Blackfin arch: add supporting for kgdb (a5ac0129) · Commits · github.com / kvm-riscv / linux

Documentation/blackfin/kgdb.txt

deleted100644 → 0

+0 −155

Original line number	Diff line number	Diff line
		A Simple Guide to Configure KGDB

		Sonic Zhang <sonic.zhang@analog.com>
		Aug. 24th 2006


		This KGDB patch enables the kernel developer to do source level debugging on
		the kernel for the Blackfin architecture. The debugging works over either the
		ethernet interface or one of the uarts. Both software breakpoints and
		hardware breakpoints are supported in this version.
		http://docs.blackfin.uclinux.org/doku.php?id=kgdb


		2 known issues:
		1. This bug:
		http://blackfin.uclinux.org/tracker/index.php?func=detail&aid=544&group_id=18&atid=145
		The GDB client for Blackfin uClinux causes incorrect values of local
		variables to be displayed when the user breaks the running of kernel in GDB.
		2. Because of a hardware bug in Blackfin 533 v1.0.3:
		05000067 - Watchpoints (Hardware Breakpoints) are not supported
		Hardware breakpoints cannot be set properly.


		Debug over Ethernet:

		1. Compile and install the cross platform version of gdb for blackfin, which
		can be found at $(BINROOT)/bfin-elf-gdb.

		2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
		"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
		With this selected, option "Full Symbolic/Source Debugging support" and
		"Compile the kernel with frame pointers" are also selected.

		3. Select option "KGDB: connect over (Ethernet)". Add "kgdboe=@target-IP/,@host-IP/" to
		the option "Compiled-in Kernel Boot Parameter" under "Kernel hacking".

		4. Connect minicom to the serial port and boot the kernel image.

		5. Configure the IP "/> ifconfig eth0 target-IP"

		6. Start GDB client "bfin-elf-gdb vmlinux".

		7. Connect to the target "(gdb) target remote udp:target-IP:6443".

		8. Set software breakpoint "(gdb) break sys_open".

		9. Continue "(gdb) c".

		10. Run ls in the target console "/> ls".

		11. Breakpoint hits. "Breakpoint 1: sys_open(..."

		12. Display local variables and function paramters.
		(*) This operation gives wrong results, see known issue 1.

		13. Single stepping "(gdb) si".

		14. Remove breakpoint 1. "(gdb) del 1"

		15. Set hardware breakpoint "(gdb) hbreak sys_open".

		16. Continue "(gdb) c".

		17. Run ls in the target console "/> ls".

		18. Hardware breakpoint hits. "Breakpoint 1: sys_open(...".
		(*) This hardware breakpoint will not be hit, see known issue 2.

		19. Continue "(gdb) c".

		20. Interrupt the target in GDB "Ctrl+C".

		21. Detach from the target "(gdb) detach".

		22. Exit GDB "(gdb) quit".


		Debug over the UART:

		1. Compile and install the cross platform version of gdb for blackfin, which
		can be found at $(BINROOT)/bfin-elf-gdb.

		2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
		"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
		With this selected, option "Full Symbolic/Source Debugging support" and
		"Compile the kernel with frame pointers" are also selected.

		3. Select option "KGDB: connect over (UART)". Set "KGDB: UART port number" to be
		a different one from the console. Don't forget to change the mode of
		blackfin serial driver to PIO. Otherwise kgdb works incorrectly on UART.

		4. If you want connect to kgdb when the kernel boots, enable
		"KGDB: Wait for gdb connection early"

		5. Compile kernel.

		6. Connect minicom to the serial port of the console and boot the kernel image.

		7. Start GDB client "bfin-elf-gdb vmlinux".

		8. Set the baud rate in GDB "(gdb) set remotebaud 57600".

		9. Connect to the target on the second serial port "(gdb) target remote /dev/ttyS1".

		10. Set software breakpoint "(gdb) break sys_open".

		11. Continue "(gdb) c".

		12. Run ls in the target console "/> ls".

		13. A breakpoint is hit. "Breakpoint 1: sys_open(..."

		14. All other operations are the same as that in KGDB over Ethernet.


		Debug over the same UART as console:

		1. Compile and install the cross platform version of gdb for blackfin, which
		can be found at $(BINROOT)/bfin-elf-gdb.

		2. Apply this patch to the 2.6.x kernel. Select the menuconfig option under
		"Kernel hacking" -> "Kernel debugging" -> "KGDB: kernel debug with remote gdb".
		With this selected, option "Full Symbolic/Source Debugging support" and
		"Compile the kernel with frame pointers" are also selected.

		3. Select option "KGDB: connect over UART". Set "KGDB: UART port number" to console.
		Don't forget to change the mode of blackfin serial driver to PIO.
		Otherwise kgdb works incorrectly on UART.

		4. If you want connect to kgdb when the kernel boots, enable
		"KGDB: Wait for gdb connection early"

		5. Connect minicom to the serial port and boot the kernel image.

		6. (Optional) Ask target to wait for gdb connection by entering Ctrl+A. In minicom, you should enter Ctrl+A+A.

		7. Start GDB client "bfin-elf-gdb vmlinux".

		8. Set the baud rate in GDB "(gdb) set remotebaud 57600".

		9. Connect to the target "(gdb) target remote /dev/ttyS0".

		10. Set software breakpoint "(gdb) break sys_open".

		11. Continue "(gdb) c". Then enter Ctrl+C twice to stop GDB connection.

		12. Run ls in the target console "/> ls". Dummy string can be seen on the console.

		13. Then connect the gdb to target again. "(gdb) target remote /dev/ttyS0".
		Now you will find a breakpoint is hit. "Breakpoint 1: sys_open(..."

		14. All other operations are the same as that in KGDB over Ethernet. The only
		difference is that after continue command in GDB, please stop GDB
		connection by 2 "Ctrl+C"s and connect again after breakpoints are hit or
		Ctrl+A is entered.

arch/blackfin/Kconfig.debug

+3 −0

Original line number	Diff line number	Diff line
		@@ -2,6 +2,9 @@ menu "Kernel hacking"

		source "lib/Kconfig.debug"

		config HAVE_ARCH_KGDB
		def_bool y

		config DEBUG_MMRS
		bool "Generate Blackfin MMR tree"
		select DEBUG_FS

arch/blackfin/include/asm/kgdb.h

+13 −8

Original line number	Diff line number	Diff line
		@@ -124,9 +124,16 @@ enum regnames {
		/* Number of bytes of registers. */
		#define NUMREGBYTES BFIN_NUM_REGS*4

		#define BREAKPOINT() asm(" EXCPT 2;");
		static inline void arch_kgdb_breakpoint(void)
		{
		asm(" EXCPT 2;");
		}
		#define BREAK_INSTR_SIZE 2
		#define HW_BREAKPOINT_NUM 6
		#define CACHE_FLUSH_IS_SAFE 1
		#define HW_INST_WATCHPOINT_NUM 6
		#define HW_WATCHPOINT_NUM 8
		#define TYPE_INST_WATCHPOINT 0
		#define TYPE_DATA_WATCHPOINT 1

		/* Instruction watchpoint address control register bits mask */
		#define WPPWR 0x1
		@@ -163,10 +170,11 @@ enum regnames {
		#define WPDAEN1 0x8
		#define WPDCNTEN0 0x10
		#define WPDCNTEN1 0x20

		#define WPDSRC0 0xc0
		#define WPDACC0 0x300
		#define WPDACC0_OFFSET 8
		#define WPDSRC1 0xc00
		#define WPDACC1 0x3000
		#define WPDACC1_OFFSET 12

		/* Watchpoint status register bits mask */
		#define STATIA0 0x1
		@@ -178,7 +186,4 @@ enum regnames {
		#define STATDA0 0x40
		#define STATDA1 0x80

		extern void kgdb_print(const char *fmt, ...);
		extern void init_kgdb_uart(void);

		#endif

arch/blackfin/kernel/kgdb.c

+553 −158

File changed.

Preview size limit exceeded, changes collapsed.

arch/blackfin/kernel/traps.c

+16 −19

Original line number	Diff line number	Diff line
		@@ -43,12 +43,11 @@
		#include <asm/dma.h>

		#ifdef CONFIG_KGDB
		# include <linux/debugger.h>
		# include <linux/kgdb.h>

		# define CHK_DEBUGGER_TRAP() \
		do { \
		CHK_DEBUGGER(trapnr, sig, info.si_code, fp, ); \
		kgdb_handle_exception(trapnr, sig, info.si_code, fp); \
		} while (0)
		# define CHK_DEBUGGER_TRAP_MAYBE() \
		do { \
		@@ -300,7 +299,7 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = SEGV_STACKFLOW;
		sig = SIGSEGV;
		printk(KERN_NOTICE EXC_0x03(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x04 - User Defined, Caught by default */
		/* 0x05 - User Defined, Caught by default */
		@@ -329,7 +328,7 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = TRAP_TRACEFLOW;
		sig = SIGTRAP;
		printk(KERN_NOTICE EXC_0x11(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x12 - Reserved, Caught by default */
		/* 0x13 - Reserved, Caught by default */
		@@ -351,35 +350,35 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = ILL_ILLOPC;
		sig = SIGILL;
		printk(KERN_NOTICE EXC_0x21(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x22 - Illegal Instruction Combination, handled here */
		case VEC_ILGAL_I:
		info.si_code = ILL_ILLPARAOP;
		sig = SIGILL;
		printk(KERN_NOTICE EXC_0x22(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x23 - Data CPLB protection violation, handled here */
		case VEC_CPLB_VL:
		info.si_code = ILL_CPLB_VI;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x23(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x24 - Data access misaligned, handled here */
		case VEC_MISALI_D:
		info.si_code = BUS_ADRALN;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x24(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x25 - Unrecoverable Event, handled here */
		case VEC_UNCOV:
		info.si_code = ILL_ILLEXCPT;
		sig = SIGILL;
		printk(KERN_NOTICE EXC_0x25(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x26 - Data CPLB Miss, normal case is handled in _cplb_hdr,
		error case is handled here */
		@@ -387,7 +386,6 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = BUS_ADRALN;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x26(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		break;
		/* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero, handled here */
		case VEC_CPLB_MHIT:
		@@ -399,7 +397,7 @@ asmlinkage void trap_c(struct pt_regs *fp)
		else
		#endif
		printk(KERN_NOTICE EXC_0x27(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x28 - Emulation Watchpoint, handled here */
		case VEC_WATCH:
		@@ -418,7 +416,7 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = BUS_OPFETCH;
		sig = SIGBUS;
		printk(KERN_NOTICE "BF535: VEC_ISTRU_VL\n");
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		#else
		/* 0x29 - Reserved, Caught by default */
		@@ -428,21 +426,20 @@ asmlinkage void trap_c(struct pt_regs *fp)
		info.si_code = BUS_ADRALN;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x2A(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x2B - Instruction CPLB protection violation, handled here */
		case VEC_CPLB_I_VL:
		info.si_code = ILL_CPLB_VI;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x2B(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x2C - Instruction CPLB miss, handled in _cplb_hdr */
		case VEC_CPLB_I_M:
		info.si_code = ILL_CPLB_MISS;
		sig = SIGBUS;
		printk(KERN_NOTICE EXC_0x2C(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		break;
		/* 0x2D - Instruction CPLB Multiple Hits, handled here */
		case VEC_CPLB_I_MHIT:
		@@ -454,14 +451,14 @@ asmlinkage void trap_c(struct pt_regs *fp)
		else
		#endif
		printk(KERN_NOTICE EXC_0x2D(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x2E - Illegal use of Supervisor Resource, handled here */
		case VEC_ILL_RES:
		info.si_code = ILL_PRVOPC;
		sig = SIGILL;
		printk(KERN_NOTICE EXC_0x2E(KERN_NOTICE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		/* 0x2F - Reserved, Caught by default */
		/* 0x30 - Reserved, Caught by default */
		@@ -508,14 +505,14 @@ asmlinkage void trap_c(struct pt_regs *fp)
		printk(KERN_NOTICE HWC_default(KERN_NOTICE));
		break;
		}
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		default:
		info.si_code = TRAP_ILLTRAP;
		sig = SIGTRAP;
		printk(KERN_EMERG "Caught Unhandled Exception, code = %08lx\n",
		(fp->seqstat & SEQSTAT_EXCAUSE));
		CHK_DEBUGGER_TRAP();
		CHK_DEBUGGER_TRAP_MAYBE();
		break;
		}