Re: [PATCH v7 00/25] Unify vDSOs across more architectures

[Vincenzo Frascino]

This is a multi-part message in MIME format.Hi Paul,

thank you for your review.

On 6/24/19 7:41 PM, Paul Burton wrote:
> Hello,
> 
> On Mon, Jun 24, 2019 at 02:34:24AM +0200, Thomas Gleixner wrote:
>> I did not merge the ARM and MIPS parts as they lack any form of
>> acknowlegment from their maintainers. Please talk to those folks. If they
>> ack/review the changes then I can pick them up and they go into 5.3 or they
>> have to go in a later cycle. Nevertheless it was well worth the trouble to
>> have those conversions done to confirm that the new common library fits a
>> bunch of different architectures.
> 
> Apologies for not being more proactive on the MIPS front here; life &
> work are extra busy at the moment... But thanks Vincenzo for including
> MIPS in the work here.
> 

No problem.

> Unfortunately after applying the 3 MIPS patches (19-21) atop the current
> tip.git timers/vdso branch at ecf9db3d1f1a ("x86/vdso: Give the
> [ph]vclock_page declarations real types") I see build failures for the
> o32 compat VDSO, shown below. This is using the gcc 8.1.0 mips-linux
> toolchain from here:
> 
>   https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/8.1.0/x86_64-gcc-8.1.0-nolibc-mips-linux.tar.xz
> 
> Configuration is 64r6el_defconfig. The following helps remove the
> implicit declaration warnings (and eww to including C files via CFLAGS),
> but it still doesn't build:
> 
>   diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
>   index 95df49402a53..aa38049bdb24 100644
>   --- a/arch/mips/vdso/Makefile
>   +++ b/arch/mips/vdso/Makefile
>   @@ -36,6 +36,8 @@ aflags-vdso := $(ccflags-vdso) \
>   
>    ifneq ($(c-gettimeofday-y),)
>    CFLAGS_vgettimeofday.o = -include $(c-gettimeofday-y)
>   +CFLAGS_vgettimeofday-o32.o = -include $(c-gettimeofday-y)
>   +CFLAGS_vgettimeofday-n32.o = -include $(c-gettimeofday-y)
>    endif
> 
>  CFLAGS_REMOVE_vgettimeofday.o = -pg
> 
> So the MIPS bits here need more work.
> 

I admit, the one proposed was a nice challenge and it took me a while to
understand the differences in between the O32, N32 and N64 binaries and what was
causing the reported issue.

In the end I concluded that all the errors seen here depend on the fact that I
tested my vdso implementation on MIPS32el only (as stated in the cover letter)
and that when I tried to compile a 32BIT binary on a 64BIT configuration I did
it wrongly for two reasons, for N32 and O32 binaries:
 - we need to undefine CONFIG_64BIT and define CONFIG_32BIT
 - we need to define CONFIG_GENERIC_ATOMIC64


I have a fix for this (patch in attachment), but I do not have the hardware to
test it. If you could provide some feedback would be appreciated (really want to
see MIPS merged with the other archs in 5.3 :) ).

> Thanks,
>     Paul
> 
>   CC      arch/mips/vdso/vgettimeofday-o32.o
> In file included from ./include/linux/bitops.h:19,
>                  from ./include/linux/kernel.h:12,
>                  from ./include/linux/list.h:9,
>                  from ./include/linux/preempt.h:11,
>                  from ./include/linux/spinlock.h:51,
>                  from ./include/linux/seqlock.h:36,
>                  from ./include/linux/time.h:6,
>                  from arch/mips/vdso/vgettimeofday.c:10:
> ./arch/mips/include/asm/bitops.h: In function '__fls':
> ./arch/mips/include/asm/bitops.h:518:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << 32))) {
>                      ^~
> ./arch/mips/include/asm/bitops.h:520:8: warning: left shift count >= width of type [-Wshift-count-overflow]
>    word <<= 32;
>         ^~~
> ./arch/mips/include/asm/bitops.h:523:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
>                      ^~
> ./arch/mips/include/asm/bitops.h:527:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
>                      ^~
> ./arch/mips/include/asm/bitops.h:531:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
>                      ^~
> ./arch/mips/include/asm/bitops.h:535:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
>                      ^~
> ./arch/mips/include/asm/bitops.h:539:21: warning: left shift count >= width of type [-Wshift-count-overflow]
>   if (!(word & (~0ul << (BITS_PER_LONG-1))))
>                      ^~
> In file included from ./arch/mips/include/asm/mmiowb.h:5,
>                  from ./include/linux/spinlock.h:60,
>                  from ./include/linux/seqlock.h:36,
>                  from ./include/linux/time.h:6,
>                  from arch/mips/vdso/vgettimeofday.c:10:
> ./arch/mips/include/asm/io.h: In function 'phys_to_virt':
> ./arch/mips/include/asm/io.h:136:9: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
>   return (void *)(address + PAGE_OFFSET - PHYS_OFFSET);
>          ^
> In file included from ./include/linux/bitops.h:5,
>                  from ./include/linux/kernel.h:12,
>                  from ./include/linux/list.h:9,
>                  from ./include/linux/preempt.h:11,
>                  from ./include/linux/spinlock.h:51,
>                  from ./include/linux/seqlock.h:36,
>                  from ./include/linux/time.h:6,
>                  from arch/mips/vdso/vgettimeofday.c:10:
> ./arch/mips/include/asm/mips-cm.h: In function 'mips_cm_max_vp_width':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:152:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MAJOR   GENMASK(15, 8)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:156:22: note: in expansion of macro 'CM_GCR_REV_MAJOR'
>    (((major) << __ffs(CM_GCR_REV_MAJOR)) | \
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:161:23: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3    CM_ENCODE_REV(8, 0)
>                        ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:367:28: note: in expansion of macro 'CM_REV_CM3'
>   if (mips_cm_revision() >= CM_REV_CM3)
>                             ^~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:153:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MINOR   GENMASK(7, 0)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:157:22: note: in expansion of macro 'CM_GCR_REV_MINOR'
>     ((minor) << __ffs(CM_GCR_REV_MINOR)))
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:161:23: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3    CM_ENCODE_REV(8, 0)
>                        ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:367:28: note: in expansion of macro 'CM_REV_CM3'
>   if (mips_cm_revision() >= CM_REV_CM3)
>                             ^~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:239:36: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_SYS_CONFIG2_MAXVPW  GENMASK(3, 0)
>                                     ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:368:35: note: in expansion of macro 'CM_GCR_SYS_CONFIG2_MAXVPW'
>    return read_gcr_sys_config2() & CM_GCR_SYS_CONFIG2_MAXVPW;
>                                    ^~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:293:33: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_Cx_CONFIG_PVPE   GENMASK(9, 0)
>                                  ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:376:32: note: in expansion of macro 'CM_GCR_Cx_CONFIG_PVPE'
>    cfg = read_gcr_cl_config() & CM_GCR_Cx_CONFIG_PVPE;
>                                 ^~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:293:33: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_Cx_CONFIG_PVPE   GENMASK(9, 0)
>                                  ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:377:24: note: in expansion of macro 'CM_GCR_Cx_CONFIG_PVPE'
>    return (cfg >> __ffs(CM_GCR_Cx_CONFIG_PVPE)) + 1;
>                         ^~~~~~~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h: In function 'mips_cps_numclusters':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:152:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MAJOR   GENMASK(15, 8)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:156:22: note: in expansion of macro 'CM_GCR_REV_MAJOR'
>    (((major) << __ffs(CM_GCR_REV_MAJOR)) | \
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:117:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5)
>                            ^~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:153:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MINOR   GENMASK(7, 0)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:157:22: note: in expansion of macro 'CM_GCR_REV_MINOR'
>     ((minor) << __ffs(CM_GCR_REV_MINOR)))
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:117:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5)
>                            ^~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:133:37: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_CONFIG_NUM_CLUSTERS  GENMASK(29, 23)
>                                      ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:120:37: note: in expansion of macro 'CM_GCR_CONFIG_NUM_CLUSTERS'
>   num_clusters = read_gcr_config() & CM_GCR_CONFIG_NUM_CLUSTERS;
>                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:133:37: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_CONFIG_NUM_CLUSTERS  GENMASK(29, 23)
>                                      ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:121:25: note: in expansion of macro 'CM_GCR_CONFIG_NUM_CLUSTERS'
>   num_clusters >>= __ffs(CM_GCR_CONFIG_NUM_CLUSTERS);
>                          ^~~~~~~~~~~~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h: In function 'mips_cps_cluster_config':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:152:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MAJOR   GENMASK(15, 8)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:156:22: note: in expansion of macro 'CM_GCR_REV_MAJOR'
>    (((major) << __ffs(CM_GCR_REV_MAJOR)) | \
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:137:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5) {
>                            ^~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:153:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MINOR   GENMASK(7, 0)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:157:22: note: in expansion of macro 'CM_GCR_REV_MINOR'
>     ((minor) << __ffs(CM_GCR_REV_MINOR)))
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:137:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5) {
>                            ^~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h: In function 'mips_cps_numcores':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:135:32: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_CONFIG_PCORES   GENMASK(7, 0)
>                                 ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:172:50: note: in expansion of macro 'CM_GCR_CONFIG_PCORES'
>   return (mips_cps_cluster_config(cluster) + 1) & CM_GCR_CONFIG_PCORES;
>                                                   ^~~~~~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h: In function 'mips_cps_numiocu':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:134:33: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_CONFIG_NUMIOCU   GENMASK(15, 8)
>                                  ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:189:48: note: in expansion of macro 'CM_GCR_CONFIG_NUMIOCU'
>   num_iocu = mips_cps_cluster_config(cluster) & CM_GCR_CONFIG_NUMIOCU;
>                                                 ^~~~~~~~~~~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:134:33: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_CONFIG_NUMIOCU   GENMASK(15, 8)
>                                  ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:190:21: note: in expansion of macro 'CM_GCR_CONFIG_NUMIOCU'
>   num_iocu >>= __ffs(CM_GCR_CONFIG_NUMIOCU);
>                      ^~~~~~~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h: In function 'mips_cps_numvps':
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:152:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MAJOR   GENMASK(15, 8)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:156:22: note: in expansion of macro 'CM_GCR_REV_MAJOR'
>    (((major) << __ffs(CM_GCR_REV_MAJOR)) | \
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:216:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5) {
>                            ^~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:153:28: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_REV_MINOR   GENMASK(7, 0)
>                             ^~~~~~~
> ./arch/mips/include/asm/mips-cm.h:157:22: note: in expansion of macro 'CM_GCR_REV_MINOR'
>     ((minor) << __ffs(CM_GCR_REV_MINOR)))
>                       ^~~~~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cm.h:162:25: note: in expansion of macro 'CM_ENCODE_REV'
>  #define CM_REV_CM3_5    CM_ENCODE_REV(9, 0)
>                          ^~~~~~~~~~~~~
> ./arch/mips/include/asm/mips-cps.h:216:27: note: in expansion of macro 'CM_REV_CM3_5'
>   if (mips_cm_revision() < CM_REV_CM3_5) {
>                            ^~~~~~~~~~~~
> ./include/linux/bits.h:20:39: warning: right shift count >= width of type [-Wshift-count-overflow]
>   (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
>                                        ^~
> ./arch/mips/include/asm/mips-cm.h:293:33: note: in expansion of macro 'GENMASK'
>  #define CM_GCR_Cx_CONFIG_PVPE   GENMASK(9, 0)
>                                  ^~~~~~~
> ./arch/mips/include/asm/mips-cps.h:233:21: note: in expansion of macro 'CM_GCR_Cx_CONFIG_PVPE'
>   return (cfg + 1) & CM_GCR_Cx_CONFIG_PVPE;
>                      ^~~~~~~~~~~~~~~~~~~~~
> arch/mips/vdso/vgettimeofday.c: In function '__vdso_clock_gettime':
> arch/mips/vdso/vgettimeofday.c:17:9: error: implicit declaration of function '__cvdso_clock_gettime32'; did you mean '__vdso_clock_gettime'? [-Werror=implicit-function-declaration]
>   return __cvdso_clock_gettime32(clock, ts);
>          ^~~~~~~~~~~~~~~~~~~~~~~
>          __vdso_clock_gettime
> arch/mips/vdso/vgettimeofday.c: In function '__vdso_gettimeofday':
> arch/mips/vdso/vgettimeofday.c:23:9: error: implicit declaration of function '__cvdso_gettimeofday'; did you mean '__vdso_gettimeofday'? [-Werror=implicit-function-declaration]
>   return __cvdso_gettimeofday(tv, tz);
>          ^~~~~~~~~~~~~~~~~~~~
>          __vdso_gettimeofday
> arch/mips/vdso/vgettimeofday.c: In function '__vdso_clock_getres':
> arch/mips/vdso/vgettimeofday.c:29:9: error: implicit declaration of function '__cvdso_clock_getres_time32'; did you mean '__vdso_clock_gettime'? [-Werror=implicit-function-declaration]
>   return __cvdso_clock_getres_time32(clock_id, res);
>          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>          __vdso_clock_gettime
> arch/mips/vdso/vgettimeofday.c: In function '__vdso_clock_gettime64':
> arch/mips/vdso/vgettimeofday.c:35:9: error: implicit declaration of function '__cvdso_clock_gettime'; did you mean '__vdso_clock_gettime'? [-Werror=implicit-function-declaration]
>   return __cvdso_clock_gettime(clock, ts);
>          ^~~~~~~~~~~~~~~~~~~~~
>          __vdso_clock_gettime
> cc1: some warnings being treated as errors
> make[1]: *** [arch/mips/vdso/Makefile:148: arch/mips/vdso/vgettimeofday-o32.o] Error 1
> make: *** [Makefile:1746: arch/mips/vdso/vgettimeofday-o32.o] Error 2
> 

-- 
Regards,
Vincenzo