Re: [Xen-devel] [PATCH v7 09/14] x86/boot: implement early command line parser in C

[Jan Beulich]

>>> On 23.09.16 at 23:47,  wrote:
> Current early command line parser implementation in assembler
> is very difficult to change to relocatable stuff using segment
> registers. This requires a lot of changes in very weird and
> fragile code. So, reimplement this functionality in C. This
> way code will be relocatable out of the box (without playing
> with segment registers) and much easier to maintain.
> 
> Additionally, put all common cmdline.c and reloc.c definitions
> into defs.h header. This way we do not duplicate needlessly
> some stuff.
> 
> And finally remove unused xen/include/asm-x86/config.h
> header from reloc.c dependencies.
> 
> Suggested-by: Andrew Cooper 
> Signed-off-by: Daniel Kiper 

Acked-by: Jan Beulich 


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[Xen-devel] [PATCH v7 09/14] x86/boot: implement early command line parser in C

[Daniel Kiper]

Current early command line parser implementation in assembler
is very difficult to change to relocatable stuff using segment
registers. This requires a lot of changes in very weird and
fragile code. So, reimplement this functionality in C. This
way code will be relocatable out of the box (without playing
with segment registers) and much easier to maintain.

Additionally, put all common cmdline.c and reloc.c definitions
into defs.h header. This way we do not duplicate needlessly
some stuff.

And finally remove unused xen/include/asm-x86/config.h
header from reloc.c dependencies.

Suggested-by: Andrew Cooper 
Signed-off-by: Daniel Kiper 
---
v7 - suggestions/fixes:
   - add min() macro
 (suggested by Jan Beulich),
   - add padding to early_boot_opts_t
 in more standard way
 (suggested by Jan Beulich),
   - simplify defs.h dependencies
 (suggested by Jan Beulich).

v6 - suggestions/fixes:
   - put common cmdline.c and reloc.c
 definitions into defs.h header
 (suggested by Jan Beulich),
   - use xen/include/xen/stdbool.h
 and bool type from it instead
 of own defined bool_t
 (suggested by Jan Beulich),
   - define delim_chars as constant
 (suggested by Jan Beulich),
   - properly align trampoline.S:early_boot_opts struct
 (suggested by Jan Beulich),
   - fix overflow check in strtoui()
 (suggested by Jan Beulich),
   - remove unused xen/include/asm-x86/config.h
 header from reloc.c dependencies,
   - improve commit message.

v4 - suggestions/fixes:
   - move to stdcall calling convention
 (suggested by Jan Beulich),
   - define bool_t and use it properly
 (suggested by Jan Beulich),
   - put list of delimiter chars into
 static const char[]
 (suggested by Jan Beulich),
   - use strlen() instead of strlen_opt()
 (suggested by Jan Beulich),
   - change strtoi() to strtoui() and
 optimize it a bit
 (suggested by Jan Beulich),
   - define strchr() and use it in strtoui()
 (suggested by Jan Beulich),
   - optimize vga_parse()
 (suggested by Jan Beulich),
   - move !cmdline check from assembly to C
 (suggested by Jan Beulich),
   - remove my name from copyright (Oracle requirement)
 (suggested by Konrad Rzeszutek Wilk).

v3 - suggestions/fixes:
   - optimize some code
 (suggested by Jan Beulich),
   - put VESA data into early_boot_opts_t members
 (suggested by Jan Beulich),
   - rename some functions and variables
 (suggested by Jan Beulich),
   - move around video.h include in xen/arch/x86/boot/trampoline.S
 (suggested by Jan Beulich),
   - fix coding style
 (suggested by Jan Beulich),
   - fix build with older GCC
 (suggested by Konrad Rzeszutek Wilk),
   - remove redundant comments
 (suggested by Jan Beulich),
   - add some comments
   - improve commit message
 (suggested by Jan Beulich).
---
 .gitignore |5 +-
 xen/arch/x86/Makefile  |2 +-
 xen/arch/x86/boot/Makefile |   11 +-
 xen/arch/x86/boot/build32.mk   |2 +
 xen/arch/x86/boot/cmdline.S|  367 
 xen/arch/x86/boot/cmdline.c|  340 +
 xen/arch/x86/boot/defs.h   |   58 +++
 xen/arch/x86/boot/edd.S|3 -
 xen/arch/x86/boot/head.S   |8 +
 xen/arch/x86/boot/reloc.c  |   13 +-
 xen/arch/x86/boot/trampoline.S |   15 ++
 xen/arch/x86/boot/video.S  |7 -
 12 files changed, 437 insertions(+), 394 deletions(-)
 delete mode 100644 xen/arch/x86/boot/cmdline.S
 create mode 100644 xen/arch/x86/boot/cmdline.c
 create mode 100644 xen/arch/x86/boot/defs.h

diff --git a/.gitignore b/.gitignore
index cc64fc9..9aa47a1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -247,9 +247,10 @@ xen/arch/arm/xen.lds
 xen/arch/x86/asm-offsets.s
 xen/arch/x86/boot/mkelf32
 xen/arch/x86/xen.lds
+xen/arch/x86/boot/cmdline.S
 xen/arch/x86/boot/reloc.S
-xen/arch/x86/boot/reloc.bin
-xen/arch/x86/boot/reloc.lnk
+xen/arch/x86/boot/*.bin
+xen/arch/x86/boot/*.lnk
 xen/arch/x86/efi.lds
 xen/arch/x86/efi/check.efi
 xen/arch/x86/efi/disabled
diff --git a/xen/arch/x86/Makefile b/xen/arch/x86/Makefile
index 49d7e59..7d37728 100644
--- a/xen/arch/x86/Makefile
+++ b/xen/arch/x86/Makefile
@@ -224,6 +224,6 @@ clean::
rm -f asm-offsets.s *.lds boot/*.o boot/*~ boot/core boot/mkelf32
rm -f $(BASEDIR)/.xen-syms.[0-9]* boot/.*.d
rm -f $(BASEDIR)/.xen.efi.[0-9]* efi/*.efi efi/disabled efi/mkreloc
-   rm -f boot/reloc.S boot/reloc.lnk boot/reloc.bin
+   rm -f boot/cmdline.S boot/reloc.S boot/*.lnk boot/*.bin
rm -f note.o
$(MAKE) -f $(BASEDIR)/Rules.mk -C test clean
diff --git a/xen/arch/x86/boot/Makefile b/xen/arch/x86/boot/Makefile
index 06893d8..c6246c8 100644
--- a/xen/arch/x86/boot/Makefile
+++ b/xen/arch/x86/boot/Makefile
@@ -1,9 +1,16 @@
 obj-bin-y += head.o
 
-RELOC_DEPS = $(BASEDIR)/include/asm-x86/config.h