[Xen-devel] [PATCH 47/52] xen: add basic support for runtime parameter changing

[Juergen Gross]

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.coop...@citrix.com>
Cc: George Dunlap <george.dun...@eu.citrix.com>
Cc: Ian Jackson <ian.jack...@eu.citrix.com>
Cc: Jan Beulich <jbeul...@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Tim Deegan <t...@xen.org>
Cc: Wei Liu <wei.l...@citrix.com>
Signed-off-by: Juergen Gross <jgr...@suse.com>
---
 xen/arch/x86/xen.lds.S |  4 ++++
 xen/common/kernel.c    |  5 +++++
 xen/include/xen/init.h | 22 ++++++++++++++++++++--
 xen/include/xen/lib.h  |  1 +
 4 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/xen.lds.S b/xen/arch/x86/xen.lds.S
index ff08bbe42a..5bd7912759 100644
--- a/xen/arch/x86/xen.lds.S
+++ b/xen/arch/x86/xen.lds.S
@@ -226,6 +226,10 @@ SECTIONS
        __start_schedulers_array = .;
        *(.data.schedulers)
        __end_schedulers_array = .;
+       . = ALIGN(POINTER_ALIGN);
+       __param_start = .;
+       *(.data.param)
+       __param_end = .;
   } :text
 
   .data : {                    /* Data */
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 0d63685c4f..6883a4f22f 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -178,6 +178,11 @@ 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 25d2eef8dd..7c7f92c6b2 100644
--- a/xen/include/xen/init.h
+++ b/xen/include/xen/init.h
@@ -87,11 +87,16 @@ 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; \
@@ -113,6 +118,19 @@ extern const struct kernel_param __setup_start[], 
__setup_end[];
     __kparam __setup_##_var = \
         { __setup_str_##_var, OPT_STR, sizeof(_var), &_var }
 
+#define __rtparam         __param(__dataparam)
+
+#define custom_param_runtime(_name, _var) \
+    __rtparam __rtpar_##_var = { _name, OPT_CUSTOM, 0, _var }
+#define boolean_param_runtime(_name, _var) \
+    __rtparam __rtpar_##_var = { _name, OPT_BOOL, sizeof(_var), &_var }
+#define integer_param_runtime(_name, _var) \
+    __rtparam __rtpar_##_var = { _name, OPT_UINT, sizeof(_var), &_var }
+#define size_param_runtime(_name, _var) \
+    __rtparam __rtpar_##_var = { _name, OPT_SIZE, sizeof(_var), &_var }
+#define string_param_runtime(_name, _var) \
+    __rtparam __rtpar_##_var = { _name, OPT_STR, sizeof(_var), &_var }
+
 #endif /* __ASSEMBLY__ */
 
 #ifdef CONFIG_LATE_HWDOM
diff --git a/xen/include/xen/lib.h b/xen/include/xen/lib.h
index 995a85a7db..5651498de2 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);
 
 /*#define DEBUG_TRACE_DUMP*/
-- 
2.12.3


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