+				addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
+				(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
+				addr == PT_SAR) {
+			*(unsigned long *) ((char *) task_regs(child) + addr) = data;
+			ret = 0;
+		}
+		break;
+
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+
+#ifdef CONFIG_COMPAT
+
+/* This function is needed to translate 32 bit pt_regs offsets in to
+ * 64 bit pt_regs offsets.  For example, a 32 bit gdb under a 64 bit kernel
+ * will request offset 12 if it wants gr3, but the lower 32 bits of
+ * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
+ * This code relies on a 32 bit pt_regs being comprised of 32 bit values
+ * except for the fp registers which (a) are 64 bits, and (b) follow
+ * the gr registers at the start of pt_regs.  The 32 bit pt_regs should
+ * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
+ * being 64 bit in both cases.
+ */
+
+static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
+{
+	if (offset < 0)
+		return sizeof(struct pt_regs);
+	else if (offset <= 32*4)	/* gr[0..31] */
+		return offset * 2 + 4;
+	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
+		return offset + 32*4;
+	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
+		return offset * 2 + 4 - 32*8;
+	else
+		return sizeof(struct pt_regs);
+}
+
+long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
+			compat_ulong_t addr, compat_ulong_t data)
+{
+	compat_uint_t tmp;
+	long ret = -EIO;
+
+	switch (request) {
+
+	case PTRACE_PEEKUSR:
+		if (addr & (sizeof(compat_uint_t)-1))
+			break;
+		addr = translate_usr_offset(addr);
+		if (addr >= sizeof(struct pt_regs))
+			break;
+
+		tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
+		ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
+		break;
+
+	/* Write the word at location addr in the USER area.  This will need
+	   to change when the kernel no longer saves all regs on a syscall.
+	   FIXME.  There is a problem at the moment in that r3-r18 are only
+	   saved if the process is ptraced on syscall entry, and even then
+	   those values are overwritten by actual register values on syscall
+	   exit. */
+	case PTRACE_POKEUSR:
+		/* Some register values written here may be ignored in
+		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
+		 * r31/r31+4, and not with the values in pt_regs.
+		 */
+		if (addr == PT_PSW) {
+			/* Since PT_PSW==0, it is valid for 32 bit processes
+			 * under 64 bit kernels as well.
+			 */
+			ret = arch_ptrace(child, request, addr, data);
+		} else {
+			if (addr & (sizeof(compat_uint_t)-1))
+				break;
+			addr = translate_usr_offset(addr);
+			if (addr >= sizeof(struct pt_regs))
+				break;
+			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
+				/* Special case, fp regs are 64 bits anyway */
+				*(__u64 *) ((char *) task_regs(child) + addr) = data;
+				ret = 0;
+			}
+			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
+					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
+					addr == PT_SAR+4) {
+				/* Zero the top 32 bits */
+				*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
+				*(__u32 *) ((char *) task_regs(child) + addr) = data;
+				ret = 0;
+			}
+		}
+		break;
+
+	default:
+		ret = compat_ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+#endif
+
+long do_syscall_trace_enter(struct pt_regs *regs)
+{
+	long ret = 0;
+
+	/* Do the secure computing check first. */
+	secure_computing_strict(regs->gr[20]);
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
+	    tracehook_report_syscall_entry(regs))
+		ret = -1L;
+
+#ifdef CONFIG_64BIT
+	if (!is_compat_task())
+		audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
+				    regs->gr[24], regs->gr[23]);
+	else
+#endif
+		audit_syscall_entry(regs->gr[20] & 0xffffffff,
+			regs->gr[26] & 0xffffffff,
+			regs->gr[25] & 0xffffffff,
+			regs->gr[24] & 0xffffffff,
+			regs->gr[23] & 0xffffffff);
+
+	return ret ? : regs->gr[20];
+}
+
+void do_syscall_trace_exit(struct pt_regs *regs)
+{
+	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
+		test_thread_flag(TIF_BLOCKSTEP);
+
+	audit_syscall_exit(regs);
+
+	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
+		tracehook_report_syscall_exit(regs, stepping);
+}