Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/kernel/dawr.c b/arch/powerpc/kernel/dawr.c
new file mode 100644
index 0000000..5f66b95
--- /dev/null
+++ b/arch/powerpc/kernel/dawr.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DAWR infrastructure
+ *
+ * Copyright 2019, Michael Neuling, IBM Corporation.
+ */
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <asm/debugfs.h>
+#include <asm/machdep.h>
+#include <asm/hvcall.h>
+
+bool dawr_force_enable;
+EXPORT_SYMBOL_GPL(dawr_force_enable);
+
+int set_dawr(struct arch_hw_breakpoint *brk)
+{
+ unsigned long dawr, dawrx, mrd;
+
+ dawr = brk->address;
+
+ dawrx = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE))
+ << (63 - 58);
+ dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) << (63 - 59);
+ dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) >> 3;
+ /*
+ * DAWR length is stored in field MDR bits 48:53. Matches range in
+ * doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
+ * 0b111111=64DW.
+ * brk->len is in bytes.
+ * This aligns up to double word size, shifts and does the bias.
+ */
+ mrd = ((brk->len + 7) >> 3) - 1;
+ dawrx |= (mrd & 0x3f) << (63 - 53);
+
+ if (ppc_md.set_dawr)
+ return ppc_md.set_dawr(dawr, dawrx);
+
+ mtspr(SPRN_DAWR, dawr);
+ mtspr(SPRN_DAWRX, dawrx);
+
+ return 0;
+}
+
+static void set_dawr_cb(void *info)
+{
+ set_dawr(info);
+}
+
+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 -ENODEV;
+
+ 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(set_dawr_cb, &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)
+{
+ 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 */
+ debugfs_create_file_unsafe("dawr_enable_dangerous", 0600,
+ powerpc_debugfs_root,
+ &dawr_force_enable,
+ &dawr_enable_fops);
+ }
+ return 0;
+}
+arch_initcall(dawr_force_setup);