From: Palmer Dabbelt <[email protected]>
As part of the MIPS conversion to use the generic GCC library routines,
Matt Redfearn discovered that I'd missed a notrace on __ucmpdi2(). This
patch rectifies the problem.
CC: Matt Redfearn <[email protected]>
CC: Antony Pavlov <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>
Reviewed-by: Matt Redfearn <[email protected]>
Signed-off-by: Matt Redfearn <[email protected]>
---
Changes in v6: None
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2:
add notrace to lib/ucmpdi2.c
lib/ucmpdi2.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/ucmpdi2.c b/lib/ucmpdi2.c
index 25ca2d4c1e19..597998169a96 100644
--- a/lib/ucmpdi2.c
+++ b/lib/ucmpdi2.c
@@ -17,7 +17,7 @@
#include <linux/module.h>
#include <linux/libgcc.h>
-word_type __ucmpdi2(unsigned long long a, unsigned long long b)
+word_type notrace __ucmpdi2(unsigned long long a, unsigned long long b)
{
const DWunion au = {.ll = a};
const DWunion bu = {.ll = b};
--
2.7.4
When these are included into arch Kconfig files, maintaining
alphabetical ordering of the selects means these get split up. To allow
for keeping things tidier and alphabetical, rename the selects to
GENERIC_LIB_*
Signed-off-by: Matt Redfearn <[email protected]>
Reviewed-by: Palmer Dabbelt <[email protected]>
---
Changes in v6: None
Changes in v5: None
Changes in v4:
Rename Kconfig symbols GENERIC_* -> GENERIC_LIB_*
Changes in v3: None
Changes in v2: None
arch/riscv/Kconfig | 6 +++---
lib/Kconfig | 12 ++++++------
lib/Makefile | 12 ++++++------
3 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 04807c7f64cc..20185aaaf933 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -104,9 +104,9 @@ config ARCH_RV32I
bool "RV32I"
select CPU_SUPPORTS_32BIT_KERNEL
select 32BIT
- select GENERIC_ASHLDI3
- select GENERIC_ASHRDI3
- select GENERIC_LSHRDI3
+ select GENERIC_LIB_ASHLDI3
+ select GENERIC_LIB_ASHRDI3
+ select GENERIC_LIB_LSHRDI3
config ARCH_RV64I
bool "RV64I"
diff --git a/lib/Kconfig b/lib/Kconfig
index e96089499371..e54ebe00937e 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -588,20 +588,20 @@ config STRING_SELFTEST
endmenu
-config GENERIC_ASHLDI3
+config GENERIC_LIB_ASHLDI3
bool
-config GENERIC_ASHRDI3
+config GENERIC_LIB_ASHRDI3
bool
-config GENERIC_LSHRDI3
+config GENERIC_LIB_LSHRDI3
bool
-config GENERIC_MULDI3
+config GENERIC_LIB_MULDI3
bool
-config GENERIC_CMPDI2
+config GENERIC_LIB_CMPDI2
bool
-config GENERIC_UCMPDI2
+config GENERIC_LIB_UCMPDI2
bool
diff --git a/lib/Makefile b/lib/Makefile
index a90d4fcd748f..7425e177f08c 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -253,9 +253,9 @@ obj-$(CONFIG_SBITMAP) += sbitmap.o
obj-$(CONFIG_PARMAN) += parman.o
# GCC library routines
-obj-$(CONFIG_GENERIC_ASHLDI3) += ashldi3.o
-obj-$(CONFIG_GENERIC_ASHRDI3) += ashrdi3.o
-obj-$(CONFIG_GENERIC_LSHRDI3) += lshrdi3.o
-obj-$(CONFIG_GENERIC_MULDI3) += muldi3.o
-obj-$(CONFIG_GENERIC_CMPDI2) += cmpdi2.o
-obj-$(CONFIG_GENERIC_UCMPDI2) += ucmpdi2.o
+obj-$(CONFIG_GENERIC_LIB_ASHLDI3) += ashldi3.o
+obj-$(CONFIG_GENERIC_LIB_ASHRDI3) += ashrdi3.o
+obj-$(CONFIG_GENERIC_LIB_LSHRDI3) += lshrdi3.o
+obj-$(CONFIG_GENERIC_LIB_MULDI3) += muldi3.o
+obj-$(CONFIG_GENERIC_LIB_CMPDI2) += cmpdi2.o
+obj-$(CONFIG_GENERIC_LIB_UCMPDI2) += ucmpdi2.o
--
2.7.4
In preparation for removing some of the MIPS compiler intrinsics from
arch/mips/lib, first update the build of vmlinuz to use the generic
ashldi3 from lib.
Both ashldi3 and bswapsi objects need to be built with different CFLAGS
for inclusion to vmlinuz rather than simply including the object built
for the main kernel image. The objects cannot be built directly from
source, since CONFIG_MODVERSIONS changes cmd_cc_o_c to prevent this.
Split the rule to ship ashldi3 and bswapsi from the relevant source
locations.
These files make no reference to other files in their directory, so the
additional CFLAGS are apparently unnecessary - remove them as well.
Signed-off-by: Matt Redfearn <[email protected]>
---
Changes in v6:
New patch to fix vmlinuz which requires ashldi3 so must be switched
to come from $(srctree)/lib before the arch/mips/ version is deleted.
This version has been build tested with every upstream defconfig since
previous versions caused problems with ci20_defconfig and
loongson1b_defconfig.
Changes in v5: None
Changes in v4: None
Changes in v3: None
Changes in v2: None
arch/mips/boot/compressed/Makefile | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index adce180f3ee4..e03f522c33ac 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -46,9 +46,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
-extra-y += ashldi3.c bswapsi.c
-$(obj)/ashldi3.o $(obj)/bswapsi.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
-$(obj)/ashldi3.c $(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
+extra-y += ashldi3.c
+$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
+ $(call cmd,shipped)
+
+extra-y += bswapsi.c
+$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
$(call cmd,shipped)
targets := $(notdir $(vmlinuzobjs-y))
--
2.7.4
From: Antony Pavlov <[email protected]>
The commit b35cd9884fa5 ("lib: Add shared copies of some GCC library
routines") makes it possible to share generic GCC library routines by
several architectures.
This commit removes several generic GCC library routines from
arch/mips/lib/ in favour of similar routines from lib/.
Signed-off-by: Antony Pavlov <[email protected]>
[Matt Redfearn] Use GENERIC_LIB_* named Kconfig entries
Signed-off-by: Matt Redfearn <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Matt Redfearn <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Ralf Baechle <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
Changes in v6: None
Changes in v5:
Actually delete the MIPS lib routines
Changes in v4:
Rework to use the new GENERIC_LIB_ Kconfig entries
Changes in v3:
Maintain alphabetical order of MIPS Kconfig
Changes in v2: None
arch/mips/Kconfig | 5 +++++
arch/mips/lib/Makefile | 3 +--
arch/mips/lib/ashldi3.c | 30 ------------------------------
arch/mips/lib/ashrdi3.c | 32 --------------------------------
arch/mips/lib/cmpdi2.c | 28 ----------------------------
arch/mips/lib/lshrdi3.c | 30 ------------------------------
arch/mips/lib/ucmpdi2.c | 22 ----------------------
7 files changed, 6 insertions(+), 144 deletions(-)
delete mode 100644 arch/mips/lib/ashldi3.c
delete mode 100644 arch/mips/lib/ashrdi3.c
delete mode 100644 arch/mips/lib/cmpdi2.c
delete mode 100644 arch/mips/lib/lshrdi3.c
delete mode 100644 arch/mips/lib/ucmpdi2.c
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 8128c3b68d6b..98955a76c656 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -22,6 +22,11 @@ config MIPS
select GENERIC_CPU_AUTOPROBE
select GENERIC_IRQ_PROBE
select GENERIC_IRQ_SHOW
+ select GENERIC_LIB_ASHLDI3
+ select GENERIC_LIB_ASHRDI3
+ select GENERIC_LIB_CMPDI2
+ select GENERIC_LIB_LSHRDI3
+ select GENERIC_LIB_UCMPDI2
select GENERIC_PCI_IOMAP
select GENERIC_SCHED_CLOCK if !CAVIUM_OCTEON_SOC
select GENERIC_SMP_IDLE_THREAD
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index e84e12655fa8..6537e022ef62 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -16,5 +16,4 @@ obj-$(CONFIG_CPU_R3000) += r3k_dump_tlb.o
obj-$(CONFIG_CPU_TX39XX) += r3k_dump_tlb.o
# libgcc-style stuff needed in the kernel
-obj-y += ashldi3.o ashrdi3.o bswapsi.o bswapdi.o cmpdi2.o lshrdi3.o multi3.o \
- ucmpdi2.o
+obj-y += bswapsi.o bswapdi.o multi3.o
diff --git a/arch/mips/lib/ashldi3.c b/arch/mips/lib/ashldi3.c
deleted file mode 100644
index 24cd6903e797..000000000000
--- a/arch/mips/lib/ashldi3.c
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/export.h>
-
-#include "libgcc.h"
-
-long long notrace __ashldi3(long long u, word_type b)
-{
- DWunion uu, w;
- word_type bm;
-
- if (b == 0)
- return u;
-
- uu.ll = u;
- bm = 32 - b;
-
- if (bm <= 0) {
- w.s.low = 0;
- w.s.high = (unsigned int) uu.s.low << -bm;
- } else {
- const unsigned int carries = (unsigned int) uu.s.low >> bm;
-
- w.s.low = (unsigned int) uu.s.low << b;
- w.s.high = ((unsigned int) uu.s.high << b) | carries;
- }
-
- return w.ll;
-}
-
-EXPORT_SYMBOL(__ashldi3);
diff --git a/arch/mips/lib/ashrdi3.c b/arch/mips/lib/ashrdi3.c
deleted file mode 100644
index 23f5295af51e..000000000000
--- a/arch/mips/lib/ashrdi3.c
+++ /dev/null
@@ -1,32 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/export.h>
-
-#include "libgcc.h"
-
-long long notrace __ashrdi3(long long u, word_type b)
-{
- DWunion uu, w;
- word_type bm;
-
- if (b == 0)
- return u;
-
- uu.ll = u;
- bm = 32 - b;
-
- if (bm <= 0) {
- /* w.s.high = 1..1 or 0..0 */
- w.s.high =
- uu.s.high >> 31;
- w.s.low = uu.s.high >> -bm;
- } else {
- const unsigned int carries = (unsigned int) uu.s.high << bm;
-
- w.s.high = uu.s.high >> b;
- w.s.low = ((unsigned int) uu.s.low >> b) | carries;
- }
-
- return w.ll;
-}
-
-EXPORT_SYMBOL(__ashrdi3);
diff --git a/arch/mips/lib/cmpdi2.c b/arch/mips/lib/cmpdi2.c
deleted file mode 100644
index 93cfc785927d..000000000000
--- a/arch/mips/lib/cmpdi2.c
+++ /dev/null
@@ -1,28 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/export.h>
-
-#include "libgcc.h"
-
-word_type notrace __cmpdi2(long long a, long long b)
-{
- const DWunion au = {
- .ll = a
- };
- const DWunion bu = {
- .ll = b
- };
-
- if (au.s.high < bu.s.high)
- return 0;
- else if (au.s.high > bu.s.high)
- return 2;
-
- if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
- return 0;
- else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
- return 2;
-
- return 1;
-}
-
-EXPORT_SYMBOL(__cmpdi2);
diff --git a/arch/mips/lib/lshrdi3.c b/arch/mips/lib/lshrdi3.c
deleted file mode 100644
index 914b971aca3b..000000000000
--- a/arch/mips/lib/lshrdi3.c
+++ /dev/null
@@ -1,30 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/export.h>
-
-#include "libgcc.h"
-
-long long notrace __lshrdi3(long long u, word_type b)
-{
- DWunion uu, w;
- word_type bm;
-
- if (b == 0)
- return u;
-
- uu.ll = u;
- bm = 32 - b;
-
- if (bm <= 0) {
- w.s.high = 0;
- w.s.low = (unsigned int) uu.s.high >> -bm;
- } else {
- const unsigned int carries = (unsigned int) uu.s.high << bm;
-
- w.s.high = (unsigned int) uu.s.high >> b;
- w.s.low = ((unsigned int) uu.s.low >> b) | carries;
- }
-
- return w.ll;
-}
-
-EXPORT_SYMBOL(__lshrdi3);
diff --git a/arch/mips/lib/ucmpdi2.c b/arch/mips/lib/ucmpdi2.c
deleted file mode 100644
index c31c78ca4175..000000000000
--- a/arch/mips/lib/ucmpdi2.c
+++ /dev/null
@@ -1,22 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-#include <linux/export.h>
-
-#include "libgcc.h"
-
-word_type notrace __ucmpdi2(unsigned long long a, unsigned long long b)
-{
- const DWunion au = {.ll = a};
- const DWunion bu = {.ll = b};
-
- if ((unsigned int) au.s.high < (unsigned int) bu.s.high)
- return 0;
- else if ((unsigned int) au.s.high > (unsigned int) bu.s.high)
- return 2;
- if ((unsigned int) au.s.low < (unsigned int) bu.s.low)
- return 0;
- else if ((unsigned int) au.s.low > (unsigned int) bu.s.low)
- return 2;
- return 1;
-}
-
-EXPORT_SYMBOL(__ucmpdi2);
--
2.7.4
On Wed, Apr 11, 2018 at 08:50:18AM +0100, Matt Redfearn wrote:
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index adce180f3ee4..e03f522c33ac 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -46,9 +46,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
>
> vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
>
> -extra-y += ashldi3.c bswapsi.c
> -$(obj)/ashldi3.o $(obj)/bswapsi.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
> -$(obj)/ashldi3.c $(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
> +extra-y += ashldi3.c
> +$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
> + $(call cmd,shipped)
> +
> +extra-y += bswapsi.c
> +$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
> $(call cmd,shipped)
ci20_defconfig:
arch/mips/boot/compressed/ashldi3.c:4:10: fatal error: libgcc.h: No such file or directory
#include "libgcc.h"
^~~~~~~~~~
It looks like it had already copied ashldi3.c from arch/mips/lib/ when
building an older commit, and it hasn't been regenerated from lib/ since
the Makefile changed, so its still using the old version.
I think it should be using FORCE and if_changed like this:
diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
index e03f522c33ac..abe77add8789 100644
--- a/arch/mips/boot/compressed/Makefile
+++ b/arch/mips/boot/compressed/Makefile
@@ -47,12 +47,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
extra-y += ashldi3.c
-$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
- $(call cmd,shipped)
+$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c FORCE
+ $(call if_changed,shipped)
extra-y += bswapsi.c
-$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
- $(call cmd,shipped)
+$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c FORCE
+ $(call if_changed,shipped)
targets := $(notdir $(vmlinuzobjs-y))
That resolves the build failures when checking out old -> new without
cleaning, since the .ashldi3.c.cmd is missing so it gets rebuilt.
It should also resolve issues if the path it copies from is updated in
future since the .ashldi3.c.cmd will get updated.
If you checkout new -> old without cleaning, the now removed
arch/mips/lib/ashldi3.c will get added which will trigger regeneration,
so it won't error.
However if you do new -> old -> new then the .ashldi3.cmd file isn't
updated while at old, so you get the same error as above. I'm not sure
there's much we can practically do about that, aside perhaps avoiding
the issue in future by somehow auto-deleting stale .*.cmd files.
Cc'ing kbuild folk in case they have any bright ideas.
At least the straightforward old->new upgrade will work with the above
fixup though. If you're okay with it I'm happy to apply as a fixup.
Cheers
James
2018-04-18 8:09 GMT+09:00 James Hogan <[email protected]>:
> On Wed, Apr 11, 2018 at 08:50:18AM +0100, Matt Redfearn wrote:
>> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
>> index adce180f3ee4..e03f522c33ac 100644
>> --- a/arch/mips/boot/compressed/Makefile
>> +++ b/arch/mips/boot/compressed/Makefile
>> @@ -46,9 +46,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
>>
>> vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
>>
>> -extra-y += ashldi3.c bswapsi.c
>> -$(obj)/ashldi3.o $(obj)/bswapsi.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
>> -$(obj)/ashldi3.c $(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
>> +extra-y += ashldi3.c
>> +$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
>> + $(call cmd,shipped)
>> +
>> +extra-y += bswapsi.c
>> +$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
>> $(call cmd,shipped)
>
> ci20_defconfig:
>
> arch/mips/boot/compressed/ashldi3.c:4:10: fatal error: libgcc.h: No such file or directory
> #include "libgcc.h"
> ^~~~~~~~~~
>
> It looks like it had already copied ashldi3.c from arch/mips/lib/ when
> building an older commit, and it hasn't been regenerated from lib/ since
> the Makefile changed, so its still using the old version.
>
> I think it should be using FORCE and if_changed like this:
>
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index e03f522c33ac..abe77add8789 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -47,12 +47,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
> vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
>
> extra-y += ashldi3.c
> -$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
> - $(call cmd,shipped)
> +$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c FORCE
> + $(call if_changed,shipped)
>
> extra-y += bswapsi.c
> -$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
> - $(call cmd,shipped)
> +$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c FORCE
> + $(call if_changed,shipped)
>
> targets := $(notdir $(vmlinuzobjs-y))
>
> That resolves the build failures when checking out old -> new without
> cleaning, since the .ashldi3.c.cmd is missing so it gets rebuilt.
>
> It should also resolve issues if the path it copies from is updated in
> future since the .ashldi3.c.cmd will get updated.
>
> If you checkout new -> old without cleaning, the now removed
> arch/mips/lib/ashldi3.c will get added which will trigger regeneration,
> so it won't error.
>
> However if you do new -> old -> new then the .ashldi3.cmd file isn't
> updated while at old, so you get the same error as above. I'm not sure
> there's much we can practically do about that, aside perhaps avoiding
> the issue in future by somehow auto-deleting stale .*.cmd files.
>
> Cc'ing kbuild folk in case they have any bright ideas.
I do not have any idea better than if_changed.
> At least the straightforward old->new upgrade will work with the above
> fixup though. If you're okay with it I'm happy to apply as a fixup.
>
--
Best Regards
Masahiro Yamada
Hi James,
On 18/04/18 00:09, James Hogan wrote:
> On Wed, Apr 11, 2018 at 08:50:18AM +0100, Matt Redfearn wrote:
>> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
>> index adce180f3ee4..e03f522c33ac 100644
>> --- a/arch/mips/boot/compressed/Makefile
>> +++ b/arch/mips/boot/compressed/Makefile
>> @@ -46,9 +46,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
>>
>> vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
>>
>> -extra-y += ashldi3.c bswapsi.c
>> -$(obj)/ashldi3.o $(obj)/bswapsi.o: KBUILD_CFLAGS += -I$(srctree)/arch/mips/lib
>> -$(obj)/ashldi3.c $(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
>> +extra-y += ashldi3.c
>> +$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
>> + $(call cmd,shipped)
>> +
>> +extra-y += bswapsi.c
>> +$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
>> $(call cmd,shipped)
>
> ci20_defconfig:
>
> arch/mips/boot/compressed/ashldi3.c:4:10: fatal error: libgcc.h: No such file or directory
> #include "libgcc.h"
> ^~~~~~~~~~
>
> It looks like it had already copied ashldi3.c from arch/mips/lib/ when
> building an older commit, and it hasn't been regenerated from lib/ since
> the Makefile changed, so its still using the old version.
>
> I think it should be using FORCE and if_changed like this:
>
> diff --git a/arch/mips/boot/compressed/Makefile b/arch/mips/boot/compressed/Makefile
> index e03f522c33ac..abe77add8789 100644
> --- a/arch/mips/boot/compressed/Makefile
> +++ b/arch/mips/boot/compressed/Makefile
> @@ -47,12 +47,12 @@ $(obj)/uart-ath79.c: $(srctree)/arch/mips/ath79/early_printk.c
> vmlinuzobjs-$(CONFIG_KERNEL_XZ) += $(obj)/ashldi3.o $(obj)/bswapsi.o
>
> extra-y += ashldi3.c
> -$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c
> - $(call cmd,shipped)
> +$(obj)/ashldi3.c: $(obj)/%.c: $(srctree)/lib/%.c FORCE
> + $(call if_changed,shipped)
>
> extra-y += bswapsi.c
> -$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c
> - $(call cmd,shipped)
> +$(obj)/bswapsi.c: $(obj)/%.c: $(srctree)/arch/mips/lib/%.c FORCE
> + $(call if_changed,shipped)
>
> targets := $(notdir $(vmlinuzobjs-y))
>
> That resolves the build failures when checking out old -> new without
> cleaning, since the .ashldi3.c.cmd is missing so it gets rebuilt.
>
> It should also resolve issues if the path it copies from is updated in
> future since the .ashldi3.c.cmd will get updated.
>
> If you checkout new -> old without cleaning, the now removed
> arch/mips/lib/ashldi3.c will get added which will trigger regeneration,
> so it won't error.
>
> However if you do new -> old -> new then the .ashldi3.cmd file isn't
> updated while at old, so you get the same error as above. I'm not sure
> there's much we can practically do about that, aside perhaps avoiding
> the issue in future by somehow auto-deleting stale .*.cmd files.
>
> Cc'ing kbuild folk in case they have any bright ideas.
>
> At least the straightforward old->new upgrade will work with the above
> fixup though. If you're okay with it I'm happy to apply as a fixup.
Unbelievable how fragile this change is proving to be :-/
Yeah fixup looks good to me.
Thanks,
Matt
>
> Cheers
> James
>