Re: [Qemu-devel] [PULL 00/21] target-arm queue

[Peter Maydell <peter.maydell@linaro.org>]

On 16 March 2016 at 17:18, Peter Maydell <peter.maydell@linaro.org> wrote:
> Here's the target-arm queue; I'm a bit hesitant about the late-landing
> various new board/SoC patches, but they won't affect anybody who isn't
> trying to use those boards, so I think it's OK.
>
> (There are a few other patches on list which I definitely want to
> get in before rc0 but they need a bit more review time I think.)
>
> thanks
> -- PMM
>
>
> The following changes since commit 0ebc03bc065329eaefb6493f5fa7df08df528f2a:
>
>   util/base64.c: Clean includes (2016-03-16 12:48:11 +0000)
>
> are available in the git repository at:
>
>   git://git.linaro.org/people/pmaydell/qemu-arm.git tags/pull-target-arm-20160316
>
> for you to fetch changes up to 10b27d1ab391dbf36f92e1a33179662082401d7a:
>
>   sd: Fix "info qtree" on boards with SD cards (2016-03-16 17:12:46 +0000)
>
> ----------------------------------------------------------------
> target-arm queue:
>  * loader: Fix incorrect parameter name in load_image_mr()
>  * Implement MRS (banked) and MSR (banked) instructions
>  * virt: Implement versioning for machine model
>  * i.MX: some initial patches preparing for i.MX6 support
>  * new ASPEED AST2400 SoC and palmetto-bmc machine
>  * bcm2835: add some more raspi2 devices
>  * sd: fix segfault running "info qtree"

Some versions of gcc appear to give false positive 'may be used
uninitialized' warnings about the msr/mrs code:

/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c: In
function ‘gen_msr_banked
.isra.45’:
/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c:4321:17:
error: ‘tgtmode’ ma
y be used uninitialized in this function [-Werror=maybe-uninitialized]
     tcg_tgtmode = tcg_const_i32(tgtmode);
                 ^
/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c:4322:15:
error: ‘regno’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
     tcg_regno = tcg_const_i32(regno);
               ^
/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c: In
function ‘gen_mrs_banked.isra.48’:
/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c:4343:17:
error: ‘tgtmode’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
     tcg_tgtmode = tcg_const_i32(tgtmode);
                 ^
/home/petmay01/linaro/qemu-for-merges/target-arm/translate.c:4344:15:
error: ‘regno’ may be used uninitialized in this function
[-Werror=maybe-uninitialized]
     tcg_regno = tcg_const_i32(regno);
               ^

Fixup:
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -4308,7 +4308,7 @@ undef:
 static void gen_msr_banked(DisasContext *s, int r, int sysm, int rn)
 {
     TCGv_i32 tcg_reg, tcg_tgtmode, tcg_regno;
-    int tgtmode, regno;
+    int tgtmode = 0, regno = 0;

     if (!msr_banked_access_decode(s, r, sysm, rn, &tgtmode, &regno)) {
         return;
@@ -4330,7 +4330,7 @@ static void gen_msr_banked(DisasContext *s, int
r, int sysm, int rn)
 static void gen_mrs_banked(DisasContext *s, int r, int sysm, int rn)
 {
     TCGv_i32 tcg_reg, tcg_tgtmode, tcg_regno;
-    int tgtmode, regno;
+    int tgtmode = 0, regno = 0;

     if (!msr_banked_access_decode(s, r, sysm, rn, &tgtmode, &regno)) {
         return;

which I'll squash into the appropriate patch and respin.

thanks
-- PMM