[PATCH v2 3/5] x86/efi: Simplify efi_arch_handle_cmdline()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

-Wwrite-strings is unhappy with assigning "xen" to a mutable pointer, but all
this work is useless; it's making a memory allocation just to prepend the
image name which cmdline_cook() intentionally strips back out.

Simply forgo the work and identify EFI_LOADER as one of the loaders which
doesn't prepend the image name.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
CC: Wei Liu <wl@xxxxxxx>
CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
CC: Julien Grall <julien@xxxxxxx>
CC: Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
CC: Bertrand Marquis <bertrand.marquis@xxxxxxx>
CC: Roberto Bagnara <roberto.bagnara@xxxxxxxxxxx>
CC: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

v2:
 * Brand new.

I can't find anything which cares about the image name in the slightest.  This
logic is from bf6501a62e80 ("x86-64: EFI boot code") when EFI was introduced,
at whcih point GRUB2 was the only excluded loader in cmdline_cook().
---
 xen/arch/x86/efi/efi-boot.h | 10 +---------
 xen/arch/x86/setup.c        |  7 +++++--
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/xen/arch/x86/efi/efi-boot.h b/xen/arch/x86/efi/efi-boot.h
index eebc54180bf7..1a2a2dd83c9b 100644
--- a/xen/arch/x86/efi/efi-boot.h
+++ b/xen/arch/x86/efi/efi-boot.h
@@ -309,6 +309,7 @@ static void __init efi_arch_handle_cmdline(CHAR16 
*image_name,
 {
     union string name;
 
+    /* NB place_string() prepends, so call in reverse order. */
     if ( cmdline_options )
     {
         name.w = cmdline_options;
@@ -317,15 +318,6 @@ static void __init efi_arch_handle_cmdline(CHAR16 
*image_name,
     }
     if ( cfgfile_options )
         place_string(&mbi.cmdline, cfgfile_options);
-    /* Insert image name last, as it gets prefixed to the other options. */
-    if ( image_name )
-    {
-        name.w = image_name;
-        w2s(&name);
-    }
-    else
-        name.s = "xen";
-    place_string(&mbi.cmdline, name.s);
 
     if ( mbi.cmdline )
         mbi.flags |= MBI_CMDLINE;
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index b171a8f4cf84..200520392481 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -850,8 +850,11 @@ static const char *__init cmdline_cook(const char *p, 
const char *loader_name)
     while ( *p == ' ' )
         p++;
 
-    /* GRUB2 and PVH don't not include image name as first item on command 
line. */
-    if ( xen_guest || loader_is_grub2(loader_name) )
+    /*
+     * PVH, our EFI loader, and GRUB2 don't not include image name as first
+     * item on command line.
+     */
+    if ( xen_guest || efi_enabled(EFI_LOADER) || loader_is_grub2(loader_name) )
         return p;
 
     /* Strip image name plus whitespace. */
-- 
2.30.2