1 files changed, 584 insertions, 0 deletions

diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c
new file mode 100644
index 0000000000..9056cd1a83
--- /dev/null
+++ b/arch/xtensa/kernel/ptrace.c
@@ -0,0 +1,584 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2007  Tensilica Inc.
+ *
+ * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
+ * Chris Zankel <chris@zankel.net>
+ * Scott Foehner<sfoehner@yahoo.com>,
+ * Kevin Chea
+ * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
+ */
+
+#include <linux/audit.h>
+#include <linux/errno.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/perf_event.h>
+#include <linux/ptrace.h>
+#include <linux/regset.h>
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/seccomp.h>
+#include <linux/security.h>
+#include <linux/signal.h>
+#include <linux/smp.h>
+#include <linux/uaccess.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+#include <asm/coprocessor.h>
+#include <asm/elf.h>
+#include <asm/page.h>
+#include <asm/ptrace.h>
+
+static int gpr_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   struct membuf to)
+{
+	struct pt_regs *regs = task_pt_regs(target);
+	struct user_pt_regs newregs = {
+		.pc = regs->pc,
+		.ps = regs->ps & ~(1 << PS_EXCM_BIT),
+		.lbeg = regs->lbeg,
+		.lend = regs->lend,
+		.lcount = regs->lcount,
+		.sar = regs->sar,
+		.threadptr = regs->threadptr,
+		.windowbase = regs->windowbase,
+		.windowstart = regs->windowstart,
+		.syscall = regs->syscall,
+	};
+
+	memcpy(newregs.a,
+	       regs->areg + XCHAL_NUM_AREGS - regs->windowbase * 4,
+	       regs->windowbase * 16);
+	memcpy(newregs.a + regs->windowbase * 4,
+	       regs->areg,
+	       (WSBITS - regs->windowbase) * 16);
+
+	return membuf_write(&to, &newregs, sizeof(newregs));
+}
+
+static int gpr_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	struct user_pt_regs newregs = {0};
+	struct pt_regs *regs;
+	const u32 ps_mask = PS_CALLINC_MASK | PS_OWB_MASK;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
+	if (ret)
+		return ret;
+
+	if (newregs.windowbase >= XCHAL_NUM_AREGS / 4)
+		return -EINVAL;
+
+	regs = task_pt_regs(target);
+	regs->pc = newregs.pc;
+	regs->ps = (regs->ps & ~ps_mask) | (newregs.ps & ps_mask);
+	regs->lbeg = newregs.lbeg;
+	regs->lend = newregs.lend;
+	regs->lcount = newregs.lcount;
+	regs->sar = newregs.sar;
+	regs->threadptr = newregs.threadptr;
+
+	if (newregs.syscall)
+		regs->syscall = newregs.syscall;
+
+	if (newregs.windowbase != regs->windowbase ||
+	    newregs.windowstart != regs->windowstart) {
+		u32 rotws, wmask;
+
+		rotws = (((newregs.windowstart |
+			   (newregs.windowstart << WSBITS)) >>
+			  newregs.windowbase) &
+			 ((1 << WSBITS) - 1)) & ~1;
+		wmask = ((rotws ? WSBITS + 1 - ffs(rotws) : 0) << 4) |
+			(rotws & 0xF) | 1;
+		regs->windowbase = newregs.windowbase;
+		regs->windowstart = newregs.windowstart;
+		regs->wmask = wmask;
+	}
+
+	memcpy(regs->areg + XCHAL_NUM_AREGS - newregs.windowbase * 4,
+	       newregs.a, newregs.windowbase * 16);
+	memcpy(regs->areg, newregs.a + newregs.windowbase * 4,
+	       (WSBITS - newregs.windowbase) * 16);
+
+	return 0;
+}
+
+static int tie_get(struct task_struct *target,
+		   const struct user_regset *regset,
+		   struct membuf to)
+{
+	int ret;
+	struct pt_regs *regs = task_pt_regs(target);
+	struct thread_info *ti = task_thread_info(target);
+	elf_xtregs_t *newregs = kzalloc(sizeof(elf_xtregs_t), GFP_KERNEL);
+
+	if (!newregs)
+		return -ENOMEM;
+
+	newregs->opt = regs->xtregs_opt;
+	newregs->user = ti->xtregs_user;
+
+#if XTENSA_HAVE_COPROCESSORS
+	/* Flush all coprocessor registers to memory. */
+	coprocessor_flush_all(ti);
+	newregs->cp0 = ti->xtregs_cp.cp0;
+	newregs->cp1 = ti->xtregs_cp.cp1;
+	newregs->cp2 = ti->xtregs_cp.cp2;
+	newregs->cp3 = ti->xtregs_cp.cp3;
+	newregs->cp4 = ti->xtregs_cp.cp4;
+	newregs->cp5 = ti->xtregs_cp.cp5;
+	newregs->cp6 = ti->xtregs_cp.cp6;
+	newregs->cp7 = ti->xtregs_cp.cp7;
+#endif
+	ret = membuf_write(&to, newregs, sizeof(*newregs));
+	kfree(newregs);
+	return ret;
+}
+
+static int tie_set(struct task_struct *target,
+		   const struct user_regset *regset,
+		   unsigned int pos, unsigned int count,
+		   const void *kbuf, const void __user *ubuf)
+{
+	int ret;
+	struct pt_regs *regs = task_pt_regs(target);
+	struct thread_info *ti = task_thread_info(target);
+	elf_xtregs_t *newregs = kzalloc(sizeof(elf_xtregs_t), GFP_KERNEL);
+
+	if (!newregs)
+		return -ENOMEM;
+
+	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
+				 newregs, 0, -1);
+
+	if (ret)
+		goto exit;
+	regs->xtregs_opt = newregs->opt;
+	ti->xtregs_user = newregs->user;
+
+#if XTENSA_HAVE_COPROCESSORS
+	/* Flush all coprocessors before we overwrite them. */
+	coprocessor_flush_release_all(ti);
+	ti->xtregs_cp.cp0 = newregs->cp0;
+	ti->xtregs_cp.cp1 = newregs->cp1;
+	ti->xtregs_cp.cp2 = newregs->cp2;
+	ti->xtregs_cp.cp3 = newregs->cp3;
+	ti->xtregs_cp.cp4 = newregs->cp4;
+	ti->xtregs_cp.cp5 = newregs->cp5;
+	ti->xtregs_cp.cp6 = newregs->cp6;
+	ti->xtregs_cp.cp7 = newregs->cp7;
+#endif
+exit:
+	kfree(newregs);
+	return ret;
+}
+
+enum xtensa_regset {
+	REGSET_GPR,
+	REGSET_TIE,
+};
+
+static const struct user_regset xtensa_regsets[] = {
+	[REGSET_GPR] = {
+		.core_note_type = NT_PRSTATUS,
+		.n = sizeof(struct user_pt_regs) / sizeof(u32),
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.regset_get = gpr_get,
+		.set = gpr_set,
+	},
+	[REGSET_TIE] = {
+		.core_note_type = NT_PRFPREG,
+		.n = sizeof(elf_xtregs_t) / sizeof(u32),
+		.size = sizeof(u32),
+		.align = sizeof(u32),
+		.regset_get = tie_get,
+		.set = tie_set,
+	},
+};
+
+static const struct user_regset_view user_xtensa_view = {
+	.name = "xtensa",
+	.e_machine = EM_XTENSA,
+	.regsets = xtensa_regsets,
+	.n = ARRAY_SIZE(xtensa_regsets)
+};
+
+const struct user_regset_view *task_user_regset_view(struct task_struct *task)
+{
+	return &user_xtensa_view;
+}
+
+void user_enable_single_step(struct task_struct *child)
+{
+	set_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+}
+
+/*
+ * Called by kernel/ptrace.c when detaching to disable single stepping.
+ */
+
+void ptrace_disable(struct task_struct *child)
+{
+	/* Nothing to do.. */
+}
+
+static int ptrace_getregs(struct task_struct *child, void __user *uregs)
+{
+	return copy_regset_to_user(child, &user_xtensa_view, REGSET_GPR,
+				   0, sizeof(xtensa_gregset_t), uregs);
+}
+
+static int ptrace_setregs(struct task_struct *child, void __user *uregs)
+{
+	return copy_regset_from_user(child, &user_xtensa_view, REGSET_GPR,
+				     0, sizeof(xtensa_gregset_t), uregs);
+}
+
+static int ptrace_getxregs(struct task_struct *child, void __user *uregs)
+{
+	return copy_regset_to_user(child, &user_xtensa_view, REGSET_TIE,
+				   0, sizeof(elf_xtregs_t), uregs);
+}
+
+static int ptrace_setxregs(struct task_struct *child, void __user *uregs)
+{
+	return copy_regset_from_user(child, &user_xtensa_view, REGSET_TIE,
+				     0, sizeof(elf_xtregs_t), uregs);
+}
+
+static int ptrace_peekusr(struct task_struct *child, long regno,
+			  long __user *ret)
+{
+	struct pt_regs *regs;
+	unsigned long tmp;
+
+	regs = task_pt_regs(child);
+	tmp = 0;  /* Default return value. */
+
+	switch(regno) {
+	case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
+		tmp = regs->areg[regno - REG_AR_BASE];
+		break;
+
+	case REG_A_BASE ... REG_A_BASE + 15:
+		tmp = regs->areg[regno - REG_A_BASE];
+		break;
+
+	case REG_PC:
+		tmp = regs->pc;
+		break;
+
+	case REG_PS:
+		/* Note: PS.EXCM is not set while user task is running;
+		 * its being set in regs is for exception handling
+		 * convenience.
+		 */
+		tmp = (regs->ps & ~(1 << PS_EXCM_BIT));
+		break;
+
+	case REG_WB:
+		break;		/* tmp = 0 */
+
+	case REG_WS:
+		{
+			unsigned long wb = regs->windowbase;
+			unsigned long ws = regs->windowstart;
+			tmp = ((ws >> wb) | (ws << (WSBITS - wb))) &
+				((1 << WSBITS) - 1);
+			break;
+		}
+	case REG_LBEG:
+		tmp = regs->lbeg;
+		break;
+
+	case REG_LEND:
+		tmp = regs->lend;
+		break;
+
+	case REG_LCOUNT:
+		tmp = regs->lcount;
+		break;
+
+	case REG_SAR:
+		tmp = regs->sar;
+		break;
+
+	case SYSCALL_NR:
+		tmp = regs->syscall;
+		break;
+
+	default:
+		return -EIO;
+	}
+	return put_user(tmp, ret);
+}
+
+static int ptrace_pokeusr(struct task_struct *child, long regno, long val)
+{
+	struct pt_regs *regs;
+	regs = task_pt_regs(child);
+
+	switch (regno) {
+	case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
+		regs->areg[regno - REG_AR_BASE] = val;
+		break;
+
+	case REG_A_BASE ... REG_A_BASE + 15:
+		regs->areg[regno - REG_A_BASE] = val;
+		break;
+
+	case REG_PC:
+		regs->pc = val;
+		break;
+
+	case SYSCALL_NR:
+		regs->syscall = val;
+		break;
+
+	default:
+		return -EIO;
+	}
+	return 0;
+}
+
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+static void ptrace_hbptriggered(struct perf_event *bp,
+				struct perf_sample_data *data,
+				struct pt_regs *regs)
+{
+	int i;
+	struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
+
+	if (bp->attr.bp_type & HW_BREAKPOINT_X) {
+		for (i = 0; i < XCHAL_NUM_IBREAK; ++i)
+			if (current->thread.ptrace_bp[i] == bp)
+				break;
+		i <<= 1;
+	} else {
+		for (i = 0; i < XCHAL_NUM_DBREAK; ++i)
+			if (current->thread.ptrace_wp[i] == bp)
+				break;
+		i = (i << 1) | 1;
+	}
+
+	force_sig_ptrace_errno_trap(i, (void __user *)bkpt->address);
+}
+
+static struct perf_event *ptrace_hbp_create(struct task_struct *tsk, int type)
+{
+	struct perf_event_attr attr;
+
+	ptrace_breakpoint_init(&attr);
+
+	/* Initialise fields to sane defaults. */
+	attr.bp_addr	= 0;
+	attr.bp_len	= 1;
+	attr.bp_type	= type;
+	attr.disabled	= 1;
+
+	return register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL,
+					   tsk);
+}
+
+/*
+ * Address bit 0 choose instruction (0) or data (1) break register, bits
+ * 31..1 are the register number.
+ * Both PTRACE_GETHBPREGS and PTRACE_SETHBPREGS transfer two 32-bit words:
+ * address (0) and control (1).
+ * Instruction breakpoint contorl word is 0 to clear breakpoint, 1 to set.
+ * Data breakpoint control word bit 31 is 'trigger on store', bit 30 is
+ * 'trigger on load, bits 29..0 are length. Length 0 is used to clear a
+ * breakpoint. To set a breakpoint length must be a power of 2 in the range
+ * 1..64 and the address must be length-aligned.
+ */
+
+static long ptrace_gethbpregs(struct task_struct *child, long addr,
+			      long __user *datap)
+{
+	struct perf_event *bp;
+	u32 user_data[2] = {0};
+	bool dbreak = addr & 1;
+	unsigned idx = addr >> 1;
+
+	if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
+	    (dbreak && idx >= XCHAL_NUM_DBREAK))
+		return -EINVAL;
+
+	if (dbreak)
+		bp = child->thread.ptrace_wp[idx];
+	else
+		bp = child->thread.ptrace_bp[idx];
+
+	if (bp) {
+		user_data[0] = bp->attr.bp_addr;
+		user_data[1] = bp->attr.disabled ? 0 : bp->attr.bp_len;
+		if (dbreak) {
+			if (bp->attr.bp_type & HW_BREAKPOINT_R)
+				user_data[1] |= DBREAKC_LOAD_MASK;
+			if (bp->attr.bp_type & HW_BREAKPOINT_W)
+				user_data[1] |= DBREAKC_STOR_MASK;
+		}
+	}
+
+	if (copy_to_user(datap, user_data, sizeof(user_data)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long ptrace_sethbpregs(struct task_struct *child, long addr,
+			      long __user *datap)
+{
+	struct perf_event *bp;
+	struct perf_event_attr attr;
+	u32 user_data[2];
+	bool dbreak = addr & 1;
+	unsigned idx = addr >> 1;
+	int bp_type = 0;
+
+	if ((!dbreak && idx >= XCHAL_NUM_IBREAK) ||
+	    (dbreak && idx >= XCHAL_NUM_DBREAK))
+		return -EINVAL;
+
+	if (copy_from_user(user_data, datap, sizeof(user_data)))
+		return -EFAULT;
+
+	if (dbreak) {
+		bp = child->thread.ptrace_wp[idx];
+		if (user_data[1] & DBREAKC_LOAD_MASK)
+			bp_type |= HW_BREAKPOINT_R;
+		if (user_data[1] & DBREAKC_STOR_MASK)
+			bp_type |= HW_BREAKPOINT_W;
+	} else {
+		bp = child->thread.ptrace_bp[idx];
+		bp_type = HW_BREAKPOINT_X;
+	}
+
+	if (!bp) {
+		bp = ptrace_hbp_create(child,
+				       bp_type ? bp_type : HW_BREAKPOINT_RW);
+		if (IS_ERR(bp))
+			return PTR_ERR(bp);
+		if (dbreak)
+			child->thread.ptrace_wp[idx] = bp;
+		else
+			child->thread.ptrace_bp[idx] = bp;
+	}
+
+	attr = bp->attr;
+	attr.bp_addr = user_data[0];
+	attr.bp_len = user_data[1] & ~(DBREAKC_LOAD_MASK | DBREAKC_STOR_MASK);
+	attr.bp_type = bp_type;
+	attr.disabled = !attr.bp_len;
+
+	return modify_user_hw_breakpoint(bp, &attr);
+}
+#endif
+
+long arch_ptrace(struct task_struct *child, long request,
+		 unsigned long addr, unsigned long data)
+{
+	int ret = -EPERM;
+	void __user *datap = (void __user *) data;
+
+	switch (request) {
+	case PTRACE_PEEKUSR:	/* read register specified by addr. */
+		ret = ptrace_peekusr(child, addr, datap);
+		break;
+
+	case PTRACE_POKEUSR:	/* write register specified by addr. */
+		ret = ptrace_pokeusr(child, addr, data);
+		break;
+
+	case PTRACE_GETREGS:
+		ret = ptrace_getregs(child, datap);
+		break;
+
+	case PTRACE_SETREGS:
+		ret = ptrace_setregs(child, datap);
+		break;
+
+	case PTRACE_GETXTREGS:
+		ret = ptrace_getxregs(child, datap);
+		break;
+
+	case PTRACE_SETXTREGS:
+		ret = ptrace_setxregs(child, datap);
+		break;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+	case PTRACE_GETHBPREGS:
+		ret = ptrace_gethbpregs(child, addr, datap);
+		break;
+
+	case PTRACE_SETHBPREGS:
+		ret = ptrace_sethbpregs(child, addr, datap);
+		break;
+#endif
+	default:
+		ret = ptrace_request(child, request, addr, data);
+		break;
+	}
+
+	return ret;
+}
+
+int do_syscall_trace_enter(struct pt_regs *regs)
+{
+	if (regs->syscall == NO_SYSCALL)
+		regs->areg[2] = -ENOSYS;
+
+	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
+	    ptrace_report_syscall_entry(regs)) {
+		regs->areg[2] = -ENOSYS;
+		regs->syscall = NO_SYSCALL;
+		return 0;
+	}
+
+	if (regs->syscall == NO_SYSCALL ||
+	    secure_computing() == -1) {
+		do_syscall_trace_leave(regs);
+		return 0;
+	}
+
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_enter(regs, syscall_get_nr(current, regs));
+
+	audit_syscall_entry(regs->syscall, regs->areg[6],
+			    regs->areg[3], regs->areg[4],
+			    regs->areg[5]);
+	return 1;
+}
+
+void do_syscall_trace_leave(struct pt_regs *regs)
+{
+	int step;
+
+	audit_syscall_exit(regs);
+
+	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
+		trace_sys_exit(regs, regs_return_value(regs));
+
+	step = test_thread_flag(TIF_SINGLESTEP);
+
+	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
+		ptrace_report_syscall_exit(regs, step);
+}