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@@ -24,6 +24,7 @@
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#define pr_fmt(fmt) "hw-breakpoint: " fmt
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#include <linux/errno.h>
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+#include <linux/hardirq.h>
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#include <linux/perf_event.h>
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#include <linux/hw_breakpoint.h>
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#include <linux/smp.h>
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@@ -44,6 +45,7 @@ static DEFINE_PER_CPU(struct perf_event *, wp_on_reg[ARM_MAX_WRP]);
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/* Number of BRP/WRP registers on this CPU. */
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static int core_num_brps;
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+static int core_num_reserved_brps;
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static int core_num_wrps;
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/* Debug architecture version. */
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@@ -52,87 +54,6 @@ static u8 debug_arch;
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/* Maximum supported watchpoint length. */
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static u8 max_watchpoint_len;
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-/* Determine number of BRP registers available. */
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-static int get_num_brps(void)
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-{
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- u32 didr;
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- ARM_DBG_READ(c0, 0, didr);
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- return ((didr >> 24) & 0xf) + 1;
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-}
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-
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-/* Determine number of WRP registers available. */
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-static int get_num_wrps(void)
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-{
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- /*
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- * FIXME: When a watchpoint fires, the only way to work out which
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- * watchpoint it was is by disassembling the faulting instruction
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- * and working out the address of the memory access.
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- *
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- * Furthermore, we can only do this if the watchpoint was precise
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- * since imprecise watchpoints prevent us from calculating register
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- * based addresses.
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- *
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- * For the time being, we only report 1 watchpoint register so we
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- * always know which watchpoint fired. In the future we can either
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- * add a disassembler and address generation emulator, or we can
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- * insert a check to see if the DFAR is set on watchpoint exception
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- * entry [the ARM ARM states that the DFAR is UNKNOWN, but
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- * experience shows that it is set on some implementations].
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- */
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-
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-#if 0
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- u32 didr, wrps;
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- ARM_DBG_READ(c0, 0, didr);
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- return ((didr >> 28) & 0xf) + 1;
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-#endif
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-
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- return 1;
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-}
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-
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-int hw_breakpoint_slots(int type)
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-{
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- /*
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- * We can be called early, so don't rely on
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- * our static variables being initialised.
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- */
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- switch (type) {
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- case TYPE_INST:
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- return get_num_brps();
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- case TYPE_DATA:
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- return get_num_wrps();
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- default:
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- pr_warning("unknown slot type: %d\n", type);
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- return 0;
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- }
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-}
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-
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-/* Determine debug architecture. */
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-static u8 get_debug_arch(void)
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-{
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- u32 didr;
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-
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- /* Do we implement the extended CPUID interface? */
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- if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
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- pr_warning("CPUID feature registers not supported. "
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- "Assuming v6 debug is present.\n");
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- return ARM_DEBUG_ARCH_V6;
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- }
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-
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- ARM_DBG_READ(c0, 0, didr);
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- return (didr >> 16) & 0xf;
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-}
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-
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-/* Does this core support mismatch breakpoints? */
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-static int core_has_mismatch_bps(void)
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-{
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- return debug_arch >= ARM_DEBUG_ARCH_V7_ECP14 && core_num_brps > 1;
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-}
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-
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-u8 arch_get_debug_arch(void)
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-{
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- return debug_arch;
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-}
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-
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#define READ_WB_REG_CASE(OP2, M, VAL) \
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case ((OP2 << 4) + M): \
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ARM_DBG_READ(c ## M, OP2, VAL); \
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@@ -210,6 +131,94 @@ static void write_wb_reg(int n, u32 val)
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isb();
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}
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+/* Determine debug architecture. */
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+static u8 get_debug_arch(void)
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+{
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+ u32 didr;
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+
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+ /* Do we implement the extended CPUID interface? */
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+ if (((read_cpuid_id() >> 16) & 0xf) != 0xf) {
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+ pr_warning("CPUID feature registers not supported. "
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+ "Assuming v6 debug is present.\n");
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+ return ARM_DEBUG_ARCH_V6;
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+ }
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+
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+ ARM_DBG_READ(c0, 0, didr);
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+ return (didr >> 16) & 0xf;
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+}
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+
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+u8 arch_get_debug_arch(void)
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+{
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+ return debug_arch;
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+}
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+
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+/* Determine number of BRP register available. */
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+static int get_num_brp_resources(void)
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+{
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+ u32 didr;
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+ ARM_DBG_READ(c0, 0, didr);
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+ return ((didr >> 24) & 0xf) + 1;
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+}
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+
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+/* Does this core support mismatch breakpoints? */
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+static int core_has_mismatch_brps(void)
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+{
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+ return (get_debug_arch() >= ARM_DEBUG_ARCH_V7_ECP14 &&
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+ get_num_brp_resources() > 1);
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+}
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+
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+/* Determine number of usable WRPs available. */
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+static int get_num_wrps(void)
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+{
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+ /*
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+ * FIXME: When a watchpoint fires, the only way to work out which
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+ * watchpoint it was is by disassembling the faulting instruction
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+ * and working out the address of the memory access.
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+ *
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+ * Furthermore, we can only do this if the watchpoint was precise
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+ * since imprecise watchpoints prevent us from calculating register
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+ * based addresses.
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+ *
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+ * Providing we have more than 1 breakpoint register, we only report
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+ * a single watchpoint register for the time being. This way, we always
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+ * know which watchpoint fired. In the future we can either add a
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+ * disassembler and address generation emulator, or we can insert a
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+ * check to see if the DFAR is set on watchpoint exception entry
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+ * [the ARM ARM states that the DFAR is UNKNOWN, but experience shows
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+ * that it is set on some implementations].
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+ */
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+
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+#if 0
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+ int wrps;
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+ u32 didr;
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+ ARM_DBG_READ(c0, 0, didr);
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+ wrps = ((didr >> 28) & 0xf) + 1;
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+#endif
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+ int wrps = 1;
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+
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+ if (core_has_mismatch_brps() && wrps >= get_num_brp_resources())
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+ wrps = get_num_brp_resources() - 1;
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+
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+ return wrps;
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+}
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+
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+/* We reserve one breakpoint for each watchpoint. */
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+static int get_num_reserved_brps(void)
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+{
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+ if (core_has_mismatch_brps())
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+ return get_num_wrps();
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+ return 0;
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+}
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+
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+/* Determine number of usable BRPs available. */
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+static int get_num_brps(void)
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+{
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+ int brps = get_num_brp_resources();
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+ if (core_has_mismatch_brps())
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+ brps -= get_num_reserved_brps();
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+ return brps;
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+}
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+
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/*
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* In order to access the breakpoint/watchpoint control registers,
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* we must be running in debug monitor mode. Unfortunately, we can
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@@ -230,8 +239,12 @@ static int enable_monitor_mode(void)
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goto out;
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}
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+ /* If monitor mode is already enabled, just return. */
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+ if (dscr & ARM_DSCR_MDBGEN)
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+ goto out;
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+
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/* Write to the corresponding DSCR. */
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- switch (debug_arch) {
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+ switch (get_debug_arch()) {
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case ARM_DEBUG_ARCH_V6:
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case ARM_DEBUG_ARCH_V6_1:
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ARM_DBG_WRITE(c1, 0, (dscr | ARM_DSCR_MDBGEN));
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@@ -246,15 +259,30 @@ static int enable_monitor_mode(void)
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/* Check that the write made it through. */
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ARM_DBG_READ(c1, 0, dscr);
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- if (WARN_ONCE(!(dscr & ARM_DSCR_MDBGEN),
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- "failed to enable monitor mode.")) {
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+ if (!(dscr & ARM_DSCR_MDBGEN))
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ret = -EPERM;
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- }
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out:
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return ret;
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}
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+int hw_breakpoint_slots(int type)
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+{
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+ /*
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+ * We can be called early, so don't rely on
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+ * our static variables being initialised.
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+ */
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+ switch (type) {
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+ case TYPE_INST:
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+ return get_num_brps();
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+ case TYPE_DATA:
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+ return get_num_wrps();
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+ default:
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+ pr_warning("unknown slot type: %d\n", type);
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+ return 0;
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+ }
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+}
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+
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/*
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* Check if 8-bit byte-address select is available.
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* This clobbers WRP 0.
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@@ -268,9 +296,6 @@ static u8 get_max_wp_len(void)
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if (debug_arch < ARM_DEBUG_ARCH_V7_ECP14)
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goto out;
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- if (enable_monitor_mode())
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- goto out;
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-
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memset(&ctrl, 0, sizeof(ctrl));
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ctrl.len = ARM_BREAKPOINT_LEN_8;
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ctrl_reg = encode_ctrl_reg(ctrl);
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@@ -289,23 +314,6 @@ u8 arch_get_max_wp_len(void)
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return max_watchpoint_len;
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}
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-/*
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- * Handler for reactivating a suspended watchpoint when the single
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- * step `mismatch' breakpoint is triggered.
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- */
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-static void wp_single_step_handler(struct perf_event *bp, int unused,
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- struct perf_sample_data *data,
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- struct pt_regs *regs)
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-{
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- perf_event_enable(counter_arch_bp(bp)->suspended_wp);
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- unregister_hw_breakpoint(bp);
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-}
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-
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-static int bp_is_single_step(struct perf_event *bp)
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-{
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- return bp->overflow_handler == wp_single_step_handler;
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-}
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-
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/*
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* Install a perf counter breakpoint.
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*/
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@@ -314,30 +322,41 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
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struct arch_hw_breakpoint *info = counter_arch_bp(bp);
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struct perf_event **slot, **slots;
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int i, max_slots, ctrl_base, val_base, ret = 0;
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+ u32 addr, ctrl;
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/* Ensure that we are in monitor mode and halting mode is disabled. */
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ret = enable_monitor_mode();
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if (ret)
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goto out;
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+ addr = info->address;
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+ ctrl = encode_ctrl_reg(info->ctrl) | 0x1;
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+
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if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
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/* Breakpoint */
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ctrl_base = ARM_BASE_BCR;
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val_base = ARM_BASE_BVR;
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- slots = __get_cpu_var(bp_on_reg);
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- max_slots = core_num_brps - 1;
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-
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- if (bp_is_single_step(bp)) {
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- info->ctrl.mismatch = 1;
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- i = max_slots;
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- slots[i] = bp;
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- goto setup;
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+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
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+ max_slots = core_num_brps;
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+ if (info->step_ctrl.enabled) {
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+ /* Override the breakpoint data with the step data. */
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+ addr = info->trigger & ~0x3;
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+ ctrl = encode_ctrl_reg(info->step_ctrl);
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}
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} else {
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/* Watchpoint */
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- ctrl_base = ARM_BASE_WCR;
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- val_base = ARM_BASE_WVR;
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- slots = __get_cpu_var(wp_on_reg);
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+ if (info->step_ctrl.enabled) {
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+ /* Install into the reserved breakpoint region. */
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+ ctrl_base = ARM_BASE_BCR + core_num_brps;
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+ val_base = ARM_BASE_BVR + core_num_brps;
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+ /* Override the watchpoint data with the step data. */
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+ addr = info->trigger & ~0x3;
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+ ctrl = encode_ctrl_reg(info->step_ctrl);
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+ } else {
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+ ctrl_base = ARM_BASE_WCR;
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+ val_base = ARM_BASE_WVR;
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+ }
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+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
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max_slots = core_num_wrps;
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}
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@@ -355,12 +374,11 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
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goto out;
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}
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-setup:
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/* Setup the address register. */
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- write_wb_reg(val_base + i, info->address);
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+ write_wb_reg(val_base + i, addr);
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/* Setup the control register. */
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- write_wb_reg(ctrl_base + i, encode_ctrl_reg(info->ctrl) | 0x1);
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+ write_wb_reg(ctrl_base + i, ctrl);
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out:
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return ret;
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@@ -375,18 +393,15 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
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if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE) {
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/* Breakpoint */
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base = ARM_BASE_BCR;
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- slots = __get_cpu_var(bp_on_reg);
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- max_slots = core_num_brps - 1;
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-
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- if (bp_is_single_step(bp)) {
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- i = max_slots;
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- slots[i] = NULL;
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- goto reset;
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- }
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+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
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+ max_slots = core_num_brps;
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} else {
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/* Watchpoint */
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- base = ARM_BASE_WCR;
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- slots = __get_cpu_var(wp_on_reg);
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+ if (info->step_ctrl.enabled)
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+ base = ARM_BASE_BCR + core_num_brps;
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+ else
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+ base = ARM_BASE_WCR;
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+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
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max_slots = core_num_wrps;
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}
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@@ -403,7 +418,6 @@ void arch_uninstall_hw_breakpoint(struct perf_event *bp)
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if (WARN_ONCE(i == max_slots, "Can't find any breakpoint slot"))
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return;
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-reset:
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/* Reset the control register. */
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write_wb_reg(base + i, 0);
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}
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@@ -537,12 +551,23 @@ static int arch_build_bp_info(struct perf_event *bp)
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return -EINVAL;
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}
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+ /*
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+ * Breakpoints must be of length 2 (thumb) or 4 (ARM) bytes.
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+ * Watchpoints can be of length 1, 2, 4 or 8 bytes if supported
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+ * by the hardware and must be aligned to the appropriate number of
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+ * bytes.
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+ */
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+ if (info->ctrl.type == ARM_BREAKPOINT_EXECUTE &&
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+ info->ctrl.len != ARM_BREAKPOINT_LEN_2 &&
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+ info->ctrl.len != ARM_BREAKPOINT_LEN_4)
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+ return -EINVAL;
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+
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/* Address */
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info->address = bp->attr.bp_addr;
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/* Privilege */
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info->ctrl.privilege = ARM_BREAKPOINT_USER;
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- if (arch_check_bp_in_kernelspace(bp) && !bp_is_single_step(bp))
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+ if (arch_check_bp_in_kernelspace(bp))
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info->ctrl.privilege |= ARM_BREAKPOINT_PRIV;
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/* Enabled? */
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@@ -561,7 +586,7 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
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{
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struct arch_hw_breakpoint *info = counter_arch_bp(bp);
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int ret = 0;
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- u32 bytelen, max_len, offset, alignment_mask = 0x3;
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+ u32 offset, alignment_mask = 0x3;
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|
|
|
/* Build the arch_hw_breakpoint. */
|
|
|
ret = arch_build_bp_info(bp);
|
|
@@ -571,84 +596,85 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
|
|
|
/* Check address alignment. */
|
|
|
if (info->ctrl.len == ARM_BREAKPOINT_LEN_8)
|
|
|
alignment_mask = 0x7;
|
|
|
- if (info->address & alignment_mask) {
|
|
|
- /*
|
|
|
- * Try to fix the alignment. This may result in a length
|
|
|
- * that is too large, so we must check for that.
|
|
|
- */
|
|
|
- bytelen = get_hbp_len(info->ctrl.len);
|
|
|
- max_len = info->ctrl.type == ARM_BREAKPOINT_EXECUTE ? 4 :
|
|
|
- max_watchpoint_len;
|
|
|
-
|
|
|
- if (max_len >= 8)
|
|
|
- offset = info->address & 0x7;
|
|
|
- else
|
|
|
- offset = info->address & 0x3;
|
|
|
-
|
|
|
- if (bytelen > (1 << ((max_len - (offset + 1)) >> 1))) {
|
|
|
- ret = -EFBIG;
|
|
|
- goto out;
|
|
|
- }
|
|
|
-
|
|
|
- info->ctrl.len <<= offset;
|
|
|
- info->address &= ~offset;
|
|
|
-
|
|
|
- pr_debug("breakpoint alignment fixup: length = 0x%x, "
|
|
|
- "address = 0x%x\n", info->ctrl.len, info->address);
|
|
|
+ offset = info->address & alignment_mask;
|
|
|
+ switch (offset) {
|
|
|
+ case 0:
|
|
|
+ /* Aligned */
|
|
|
+ break;
|
|
|
+ case 1:
|
|
|
+ /* Allow single byte watchpoint. */
|
|
|
+ if (info->ctrl.len == ARM_BREAKPOINT_LEN_1)
|
|
|
+ break;
|
|
|
+ case 2:
|
|
|
+ /* Allow halfword watchpoints and breakpoints. */
|
|
|
+ if (info->ctrl.len == ARM_BREAKPOINT_LEN_2)
|
|
|
+ break;
|
|
|
+ default:
|
|
|
+ ret = -EINVAL;
|
|
|
+ goto out;
|
|
|
}
|
|
|
|
|
|
+ info->address &= ~alignment_mask;
|
|
|
+ info->ctrl.len <<= offset;
|
|
|
+
|
|
|
/*
|
|
|
* Currently we rely on an overflow handler to take
|
|
|
* care of single-stepping the breakpoint when it fires.
|
|
|
* In the case of userspace breakpoints on a core with V7 debug,
|
|
|
- * we can use the mismatch feature as a poor-man's hardware single-step.
|
|
|
+ * we can use the mismatch feature as a poor-man's hardware
|
|
|
+ * single-step, but this only works for per-task breakpoints.
|
|
|
*/
|
|
|
if (WARN_ONCE(!bp->overflow_handler &&
|
|
|
- (arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_bps()),
|
|
|
+ (arch_check_bp_in_kernelspace(bp) || !core_has_mismatch_brps()
|
|
|
+ || !bp->hw.bp_target),
|
|
|
"overflow handler required but none found")) {
|
|
|
ret = -EINVAL;
|
|
|
- goto out;
|
|
|
}
|
|
|
out:
|
|
|
return ret;
|
|
|
}
|
|
|
|
|
|
-static void update_mismatch_flag(int idx, int flag)
|
|
|
+/*
|
|
|
+ * Enable/disable single-stepping over the breakpoint bp at address addr.
|
|
|
+ */
|
|
|
+static void enable_single_step(struct perf_event *bp, u32 addr)
|
|
|
{
|
|
|
- struct perf_event *bp = __get_cpu_var(bp_on_reg[idx]);
|
|
|
- struct arch_hw_breakpoint *info;
|
|
|
-
|
|
|
- if (bp == NULL)
|
|
|
- return;
|
|
|
+ struct arch_hw_breakpoint *info = counter_arch_bp(bp);
|
|
|
|
|
|
- info = counter_arch_bp(bp);
|
|
|
+ arch_uninstall_hw_breakpoint(bp);
|
|
|
+ info->step_ctrl.mismatch = 1;
|
|
|
+ info->step_ctrl.len = ARM_BREAKPOINT_LEN_4;
|
|
|
+ info->step_ctrl.type = ARM_BREAKPOINT_EXECUTE;
|
|
|
+ info->step_ctrl.privilege = info->ctrl.privilege;
|
|
|
+ info->step_ctrl.enabled = 1;
|
|
|
+ info->trigger = addr;
|
|
|
+ arch_install_hw_breakpoint(bp);
|
|
|
+}
|
|
|
|
|
|
- /* Update the mismatch field to enter/exit `single-step' mode */
|
|
|
- if (!bp->overflow_handler && info->ctrl.mismatch != flag) {
|
|
|
- info->ctrl.mismatch = flag;
|
|
|
- write_wb_reg(ARM_BASE_BCR + idx, encode_ctrl_reg(info->ctrl) | 0x1);
|
|
|
- }
|
|
|
+static void disable_single_step(struct perf_event *bp)
|
|
|
+{
|
|
|
+ arch_uninstall_hw_breakpoint(bp);
|
|
|
+ counter_arch_bp(bp)->step_ctrl.enabled = 0;
|
|
|
+ arch_install_hw_breakpoint(bp);
|
|
|
}
|
|
|
|
|
|
static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
|
{
|
|
|
int i;
|
|
|
- struct perf_event *bp, **slots = __get_cpu_var(wp_on_reg);
|
|
|
+ struct perf_event *wp, **slots;
|
|
|
struct arch_hw_breakpoint *info;
|
|
|
- struct perf_event_attr attr;
|
|
|
+
|
|
|
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
|
|
|
|
|
|
/* Without a disassembler, we can only handle 1 watchpoint. */
|
|
|
BUG_ON(core_num_wrps > 1);
|
|
|
|
|
|
- hw_breakpoint_init(&attr);
|
|
|
- attr.bp_addr = regs->ARM_pc & ~0x3;
|
|
|
- attr.bp_len = HW_BREAKPOINT_LEN_4;
|
|
|
- attr.bp_type = HW_BREAKPOINT_X;
|
|
|
-
|
|
|
for (i = 0; i < core_num_wrps; ++i) {
|
|
|
rcu_read_lock();
|
|
|
|
|
|
- if (slots[i] == NULL) {
|
|
|
+ wp = slots[i];
|
|
|
+
|
|
|
+ if (wp == NULL) {
|
|
|
rcu_read_unlock();
|
|
|
continue;
|
|
|
}
|
|
@@ -658,24 +684,51 @@ static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
|
* single watchpoint, we can set the trigger to the lowest
|
|
|
* possible faulting address.
|
|
|
*/
|
|
|
- info = counter_arch_bp(slots[i]);
|
|
|
- info->trigger = slots[i]->attr.bp_addr;
|
|
|
+ info = counter_arch_bp(wp);
|
|
|
+ info->trigger = wp->attr.bp_addr;
|
|
|
pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);
|
|
|
- perf_bp_event(slots[i], regs);
|
|
|
+ perf_bp_event(wp, regs);
|
|
|
|
|
|
/*
|
|
|
* If no overflow handler is present, insert a temporary
|
|
|
* mismatch breakpoint so we can single-step over the
|
|
|
* watchpoint trigger.
|
|
|
*/
|
|
|
- if (!slots[i]->overflow_handler) {
|
|
|
- bp = register_user_hw_breakpoint(&attr,
|
|
|
- wp_single_step_handler,
|
|
|
- current);
|
|
|
- counter_arch_bp(bp)->suspended_wp = slots[i];
|
|
|
- perf_event_disable(slots[i]);
|
|
|
- }
|
|
|
+ if (!wp->overflow_handler)
|
|
|
+ enable_single_step(wp, instruction_pointer(regs));
|
|
|
+
|
|
|
+ rcu_read_unlock();
|
|
|
+ }
|
|
|
+}
|
|
|
|
|
|
+static void watchpoint_single_step_handler(unsigned long pc)
|
|
|
+{
|
|
|
+ int i;
|
|
|
+ struct perf_event *wp, **slots;
|
|
|
+ struct arch_hw_breakpoint *info;
|
|
|
+
|
|
|
+ slots = (struct perf_event **)__get_cpu_var(wp_on_reg);
|
|
|
+
|
|
|
+ for (i = 0; i < core_num_reserved_brps; ++i) {
|
|
|
+ rcu_read_lock();
|
|
|
+
|
|
|
+ wp = slots[i];
|
|
|
+
|
|
|
+ if (wp == NULL)
|
|
|
+ goto unlock;
|
|
|
+
|
|
|
+ info = counter_arch_bp(wp);
|
|
|
+ if (!info->step_ctrl.enabled)
|
|
|
+ goto unlock;
|
|
|
+
|
|
|
+ /*
|
|
|
+ * Restore the original watchpoint if we've completed the
|
|
|
+ * single-step.
|
|
|
+ */
|
|
|
+ if (info->trigger != pc)
|
|
|
+ disable_single_step(wp);
|
|
|
+
|
|
|
+unlock:
|
|
|
rcu_read_unlock();
|
|
|
}
|
|
|
}
|
|
@@ -683,62 +736,69 @@ static void watchpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
|
static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
|
|
|
{
|
|
|
int i;
|
|
|
- int mismatch;
|
|
|
u32 ctrl_reg, val, addr;
|
|
|
- struct perf_event *bp, **slots = __get_cpu_var(bp_on_reg);
|
|
|
+ struct perf_event *bp, **slots;
|
|
|
struct arch_hw_breakpoint *info;
|
|
|
struct arch_hw_breakpoint_ctrl ctrl;
|
|
|
|
|
|
+ slots = (struct perf_event **)__get_cpu_var(bp_on_reg);
|
|
|
+
|
|
|
/* The exception entry code places the amended lr in the PC. */
|
|
|
addr = regs->ARM_pc;
|
|
|
|
|
|
+ /* Check the currently installed breakpoints first. */
|
|
|
for (i = 0; i < core_num_brps; ++i) {
|
|
|
rcu_read_lock();
|
|
|
|
|
|
bp = slots[i];
|
|
|
|
|
|
- if (bp == NULL) {
|
|
|
- rcu_read_unlock();
|
|
|
- continue;
|
|
|
- }
|
|
|
+ if (bp == NULL)
|
|
|
+ goto unlock;
|
|
|
|
|
|
- mismatch = 0;
|
|
|
+ info = counter_arch_bp(bp);
|
|
|
|
|
|
/* Check if the breakpoint value matches. */
|
|
|
val = read_wb_reg(ARM_BASE_BVR + i);
|
|
|
if (val != (addr & ~0x3))
|
|
|
- goto unlock;
|
|
|
+ goto mismatch;
|
|
|
|
|
|
/* Possible match, check the byte address select to confirm. */
|
|
|
ctrl_reg = read_wb_reg(ARM_BASE_BCR + i);
|
|
|
decode_ctrl_reg(ctrl_reg, &ctrl);
|
|
|
if ((1 << (addr & 0x3)) & ctrl.len) {
|
|
|
- mismatch = 1;
|
|
|
- info = counter_arch_bp(bp);
|
|
|
info->trigger = addr;
|
|
|
- }
|
|
|
-
|
|
|
-unlock:
|
|
|
- if ((mismatch && !info->ctrl.mismatch) || bp_is_single_step(bp)) {
|
|
|
pr_debug("breakpoint fired: address = 0x%x\n", addr);
|
|
|
perf_bp_event(bp, regs);
|
|
|
+ if (!bp->overflow_handler)
|
|
|
+ enable_single_step(bp, addr);
|
|
|
+ goto unlock;
|
|
|
}
|
|
|
|
|
|
- update_mismatch_flag(i, mismatch);
|
|
|
+mismatch:
|
|
|
+ /* If we're stepping a breakpoint, it can now be restored. */
|
|
|
+ if (info->step_ctrl.enabled)
|
|
|
+ disable_single_step(bp);
|
|
|
+unlock:
|
|
|
rcu_read_unlock();
|
|
|
}
|
|
|
+
|
|
|
+ /* Handle any pending watchpoint single-step breakpoints. */
|
|
|
+ watchpoint_single_step_handler(addr);
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
* Called from either the Data Abort Handler [watchpoint] or the
|
|
|
- * Prefetch Abort Handler [breakpoint].
|
|
|
+ * Prefetch Abort Handler [breakpoint] with preemption disabled.
|
|
|
*/
|
|
|
static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
|
|
|
struct pt_regs *regs)
|
|
|
{
|
|
|
- int ret = 1; /* Unhandled fault. */
|
|
|
+ int ret = 0;
|
|
|
u32 dscr;
|
|
|
|
|
|
+ /* We must be called with preemption disabled. */
|
|
|
+ WARN_ON(preemptible());
|
|
|
+
|
|
|
/* We only handle watchpoints and hardware breakpoints. */
|
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
|
|
|
@@ -753,25 +813,47 @@ static int hw_breakpoint_pending(unsigned long addr, unsigned int fsr,
|
|
|
watchpoint_handler(addr, regs);
|
|
|
break;
|
|
|
default:
|
|
|
- goto out;
|
|
|
+ ret = 1; /* Unhandled fault. */
|
|
|
}
|
|
|
|
|
|
- ret = 0;
|
|
|
-out:
|
|
|
+ /*
|
|
|
+ * Re-enable preemption after it was disabled in the
|
|
|
+ * low-level exception handling code.
|
|
|
+ */
|
|
|
+ preempt_enable();
|
|
|
+
|
|
|
return ret;
|
|
|
}
|
|
|
|
|
|
/*
|
|
|
* One-time initialisation.
|
|
|
*/
|
|
|
-static void __init reset_ctrl_regs(void *unused)
|
|
|
+static void reset_ctrl_regs(void *unused)
|
|
|
{
|
|
|
int i;
|
|
|
|
|
|
+ /*
|
|
|
+ * v7 debug contains save and restore registers so that debug state
|
|
|
+ * can be maintained across low-power modes without leaving
|
|
|
+ * the debug logic powered up. It is IMPLEMENTATION DEFINED whether
|
|
|
+ * we can write to the debug registers out of reset, so we must
|
|
|
+ * unlock the OS Lock Access Register to avoid taking undefined
|
|
|
+ * instruction exceptions later on.
|
|
|
+ */
|
|
|
+ if (debug_arch >= ARM_DEBUG_ARCH_V7_ECP14) {
|
|
|
+ /*
|
|
|
+ * Unconditionally clear the lock by writing a value
|
|
|
+ * other than 0xC5ACCE55 to the access register.
|
|
|
+ */
|
|
|
+ asm volatile("mcr p14, 0, %0, c1, c0, 4" : : "r" (0));
|
|
|
+ isb();
|
|
|
+ }
|
|
|
+
|
|
|
if (enable_monitor_mode())
|
|
|
return;
|
|
|
|
|
|
- for (i = 0; i < core_num_brps; ++i) {
|
|
|
+ /* We must also reset any reserved registers. */
|
|
|
+ for (i = 0; i < core_num_brps + core_num_reserved_brps; ++i) {
|
|
|
write_wb_reg(ARM_BASE_BCR + i, 0UL);
|
|
|
write_wb_reg(ARM_BASE_BVR + i, 0UL);
|
|
|
}
|
|
@@ -782,45 +864,57 @@ static void __init reset_ctrl_regs(void *unused)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
+static int __cpuinit dbg_reset_notify(struct notifier_block *self,
|
|
|
+ unsigned long action, void *cpu)
|
|
|
+{
|
|
|
+ if (action == CPU_ONLINE)
|
|
|
+ smp_call_function_single((int)cpu, reset_ctrl_regs, NULL, 1);
|
|
|
+ return NOTIFY_OK;
|
|
|
+}
|
|
|
+
|
|
|
+static struct notifier_block __cpuinitdata dbg_reset_nb = {
|
|
|
+ .notifier_call = dbg_reset_notify,
|
|
|
+};
|
|
|
+
|
|
|
static int __init arch_hw_breakpoint_init(void)
|
|
|
{
|
|
|
- int ret = 0;
|
|
|
u32 dscr;
|
|
|
|
|
|
debug_arch = get_debug_arch();
|
|
|
|
|
|
if (debug_arch > ARM_DEBUG_ARCH_V7_ECP14) {
|
|
|
pr_info("debug architecture 0x%x unsupported.\n", debug_arch);
|
|
|
- ret = -ENODEV;
|
|
|
- goto out;
|
|
|
+ return 0;
|
|
|
}
|
|
|
|
|
|
/* Determine how many BRPs/WRPs are available. */
|
|
|
core_num_brps = get_num_brps();
|
|
|
+ core_num_reserved_brps = get_num_reserved_brps();
|
|
|
core_num_wrps = get_num_wrps();
|
|
|
|
|
|
pr_info("found %d breakpoint and %d watchpoint registers.\n",
|
|
|
- core_num_brps, core_num_wrps);
|
|
|
+ core_num_brps + core_num_reserved_brps, core_num_wrps);
|
|
|
|
|
|
- if (core_has_mismatch_bps())
|
|
|
- pr_info("1 breakpoint reserved for watchpoint single-step.\n");
|
|
|
+ if (core_num_reserved_brps)
|
|
|
+ pr_info("%d breakpoint(s) reserved for watchpoint "
|
|
|
+ "single-step.\n", core_num_reserved_brps);
|
|
|
|
|
|
ARM_DBG_READ(c1, 0, dscr);
|
|
|
if (dscr & ARM_DSCR_HDBGEN) {
|
|
|
pr_warning("halting debug mode enabled. Assuming maximum "
|
|
|
"watchpoint size of 4 bytes.");
|
|
|
} else {
|
|
|
- /* Work out the maximum supported watchpoint length. */
|
|
|
- max_watchpoint_len = get_max_wp_len();
|
|
|
- pr_info("maximum watchpoint size is %u bytes.\n",
|
|
|
- max_watchpoint_len);
|
|
|
-
|
|
|
/*
|
|
|
* Reset the breakpoint resources. We assume that a halting
|
|
|
* debugger will leave the world in a nice state for us.
|
|
|
*/
|
|
|
smp_call_function(reset_ctrl_regs, NULL, 1);
|
|
|
reset_ctrl_regs(NULL);
|
|
|
+
|
|
|
+ /* Work out the maximum supported watchpoint length. */
|
|
|
+ max_watchpoint_len = get_max_wp_len();
|
|
|
+ pr_info("maximum watchpoint size is %u bytes.\n",
|
|
|
+ max_watchpoint_len);
|
|
|
}
|
|
|
|
|
|
/* Register debug fault handler. */
|
|
@@ -829,8 +923,9 @@ static int __init arch_hw_breakpoint_init(void)
|
|
|
hook_ifault_code(2, hw_breakpoint_pending, SIGTRAP, TRAP_HWBKPT,
|
|
|
"breakpoint debug exception");
|
|
|
|
|
|
-out:
|
|
|
- return ret;
|
|
|
+ /* Register hotplug notifier. */
|
|
|
+ register_cpu_notifier(&dbg_reset_nb);
|
|
|
+ return 0;
|
|
|
}
|
|
|
arch_initcall(arch_hw_breakpoint_init);
|
|
|
|