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-rw-r--r--arch/mn10300/include/asm/thread_info.h4
-rw-r--r--arch/mn10300/kernel/kgdb.c322
-rw-r--r--arch/mn10300/kernel/switch_to.S111
3 files changed, 425 insertions, 12 deletions
diff --git a/arch/mn10300/include/asm/thread_info.h b/arch/mn10300/include/asm/thread_info.h
index aa07a4a5d794..c139fa17e2e4 100644
--- a/arch/mn10300/include/asm/thread_info.h
+++ b/arch/mn10300/include/asm/thread_info.h
@@ -129,7 +129,11 @@ static inline unsigned long current_stack_pointer(void)
#define alloc_thread_info(tsk) kmalloc(THREAD_SIZE, GFP_KERNEL)
#endif
+#ifndef CONFIG_KGDB
#define free_thread_info(ti) kfree((ti))
+#else
+extern void free_thread_info(struct thread_info *);
+#endif
#define get_thread_info(ti) get_task_struct((ti)->task)
#define put_thread_info(ti) put_task_struct((ti)->task)
diff --git a/arch/mn10300/kernel/kgdb.c b/arch/mn10300/kernel/kgdb.c
index 7d575f553099..f6c981db2a36 100644
--- a/arch/mn10300/kernel/kgdb.c
+++ b/arch/mn10300/kernel/kgdb.c
@@ -9,6 +9,7 @@
* 2 of the Licence, or (at your option) any later version.
*/
+#include <linux/slab.h>
#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/uaccess.h>
@@ -19,6 +20,13 @@
#include "internal.h"
/*
+ * Software single-stepping breakpoint save (used by __switch_to())
+ */
+static struct thread_info *kgdb_sstep_thread;
+u8 *kgdb_sstep_bp_addr[2];
+u8 kgdb_sstep_bp[2];
+
+/*
* Copy kernel exception frame registers to the GDB register file
*/
void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
@@ -118,8 +126,293 @@ struct kgdb_arch arch_kgdb_ops = {
.flags = KGDB_HW_BREAKPOINT,
};
+static const unsigned char mn10300_kgdb_insn_sizes[256] =
+{
+ /* 1 2 3 4 5 6 7 8 9 a b c d e f */
+ 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, 1, 3, 3, 3, /* 0 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 1 */
+ 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 3, 3, 3, 3, /* 2 */
+ 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, /* 3 */
+ 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 2, /* 4 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, /* 5 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 6 */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* 7 */
+ 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 8 */
+ 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* 9 */
+ 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* a */
+ 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 2, /* b */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 2, 2, /* c */
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* d */
+ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, /* e */
+ 0, 2, 2, 2, 2, 2, 2, 4, 0, 3, 0, 4, 0, 6, 7, 1 /* f */
+};
+
/*
- * Handle unknown packets and [Ccs] packets
+ * Attempt to emulate single stepping by means of breakpoint instructions.
+ * Although there is a single-step trace flag in EPSW, its use is not
+ * sufficiently documented and is only intended for use with the JTAG debugger.
+ */
+static int kgdb_arch_do_singlestep(struct pt_regs *regs)
+{
+ unsigned long arg;
+ unsigned size;
+ u8 *pc = (u8 *)regs->pc, *sp = (u8 *)(regs + 1), cur;
+ u8 *x = NULL, *y = NULL;
+ int ret;
+
+ ret = probe_kernel_read(&cur, pc, 1);
+ if (ret < 0)
+ return ret;
+
+ size = mn10300_kgdb_insn_sizes[cur];
+ if (size > 0) {
+ x = pc + size;
+ goto set_x;
+ }
+
+ switch (cur) {
+ /* Bxx (d8,PC) */
+ case 0xc0 ... 0xca:
+ ret = probe_kernel_read(&arg, pc + 1, 1);
+ if (ret < 0)
+ return ret;
+ x = pc + 2;
+ if (arg >= 0 && arg <= 2)
+ goto set_x;
+ y = pc + (s8)arg;
+ goto set_x_and_y;
+
+ /* LXX (d8,PC) */
+ case 0xd0 ... 0xda:
+ x = pc + 1;
+ if (regs->pc == regs->lar)
+ goto set_x;
+ y = (u8 *)regs->lar;
+ goto set_x_and_y;
+
+ /* SETLB - loads the next four bytes into the LIR register
+ * (which mustn't include a breakpoint instruction) */
+ case 0xdb:
+ x = pc + 5;
+ goto set_x;
+
+ /* JMP (d16,PC) or CALL (d16,PC) */
+ case 0xcc:
+ case 0xcd:
+ ret = probe_kernel_read(&arg, pc + 1, 2);
+ if (ret < 0)
+ return ret;
+ x = pc + (s16)arg;
+ goto set_x;
+
+ /* JMP (d32,PC) or CALL (d32,PC) */
+ case 0xdc:
+ case 0xdd:
+ ret = probe_kernel_read(&arg, pc + 1, 4);
+ if (ret < 0)
+ return ret;
+ x = pc + (s32)arg;
+ goto set_x;
+
+ /* RETF */
+ case 0xde:
+ x = (u8 *)regs->mdr;
+ goto set_x;
+
+ /* RET */
+ case 0xdf:
+ ret = probe_kernel_read(&arg, pc + 2, 1);
+ if (ret < 0)
+ return ret;
+ ret = probe_kernel_read(&x, sp + (s8)arg, 4);
+ if (ret < 0)
+ return ret;
+ goto set_x;
+
+ case 0xf0:
+ ret = probe_kernel_read(&cur, pc + 1, 1);
+ if (ret < 0)
+ return ret;
+
+ if (cur >= 0xf0 && cur <= 0xf7) {
+ /* JMP (An) / CALLS (An) */
+ switch (cur & 3) {
+ case 0: x = (u8 *)regs->a0; break;
+ case 1: x = (u8 *)regs->a1; break;
+ case 2: x = (u8 *)regs->a2; break;
+ case 3: x = (u8 *)regs->a3; break;
+ }
+ goto set_x;
+ } else if (cur == 0xfc) {
+ /* RETS */
+ ret = probe_kernel_read(&x, sp, 4);
+ if (ret < 0)
+ return ret;
+ goto set_x;
+ } else if (cur == 0xfd) {
+ /* RTI */
+ ret = probe_kernel_read(&x, sp + 4, 4);
+ if (ret < 0)
+ return ret;
+ goto set_x;
+ } else {
+ x = pc + 2;
+ goto set_x;
+ }
+ break;
+
+ /* potential 3-byte conditional branches */
+ case 0xf8:
+ ret = probe_kernel_read(&cur, pc + 1, 1);
+ if (ret < 0)
+ return ret;
+ x = pc + 3;
+
+ if (cur >= 0xe8 && cur <= 0xeb) {
+ ret = probe_kernel_read(&arg, pc + 2, 1);
+ if (ret < 0)
+ return ret;
+ if (arg >= 0 && arg <= 3)
+ goto set_x;
+ y = pc + (s8)arg;
+ goto set_x_and_y;
+ }
+ goto set_x;
+
+ case 0xfa:
+ ret = probe_kernel_read(&cur, pc + 1, 1);
+ if (ret < 0)
+ return ret;
+
+ if (cur == 0xff) {
+ /* CALLS (d16,PC) */
+ ret = probe_kernel_read(&arg, pc + 2, 2);
+ if (ret < 0)
+ return ret;
+ x = pc + (s16)arg;
+ goto set_x;
+ }
+
+ x = pc + 4;
+ goto set_x;
+
+ case 0xfc:
+ ret = probe_kernel_read(&cur, pc + 1, 1);
+ if (ret < 0)
+ return ret;
+
+ if (cur == 0xff) {
+ /* CALLS (d32,PC) */
+ ret = probe_kernel_read(&arg, pc + 2, 4);
+ if (ret < 0)
+ return ret;
+ x = pc + (s32)arg;
+ goto set_x;
+ }
+
+ x = pc + 6;
+ goto set_x;
+ }
+
+ return 0;
+
+set_x:
+ kgdb_sstep_bp_addr[0] = x;
+ kgdb_sstep_bp_addr[1] = NULL;
+ ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
+ if (ret < 0)
+ return ret;
+ ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
+ if (ret < 0)
+ return ret;
+ kgdb_sstep_thread = current_thread_info();
+ debugger_local_cache_flushinv_one(x);
+ return ret;
+
+set_x_and_y:
+ kgdb_sstep_bp_addr[0] = x;
+ kgdb_sstep_bp_addr[1] = y;
+ ret = probe_kernel_read(&kgdb_sstep_bp[0], x, 1);
+ if (ret < 0)
+ return ret;
+ ret = probe_kernel_read(&kgdb_sstep_bp[1], y, 1);
+ if (ret < 0)
+ return ret;
+ ret = probe_kernel_write(x, &arch_kgdb_ops.gdb_bpt_instr, 1);
+ if (ret < 0)
+ return ret;
+ ret = probe_kernel_write(y, &arch_kgdb_ops.gdb_bpt_instr, 1);
+ if (ret < 0) {
+ probe_kernel_write(kgdb_sstep_bp_addr[0],
+ &kgdb_sstep_bp[0], 1);
+ } else {
+ kgdb_sstep_thread = current_thread_info();
+ }
+ debugger_local_cache_flushinv_one(x);
+ debugger_local_cache_flushinv_one(y);
+ return ret;
+}
+
+/*
+ * Remove emplaced single-step breakpoints, returning true if we hit one of
+ * them.
+ */
+static bool kgdb_arch_undo_singlestep(struct pt_regs *regs)
+{
+ bool hit = false;
+ u8 *x = kgdb_sstep_bp_addr[0], *y = kgdb_sstep_bp_addr[1];
+ u8 opcode;
+
+ if (kgdb_sstep_thread == current_thread_info()) {
+ if (x) {
+ if (x == (u8 *)regs->pc)
+ hit = true;
+ if (probe_kernel_read(&opcode, x,
+ 1) < 0 ||
+ opcode != 0xff)
+ BUG();
+ probe_kernel_write(x, &kgdb_sstep_bp[0], 1);
+ debugger_local_cache_flushinv_one(x);
+ }
+ if (y) {
+ if (y == (u8 *)regs->pc)
+ hit = true;
+ if (probe_kernel_read(&opcode, y,
+ 1) < 0 ||
+ opcode != 0xff)
+ BUG();
+ probe_kernel_write(y, &kgdb_sstep_bp[1], 1);
+ debugger_local_cache_flushinv_one(y);
+ }
+ }
+
+ kgdb_sstep_bp_addr[0] = NULL;
+ kgdb_sstep_bp_addr[1] = NULL;
+ kgdb_sstep_thread = NULL;
+ return hit;
+}
+
+/*
+ * Catch a single-step-pending thread being deleted and make sure the global
+ * single-step state is cleared. At this point the breakpoints should have
+ * been removed by __switch_to().
+ */
+void free_thread_info(struct thread_info *ti)
+{
+ if (kgdb_sstep_thread == ti) {
+ kgdb_sstep_thread = NULL;
+
+ /* However, we may now be running in degraded mode, with most
+ * of the CPUs disabled until such a time as KGDB is reentered,
+ * so force immediate reentry */
+ kgdb_breakpoint();
+ }
+ kfree(ti);
+}
+
+/*
+ * Handle unknown packets and [CcsDk] packets
+ * - at this point breakpoints have been installed
*/
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
char *remcom_in_buffer, char *remcom_out_buffer,
@@ -130,21 +423,22 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
switch (remcom_in_buffer[0]) {
case 'c':
- if (kgdb_contthread && kgdb_contthread != current) {
- strcpy(remcom_out_buffer, "E00");
- break;
- }
-
- kgdb_contthread = NULL;
-
+ case 's':
/* try to read optional parameter, pc unchanged if no parm */
ptr = &remcom_in_buffer[1];
if (kgdb_hex2long(&ptr, &addr))
regs->pc = addr;
- return 0;
+ case 'D':
+ case 'k':
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
- case 's':
- break; /* we don't do hardware single stepping */
+ if (remcom_in_buffer[0] == 's') {
+ kgdb_arch_do_singlestep(regs);
+ kgdb_single_step = 1;
+ atomic_set(&kgdb_cpu_doing_single_step,
+ raw_smp_processor_id());
+ }
+ return 0;
}
return -1; /* this means that we do not want to exit from the handler */
}
@@ -158,6 +452,12 @@ int debugger_intercept(enum exception_code excep, int signo, int si_code,
{
int ret;
+ if (kgdb_arch_undo_singlestep(regs)) {
+ excep = EXCEP_TRAP;
+ signo = SIGTRAP;
+ si_code = TRAP_TRACE;
+ }
+
ret = kgdb_handle_exception(excep, signo, si_code, regs);
debugger_local_cache_flushinv();
diff --git a/arch/mn10300/kernel/switch_to.S b/arch/mn10300/kernel/switch_to.S
index 9074d0fb8788..de3e74fc9ea0 100644
--- a/arch/mn10300/kernel/switch_to.S
+++ b/arch/mn10300/kernel/switch_to.S
@@ -39,11 +39,17 @@ ENTRY(__switch_to)
# save prev context
mov __switch_back,d0
- mov d0,(THREAD_PC,a0)
mov sp,a2
mov a2,(THREAD_SP,a0)
mov a3,(THREAD_A3,a0)
+#ifdef CONFIG_KGDB
+ btst 0xff,(kgdb_single_step)
+ bne __switch_to__lift_sstep_bp
+__switch_to__continue:
+#endif
+ mov d0,(THREAD_PC,a0)
+
mov (THREAD_A3,a1),a3
mov (THREAD_SP,a1),a2
@@ -68,3 +74,106 @@ ENTRY(__switch_to)
__switch_back:
and ~EPSW_NMID,epsw
ret [d2,d3,a2,a3,exreg1],32
+
+#ifdef CONFIG_KGDB
+###############################################################################
+#
+# Lift the single-step breakpoints when the task being traced is switched out
+# A0 = prev
+# A1 = next
+#
+###############################################################################
+__switch_to__lift_sstep_bp:
+ add -12,sp
+ mov a0,e4
+ mov a1,e5
+
+ # Clear the single-step flag to prevent us coming this way until we get
+ # switched back in
+ bclr 0xff,(kgdb_single_step)
+
+ # Remove first breakpoint
+ mov (kgdb_sstep_bp_addr),a2
+ cmp 0,a2
+ beq 1f
+ movbu (kgdb_sstep_bp),d0
+ movbu d0,(a2)
+#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE)
+ mov a2,d0
+ mov a2,d1
+ add 1,d1
+ calls flush_icache_range
+#endif
+1:
+
+ # Remove second breakpoint
+ mov (kgdb_sstep_bp_addr+4),a2
+ cmp 0,a2
+ beq 2f
+ movbu (kgdb_sstep_bp+1),d0
+ movbu d0,(a2)
+#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE)
+ mov a2,d0
+ mov a2,d1
+ add 1,d1
+ calls flush_icache_range
+#endif
+2:
+
+ # Change the resumption address and return
+ mov __switch_back__reinstall_sstep_bp,d0
+ mov e4,a0
+ mov e5,a1
+ add 12,sp
+ bra __switch_to__continue
+
+###############################################################################
+#
+# Reinstall the single-step breakpoints when the task being traced is switched
+# back in (A1 points to the new thread_struct).
+#
+###############################################################################
+__switch_back__reinstall_sstep_bp:
+ add -12,sp
+ mov a0,e4 # save the return value
+ mov 0xff,d3
+
+ # Reinstall first breakpoint
+ mov (kgdb_sstep_bp_addr),a2
+ cmp 0,a2
+ beq 1f
+ movbu (a2),d0
+ movbu d0,(kgdb_sstep_bp)
+ movbu d3,(a2)
+#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE)
+ mov a2,d0
+ mov a2,d1
+ add 1,d1
+ calls flush_icache_range
+#endif
+1:
+
+ # Reinstall second breakpoint
+ mov (kgdb_sstep_bp_addr+4),a2
+ cmp 0,a2
+ beq 2f
+ movbu (a2),d0
+ movbu d0,(kgdb_sstep_bp+1)
+ movbu d3,(a2)
+#if defined(CONFIG_MN10300_CACHE_FLUSH_ICACHE) || defined(CONFIG_MN10300_CACHE_INV_ICACHE)
+ mov a2,d0
+ mov a2,d1
+ add 1,d1
+ calls flush_icache_range
+#endif
+2:
+
+ mov d3,(kgdb_single_step)
+
+ # Restore the return value (the previous thread_struct pointer)
+ mov e4,a0
+ mov a0,d0
+ add 12,sp
+ bra __switch_back
+
+#endif /* CONFIG_KGDB */
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-01 07:37:48 +0300