Hello Albert,
On do, 2014-09-11 at 10:32 +0200, Albert ARIBAUD wrote:
>
> On Wed, 10 Sep 2014 20:08:50 +0200, Jeroen Hofstee
> <jer...@myspectrum.nl> wrote:
>
> > Changes since v2:
> > - As Albert pointed out the clang instructions don't work with
> > Debian based binary packages. While I was aware of that it is
> > for a different reason then I thought, it is not that ARM is not
> > enabled as a backend but older versions are a bit more picky on
> > the target argument and don't tolerate a trailing dash to it as
> > used for CROSS_COMPILE etc. The README is updated accordingly.
> >
> > As a side note clang3.5-svn as shipped in Ubuntu is not the 3.5
> > release but an snapshot of some svn commit and hence explain why
> > the recompiled 3.5 can behave different then the ubuntu clang-3.5.
> > Since it misses some patches, the clang3.5-svn can build less
> > boards then 3.4 or an actual 3.5 release.
> >
> > - While add it, include Masahiro suggestion to also use c++ instead
> > of g++.
> > - Drop dependencies from the cover-letter as they are merged.
> > - only patch 7/8 and 8/8 are reposted. 1..6 are the same as v2.
>
> Thanks, tested building rpi_b, it works now.
>
> The, tested on versatileqemu out of curiosity and got the following
> results:
>
> 1.
>
> clang warns about Unused static functions in common/console.c, namely
> console_printdevs and console_doenv (1). Why gcc does not flag this?
> We have -Wall set which is supposed to imply -Wunused-functions.
It is a gcc feature, see [1]: "Warn whenever a static function is
declared but not defined or a _non-inline static function_ is unused.
This warning is enabled by -Wall."
>
> There is also an unused variable warning in disk/part.c28
> (block_drvr). I haven't looked at why clang warns about it and not gcc,
> but it could raise the same question as the functions above.
>
Also a gcc feature, see [2]. The constant is indeed not used.
> 2.
>
> clang errors on arch/arm/lib/cache.c:28 for this:
> asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
> and that is a clang mistake, as for ARM926EJS r15 is a valid (albeit
> quite special semantically) Rd for Test and Clean DCache, see page 2-24.
>
This is the integrated-as complaining (the README tells you to disable
it for the moment). The clang folks push UAL hard, up to a point we need
to think about minimum gcc version etc. To avoid that, I just left out
such changes and just use gas instead, at least for the time being.
Below are some changes to compile versatileqemu with llvm integrated-as
and gcc/gas. No idea if it actually boots though.
> Jeroen, do you feel like raising point 2 to the clang/LLVM folks?
It is removed on purpose as far as I understood. I don't think they
regards it as a bug, see obfuscated patch below.
> Other than that, the patch series seems to be good. I'll apply it
> soonish.
>
Thanks,
Jeroen
[1] https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
[2] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=13029
s/~/-/g
~~~
>From dbc16575725693378ad5dac84d6fb945545c3b63 Mon Sep 17 00:00:00 2001
From: Jeroen Hofstee <jer...@myspectrum.nl>
Date: Thu, 11 Sep 2014 12:46:35 +0200
Subject: [PATCH] versatileqemu ual build
~~~
arch/arm/cpu/arm926ejs/cache.c | 2 +~
arch/arm/cpu/arm926ejs/start.S | 2 +~
arch/arm/lib/cache.c | 2 +~
include/configs/versatile.h | 2 ++
4 files changed, 5 insertions(+), 3 deletions(~)
diff ~~git a/arch/arm/cpu/arm926ejs/cache.c
b/arch/arm/cpu/arm926ejs/cache.c
index e86c2ed..b1aae13 100644
~~~ a/arch/arm/cpu/arm926ejs/cache.c
+++ b/arch/arm/cpu/arm926ejs/cache.c
@@ ~22,7 +22,7 @@ void flush_dcache_all(void)
{
asm volatile(
"0:"
~ "mrc p15, 0, r15, c7, c14, 3\n"
+ "mrc p15, 0, apsr_nzcv, c7, c14, 3\n"
"bne 0b\n"
"mcr p15, 0, %0, c7, c10, 4\n"
: : "r"(0) : "memory"
diff ~~git a/arch/arm/cpu/arm926ejs/start.S
b/arch/arm/cpu/arm926ejs/start.S
index 8eb2494..b9d2ae2 100644
~~~ a/arch/arm/cpu/arm926ejs/start.S
+++ b/arch/arm/cpu/arm926ejs/start.S
@@ ~78,7 +78,7 @@ cpu_init_crit:
*/
mov r0, #0
flush_dcache:
~ mrc p15, 0, r15, c7, c10, 3
+ mrc p15, 0, apsr_nzcv, c7, c10, 3
bne flush_dcache
mcr p15, 0, r0, c8, c7, 0 /* invalidate TLB */
diff ~~git a/arch/arm/lib/cache.c b/arch/arm/lib/cache.c
index 4e597a4..d12ea2b 100644
~~~ a/arch/arm/lib/cache.c
+++ b/arch/arm/lib/cache.c
@@ ~25,7 +25,7 @@ __weak void flush_cache(unsigned long start, unsigned
long size)
#ifdef CONFIG_ARM926EJS
/* test and clean, page 2~23 of arm926ejs manual */
~ asm("0: mrc p15, 0, r15, c7, c10, 3\n\t" "bne 0b\n" : : : "memory");
+ asm("0: mrc p15, 0, apsr_nzcv, c7, c10, 3\n\t" "bne 0b\n" : : :
"memory");
/* disable write buffer as well (page 2~22) */
asm("mcr p15, 0, %0, c7, c10, 4" : : "r" (0));
#endif /* CONFIG_ARM926EJS */
diff ~~git a/include/configs/versatile.h b/include/configs/versatile.h
index 29c32fe..52d2af3 100644
~~~ a/include/configs/versatile.h
+++ b/include/configs/versatile.h
@@ ~23,6 +23,8 @@
#define CONFIG_VERSATILE 1 /* in Versatile Platform Board */
#define CONFIG_ARCH_VERSATILE 1 /* Specifically, a Versatile */
+#define CONFIG_SYS_GENERIC_BOARD
+
#define CONFIG_SYS_MEMTEST_START 0x100000
#define CONFIG_SYS_MEMTEST_END 0x10000000
~~
2.1.0
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