[patch 00/36] Hexagon: Add support for Qualcomm Hexagon architecture

August 17th, 2011 - 01:10 pm ET by Richard Kuo | Report spam
The following patch set is intended to add support for the Qualcomm Hexagon
architecture to the Linux kernel.

The Hexagon architecture is designed to deliver performance with low power
over a variety of applications. It has features such as multithreading,
privilege levels, VLIW, and instructions geared toward efficient signal
processing. The port of Linux for Hexagon runs under a hypervisor layer.

I realize we are not currently in a merge window, but I felt it would be best
to go ahead and send it out so that the community gets an ample chance to
review it. This is a very large patch set, but we've tried to break it up
into functional pieces to make review easier.

These changes are available in patch form on the Code Aurora Forum:

https://www.codeaurora.org/patches/...817.tar.gz

and will also be available via git:

git://git.kernel.org/pub/scm/linux/...exagon.git hexagon

Any feedback will be greatly appreciated.

Thanks,
Richard Kuo


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#1 Richard Kuo
August 17th, 2011 - 01:10 pm ET | Report spam
Signed-off-by: Linas Vepstas


arch/hexagon/include/asm/kgdb.h | 39 ++++++
arch/hexagon/kernel/kgdb.c | 241 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 280 insertions(+)

Index: linux-hexagon-kernel/arch/hexagon/include/asm/kgdb.h
/dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/include/asm/kgdb.h 2011-07-20 15:19:44.505151353 -0500
@@ -0,0 +1,39 @@
+/*
+ * arch/hexagon/include/asm/kgdb.h - Hexagon KGDB Support
+ *
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef __HEXAGON_KGDB_H__
+#define __HEXAGON_KGDB_H__
+
+#define BREAK_INSTR_SIZE 4
+#define CACHE_FLUSH_IS_SAFE 1
+#define BUFMAX ((NUMREGBYTES * 2) + 512)
+
+static inline void arch_kgdb_breakpoint(void)
+{
+ asm("trap0(#0xDB)");
+}
+
+/* Registers:
+ * 32 gpr + sa0/1 + lc0/1 + m0/1 + gp + ugp + pred + pc = 42 total.
+ */
+#define NUMREGBYTES (42*4)
+#define DBG_MAX_REG_NUM 42
+
+#endif /* __HEXAGON_KGDB_H__ */
Index: linux-hexagon-kernel/arch/hexagon/kernel/kgdb.c
/dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-hexagon-kernel/arch/hexagon/kernel/kgdb.c 2011-07-20 15:19:44.505151353 -0500
@@ -0,0 +1,241 @@
+/*
+ * arch/hexagon/kernel/kgdb.c - Hexagon KGDB Support
+ *
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/kdebug.h>
+#include <linux/kgdb.h>
+
+/* All registers are 4 bytes, for now */
+#define GDB_SIZEOF_REG 4
+
+/* The register names are used during printing of the regs;
+ * Keep these at three letters to pretty-print. */
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
+ { " r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, r00)},
+ { " r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, r01)},
+ { " r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, r02)},
+ { " r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, r03)},
+ { " r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, r04)},
+ { " r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, r05)},
+ { " r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, r06)},
+ { " r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, r07)},
+ { " r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, r08)},
+ { " r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, r09)},
+ { "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, r10)},
+ { "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, r11)},
+ { "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, r12)},
+ { "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, r13)},
+ { "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, r14)},
+ { "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, r15)},
+ { "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, r16)},
+ { "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, r17)},
+ { "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, r18)},
+ { "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, r19)},
+ { "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, r20)},
+ { "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, r21)},
+ { "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, r22)},
+ { "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, r23)},
+ { "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, r24)},
+ { "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, r25)},
+ { "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, r26)},
+ { "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, r27)},
+ { "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, r28)},
+ { "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, r29)},
+ { "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, r30)},
+ { "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, r31)},
+
+ { "usr", GDB_SIZEOF_REG, offsetof(struct pt_regs, usr)},
+ { "preds", GDB_SIZEOF_REG, offsetof(struct pt_regs, preds)},
+ { " m0", GDB_SIZEOF_REG, offsetof(struct pt_regs, m0)},
+ { " m1", GDB_SIZEOF_REG, offsetof(struct pt_regs, m1)},
+ { "sa0", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa0)},
+ { "sa1", GDB_SIZEOF_REG, offsetof(struct pt_regs, sa1)},
+ { "lc0", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc0)},
+ { "lc1", GDB_SIZEOF_REG, offsetof(struct pt_regs, lc1)},
+ { " gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, gp)},
+ { "ugp", GDB_SIZEOF_REG, offsetof(struct pt_regs, ugp)},
+};
+
+struct kgdb_arch arch_kgdb_ops = {
+ /* trap0(#0xDB) 0x0cdb0054 */
+ .gdb_bpt_instr = {0x54, 0x00, 0xdb, 0x0c},
+};
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return NULL;
+
+ *((unsigned long *) mem) = *((unsigned long *) ((void *)regs +
+ dbg_reg_def[regno].offset));
+
+ return dbg_reg_def[regno].name;
+}
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return -EINVAL;
+
+ *((unsigned long *) ((void *)regs + dbg_reg_def[regno].offset)) + *((unsigned long *) mem);
+
+ return 0;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ instruction_pointer(regs) = pc;
+}
+
+#ifdef CONFIG_SMP
+
+/**
+ * kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ * @flags: Current IRQ state
+ *
+ * On SMP systems, we need to get the attention of the other CPUs
+ * and get them be in a known state. This should do what is needed
+ * to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ * the NMI approach is not used for rounding up all the CPUs. For example,
+ * in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ * this case, we have to make sure that interrupts are enabled before
+ * calling smp_call_function(). The argument to this function is
+ * the flags that will be used when restoring the interrupts. There is
+ * local_irq_save() call before kgdb_roundup_cpus().
+ *
+ * On non-SMP systems, this is not called.
+ */
+
+static void hexagon_kgdb_nmi_hook(void *ignored)
+{
+ kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+}
+
+void kgdb_roundup_cpus(unsigned long flags)
+{
+ smp_call_function(hexagon_kgdb_nmi_hook, NULL, 0);
+}
+#endif
+
+
+/* Not yet working */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs,
+ struct task_struct *task)
+{
+ struct pt_regs *thread_regs;
+
+ if (task == NULL)
+ return;
+
+ /* Initialize to zero */
+ memset(gdb_regs, 0, NUMREGBYTES);
+
+ /* Otherwise, we have only some registers from switch_to() */
+ thread_regs = task_pt_regs(task);
+ gdb_regs[PT_R0] = thread_regs->r00;
+}
+
+/**
+ * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ * @vector: The error vector of the exception that happened.
+ * @signo: The signal number of the exception that happened.
+ * @err_code: The error code of the exception that happened.
+ * @remcom_in_buffer: The buffer of the packet we have read.
+ * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ * @regs: The &struct pt_regs of the current process.
+ *
+ * This function MUST handle the 'c' and 's' command packets,
+ * as well packets to set / remove a hardware breakpoint, if used.
+ * If there are additional packets which the hardware needs to handle,
+ * they are handled here. The code should return -1 if it wants to
+ * process more packets, and a %0 or %1 if it wants to exit from the
+ * kgdb callback.
+ *
+ * Not yet working.
+ */
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+ char *remcom_in_buffer, char *remcom_out_buffer,
+ struct pt_regs *linux_regs)
+{
+ switch (remcom_in_buffer[0]) {
+ case 's':
+ case 'c':
+ return 0;
+ }
+ /* Stay in the debugger. */
+ return -1;
+}
+
+static int __kgdb_notify(struct die_args *args, unsigned long cmd)
+{
+ struct pt_regs *regs = args->regs;
+#if 0
+ ret = kgdb_handle_exception(args->trapnr & 0xff, args->signr, args->err,
+ regs);
+ if (ret)
+ return NOTIFY_DONE;
+#endif
+ return NOTIFY_STOP;
+}
+
+static int
+kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
+{
+ unsigned long flags;
+ int ret;
+
+ local_irq_save(flags);
+ ret = __kgdb_notify(ptr, cmd);
+ local_irq_restore(flags);
+
+ return ret;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_notify,
+
+ /*
+ * Lowest-prio notifier priority, we want to be notified last:
+ */
+ .priority = -INT_MAX,
+};
+
+/**
+ * kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ * This function will handle the initalization of any architecture
+ * specific callbacks.
+ */
+int kgdb_arch_init(void)
+{
+ return register_die_notifier(&kgdb_notifier);
+}
+
+/**
+ * kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ * This function will handle the uninitalization of any architecture
+ * specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+ unregister_die_notifier(&kgdb_notifier);
+}
+

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The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.

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