2d5973cb5a
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 <monstr@monstr.eu> CC: Jason Wessel <jason.wessel@windriver.com> CC: John Williams <john.williams@petalogix.com> CC: Edgar E. Iglesias <edgar.iglesias@petalogix.com> CC: linux-kernel@vger.kernel.org Acked-by: Jason Wessel <jason.wessel@windriver.com>
147 lines
3.8 KiB
C
147 lines
3.8 KiB
C
/*
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* Microblaze KGDB support
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/kgdb.h>
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#include <linux/kdebug.h>
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#include <linux/irq.h>
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#include <linux/io.h>
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#include <asm/cacheflush.h>
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#include <asm/asm-offsets.h>
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#include <asm/pvr.h>
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#define GDB_REG 0
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#define GDB_PC 32
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#define GDB_MSR 33
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#define GDB_EAR 34
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#define GDB_ESR 35
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#define GDB_FSR 36
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#define GDB_BTR 37
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#define GDB_PVR 38
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#define GDB_REDR 50
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#define GDB_RPID 51
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#define GDB_RZPR 52
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#define GDB_RTLBX 53
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#define GDB_RTLBSX 54 /* mfs can't read it */
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#define GDB_RTLBLO 55
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#define GDB_RTLBHI 56
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/* keep pvr separately because it is unchangeble */
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struct pvr_s pvr;
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void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)regs;
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int temp;
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/* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
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for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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gdb_regs[i] = pt_regb[i];
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/* Branch target register can't be changed */
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__asm__ __volatile__ ("mfs %0, rbtr;" : "=r"(temp) : );
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gdb_regs[GDB_BTR] = temp;
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/* pvr part - we have 11 pvr regs */
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for (i = 0; i < sizeof(struct pvr_s)/4; i++)
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gdb_regs[GDB_PVR + i] = pvr.pvr[i];
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/* read special registers - can't be changed */
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__asm__ __volatile__ ("mfs %0, redr;" : "=r"(temp) : );
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gdb_regs[GDB_REDR] = temp;
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__asm__ __volatile__ ("mfs %0, rpid;" : "=r"(temp) : );
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gdb_regs[GDB_RPID] = temp;
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__asm__ __volatile__ ("mfs %0, rzpr;" : "=r"(temp) : );
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gdb_regs[GDB_RZPR] = temp;
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__asm__ __volatile__ ("mfs %0, rtlbx;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBX] = temp;
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__asm__ __volatile__ ("mfs %0, rtlblo;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBLO] = temp;
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__asm__ __volatile__ ("mfs %0, rtlbhi;" : "=r"(temp) : );
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gdb_regs[GDB_RTLBHI] = temp;
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}
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void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)regs;
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/* pt_regs and gdb_regs have the same 37 values.
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* The rest of gdb_regs are unused and can't be changed.
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* r0 register value can't be changed too. */
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for (i = 1; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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pt_regb[i] = gdb_regs[i];
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}
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void microblaze_kgdb_break(struct pt_regs *regs)
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{
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if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
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return 0;
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/* Jump over the first arch_kgdb_breakpoint which is barrier to
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* get kgdb work. The same solution is used for powerpc */
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if (*(u32 *) (regs->pc) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
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regs->pc += BREAK_INSTR_SIZE;
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}
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/* untested */
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void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
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{
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int i;
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unsigned long *pt_regb = (unsigned long *)(p->thread.regs);
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/* registers r0 - r31, pc, msr, ear, esr, fsr + do not save pt_mode */
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for (i = 0; i < (sizeof(struct pt_regs) / 4) - 1; i++)
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gdb_regs[i] = pt_regb[i];
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/* pvr part - we have 11 pvr regs */
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for (i = 0; i < sizeof(struct pvr_s)/4; i++)
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gdb_regs[GDB_PVR + i] = pvr.pvr[i];
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}
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void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
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{
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regs->pc = ip;
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}
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int kgdb_arch_handle_exception(int vector, int signo, int err_code,
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char *remcom_in_buffer, char *remcom_out_buffer,
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struct pt_regs *regs)
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{
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char *ptr;
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unsigned long address;
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int cpu = smp_processor_id();
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switch (remcom_in_buffer[0]) {
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case 'c':
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/* handle the optional parameter */
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ptr = &remcom_in_buffer[1];
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if (kgdb_hex2long(&ptr, &address))
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regs->pc = address;
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return 0;
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}
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return -1; /* this means that we do not want to exit from the handler */
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}
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int kgdb_arch_init(void)
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{
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get_pvr(&pvr); /* Fill PVR structure */
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return 0;
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}
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void kgdb_arch_exit(void)
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{
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/* Nothing to do */
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}
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/*
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* Global data
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*/
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struct kgdb_arch arch_kgdb_ops = {
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.gdb_bpt_instr = {0xba, 0x0c, 0x00, 0x18}, /* brki r16, 0x18 */
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};
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