Blackfin arch: Add ability to expend the hardware trace buffer (518039bc) · Commits · 戴 / test

arch/blackfin/Kconfig

+81 −0

Original line number	Diff line number	Diff line
		@@ -1024,8 +1024,89 @@ config DEBUG_HUNT_FOR_ZERO
		Enabling this option will take up an extra entry in CPLB table.
		Otherwise, there is no extra overhead.

		config DEBUG_BFIN_HWTRACE_ON
		bool "Turn on Blackfin's Hardware Trace"
		default y
		help
		All Blackfins include a Trace Unit which stores a history of the last
		16 changes in program flow taken by the program sequencer. The history
		allows the user to recreate the program sequencer’s recent path. This
		can be handy when an application dies - we print out the execution
		path of how it got to the offending instruction.

		By turning this off, you may save a tiny amount of power.

		choice
		prompt "Omit loop Tracing"
		default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
		depends on DEBUG_BFIN_HWTRACE_ON
		help
		The trace buffer can be configured to omit recording of changes in
		program flow that match either the last entry or one of the last
		two entries. Omitting one of these entries from the record prevents
		the trace buffer from overflowing because of any sort of loop (for, do
		while, etc) in the program.

		Because zero-overhead Hardware loops are not recorded in the trace buffer,
		this feature can be used to prevent trace overflow from loops that
		are nested four deep.

		config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
		bool "Trace all Loops"
		help
		The trace buffer records all changes of flow

		config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
		bool "Compress single-level loops"
		help
		The trace buffer does not record single loops - helpful if trace
		is spinning on a while or do loop.

		config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
		bool "Compress two-level loops"
		help
		The trace buffer does not record loops two levels deep. Helpful if
		the trace is spinning in a nested loop

		endchoice

		config DEBUG_BFIN_HWTRACE_COMPRESSION
		int
		depends on DEBUG_BFIN_HWTRACE_ON
		default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
		default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
		default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO


		config DEBUG_BFIN_HWTRACE_EXPAND
		bool "Expand Trace Buffer greater than 16 entries"
		depends on DEBUG_BFIN_HWTRACE_ON
		default n
		help
		By selecting this option, every time the 16 hardware entries in
		the Blackfin's HW Trace buffer are full, the kernel will move them
		into a software buffer, for dumping when there is an issue. This
		has a great impact on performance, (an interrupt every 16 change of
		flows) and should normally be turned off, except in those nasty
		debugging sessions

		config DEBUG_BFIN_HWTRACE_EXPAND_LEN
		int "Size of Trace buffer (in power of 2k)"
		range 0 4
		depends on DEBUG_BFIN_HWTRACE_EXPAND
		default 1
		help
		This sets the size of the software buffer that the trace information
		is kept in.
		0 for (2^0) 1k, or 256 entries,
		1 for (2^1) 2k, or 512 entries,
		2 for (2^2) 4k, or 1024 entries,
		3 for (2^3) 8k, or 2048 entries,
		4 for (2^4) 16k, or 4096 entries

		config DEBUG_BFIN_NO_KERN_HWTRACE
		bool "Trace user apps (turn off hwtrace in kernel)"
		depends on DEBUG_BFIN_HWTRACE_ON
		default n
		help
		Some pieces of the kernel contain a lot of flow changes which can

arch/blackfin/kernel/irqchip.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -34,6 +34,7 @@
		#include <linux/kallsyms.h>
		#include <linux/interrupt.h>
		#include <linux/irq.h>
		#include <asm/trace.h>

		static unsigned long irq_err_count;
		static spinlock_t irq_controller_lock;
		@@ -144,4 +145,12 @@ void __init init_IRQ(void)
		}

		init_arch_irq();

		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
		/* Now that evt_ivhw is set up, turn this on */
		trace_buff_offset = 0;
		bfin_write_TBUFCTL(BFIN_TRACE_ON);
		printk(KERN_INFO "Hardware Trace expanded to %ik\n",
		1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN);
		#endif
		}

arch/blackfin/kernel/traps.c

+46 −7

Original line number	Diff line number	Diff line
		@@ -55,6 +55,7 @@ asmlinkage void trap_c(struct pt_regs *fp);

		int kstack_depth_to_print = 48;

		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
		static int printk_address(unsigned long address)
		{
		struct vm_list_struct *vml;
		@@ -131,10 +132,14 @@ static int printk_address(unsigned long address)
		/* we were unable to find this address anywhere */
		return printk("[<0x%p>]", (void *)address);
		}
		#endif

		asmlinkage void trap_c(struct pt_regs *fp)
		{
		int j, sig = 0;
		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
		int j;
		#endif
		int sig = 0;
		siginfo_t info;
		unsigned long trapnr = fp->seqstat & SEQSTAT_EXCAUSE;

		@@ -429,16 +434,23 @@ asmlinkage void trap_c(struct pt_regs *fp)

		/* Typical exception handling routines */

		#define EXPAND_LEN ((1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN) * 256 - 1)

		void dump_bfin_trace_buffer(void)
		{
		int tflags;
		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
		int tflags, i = 0;
		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
		int j, index;
		#endif

		trace_buffer_save(tflags);

		if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
		int i;
		printk(KERN_EMERG "Hardware Trace:\n");
		for (i = 0; bfin_read_TBUFSTAT() & TBUFCNT; i++) {
		printk(KERN_EMERG "%2i Target : ", i);

		if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
		for (; bfin_read_TBUFSTAT() & TBUFCNT; i++) {
		printk(KERN_EMERG "%4i Target : ", i);
		printk_address((unsigned long)bfin_read_TBUF());
		printk("\n" KERN_EMERG " Source : ");
		printk_address((unsigned long)bfin_read_TBUF());
		@@ -446,7 +458,32 @@ void dump_bfin_trace_buffer(void)
		}
		}

		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_EXPAND
		if (trace_buff_offset)
		index = trace_buff_offset/4 - 1;
		else
		index = EXPAND_LEN;

		j = (1 << CONFIG_DEBUG_BFIN_HWTRACE_EXPAND_LEN) * 128;
		while (j) {
		printk(KERN_EMERG "%4i Target : ", i);
		printk_address(software_trace_buff[index]);
		index -= 1;
		if (index < 0 )
		index = EXPAND_LEN;
		printk("\n" KERN_EMERG " Source : ");
		printk_address(software_trace_buff[index]);
		index -= 1;
		if (index < 0)
		index = EXPAND_LEN;
		printk("\n");
		j--;
		i++;
		}
		#endif

		trace_buffer_restore(tflags);
		#endif
		}
		EXPORT_SYMBOL(dump_bfin_trace_buffer);

		@@ -510,7 +547,9 @@ void show_stack(struct task_struct task, unsigned long stack)
		void dump_stack(void)
		{
		unsigned long stack;
		#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
		int tflags;
		#endif
		trace_buffer_save(tflags);
		dump_bfin_trace_buffer();
		show_stack(current, &stack);

arch/blackfin/mach-bf533/head.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -98,7 +98,7 @@ ENTRY(__start)
		M2 = r0;
		M3 = r0;

		trace_buffer_start(p0,r0);
		trace_buffer_init(p0,r0);
		P0 = R1;
		R0 = R1;

arch/blackfin/mach-bf537/head.S

+1 −1

Original line number	Diff line number	Diff line
		@@ -96,7 +96,7 @@ ENTRY(__start)
		M2 = r0;
		M3 = r0;

		trace_buffer_start(p0,r0);
		trace_buffer_init(p0,r0);
		P0 = R1;
		R0 = R1;

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