MIPS: Add SysRq operation to dump TLBs on all CPUs

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@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10072/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index d3d2ff2d76dc8f2e3643e9255226975e8e4699a4..a2debcbedb6ddbc5d0d7c960026f7b7b8466ce7a 100644 (file)
--- 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 (file)
index 0000000..5b539f5
--- /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 843f2cdc280b9d178d09469eb0363658d6a69805..8ba52e56bb8bac54b6f93e41a14d6aded2f9ae80 100644 (file)
--- 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 */