[Xen-changelog] [xen staging] xen/cmdline: Work around some specific command line warnings

[patchbot@xxxxxxx]

commit 68cda62e50c34f938747c1558117ee2c37134b30
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Tue Jan 29 19:07:40 2019 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Wed Jan 30 17:27:44 2019 +0000

    xen/cmdline: Work around some specific command line warnings
    
    Xen will warn when an unknown parameter is found in the command line.  e.g.
    
      (d8) [ 1556.334664] (XEN) parameter "pv-shim" unknown!
    
    One case where this goes wrong is a workaround for an old grub bug, which
    resulted in "placeholder" being prepended to the command line.
    
    Another case is when booting a CONFIG_PV_SHIM_EXCLUSIVE build, in which the
    parsing for the "pv-shim" parameter is discarded.
    
    Introduce ignore_param() and OPT_IGNORE to cope with known cases, where
    issuing a warning is the wrong course of action to take.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
    Release-acked-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/arch/x86/pv/shim.c | 5 ++++-
 xen/arch/x86/setup.c   | 6 ++++++
 xen/common/kernel.c    | 2 ++
 xen/include/xen/init.h | 8 +++++++-
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/xen/arch/x86/pv/shim.c b/xen/arch/x86/pv/shim.c
index 636a9d6a10..324ca27f93 100644
--- a/xen/arch/x86/pv/shim.c
+++ b/xen/arch/x86/pv/shim.c
@@ -40,7 +40,10 @@
 #undef virt_to_mfn
 #define virt_to_mfn(va) _mfn(__virt_to_mfn(va))
 
-#ifndef CONFIG_PV_SHIM_EXCLUSIVE
+#ifdef CONFIG_PV_SHIM_EXCLUSIVE
+/* Tolerate "pv-shim" being passed to a CONFIG_PV_SHIM_EXCLUSIVE hypervisor. */
+ignore_param("pv-shim");
+#else
 bool pv_shim;
 boolean_param("pv-shim", pv_shim);
 #endif
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 06eb483cb4..92da060915 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -639,6 +639,12 @@ static void __init noreturn reinit_bsp_stack(void)
     reset_stack_and_jump(init_done);
 }
 
+/*
+ * Some scripts add "placeholder" to work around a grub error where it ate the
+ * first parameter.
+ */
+ignore_param("placeholder");
+
 static bool __init loader_is_grub2(const char *loader_name)
 {
     /* GRUB1="GNU GRUB 0.xx"; GRUB2="GRUB 1.xx" */
diff --git a/xen/common/kernel.c b/xen/common/kernel.c
index 053c31d391..612575430f 100644
--- a/xen/common/kernel.c
+++ b/xen/common/kernel.c
@@ -162,6 +162,8 @@ static int parse_params(const char *cmdline, const struct 
kernel_param *start,
                 }
                 rctmp = param->par.func(optval);
                 break;
+            case OPT_IGNORE:
+                break;
             default:
                 BUG();
                 break;
diff --git a/xen/include/xen/init.h b/xen/include/xen/init.h
index c6b453adfe..d0f3a007d0 100644
--- a/xen/include/xen/init.h
+++ b/xen/include/xen/init.h
@@ -81,7 +81,8 @@ struct kernel_param {
         OPT_UINT,
         OPT_BOOL,
         OPT_SIZE,
-        OPT_CUSTOM
+        OPT_CUSTOM,
+        OPT_IGNORE,
     } type;
     unsigned int len;
     union {
@@ -136,6 +137,11 @@ extern const struct kernel_param __param_start[], 
__param_end[];
           .type = OPT_STR, \
           .len = sizeof(_var), \
           .par.var = &_var }
+#define ignore_param(_name)                 \
+    __setup_str setup_str_ign[] = _name;    \
+    __kparam setup_ign =                    \
+        { .name = setup_str_ign,            \
+          .type = OPT_IGNORE }
 
 #define __rtparam         __param(__dataparam)
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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