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Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/kgdb.c138
-rw-r--r--arch/x86/kernel/setup64.c16
2 files changed, 154 insertions, 0 deletions
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 5d7a21119bf..7d651adcb22 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -182,6 +182,122 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
#endif
}
+static struct hw_breakpoint {
+ unsigned enabled;
+ unsigned type;
+ unsigned len;
+ unsigned long addr;
+} breakinfo[4];
+
+static void kgdb_correct_hw_break(void)
+{
+ unsigned long dr7;
+ int correctit = 0;
+ int breakbit;
+ int breakno;
+
+ get_debugreg(dr7, 7);
+ for (breakno = 0; breakno < 4; breakno++) {
+ breakbit = 2 << (breakno << 1);
+ if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 |= breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ dr7 |= ((breakinfo[breakno].len << 2) |
+ breakinfo[breakno].type) <<
+ ((breakno << 2) + 16);
+ if (breakno >= 0 && breakno <= 3)
+ set_debugreg(breakinfo[breakno].addr, breakno);
+
+ } else {
+ if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 &= ~breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ }
+ }
+ }
+ if (correctit)
+ set_debugreg(dr7, 7);
+}
+
+static int
+kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ int i;
+
+ for (i = 0; i < 4; i++)
+ if (breakinfo[i].addr == addr && breakinfo[i].enabled)
+ break;
+ if (i == 4)
+ return -1;
+
+ breakinfo[i].enabled = 0;
+
+ return 0;
+}
+
+static void kgdb_remove_all_hw_break(void)
+{
+ int i;
+
+ for (i = 0; i < 4; i++)
+ memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint));
+}
+
+static int
+kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype)
+{
+ unsigned type;
+ int i;
+
+ for (i = 0; i < 4; i++)
+ if (!breakinfo[i].enabled)
+ break;
+ if (i == 4)
+ return -1;
+
+ switch (bptype) {
+ case BP_HARDWARE_BREAKPOINT:
+ type = 0;
+ len = 1;
+ break;
+ case BP_WRITE_WATCHPOINT:
+ type = 1;
+ break;
+ case BP_ACCESS_WATCHPOINT:
+ type = 3;
+ break;
+ default:
+ return -1;
+ }
+
+ if (len == 1 || len == 2 || len == 4)
+ breakinfo[i].len = len - 1;
+ else
+ return -1;
+
+ breakinfo[i].enabled = 1;
+ breakinfo[i].addr = addr;
+ breakinfo[i].type = type;
+
+ return 0;
+}
+
+/**
+ * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ * @regs: Current &struct pt_regs.
+ *
+ * This function will be called if the particular architecture must
+ * disable hardware debugging while it is processing gdb packets or
+ * handling exception.
+ */
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+ /* Disable hardware debugging while we are in kgdb: */
+ set_debugreg(0UL, 7);
+}
+
/**
* kgdb_post_primary_code - Save error vector/code numbers.
* @regs: Original pt_regs.
@@ -243,6 +359,7 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
struct pt_regs *linux_regs)
{
unsigned long addr;
+ unsigned long dr6;
char *ptr;
int newPC;
@@ -269,6 +386,22 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
}
}
+ get_debugreg(dr6, 6);
+ if (!(dr6 & 0x4000)) {
+ int breakno;
+
+ for (breakno = 0; breakno < 4; breakno++) {
+ if (dr6 & (1 << breakno) &&
+ breakinfo[breakno].type == 0) {
+ /* Set restore flag: */
+ linux_regs->flags |= X86_EFLAGS_RF;
+ break;
+ }
+ }
+ }
+ set_debugreg(0UL, 6);
+ kgdb_correct_hw_break();
+
return 0;
}
@@ -426,4 +559,9 @@ unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
struct kgdb_arch arch_kgdb_ops = {
/* Breakpoint instruction: */
.gdb_bpt_instr = { 0xcc },
+ .flags = KGDB_HW_BREAKPOINT,
+ .set_hw_breakpoint = kgdb_set_hw_break,
+ .remove_hw_breakpoint = kgdb_remove_hw_break,
+ .remove_all_hw_break = kgdb_remove_all_hw_break,
+ .correct_hw_break = kgdb_correct_hw_break,
};
diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c
index e24c4567709..143aa78c566 100644
--- a/arch/x86/kernel/setup64.c
+++ b/arch/x86/kernel/setup64.c
@@ -11,6 +11,7 @@
#include <linux/bootmem.h>
#include <linux/bitops.h>
#include <linux/module.h>
+#include <linux/kgdb.h>
#include <asm/pda.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
@@ -327,6 +328,17 @@ void __cpuinit cpu_init (void)
load_TR_desc();
load_LDT(&init_mm.context);
+#ifdef CONFIG_KGDB
+ /*
+ * If the kgdb is connected no debug regs should be altered. This
+ * is only applicable when KGDB and a KGDB I/O module are built
+ * into the kernel and you are using early debugging with
+ * kgdbwait. KGDB will control the kernel HW breakpoint registers.
+ */
+ if (kgdb_connected && arch_kgdb_ops.correct_hw_break)
+ arch_kgdb_ops.correct_hw_break();
+ else {
+#endif
/*
* Clear all 6 debug registers:
*/
@@ -337,6 +349,10 @@ void __cpuinit cpu_init (void)
set_debugreg(0UL, 3);
set_debugreg(0UL, 6);
set_debugreg(0UL, 7);
+#ifdef CONFIG_KGDB
+ /* If the kgdb is connected no debug regs should be altered. */
+ }
+#endif
fpu_init();