From 2d5973cb5ac5d04662f86e19a06a4c52fa4c4ae3 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Tue, 3 Aug 2010 11:45:08 +0200 Subject: microblaze: Add KGDB support Kgdb uses brki r16, 0x18 instruction to call low level _debug_exception function which save current state to pt_regs and call microblaze_kgdb_break function. _debug_exception should be called only from the kernel space. User space calling is not supported because user application debugging uses different handling. pt_regs_to_gdb_regs loads additional special registers which can't be changed * Enable KGDB in Kconfig * Remove ancient not-tested KGDB support * Remove ancient _debug_exception code from entry.S Only MMU KGDB support is supported. Signed-off-by: Michal Simek CC: Jason Wessel CC: John Williams CC: Edgar E. Iglesias CC: linux-kernel@vger.kernel.org Acked-by: Jason Wessel --- arch/microblaze/kernel/kgdb.c | 147 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) create mode 100644 arch/microblaze/kernel/kgdb.c (limited to 'arch/microblaze/kernel/kgdb.c') diff --git a/arch/microblaze/kernel/kgdb.c b/arch/microblaze/kernel/kgdb.c new file mode 100644 index 000000000000..bfc006b7f2d8 --- /dev/null +++ b/arch/microblaze/kernel/kgdb.c @@ -0,0 +1,147 @@ +/* + * Microblaze KGDB support + * + * 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. + */ + +#include +#include +#include +#include +#include +#include +#include + +#define GDB_REG 0 +#define GDB_PC 32 +#define GDB_MSR 33 +#define GDB_EAR 34 +#define GDB_ESR 35 +#define GDB_FSR 36 +#define GDB_BTR 37 +#define GDB_PVR 38 +#define GDB_REDR 50 +#define GDB_RPID 51 +#define GDB_RZPR 52 +#define GDB_RTLBX 53 +#define GDB_RTLBSX 54 /* mfs can't read it */ +#define GDB_RTLBLO 55 +#define GDB_RTLBHI 56 + +/* keep pvr separately because it is unchangeble */ +struct pvr_s pvr; + +void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + int i; + unsigned long *pt_regb = (unsigned long *)regs; + int temp; + /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */ + for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++) + gdb_regs[i] = pt_regb[i]; + + /* Branch target register can't be changed */ + __asm__ __volatile__ ("mfs %0, rbtr;" : "=r"(temp) : ); + gdb_regs[GDB_BTR] = temp; + + /* pvr part - we have 11 pvr regs */ + for (i = 0; i < sizeof(struct pvr_s)/4; i++) + gdb_regs[GDB_PVR + i] = pvr.pvr[i]; + + /* read special registers - can't be changed */ + __asm__ __volatile__ ("mfs %0, redr;" : "=r"(temp) : ); + gdb_regs[GDB_REDR] = temp; + __asm__ __volatile__ ("mfs %0, rpid;" : "=r"(temp) : ); + gdb_regs[GDB_RPID] = temp; + __asm__ __volatile__ ("mfs %0, rzpr;" : "=r"(temp) : ); + gdb_regs[GDB_RZPR] = temp; + __asm__ __volatile__ ("mfs %0, rtlbx;" : "=r"(temp) : ); + gdb_regs[GDB_RTLBX] = temp; + __asm__ __volatile__ ("mfs %0, rtlblo;" : "=r"(temp) : ); + gdb_regs[GDB_RTLBLO] = temp; + __asm__ __volatile__ ("mfs %0, rtlbhi;" : "=r"(temp) : ); + gdb_regs[GDB_RTLBHI] = temp; +} + +void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + int i; + unsigned long *pt_regb = (unsigned long *)regs; + + /* pt_regs and gdb_regs have the same 37 values. + * The rest of gdb_regs are unused and can't be changed. + * r0 register value can't be changed too. */ + for (i = 1; i < (sizeof(struct pt_regs) / 4) - 1; i++) + pt_regb[i] = gdb_regs[i]; +} + +void microblaze_kgdb_break(struct pt_regs *regs) +{ + if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) + return 0; + + /* Jump over the first arch_kgdb_breakpoint which is barrier to + * get kgdb work. The same solution is used for powerpc */ + if (*(u32 *) (regs->pc) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) + regs->pc += BREAK_INSTR_SIZE; +} + +/* untested */ +void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) +{ + int i; + unsigned long *pt_regb = (unsigned long *)(p->thread.regs); + + /* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */ + for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++) + gdb_regs[i] = pt_regb[i]; + + /* pvr part - we have 11 pvr regs */ + for (i = 0; i < sizeof(struct pvr_s)/4; i++) + gdb_regs[GDB_PVR + i] = pvr.pvr[i]; +} + +void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip) +{ + regs->pc = ip; +} + +int kgdb_arch_handle_exception(int vector, int signo, int err_code, + char *remcom_in_buffer, char *remcom_out_buffer, + struct pt_regs *regs) +{ + char *ptr; + unsigned long address; + int cpu = smp_processor_id(); + + switch (remcom_in_buffer[0]) { + case 'c': + /* handle the optional parameter */ + ptr = &remcom_in_buffer[1]; + if (kgdb_hex2long(&ptr, &address)) + regs->pc = address; + + return 0; + } + return -1; /* this means that we do not want to exit from the handler */ +} + +int kgdb_arch_init(void) +{ + get_pvr(&pvr); /* Fill PVR structure */ + return 0; +} + +void kgdb_arch_exit(void) +{ + /* Nothing to do */ +} + +/* + * Global data + */ +struct kgdb_arch arch_kgdb_ops = { + .gdb_bpt_instr = {0xba, 0x0c, 0x00, 0x18}, /* brki r16, 0x18 */ +}; -- cgit v1.2.1