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Diffstat (limited to 'arch/powerpc/kernel/hw_breakpoint.c')
-rw-r--r--arch/powerpc/kernel/hw_breakpoint.c62
1 files changed, 61 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index fec8a6773119..da307dd93ee3 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -29,11 +29,15 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
+#include <linux/debugfs.h>
+#include <linux/init.h>
#include <asm/hw_breakpoint.h>
#include <asm/processor.h>
#include <asm/sstep.h>
#include <asm/debug.h>
+#include <asm/debugfs.h>
+#include <asm/hvcall.h>
#include <linux/uaccess.h>
/*
@@ -174,7 +178,7 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
if (!ppc_breakpoint_available())
return -ENODEV;
length_max = 8; /* DABR */
- if (cpu_has_feature(CPU_FTR_DAWR)) {
+ if (dawr_enabled()) {
length_max = 512 ; /* 64 doublewords */
/* DAWR region can't cross 512 boundary */
if ((attr->bp_addr >> 9) !=
@@ -376,3 +380,59 @@ void hw_breakpoint_pmu_read(struct perf_event *bp)
{
/* TODO */
}
+
+bool dawr_force_enable;
+EXPORT_SYMBOL_GPL(dawr_force_enable);
+
+static ssize_t dawr_write_file_bool(struct file *file,
+ const char __user *user_buf,
+ size_t count, loff_t *ppos)
+{
+ struct arch_hw_breakpoint null_brk = {0, 0, 0};
+ size_t rc;
+
+ /* Send error to user if they hypervisor won't allow us to write DAWR */
+ if ((!dawr_force_enable) &&
+ (firmware_has_feature(FW_FEATURE_LPAR)) &&
+ (set_dawr(&null_brk) != H_SUCCESS))
+ return -1;
+
+ rc = debugfs_write_file_bool(file, user_buf, count, ppos);
+ if (rc)
+ return rc;
+
+ /* If we are clearing, make sure all CPUs have the DAWR cleared */
+ if (!dawr_force_enable)
+ smp_call_function((smp_call_func_t)set_dawr, &null_brk, 0);
+
+ return rc;
+}
+
+static const struct file_operations dawr_enable_fops = {
+ .read = debugfs_read_file_bool,
+ .write = dawr_write_file_bool,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+static int __init dawr_force_setup(void)
+{
+ dawr_force_enable = false;
+
+ if (cpu_has_feature(CPU_FTR_DAWR)) {
+ /* Don't setup sysfs file for user control on P8 */
+ dawr_force_enable = true;
+ return 0;
+ }
+
+ if (PVR_VER(mfspr(SPRN_PVR)) == PVR_POWER9) {
+ /* Turn DAWR off by default, but allow admin to turn it on */
+ dawr_force_enable = false;
+ debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,
+ powerpc_debugfs_root,
+ &dawr_force_enable,
+ &dawr_enable_fops);
+ }
+ return 0;
+}
+arch_initcall(dawr_force_setup);