Add a MIPS specific SysRq operation to dump the TLB entries on all CPUs,
using the 'x' trigger key.
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
This was mainly for debug purposes, however I've included it for
completeness as an RFC patch, in case others find it helpful.
---
arch/mips/kernel/Makefile | 1 +
arch/mips/kernel/sysrq.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/tty/sysrq.c | 1 +
3 files changed, 79 insertions(+)
create mode 100644 arch/mips/kernel/sysrq.c
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index d3d2ff2d76dc..a2debcbedb6d 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_MIPS32_O32) += binfmt_elfo32.o scall64-o32.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_PROC_FS) += proc.o
+obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o
obj-$(CONFIG_64BIT) += cpu-bugs64.o
diff --git a/arch/mips/kernel/sysrq.c b/arch/mips/kernel/sysrq.c
new file mode 100644
index 000000000000..5b539f5fc9d9
--- /dev/null
+++ b/arch/mips/kernel/sysrq.c
@@ -0,0 +1,77 @@
+/*
+ * MIPS specific sysrq operations.
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ */
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/sysrq.h>
+#include <linux/workqueue.h>
+
+#include <asm/cpu-features.h>
+#include <asm/mipsregs.h>
+#include <asm/tlbdebug.h>
+
+/*
+ * Dump TLB entries on all CPUs.
+ */
+
+static DEFINE_SPINLOCK(show_lock);
+
+static void sysrq_tlbdump_single(void *dummy)
+{
+ const int field = 2 * sizeof(unsigned long);
+ unsigned long flags;
+
+ spin_lock_irqsave(&show_lock, flags);
+
+ pr_info("CPU%d:\n", smp_processor_id());
+ pr_info("Index : %0x\n", read_c0_index());
+ pr_info("Pagemask: %0x\n", read_c0_pagemask());
+ pr_info("EntryHi : %0*lx\n", field, read_c0_entryhi());
+ pr_info("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
+ pr_info("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
+ pr_info("Wired : %0x\n", read_c0_wired());
+ pr_info("Pagegrain: %0x\n", read_c0_pagegrain());
+ if (cpu_has_htw) {
+ pr_info("PWField : %0*lx\n", field, read_c0_pwfield());
+ pr_info("PWSize : %0*lx\n", field, read_c0_pwsize());
+ pr_info("PWCtl : %0x\n", read_c0_pwctl());
+ }
+ pr_info("\n");
+ dump_tlb_all();
+ pr_info("\n");
+
+ spin_unlock_irqrestore(&show_lock, flags);
+}
+
+#ifdef CONFIG_SMP
+static void sysrq_tlbdump_othercpus(struct work_struct *dummy)
+{
+ smp_call_function(sysrq_tlbdump_single, NULL, 0);
+}
+
+static DECLARE_WORK(sysrq_tlbdump, sysrq_tlbdump_othercpus);
+#endif
+
+static void sysrq_handle_tlbdump(int key)
+{
+ sysrq_tlbdump_single(NULL);
+#ifdef CONFIG_SMP
+ schedule_work(&sysrq_tlbdump);
+#endif
+}
+
+static struct sysrq_key_op sysrq_tlbdump_op = {
+ .handler = sysrq_handle_tlbdump,
+ .help_msg = "show-tlbs(x)",
+ .action_msg = "Show TLB entries",
+ .enable_mask = SYSRQ_ENABLE_DUMP,
+};
+
+static int __init mips_sysrq_init(void)
+{
+ return register_sysrq_key('x', &sysrq_tlbdump_op);
+}
+arch_initcall(mips_sysrq_init);
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 843f2cdc280b..8ba52e56bb8b 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -463,6 +463,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
/* v: May be registered for frame buffer console restore */
NULL, /* v */
&sysrq_showstate_blocked_op, /* w */
+ /* x: May be registered on mips for TLB dump */
/* x: May be registered on ppc/powerpc for xmon */
/* x: May be registered on sparc64 for global PMU dump */
NULL, /* x */
--
2.3.6
