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authorMichal Simek <monstr@monstr.eu>2010-08-03 11:45:08 +0200
committerMichal Simek <monstr@monstr.eu>2010-08-04 10:45:17 +0200
commit2d5973cb5ac5d04662f86e19a06a4c52fa4c4ae3 (patch)
tree21ddc58eed5ccad856fc44dfb0ee794da41d5b16 /arch/microblaze/kernel/kgdb.c
parent751f1605e03533a6279ccf456e938e9595c7d888 (diff)
downloadop-kernel-dev-2d5973cb5ac5d04662f86e19a06a4c52fa4c4ae3.zip
op-kernel-dev-2d5973cb5ac5d04662f86e19a06a4c52fa4c4ae3.tar.gz
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 <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>
Diffstat (limited to 'arch/microblaze/kernel/kgdb.c')
-rw-r--r--arch/microblaze/kernel/kgdb.c147
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/microblaze/kernel/kgdb.c b/arch/microblaze/kernel/kgdb.c
new file mode 100644
index 0000000..bfc006b
--- /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 <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <asm/cacheflush.h>
+#include <asm/asm-offsets.h>
+#include <asm/pvr.h>
+
+#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 */
+};
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