[PATCH v4 48/53] xen: add basic support for runtime parameter changing

[Juergen Gross <jgross@suse.com>]

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.

Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tim Deegan <tim@xen.org>
Cc: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V2:
- added modification of ARM linker script (Wei Liu)

V3:
- moved runtime parameter array in linker scripts (Jan Beulich)
- renamed macros to *_runtime_param() (Jan Beulich)
- added *runtime_only_param() macros (Jan Beulich)
- let *_runtime_param() macros include boot param functionality
  (Jan Beulich)
---
 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 ff08bbe42a..6a7bbb8ca1 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 65cd3a92ba..da1a709146 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*/
-- 
2.12.3


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