1 files changed, 240 insertions, 0 deletions

diff --git a/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c b/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c
new file mode 100644
index 000000000000..8b3e0137be1a
--- /dev/null
+++ b/drivers/staging/android/fiq_debugger/fiq_debugger_arm.c
@@ -0,0 +1,240 @@
+/*
+ * Copyright (C) 2014 Google, Inc.
+ * Author: Colin Cross <ccross@android.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/ptrace.h>
+#include <linux/uaccess.h>
+
+#include <asm/stacktrace.h>
+
+#include "fiq_debugger_priv.h"
+
+static char *mode_name(unsigned cpsr)
+{
+	switch (cpsr & MODE_MASK) {
+	case USR_MODE: return "USR";
+	case FIQ_MODE: return "FIQ";
+	case IRQ_MODE: return "IRQ";
+	case SVC_MODE: return "SVC";
+	case ABT_MODE: return "ABT";
+	case UND_MODE: return "UND";
+	case SYSTEM_MODE: return "SYS";
+	default: return "???";
+	}
+}
+
+void fiq_debugger_dump_pc(struct fiq_debugger_output *output,
+		const struct pt_regs *regs)
+{
+	output->printf(output, " pc %08x cpsr %08x mode %s\n",
+		regs->ARM_pc, regs->ARM_cpsr, mode_name(regs->ARM_cpsr));
+}
+
+void fiq_debugger_dump_regs(struct fiq_debugger_output *output,
+		const struct pt_regs *regs)
+{
+	output->printf(output,
+			" r0 %08x  r1 %08x  r2 %08x  r3 %08x\n",
+			regs->ARM_r0, regs->ARM_r1, regs->ARM_r2, regs->ARM_r3);
+	output->printf(output,
+			" r4 %08x  r5 %08x  r6 %08x  r7 %08x\n",
+			regs->ARM_r4, regs->ARM_r5, regs->ARM_r6, regs->ARM_r7);
+	output->printf(output,
+			" r8 %08x  r9 %08x r10 %08x r11 %08x  mode %s\n",
+			regs->ARM_r8, regs->ARM_r9, regs->ARM_r10, regs->ARM_fp,
+			mode_name(regs->ARM_cpsr));
+	output->printf(output,
+			" ip %08x  sp %08x  lr %08x  pc %08x cpsr %08x\n",
+			regs->ARM_ip, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc,
+			regs->ARM_cpsr);
+}
+
+struct mode_regs {
+	unsigned long sp_svc;
+	unsigned long lr_svc;
+	unsigned long spsr_svc;
+
+	unsigned long sp_abt;
+	unsigned long lr_abt;
+	unsigned long spsr_abt;
+
+	unsigned long sp_und;
+	unsigned long lr_und;
+	unsigned long spsr_und;
+
+	unsigned long sp_irq;
+	unsigned long lr_irq;
+	unsigned long spsr_irq;
+
+	unsigned long r8_fiq;
+	unsigned long r9_fiq;
+	unsigned long r10_fiq;
+	unsigned long r11_fiq;
+	unsigned long r12_fiq;
+	unsigned long sp_fiq;
+	unsigned long lr_fiq;
+	unsigned long spsr_fiq;
+};
+
+static void __naked get_mode_regs(struct mode_regs *regs)
+{
+	asm volatile (
+	"mrs	r1, cpsr\n"
+	"msr	cpsr_c, #0xd3 @(SVC_MODE | PSR_I_BIT | PSR_F_BIT)\n"
+	"stmia	r0!, {r13 - r14}\n"
+	"mrs	r2, spsr\n"
+	"msr	cpsr_c, #0xd7 @(ABT_MODE | PSR_I_BIT | PSR_F_BIT)\n"
+	"stmia	r0!, {r2, r13 - r14}\n"
+	"mrs	r2, spsr\n"
+	"msr	cpsr_c, #0xdb @(UND_MODE | PSR_I_BIT | PSR_F_BIT)\n"
+	"stmia	r0!, {r2, r13 - r14}\n"
+	"mrs	r2, spsr\n"
+	"msr	cpsr_c, #0xd2 @(IRQ_MODE | PSR_I_BIT | PSR_F_BIT)\n"
+	"stmia	r0!, {r2, r13 - r14}\n"
+	"mrs	r2, spsr\n"
+	"msr	cpsr_c, #0xd1 @(FIQ_MODE | PSR_I_BIT | PSR_F_BIT)\n"
+	"stmia	r0!, {r2, r8 - r14}\n"
+	"mrs	r2, spsr\n"
+	"stmia	r0!, {r2}\n"
+	"msr	cpsr_c, r1\n"
+	"bx	lr\n");
+}
+
+
+void fiq_debugger_dump_allregs(struct fiq_debugger_output *output,
+		const struct pt_regs *regs)
+{
+	struct mode_regs mode_regs;
+	unsigned long mode = regs->ARM_cpsr & MODE_MASK;
+
+	fiq_debugger_dump_regs(output, regs);
+	get_mode_regs(&mode_regs);
+
+	output->printf(output,
+			"%csvc: sp %08x  lr %08x  spsr %08x\n",
+			mode == SVC_MODE ? '*' : ' ',
+			mode_regs.sp_svc, mode_regs.lr_svc, mode_regs.spsr_svc);
+	output->printf(output,
+			"%cabt: sp %08x  lr %08x  spsr %08x\n",
+			mode == ABT_MODE ? '*' : ' ',
+			mode_regs.sp_abt, mode_regs.lr_abt, mode_regs.spsr_abt);
+	output->printf(output,
+			"%cund: sp %08x  lr %08x  spsr %08x\n",
+			mode == UND_MODE ? '*' : ' ',
+			mode_regs.sp_und, mode_regs.lr_und, mode_regs.spsr_und);
+	output->printf(output,
+			"%cirq: sp %08x  lr %08x  spsr %08x\n",
+			mode == IRQ_MODE ? '*' : ' ',
+			mode_regs.sp_irq, mode_regs.lr_irq, mode_regs.spsr_irq);
+	output->printf(output,
+			"%cfiq: r8 %08x  r9 %08x  r10 %08x  r11 %08x  r12 %08x\n",
+			mode == FIQ_MODE ? '*' : ' ',
+			mode_regs.r8_fiq, mode_regs.r9_fiq, mode_regs.r10_fiq,
+			mode_regs.r11_fiq, mode_regs.r12_fiq);
+	output->printf(output,
+			" fiq: sp %08x  lr %08x  spsr %08x\n",
+			mode_regs.sp_fiq, mode_regs.lr_fiq, mode_regs.spsr_fiq);
+}
+
+struct stacktrace_state {
+	struct fiq_debugger_output *output;
+	unsigned int depth;
+};
+
+static int report_trace(struct stackframe *frame, void *d)
+{
+	struct stacktrace_state *sts = d;
+
+	if (sts->depth) {
+		sts->output->printf(sts->output,
+			"  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
+			frame->pc, frame->pc, frame->lr, frame->lr,
+			frame->sp, frame->fp);
+		sts->depth--;
+		return 0;
+	}
+	sts->output->printf(sts->output, "  ...\n");
+
+	return sts->depth == 0;
+}
+
+struct frame_tail {
+	struct frame_tail *fp;
+	unsigned long sp;
+	unsigned long lr;
+} __attribute__((packed));
+
+static struct frame_tail *user_backtrace(struct fiq_debugger_output *output,
+					struct frame_tail *tail)
+{
+	struct frame_tail buftail[2];
+
+	/* Also check accessibility of one struct frame_tail beyond */
+	if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) {
+		output->printf(output, "  invalid frame pointer %p\n",
+				tail);
+		return NULL;
+	}
+	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) {
+		output->printf(output,
+			"  failed to copy frame pointer %p\n", tail);
+		return NULL;
+	}
+
+	output->printf(output, "  %p\n", buftail[0].lr);
+
+	/* frame pointers should strictly progress back up the stack
+	 * (towards higher addresses) */
+	if (tail >= buftail[0].fp)
+		return NULL;
+
+	return buftail[0].fp-1;
+}
+
+void fiq_debugger_dump_stacktrace(struct fiq_debugger_output *output,
+		const struct pt_regs *regs, unsigned int depth, void *ssp)
+{
+	struct frame_tail *tail;
+	struct thread_info *real_thread_info = THREAD_INFO(ssp);
+	struct stacktrace_state sts;
+
+	sts.depth = depth;
+	sts.output = output;
+	*current_thread_info() = *real_thread_info;
+
+	if (!current)
+		output->printf(output, "current NULL\n");
+	else
+		output->printf(output, "pid: %d  comm: %s\n",
+			current->pid, current->comm);
+	fiq_debugger_dump_regs(output, regs);
+
+	if (!user_mode(regs)) {
+		struct stackframe frame;
+		frame.fp = regs->ARM_fp;
+		frame.sp = regs->ARM_sp;
+		frame.lr = regs->ARM_lr;
+		frame.pc = regs->ARM_pc;
+		output->printf(output,
+			"  pc: %p (%pF), lr %p (%pF), sp %p, fp %p\n",
+			regs->ARM_pc, regs->ARM_pc, regs->ARM_lr, regs->ARM_lr,
+			regs->ARM_sp, regs->ARM_fp);
+		walk_stackframe(&frame, report_trace, &sts);
+		return;
+	}
+
+	tail = ((struct frame_tail *) regs->ARM_fp) - 1;
+	while (depth-- && tail && !((unsigned long) tail & 3))
+		tail = user_backtrace(output, tail);
+}