From 19a4f60dabe90846a49399fc81cf5a3c8f2aa722 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Mon, 28 Aug 2017 09:35:00 +0200
Subject: [PATCH] xen: add basic support for runtime parameter changing

Add the needed infrastructure for runtime parameter changing similar
to that used at boot time via cmdline. We are using the same parsing
functions as for cmdline parsing, but with a different array of
parameter definitions.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
 xen/arch/arm/xen.lds.S |  4 +++
 xen/arch/x86/xen.lds.S |  4 +++
 xen/common/kernel.c    |  5 ++++
 xen/include/xen/init.h | 57 ++++++++++++++++++++++++++++++++++++++++--
 xen/include/xen/lib.h  |  1 +
 5 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 2d54f224ec..c9b9546435 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -61,6 +61,10 @@ SECTIONS
        *(.lockprofile.data)
        __lock_profile_end = .;
 #endif
+       . = ALIGN(POINTER_ALIGN);
+       __param_start = .;
+       *(.data.param)
+       __param_end = .;
   } :text
 
 #if defined(BUILD_ID)
diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index e48ab6a1ad..d5e8821d41 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -120,6 +120,10 @@ SECTIONS
        *(.lockprofile.data)
        __lock_profile_end = .;
 #endif
+       . = ALIGN(POINTER_ALIGN);
+       __param_start = .;
+       *(.data.param)
+       __param_end = .;
   } :text
 
 #if defined(BUILD_ID)
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 6e2f5ed9da..f96e402515 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -192,6 +192,11 @@ static void __init _cmdline_parse(const char *cmdline)
     parse_params(cmdline, __setup_start, __setup_end);
 }
 
+int runtime_parse(const char *line)
+{
+    return parse_params(line, __param_start, __param_end);
+}
+
 /**
  *    cmdline_parse -- parses the xen command line.
  * If CONFIG_CMDLINE is set, it would be parsed prior to @cmdline.
diff --git a/xen/include/xen/init.h b/xen/include/xen/init.h
index 234ec25aae..db06c76fdf 100644
--- a/xen/include/xen/init.h
+++ b/xen/include/xen/init.h
@@ -90,11 +90,16 @@ struct kernel_param {
 };
 
 extern const struct kernel_param __setup_start[], __setup_end[];
+extern const struct kernel_param __param_start[], __param_end[];
+
+#define __dataparam       __used_section(".data.param")
+
+#define __param(att)      static const att \
+    __attribute__((__aligned__(sizeof(void *)))) struct kernel_param
 
 #define __setup_str static const __initconst \
     __attribute__((__aligned__(1))) char
-#define __kparam static const __initsetup \
-    __attribute__((__aligned__(sizeof(void *)))) struct kernel_param
+#define __kparam          __param(__initsetup)
 
 #define custom_param(_name, _var) \
     __setup_str __setup_str_##_var[] = _name; \
@@ -131,6 +136,54 @@ extern const struct kernel_param __setup_start[], __setup_end[];
           .len = sizeof(_var), \
           .par.var = &_var }
 
+#define __rtparam         __param(__dataparam)
+
+#define custom_runtime_only_param(_name, _var) \
+    __rtparam __rtpar_##_var = \
+      { .name = _name, \
+          .type = OPT_CUSTOM, \
+          .par.func = _var }
+#define boolean_runtime_only_param(_name, _var) \
+    __rtparam __rtpar_##_var = \
+        { .name = _name, \
+          .type = OPT_BOOL, \
+          .len = sizeof(_var), \
+          .par.var = &_var }
+#define integer_runtime_only_param(_name, _var) \
+    __rtparam __rtpar_##_var = \
+        { .name = _name, \
+          .type = OPT_UINT, \
+          .len = sizeof(_var), \
+          .par.var = &_var }
+#define size_runtime_only_param(_name, _var) \
+    __rtparam __rtpar_##_var = \
+        { .name = _name, \
+          .type = OPT_SIZE, \
+          .len = sizeof(_var), \
+          .par.var = &_var }
+#define string_runtime_only_param(_name, _var) \
+    __rtparam __rtpar_##_var = \
+        { .name = _name, \
+          .type = OPT_STR, \
+          .len = sizeof(_var), \
+          .par.var = &_var }
+
+#define custom_runtime_param(_name, _var) \
+    custom_param(_name, _var); \
+    custom_runtime_only_param(_name, _var)
+#define boolean_runtime_param(_name, _var) \
+    boolean_param(_name, _var); \
+    boolean_runtime_only_param(_name, _var)
+#define integer_runtime_param(_name, _var) \
+    integer_param(_name, _var); \
+    integer_runtime_only_param(_name, _var)
+#define size_runtime_param(_name, _var) \
+    size_param(_name, _var); \
+    size_runtime_only_param(_name, _var)
+#define string_runtime_param(_name, _var) \
+    string_param(_name, _var); \
+    string_runtime_only_param(_name, _var)
+
 #endif /* __ASSEMBLY__ */
 
 #ifdef CONFIG_LATE_HWDOM
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 8e57bbd021..ed00ae1379 100644
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -71,6 +71,7 @@
 struct domain;
 
 void cmdline_parse(const char *cmdline);
+int runtime_parse(const char *line);
 int parse_bool(const char *s, const char *e);
 
 /*#define DEBUG_TRACE_DUMP*/
-- 
2.39.5