linux.git/arch/powerpc/Makefile, branch v4.19.151

powerpc: vdso: Make vdso32 installation conditional in vdso_install

2020-01-27T13:50:40+00:00

[ Upstream commit ff6d27823f619892ab96f7461764840e0d786b15 ]

The 32-bit vDSO is not needed and not normally built for 64-bit
little-endian configurations.  However, the vdso_install target still
builds and installs it.  Add the same config condition as is normally
used for the build.

Fixes: e0d005916994 ("powerpc/vdso: Disable building the 32-bit VDSO ...")
Signed-off-by: Ben Hutchings 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

powerpc: Don't add -mabi= flags when building with Clang

2020-01-04T18:13:10+00:00

[ Upstream commit 465bfd9c44dea6b55962b5788a23ac87a467c923 ]

When building pseries_defconfig, building vdso32 errors out:

  error: unknown target ABI 'elfv1'

This happens because -m32 in clang changes the target to 32-bit,
which does not allow the ABI to be changed.

Commit 4dc831aa8813 ("powerpc: Fix compiling a BE kernel with a
powerpc64le toolchain") added these flags to fix building big endian
kernels with a little endian GCC.

Clang doesn't need -mabi because the target triple controls the
default value. -mlittle-endian and -mbig-endian manipulate the triple
into either powerpc64-* or powerpc64le-*, which properly sets the
default ABI.

Adding a debug print out in the PPC64TargetInfo constructor after line
383 above shows this:

  $ echo | ./clang -E --target=powerpc64-linux -mbig-endian -o /dev/null -
  Default ABI: elfv1

  $ echo | ./clang -E --target=powerpc64-linux -mlittle-endian -o /dev/null -
  Default ABI: elfv2

  $ echo | ./clang -E --target=powerpc64le-linux -mbig-endian -o /dev/null -
  Default ABI: elfv1

  $ echo | ./clang -E --target=powerpc64le-linux -mlittle-endian -o /dev/null -
  Default ABI: elfv2

Don't specify -mabi when building with clang to avoid the build error
with -m32 and not change any code generation.

-mcall-aixdesc is not an implemented flag in clang so it can be safely
excluded as well, see commit 238abecde8ad ("powerpc: Don't use gcc
specific options on clang").

pseries_defconfig successfully builds after this patch and
powernv_defconfig and ppc44x_defconfig don't regress.

Reviewed-by: Daniel Axtens 
Signed-off-by: Nathan Chancellor 
[mpe: Trim clang links in change log]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20191119045712.39633-2-natechancellor@gmail.com
Signed-off-by: Sasha Levin

powerpc/32: Avoid unsupported flags with clang

2019-12-05T08:20:42+00:00

[ Upstream commit 72e7bcc2cdf82bf03caaa5e6c9b0134c2fc2ee7d ]

When building for ppc32 with clang these flags are unsupported:

  -ffixed-r2 and -mmultiple

llvm's lib/Target/PowerPC/PPCRegisterInfo.cpp marks r2 as reserved on
when building for SVR4ABI and !ppc64:

  // The SVR4 ABI reserves r2 and r13
  if (Subtarget.isSVR4ABI()) {
    // We only reserve r2 if we need to use the TOC pointer. If we have no
    // explicit uses of the TOC pointer (meaning we're a leaf function with
    // no constant-pool loads, etc.) and we have no potential uses inside an
    // inline asm block, then we can treat r2 has an ordinary callee-saved
    // register.
    const PPCFunctionInfo *FuncInfo = MF.getInfo();
    if (!TM.isPPC64() || FuncInfo->usesTOCBasePtr() || MF.hasInlineAsm())
      markSuperRegs(Reserved, PPC::R2);  // System-reserved register
    markSuperRegs(Reserved, PPC::R13); // Small Data Area pointer register
  }

This means we can safely omit -ffixed-r2 when building for 32-bit
targets.

The -mmultiple/-mno-multiple flags are not supported by clang, so
platforms that might support multiple miss out on using multiple word
instructions.

We wrap these flags in cc-option so that when Clang gains support the
kernel will be able use these flags.

Clang 8 can then build a ppc44x_defconfig which boots in Qemu:

  make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-  ppc44x_defconfig
  ./scripts/config -e CONFIG_DEVTMPFS -d DEVTMPFS_MOUNT
  make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-

  qemu-system-ppc -M bamboo \
   -kernel arch/powerpc/boot/zImage \
   -dtb arch/powerpc/boot/dts/bamboo.dtb \
   -initrd ~/ppc32-440-rootfs.cpio \
   -nographic -serial stdio -monitor pty -append "console=ttyS0"

Link: https://github.com/ClangBuiltLinux/linux/issues/261
Link: https://bugs.llvm.org/show_bug.cgi?id=39556
Link: https://bugs.llvm.org/show_bug.cgi?id=39555
Signed-off-by: Joel Stanley 
Reviewed-by: Nick Desaulniers 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin

powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer

2019-01-13T08:51:05+00:00

commit 6977f95e63b9b3fb4a5973481a800dd9f48a1338 upstream.

Signed-off-by: Nicholas Piggin 
Reviewed-by: Joel Stanley 
Signed-off-by: Michael Ellerman 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

powerpc: consolidate -mno-sched-epilog into FTRACE flags

2019-01-13T08:51:05+00:00

commit 2a056f58fd33ccc6a0261b552b0f17e7fa4a12f3 upstream.

Signed-off-by: Nicholas Piggin 
Reviewed-by: Joel Stanley 
Signed-off-by: Michael Ellerman 
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

powerpc: remove old GCC version checks

2019-01-13T08:51:05+00:00

commit f2910f0e6835339e6ce82cef22fa15718b7e3bfa upstream.

GCC 4.6 is the minimum supported now.

Signed-off-by: Nicholas Piggin 
Reviewed-by: Joel Stanley 
Signed-off-by: Michael Ellerman 
[nc: Applied to minimize unnecessary conflicts]
Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

powerpc/Makefile: Fix PPC_BOOK3S_64 ASFLAGS

2018-11-21T08:19:08+00:00

[ Upstream commit 960e30029863db95ec79a71009272d4661db5991 ]

Ever since commit 15a3204d24a3 ("powerpc/64s: Set assembler machine type
to POWER4") we force -mpower4 to be passed to the assembler
irrespective of the CFLAGS used (for Book3s 64).

When building a powerpc64 kernel with clang, clang will not add -many
to the assembler flags, so any instructions that the compiler has
generated that are not available on power4 will cause an error:

  /usr/bin/as -a64 -mppc64 -mlittle-endian -mpower8 \
   -I ./arch/powerpc/include -I ./arch/powerpc/include/generated \
   -I ./include -I ./arch/powerpc/include/uapi \
   -I ./arch/powerpc/include/generated/uapi -I ./include/uapi \
   -I ./include/generated/uapi -I arch/powerpc -I arch/powerpc \
   -maltivec -mpower4 -o init/do_mounts.o /tmp/do_mounts-3b0a3d.s
  /tmp/do_mounts-51ce54.s:748: Error: unrecognized opcode: `isel'

GCC does include -many, so the GCC driven gas call will succeed:

  as -v -I ./arch/powerpc/include -I ./arch/powerpc/include/generated -I
  ./include -I ./arch/powerpc/include/uapi
  -I ./arch/powerpc/include/generated/uapi -I ./include/uapi
  -I ./include/generated/uapi -I arch/powerpc -I arch/powerpc
   -a64 -mpower8 -many -mlittle -maltivec -mpower4 -o init/do_mounts.o

Note that isel is power7 and above for IBM CPUs. GCC only generates it
for Power9 and above, but the above test was run against the clang
generated assembly.

Peter Bergner explains:

  When using -many -mpower4, gas will first try and find a matching
  power4 mnemonic and failing that, it will then allow any valid
  mnemonic that gas knows about. GCC's use of -many predates me
  though.

  IIRC, Alan looked at trying to remove it, but I forget why he
  didn't. Could be either a gcc or gas issue at the time. I'm not sure
  whether issue still exists or not. He and I have modified how gas
  works internally a fair amount since he tried removing gcc use of
  -many.

  I will also note that when using -many, gas will choose the first
  mnemonic that matches in the mnemonic table and we have (mostly)
  sorted the table so that server mnemonics show up earlier in the
  table than other mnemonics, so they'll be seen/chosen first.

By explicitly setting -many we can build with Clang and GCC while
retaining the -mpower4 option.

Signed-off-by: Joel Stanley 
Signed-off-by: Michael Ellerman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

kbuild: rename LDFLAGS to KBUILD_LDFLAGS

2018-08-23T23:22:08+00:00

Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add
additional options to CC") renamed CFLAGS to KBUILD_CFLAGS.

Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add
additional options to AS") renamed AFLAGS to KBUILD_AFLAGS.

Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add
additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS.

For some reason, LDFLAGS was not renamed.

Using a well-known variable like LDFLAGS may result in accidental
override of the variable.

Kbuild generally uses KBUILD_ prefixed variables for the internally
appended options, so here is one more conversion to sanitize the
naming convention.

I did not touch Makefiles under tools/ since the tools build system
is a different world.

Signed-off-by: Masahiro Yamada 
Acked-by: Kirill A. Shutemov 
Reviewed-by: Palmer Dabbelt

Merge branch 'fixes' into next

2018-08-13T05:59:06+00:00

Merge our fixes branch from the 4.18 cycle to resolve some minor
conflicts.

powerpc: Make CPU selection logic generic in Makefile

2018-08-07T14:32:36+00:00

At the time being, when adding a new CPU for selection, both
Kconfig.cputype and Makefile have to be modified.

This patch moves into Kconfig.cputype the name of the CPU to me
passed to the -mcpu= argument.

Signed-off-by: Christophe Leroy 
Reviewed-by: Nicholas Piggin 
[mpe: Rename the option to TARGET_CPU to echo the gcc documentation]
Signed-off-by: Michael Ellerman