@@ -172,6 +172,24 @@ config GENERIC_ISA_DMA
config FIQ
bool
+config ARCH_MIGHT_HAVE_FIQ
+ bool
+
+config KGDB_FIQ
+ bool "KGDB/KDB FIQ debugger"
+ depends on KGDB_KDB && ARCH_MIGHT_HAVE_FIQ && !THUMB2_KERNEL
+ select FIQ
+ help
+ The FIQ debugger may be used to debug situations when the
+ kernel stuck in uninterruptable sections, e.g. the kernel
+ infinitely loops or deadlocked in an interrupt or with
+ interrupts disabled.
+
+ By default KGDB FIQ is disabled in runtime, but can be
+ enabled with kgdb_fiq.enable=1 kernel command line option.
+
+ If unsure, say N.
+
config NEED_RET_TO_USER
bool
@@ -11,6 +11,8 @@
#define __ARM_KGDB_H__
#include <linux/ptrace.h>
+#include <linux/linkage.h>
+#include <asm/exception.h>
/*
* GDB assumes that we're a user process being debugged, so
@@ -47,6 +49,12 @@ static inline void arch_kgdb_breakpoint(void)
extern void kgdb_handle_bus_error(void);
extern int kgdb_fault_expected;
+extern char kgdb_fiq_handler;
+extern char kgdb_fiq_handler_end;
+asmlinkage void __exception_irq_entry kgdb_fiq_do_handle(struct pt_regs *regs);
+extern int __init kgdb_register_fiq(unsigned int mach_kgdb_fiq,
+ void (*mach_kgdb_enable_fiq)(unsigned int irq, bool on),
+ bool (*mach_is_kgdb_fiq)(unsigned int irq));
#endif /* !__ASSEMBLY__ */
/*
@@ -56,6 +56,7 @@ obj-$(CONFIG_ATAGS_PROC) += atags.o
obj-$(CONFIG_OABI_COMPAT) += sys_oabi-compat.o
obj-$(CONFIG_ARM_THUMBEE) += thumbee.o
obj-$(CONFIG_KGDB) += kgdb.o
+obj-$(CONFIG_KGDB_FIQ) += kgdb_fiq_entry.o kgdb_fiq.o
obj-$(CONFIG_ARM_UNWIND) += unwind.o
obj-$(CONFIG_HAVE_TCM) += tcm.o
obj-$(CONFIG_OF) += devtree.o
new file mode 100644
@@ -0,0 +1,101 @@
+/*
+ * KGDB FIQ entry
+ *
+ * Copyright 2010 Google, Inc.
+ * Arve Hjønnevåg <arve@android.com>
+ * Colin Cross <ccross@android.com>
+ * Copyright 2012 Linaro Ltd.
+ * Anton Vorontsov <anton.vorontsov@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/hardirq.h>
+#include <linux/kgdb.h>
+#include <asm/fiq.h>
+#include <asm/exception.h>
+
+static int kgdb_fiq_enabled;
+module_param_named(enable, kgdb_fiq_enabled, int, 0600);
+MODULE_PARM_DESC(enable, "set to 1 to enable FIQ KGDB");
+
+static unsigned int kgdb_fiq;
+static void (*kgdb_enable_fiq)(unsigned int irq, bool on);
+static bool (*is_kgdb_fiq)(unsigned int irq);
+
+asmlinkage void __exception_irq_entry kgdb_fiq_do_handle(struct pt_regs *regs)
+{
+ if (!is_kgdb_fiq(kgdb_fiq))
+ return;
+ dbg_io_ops->clear_irqs();
+
+ nmi_enter();
+ kgdb_handle_exception(1, 0, 0, regs);
+ nmi_exit();
+}
+
+static struct fiq_handler kgdb_fiq_desc = {
+ .name = "kgdb",
+};
+
+static long kgdb_fiq_setup_stack(void *info)
+{
+ struct pt_regs regs;
+
+ regs.ARM_sp = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER) +
+ THREAD_START_SP;
+ WARN_ON(!regs.ARM_sp);
+
+ set_fiq_regs(®s);
+ return 0;
+}
+
+int kgdb_arch_enable_nmi(bool on)
+{
+ static int cnt;
+
+ if (cnt > 0 && on)
+ return cnt;
+ cnt += on ? 1 : -1;
+ kgdb_enable_fiq(kgdb_fiq, cnt > 0);
+ return cnt;
+}
+
+int __init kgdb_register_fiq(unsigned int mach_kgdb_fiq,
+ void (*mach_kgdb_enable_fiq)(unsigned int irq, bool on),
+ bool (*mach_is_kgdb_fiq)(unsigned int irq))
+{
+ int err;
+ int cpu;
+
+ if (!kgdb_fiq_enabled)
+ return -ENODEV;
+ if (kgdb_fiq)
+ return -EBUSY;
+
+ kgdb_fiq = mach_kgdb_fiq;
+ kgdb_enable_fiq = mach_kgdb_enable_fiq;
+ is_kgdb_fiq = mach_is_kgdb_fiq;
+
+ err = claim_fiq(&kgdb_fiq_desc);
+ if (err) {
+ pr_warn("%s: unable to claim fiq", __func__);
+ return err;
+ }
+
+ for_each_possible_cpu(cpu)
+ work_on_cpu(cpu, kgdb_fiq_setup_stack, NULL);
+
+ set_fiq_handler(&kgdb_fiq_handler,
+ &kgdb_fiq_handler_end - &kgdb_fiq_handler);
+
+ kgdb_arch_enable_nmi(1);
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,92 @@
+/*
+ * KGDB FIQ entry
+ *
+ * Copyright 1996,1997,1998 Russell King.
+ * Copyright 2012 Linaro Ltd.
+ * Anton Vorontsov <anton.vorontsov@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/memory.h>
+#include <asm/unwind.h>
+#include "entry-header.S"
+
+ .text
+
+@ This is needed for usr_entry/alignment_trap
+.LCcralign:
+ .long cr_alignment
+.LCdohandle:
+ .long kgdb_fiq_do_handle
+
+ .macro fiq_handler
+ ldr r1, =.LCdohandle
+ mov r0, sp
+ adr lr, BSYM(9997f)
+ ldr pc, [r1]
+9997:
+ .endm
+
+ .align 5
+__fiq_svc:
+ svc_entry
+ fiq_handler
+ mrs r4, cpsr
+ msr cpsr_c, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+ ldr r1, [sp, #8]
+ msr cpsr_c, r4
+ msr spsr_cxsf, r1
+ mov r0, sp
+ ldmib r0, {r1 - r14}
+ msr cpsr_c, #FIQ_MODE | PSR_I_BIT | PSR_F_BIT
+ add r8, r0, #S_PC
+ ldr r9, [r0, #S_PSR]
+ msr spsr_cxsf, r9
+ ldr r0, [r0, #S_R0]
+ ldmia r8, {pc}^
+
+ UNWIND(.fnend )
+ENDPROC(__fiq_svc)
+ .ltorg
+
+ .align 5
+__fiq_usr:
+ usr_entry
+ kuser_cmpxchg_check
+ fiq_handler
+ get_thread_info tsk
+ mov why, #0
+ b ret_to_user_from_irq
+ UNWIND(.fnend )
+ENDPROC(__fiq_usr)
+ .ltorg
+
+ .global kgdb_fiq_handler
+kgdb_fiq_handler:
+
+ vector_stub fiq, FIQ_MODE, 4
+
+ .long __fiq_usr @ 0 (USR_26 / USR_32)
+ .long __fiq_svc @ 1 (FIQ_26 / FIQ_32)
+ .long __fiq_svc @ 2 (IRQ_26 / IRQ_32)
+ .long __fiq_svc @ 3 (SVC_26 / SVC_32)
+ .long __fiq_svc @ 4
+ .long __fiq_svc @ 5
+ .long __fiq_svc @ 6
+ .long __fiq_svc @ 7
+ .long __fiq_svc @ 8
+ .long __fiq_svc @ 9
+ .long __fiq_svc @ a
+ .long __fiq_svc @ b
+ .long __fiq_svc @ c
+ .long __fiq_svc @ d
+ .long __fiq_svc @ e
+ .long __fiq_svc @ f
+
+ .global kgdb_fiq_handler_end
+kgdb_fiq_handler_end: