[PATCH v6 0/8] tools/nolibc: add 32/64-bit powerpc support

[PATCH v6 0/8] tools/nolibc: add 32/64-bit powerpc support

[Zhangjin Wu]

Hi, Willy

Now, the dependent pmac32_defconfig patch has been merged into the
powerpc next-test branch [1] ;-)

v6 here with a clean up of the CFLAGS for ppc variants, removed the
redundant -Wl options and call cc-option to check the -mmultiple option
for llvm as kernel does. v5 is [2].

Tests run with local toolchains and latest toolchains.

    $ for arch in ppc ppc64 ppc64le; do \
        make run-user XARCH=$arch | grep "status: "; \
      done
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning

    $ for arch in ppc ppc64 ppc64le; do \
        make run-user XARCH=$arch CC=/labs/linux-lab/prebuilt/toolchains/ppc64/gcc-13.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc | grep "status: "; \
      done
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning
    166 test(s): 158 passed,   8 skipped,   0 failed => status: warning

Changes from v5 --> v6:

* selftests/nolibc: add test support for ppc
  selftests/nolibc: add test support for ppc64le
  selftests/nolibc: add test support for ppc64

    Removed the -Wl options.

    As comment from arch/powerpc/Makefile, use -mmultiple with cc-option for llvm has no such options.

* tools/nolibc: add support for powerpc
  tools/nolibc: add support for powerpc64
  selftests/nolibc: add XARCH and ARCH mapping support
  selftests/nolibc: allow customize CROSS_COMPILE by architecture
  selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

    No changes.


BR,
Zhangjin Wu
---
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?h=next-test
[2]: https://lore.kernel.org/lkml/cover.1691062722.git.falcon@tinylab.org/

Zhangjin Wu (8):
  tools/nolibc: add support for powerpc
  tools/nolibc: add support for powerpc64
  selftests/nolibc: add XARCH and ARCH mapping support
  selftests/nolibc: add test support for ppc
  selftests/nolibc: add test support for ppc64le
  selftests/nolibc: add test support for ppc64
  selftests/nolibc: allow customize CROSS_COMPILE by architecture
  selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

 tools/include/nolibc/arch-powerpc.h     | 213 ++++++++++++++++++++++++
 tools/include/nolibc/arch.h             |   2 +
 tools/testing/selftests/nolibc/Makefile |  74 ++++++--
 3 files changed, 277 insertions(+), 12 deletions(-)
 create mode 100644 tools/include/nolibc/arch-powerpc.h

-- 
2.25.1

[PATCH v6 1/8] tools/nolibc: add support for powerpc

[Zhangjin Wu]

Both syscall declarations and _start code definition are added for
powerpc to nolibc.

Like mips, powerpc uses a register (exactly, the summary overflow bit)
to record the error occurred, and uses another register to return the
value [1]. So, the return value of every syscall declaration must be
normalized to match the __sysret() helper, return -value when there is
an error, otheriwse, return value directly.

Glibc and musl use different methods to check the summary overflow bit,
glibc (sysdeps/unix/sysv/linux/powerpc/sysdep.h) saves the cr register
to r0 at first, and then check the summary overflow bit in cr0:

    mfcr r0
    r0 & (1 << 28) ? -r3 : r3

    -->

    10003c14:       7c 00 00 26     mfcr    r0
    10003c18:       74 09 10 00     andis.  r9,r0,4096
    10003c1c:       41 82 00 08     beq     0x10003c24
    10003c20:       7c 63 00 d0     neg     r3,r3

Musl (arch/powerpc/syscall_arch.h) directly checks the summary overflow
bit with the 'bns' instruction, it is smaller:

    /* no summary overflow bit means no error, return value directly */
    bns+ 1f
    /* otherwise, return negated value */
    neg r3, r3
    1:

    -->

    10000418:       40 a3 00 08     bns     0x10000420
    1000041c:       7c 63 00 d0     neg     r3,r3

Like musl, Linux (arch/powerpc/include/asm/vdso/gettimeofday.h) uses the
same method for do_syscall_2() too.

Here applies the second method to get smaller size.

[1]: https://man7.org/linux/man-pages/man2/syscall.2.html

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/include/nolibc/arch-powerpc.h | 197 ++++++++++++++++++++++++++++
 tools/include/nolibc/arch.h         |   2 +
 2 files changed, 199 insertions(+)
 create mode 100644 tools/include/nolibc/arch-powerpc.h

diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h
new file mode 100644
index 000000000000..8332c9d3e5d6
--- /dev/null
+++ b/tools/include/nolibc/arch-powerpc.h
@@ -0,0 +1,197 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * PowerPC specific definitions for NOLIBC
+ * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org>
+ */
+
+#ifndef _NOLIBC_ARCH_POWERPC_H
+#define _NOLIBC_ARCH_POWERPC_H
+
+#include "compiler.h"
+#include "crt.h"
+
+/* Syscalls for PowerPC :
+ *   - stack is 16-byte aligned
+ *   - syscall number is passed in r0
+ *   - arguments are in r3, r4, r5, r6, r7, r8, r9
+ *   - the system call is performed by calling "sc"
+ *   - syscall return comes in r3, and the summary overflow bit is checked
+ *     to know if an error occurred, in which case errno is in r3.
+ *   - the arguments are cast to long and assigned into the target
+ *     registers which are then simply passed as registers to the asm code,
+ *     so that we don't have to experience issues with register constraints.
+ */
+
+#define _NOLIBC_SYSCALL_CLOBBERLIST \
+	"memory", "cr0", "r12", "r11", "r10", "r9"
+
+#define my_syscall0(num)                                                     \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num)                                     \
+		:                                                            \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4"  \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+#define my_syscall1(num, arg1)                                               \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num)                                     \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5", "r4"  \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+
+#define my_syscall2(num, arg1, arg2)                                         \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+	register long _arg2 __asm__ ("r4") = (long)(arg2);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num), "+r"(_arg2)                        \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6", "r5"        \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+
+#define my_syscall3(num, arg1, arg2, arg3)                                   \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+	register long _arg2 __asm__ ("r4") = (long)(arg2);                   \
+	register long _arg3 __asm__ ("r5") = (long)(arg3);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3)           \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7", "r6"              \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+
+#define my_syscall4(num, arg1, arg2, arg3, arg4)                             \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+	register long _arg2 __asm__ ("r4") = (long)(arg2);                   \
+	register long _arg3 __asm__ ("r5") = (long)(arg3);                   \
+	register long _arg4 __asm__ ("r6") = (long)(arg4);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3),          \
+		  "+r"(_arg4)                                                \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8", "r7"                    \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+
+#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5)                       \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+	register long _arg2 __asm__ ("r4") = (long)(arg2);                   \
+	register long _arg3 __asm__ ("r5") = (long)(arg3);                   \
+	register long _arg4 __asm__ ("r6") = (long)(arg4);                   \
+	register long _arg5 __asm__ ("r7") = (long)(arg5);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3),          \
+		  "+r"(_arg4), "+r"(_arg5)                                   \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST, "r8"                          \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6)                 \
+({                                                                           \
+	register long _ret  __asm__ ("r3");                                  \
+	register long _num  __asm__ ("r0") = (num);                          \
+	register long _arg1 __asm__ ("r3") = (long)(arg1);                   \
+	register long _arg2 __asm__ ("r4") = (long)(arg2);                   \
+	register long _arg3 __asm__ ("r5") = (long)(arg3);                   \
+	register long _arg4 __asm__ ("r6") = (long)(arg4);                   \
+	register long _arg5 __asm__ ("r7") = (long)(arg5);                   \
+	register long _arg6 __asm__ ("r8") = (long)(arg6);                   \
+									     \
+	__asm__ volatile (                                                   \
+		"	sc\n"                                                \
+		"	bns+ 1f\n"                                           \
+		"	neg  %0, %0\n"                                       \
+		"1:\n"                                                       \
+		: "=r"(_ret), "+r"(_num), "+r"(_arg2), "+r"(_arg3),          \
+		  "+r"(_arg4), "+r"(_arg5), "+r"(_arg6)                      \
+		: "0"(_arg1)                                                 \
+		: _NOLIBC_SYSCALL_CLOBBERLIST                                \
+	);                                                                   \
+	_ret;                                                                \
+})
+
+/* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0),
+ * "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but
+ * works with __attribute__((__optimize__("-fno-stack-protector")))
+ */
+#ifdef __no_stack_protector
+#undef __no_stack_protector
+#define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
+#endif
+
+/* startup code */
+void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+{
+	__asm__ volatile (
+		"mr     3, 1\n"         /* save stack pointer to r3, as arg1 of _start_c */
+		"clrrwi 1, 1, 4\n"      /* align the stack to 16 bytes                   */
+		"li     0, 0\n"         /* zero the frame pointer                        */
+		"stwu   1, -16(1)\n"    /* the initial stack frame                       */
+		"bl     _start_c\n"     /* transfer to c runtime                         */
+	);
+	__builtin_unreachable();
+}
+
+#endif /* _NOLIBC_ARCH_POWERPC_H */
diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h
index 82b43935650f..e276fb0680af 100644
--- a/tools/include/nolibc/arch.h
+++ b/tools/include/nolibc/arch.h
@@ -25,6 +25,8 @@
 #include "arch-aarch64.h"
 #elif defined(__mips__) && defined(_ABIO32)
 #include "arch-mips.h"
+#elif defined(__powerpc__)
+#include "arch-powerpc.h"
 #elif defined(__riscv)
 #include "arch-riscv.h"
 #elif defined(__s390x__)
-- 
2.25.1

[PATCH v6 2/8] tools/nolibc: add support for powerpc64

[Zhangjin Wu]

This follows the 64-bit PowerPC ABI [1], refers to the slides: "A new
ABI for little-endian PowerPC64 Design & Implementation" [2] and the
musl code in arch/powerpc64/crt_arch.h.

First, stdu and clrrdi are used instead of stwu and clrrwi for
powerpc64.

Second, the stack frame size is increased to 32 bytes for powerpc64, 32
bytes is the minimal stack frame size supported described in [2].

Besides, the TOC pointer (GOT pointer) must be saved to r2.

This works on both little endian and big endian 64-bit PowerPC.

[1]: https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.pdf
[2]: https://www.llvm.org/devmtg/2014-04/PDFs/Talks/Euro-LLVM-2014-Weigand.pdf

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/include/nolibc/arch-powerpc.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h
index 8332c9d3e5d6..76c3784f9dc7 100644
--- a/tools/include/nolibc/arch-powerpc.h
+++ b/tools/include/nolibc/arch-powerpc.h
@@ -172,6 +172,7 @@
 	_ret;                                                                \
 })
 
+#ifndef __powerpc64__
 /* FIXME: For 32-bit PowerPC, with newer gcc compilers (e.g. gcc 13.1.0),
  * "omit-frame-pointer" fails with __attribute__((no_stack_protector)) but
  * works with __attribute__((__optimize__("-fno-stack-protector")))
@@ -180,10 +181,24 @@
 #undef __no_stack_protector
 #define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
 #endif
+#endif /* !__powerpc64__ */
 
 /* startup code */
 void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
 {
+#ifdef __powerpc64__
+	/* On 64-bit PowerPC, save TOC/GOT pointer to r2 */
+	extern char TOC __asm__ (".TOC.");
+	register volatile long r2 __asm__ ("r2") = (void *)&TOC - (void *)_start;
+
+	__asm__ volatile (
+		"mr     3, 1\n"         /* save stack pointer to r3, as arg1 of _start_c */
+		"clrrdi 1, 1, 4\n"      /* align the stack to 16 bytes                   */
+		"li     0, 0\n"         /* zero the frame pointer                        */
+		"stdu   1, -32(1)\n"    /* the initial stack frame                       */
+		"bl     _start_c\n"     /* transfer to c runtime                         */
+	);
+#else
 	__asm__ volatile (
 		"mr     3, 1\n"         /* save stack pointer to r3, as arg1 of _start_c */
 		"clrrwi 1, 1, 4\n"      /* align the stack to 16 bytes                   */
@@ -191,6 +206,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"stwu   1, -16(1)\n"    /* the initial stack frame                       */
 		"bl     _start_c\n"     /* transfer to c runtime                         */
 	);
+#endif
 	__builtin_unreachable();
 }
 
-- 
2.25.1

[PATCH v6 3/8] selftests/nolibc: add XARCH and ARCH mapping support

[Zhangjin Wu]

Most of the CPU architectures have different variants, but kernel
usually only accepts parts of them via the ARCH variable, the others
should be customized via kernel config files.

To simplify testing, a new XARCH variable is added to extend the
kernel's ARCH with a few variants of the same architecture, and it is
used to customize variant specific variables, at last XARCH is converted
to the kernel's ARCH:

  e.g. make run XARCH=<one of the supported variants>
                | \
                |  `-> variant specific variables:
                |      IMAGE, DEFCONFIG, QEMU_ARCH, QEMU_ARGS, CFLAGS ...
                \
                 `---> kernel's ARCH

XARCH and ARCH are carefully mapped to allow users to pass architecture
variants via XARCH or pass architecture via ARCH from cmdline.

PowerPC is the first user and also a very good reference architecture of
this mapping, it has variants with different combinations of
32-bit/64-bit and bit endian/little endian.

To use this mapping, the other architectures can refer to PowerPC, If
the target architecture only has one variant, XARCH is simply an alias
of ARCH, no additional mapping required.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230702171715.GD16233@1wt.eu/
Link: https://lore.kernel.org/lkml/20230730061801.GA7690@1wt.eu/
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 46 ++++++++++++++++++-------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index f42adef87e12..46a2312b06f5 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -14,6 +14,27 @@ include $(srctree)/scripts/subarch.include
 ARCH = $(SUBARCH)
 endif
 
+# XARCH extends the kernel's ARCH with a few variants of the same
+# architecture that only differ by the configuration, the toolchain
+# and the Qemu program used. It is copied as-is into ARCH except for
+# a few specific values which are mapped like this:
+#
+#  XARCH        | ARCH      | config
+#  -------------|-----------|-------------------------
+#  ppc          | powerpc   | 32 bits
+#  ppc64        | powerpc   | 64 bits big endian
+#  ppc64le      | powerpc   | 64 bits little endian
+#
+# It is recommended to only use XARCH, though it does not harm if
+# ARCH is already set. For simplicity, ARCH is sufficient for all
+# architectures where both are equal.
+
+# configure default variants for target kernel supported architectures
+XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH))
+
+# map from user input variants to their kernel supported architectures
+ARCH            := $(or $(ARCH_$(XARCH)),$(XARCH))
+
 # kernel image names by architecture
 IMAGE_i386       = arch/x86/boot/bzImage
 IMAGE_x86_64     = arch/x86/boot/bzImage
@@ -24,7 +45,7 @@ IMAGE_mips       = vmlinuz
 IMAGE_riscv      = arch/riscv/boot/Image
 IMAGE_s390       = arch/s390/boot/bzImage
 IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
-IMAGE            = $(IMAGE_$(ARCH))
+IMAGE            = $(IMAGE_$(XARCH))
 IMAGE_NAME       = $(notdir $(IMAGE))
 
 # default kernel configurations that appear to be usable
@@ -37,7 +58,7 @@ DEFCONFIG_mips       = malta_defconfig
 DEFCONFIG_riscv      = defconfig
 DEFCONFIG_s390       = defconfig
 DEFCONFIG_loongarch  = defconfig
-DEFCONFIG            = $(DEFCONFIG_$(ARCH))
+DEFCONFIG            = $(DEFCONFIG_$(XARCH))
 
 # optional tests to run (default = all)
 TEST =
@@ -52,7 +73,7 @@ QEMU_ARCH_mips       = mipsel  # works with malta_defconfig
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
-QEMU_ARCH            = $(QEMU_ARCH_$(ARCH))
+QEMU_ARCH            = $(QEMU_ARCH_$(XARCH))
 
 # QEMU_ARGS : some arch-specific args to pass to qemu
 QEMU_ARGS_i386       = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -64,7 +85,7 @@ QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
-QEMU_ARGS            = $(QEMU_ARGS_$(ARCH)) $(QEMU_ARGS_EXTRA)
+QEMU_ARGS            = $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_EXTRA)
 
 # OUTPUT is only set when run from the main makefile, otherwise
 # it defaults to this nolibc directory.
@@ -81,7 +102,7 @@ CFLAGS_mips = -EL
 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
 CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \
 		$(call cc-option,-fno-stack-protector) \
-		$(CFLAGS_$(ARCH)) $(CFLAGS_STACKPROTECTOR)
+		$(CFLAGS_$(XARCH)) $(CFLAGS_STACKPROTECTOR)
 LDFLAGS := -s
 
 REPORT  ?= awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{if (!f) printf("\n"); f++; print;} /\[SKIPPED\][\r]*$$/{s++} \
@@ -96,24 +117,25 @@ help:
 	@echo "  sysroot      create the nolibc sysroot here (uses \$$ARCH)"
 	@echo "  nolibc-test  build the executable (uses \$$CC and \$$CROSS_COMPILE)"
 	@echo "  libc-test    build an executable using the compiler's default libc instead"
-	@echo "  run-user     runs the executable under QEMU (uses \$$ARCH, \$$TEST)"
+	@echo "  run-user     runs the executable under QEMU (uses \$$XARCH, \$$TEST)"
 	@echo "  initramfs    prepare the initramfs with nolibc-test"
-	@echo "  defconfig    create a fresh new default config (uses \$$ARCH)"
-	@echo "  kernel       (re)build the kernel with the initramfs (uses \$$ARCH)"
-	@echo "  run          runs the kernel in QEMU after building it (uses \$$ARCH, \$$TEST)"
-	@echo "  rerun        runs a previously prebuilt kernel in QEMU (uses \$$ARCH, \$$TEST)"
+	@echo "  defconfig    create a fresh new default config (uses \$$XARCH)"
+	@echo "  kernel       (re)build the kernel with the initramfs (uses \$$XARCH)"
+	@echo "  run          runs the kernel in QEMU after building it (uses \$$XARCH, \$$TEST)"
+	@echo "  rerun        runs a previously prebuilt kernel in QEMU (uses \$$XARCH, \$$TEST)"
 	@echo "  clean        clean the sysroot, initramfs, build and output files"
 	@echo ""
 	@echo "The output file is \"run.out\". Test ranges may be passed using \$$TEST."
 	@echo ""
 	@echo "Currently using the following variables:"
 	@echo "  ARCH          = $(ARCH)"
+	@echo "  XARCH         = $(XARCH)"
 	@echo "  CROSS_COMPILE = $(CROSS_COMPILE)"
 	@echo "  CC            = $(CC)"
 	@echo "  OUTPUT        = $(OUTPUT)"
 	@echo "  TEST          = $(TEST)"
-	@echo "  QEMU_ARCH     = $(if $(QEMU_ARCH),$(QEMU_ARCH),UNKNOWN_ARCH) [determined from \$$ARCH]"
-	@echo "  IMAGE_NAME    = $(if $(IMAGE_NAME),$(IMAGE_NAME),UNKNOWN_ARCH) [determined from \$$ARCH]"
+	@echo "  QEMU_ARCH     = $(if $(QEMU_ARCH),$(QEMU_ARCH),UNKNOWN_ARCH) [determined from \$$XARCH]"
+	@echo "  IMAGE_NAME    = $(if $(IMAGE_NAME),$(IMAGE_NAME),UNKNOWN_ARCH) [determined from \$$XARCH]"
 	@echo ""
 
 all: run
-- 
2.25.1

[PATCH v6 4/8] selftests/nolibc: add test support for ppc

[Zhangjin Wu]

Kernel uses ARCH=powerpc for both 32-bit and 64-bit PowerPC, here adds a
ppc variant for 32-bit PowerPC and uses it as the default variant of
powerpc architecture.

Users can pass XARCH=ppc (or ARCH=powerpc) to test 32-bit PowerPC.

The default qemu-system-ppc g3beige machine [1] is used to run 32-bit
powerpc kernel with pmac32_defconfig. The missing PMACZILOG serial tty
and console are enabled in another patch [2].

Note,

- zImage doesn't boot due to "qemu-system-ppc: Some ROM regions are
  overlapping" error, so, vmlinux is used instead.

- since the VSX support may be disabled in kernel side, to avoid
  "illegal instruction" errors due to missing VSX kernel support, let's
  simply let compiler not generate vector/scalar (VSX) instructions via
  the '-mno-vsx' option.

- as 'man gcc' shows, '-mmultiple' is used to generate code that uses
  the load multiple word instructions and the store multiple word
  instructions. Those instructions do not work when the processor is in
  little-endian mode (except PPC740/PPC750), so, we only enable it
  for big endian powerpc.

[1]: https://qemu.readthedocs.io/en/latest/system/ppc/powermac.html
[2]: https://lore.kernel.org/lkml/bb7b5f9958b3e3a20f6573ff7ce7c5dc566e7e32.1690982937.git.tanyuan@tinylab.org/

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/ZL9leVOI25S2+0+g@1wt.eu/
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 46a2312b06f5..cac501e0c7cf 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -30,9 +30,11 @@ endif
 # architectures where both are equal.
 
 # configure default variants for target kernel supported architectures
+XARCH_powerpc    = ppc
 XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH))
 
 # map from user input variants to their kernel supported architectures
+ARCH_ppc         = powerpc
 ARCH            := $(or $(ARCH_$(XARCH)),$(XARCH))
 
 # kernel image names by architecture
@@ -42,6 +44,7 @@ IMAGE_x86        = arch/x86/boot/bzImage
 IMAGE_arm64      = arch/arm64/boot/Image
 IMAGE_arm        = arch/arm/boot/zImage
 IMAGE_mips       = vmlinuz
+IMAGE_ppc        = vmlinux
 IMAGE_riscv      = arch/riscv/boot/Image
 IMAGE_s390       = arch/s390/boot/bzImage
 IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
@@ -55,6 +58,7 @@ DEFCONFIG_x86        = defconfig
 DEFCONFIG_arm64      = defconfig
 DEFCONFIG_arm        = multi_v7_defconfig
 DEFCONFIG_mips       = malta_defconfig
+DEFCONFIG_ppc        = pmac32_defconfig
 DEFCONFIG_riscv      = defconfig
 DEFCONFIG_s390       = defconfig
 DEFCONFIG_loongarch  = defconfig
@@ -70,6 +74,7 @@ QEMU_ARCH_x86        = x86_64
 QEMU_ARCH_arm64      = aarch64
 QEMU_ARCH_arm        = arm
 QEMU_ARCH_mips       = mipsel  # works with malta_defconfig
+QEMU_ARCH_ppc        = ppc
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
@@ -82,6 +87,7 @@ QEMU_ARGS_x86        = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(
 QEMU_ARGS_arm64      = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_arm        = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_ppc        = -M g3beige -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -97,6 +103,7 @@ else
 Q=@
 endif
 
+CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_s390 = -m64
 CFLAGS_mips = -EL
 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
-- 
2.25.1

[PATCH v6 5/8] selftests/nolibc: add test support for ppc64le

[Zhangjin Wu]

Kernel uses ARCH=powerpc for both 32-bit and 64-bit PowerPC, here adds a
ppc64le variant for little endian 64-bit PowerPC, users can pass
XARCH=ppc64le to test it.

The powernv machine of qemu-system-ppc64le is used for there is just a
working powernv_defconfig.

As the document [1] shows:

  PowerNV (as Non-Virtualized) is the “bare metal” platform using the
  OPAL firmware. It runs Linux on IBM and OpenPOWER systems and it can be
  used as an hypervisor OS, running KVM guests, or simply as a host OS.

Notes,

- since the VSX support may be disabled in kernel side, to avoid
  "illegal instruction" errors due to missing VSX kernel support, let's
  simply let compiler not generate vector/scalar (VSX) instructions via
  the '-mno-vsx' option.

- little endian ppc64 prefers elfv2 to elfv1 if the toolchain (e.g. gcc
  13.1.0) supports it, let's align with kernel, otherwise, our elfv1
  binary will not run on kernel with elfv2 ABI.

[1]: https://qemu.readthedocs.io/en/latest/system/ppc/powernv.html

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230722120747.GC17311@1wt.eu/
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index cac501e0c7cf..586f278ddd66 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -35,6 +35,7 @@ XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH))
 
 # map from user input variants to their kernel supported architectures
 ARCH_ppc         = powerpc
+ARCH_ppc64le     = powerpc
 ARCH            := $(or $(ARCH_$(XARCH)),$(XARCH))
 
 # kernel image names by architecture
@@ -45,6 +46,7 @@ IMAGE_arm64      = arch/arm64/boot/Image
 IMAGE_arm        = arch/arm/boot/zImage
 IMAGE_mips       = vmlinuz
 IMAGE_ppc        = vmlinux
+IMAGE_ppc64le    = arch/powerpc/boot/zImage
 IMAGE_riscv      = arch/riscv/boot/Image
 IMAGE_s390       = arch/s390/boot/bzImage
 IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
@@ -59,6 +61,7 @@ DEFCONFIG_arm64      = defconfig
 DEFCONFIG_arm        = multi_v7_defconfig
 DEFCONFIG_mips       = malta_defconfig
 DEFCONFIG_ppc        = pmac32_defconfig
+DEFCONFIG_ppc64le    = powernv_defconfig
 DEFCONFIG_riscv      = defconfig
 DEFCONFIG_s390       = defconfig
 DEFCONFIG_loongarch  = defconfig
@@ -75,6 +78,7 @@ QEMU_ARCH_arm64      = aarch64
 QEMU_ARCH_arm        = arm
 QEMU_ARCH_mips       = mipsel  # works with malta_defconfig
 QEMU_ARCH_ppc        = ppc
+QEMU_ARCH_ppc64le    = ppc64le
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
@@ -88,6 +92,7 @@ QEMU_ARGS_arm64      = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC
 QEMU_ARGS_arm        = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_ppc        = -M g3beige -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_ppc64le    = -M powernv -append "console=hvc0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -104,6 +109,7 @@ Q=@
 endif
 
 CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
+CFLAGS_ppc64le = -m64 -mlittle-endian -mno-vsx $(call cc-option,-mabi=elfv2)
 CFLAGS_s390 = -m64
 CFLAGS_mips = -EL
 CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
-- 
2.25.1

[PATCH v6 6/8] selftests/nolibc: add test support for ppc64

[Zhangjin Wu]

Kernel uses ARCH=powerpc for both 32-bit and 64-bit PowerPC, here adds a
ppc64 variant for big endian 64-bit PowerPC, users can pass XARCH=ppc64
to test it.

The powernv machine of qemu-system-ppc64 is used with
powernv_be_defconfig.

As the document [1] shows:

  PowerNV (as Non-Virtualized) is the “bare metal” platform using the
  OPAL firmware. It runs Linux on IBM and OpenPOWER systems and it can be
  used as an hypervisor OS, running KVM guests, or simply as a host OS.

Notes,

- differs from little endian 64-bit PowerPC, vmlinux is used instead of
  zImage, because big endian zImage [2] only boot on qemu with x-vof=on
  (added from qemu v7.0) and a fixup patch [3] for qemu v7.0.51:

- since the VSX support may be disabled in kernel side, to avoid
  "illegal instruction" errors due to missing VSX kernel support, let's
  simply let compiler not generate vector/scalar (VSX) instructions via
  the '-mno-vsx' option.

- as 'man gcc' shows, '-mmultiple' is used to generate code that uses
  the load multiple word instructions and the store multiple word
  instructions. Those instructions do not work when the processor is in
  little-endian mode (except PPC740/PPC750), so, we only enable it
  for big endian powerpc.

- for big endian ppc64, as the help message from arch/powerpc/Kconfig
  shows, the V2 ABI is standard for 64-bit little-endian, but for
  big-endian it is less well tested by kernel and toolchain, so, use
  elfv1 as-is, no need to explicitly ask toolchain to use elfv2 here.

[1]: https://qemu.readthedocs.io/en/latest/system/ppc/powernv.html
[2]: https://github.com/linuxppc/issues/issues/402
[3]: https://lore.kernel.org/qemu-devel/20220504065536.3534488-1-aik@ozlabs.ru/

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/20230722121019.GD17311@1wt.eu/
Link: https://lore.kernel.org/lkml/20230719043353.GC5331@1wt.eu/
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 586f278ddd66..452d8e424d28 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -35,6 +35,7 @@ XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH))
 
 # map from user input variants to their kernel supported architectures
 ARCH_ppc         = powerpc
+ARCH_ppc64       = powerpc
 ARCH_ppc64le     = powerpc
 ARCH            := $(or $(ARCH_$(XARCH)),$(XARCH))
 
@@ -46,6 +47,7 @@ IMAGE_arm64      = arch/arm64/boot/Image
 IMAGE_arm        = arch/arm/boot/zImage
 IMAGE_mips       = vmlinuz
 IMAGE_ppc        = vmlinux
+IMAGE_ppc64      = vmlinux
 IMAGE_ppc64le    = arch/powerpc/boot/zImage
 IMAGE_riscv      = arch/riscv/boot/Image
 IMAGE_s390       = arch/s390/boot/bzImage
@@ -61,6 +63,7 @@ DEFCONFIG_arm64      = defconfig
 DEFCONFIG_arm        = multi_v7_defconfig
 DEFCONFIG_mips       = malta_defconfig
 DEFCONFIG_ppc        = pmac32_defconfig
+DEFCONFIG_ppc64      = powernv_be_defconfig
 DEFCONFIG_ppc64le    = powernv_defconfig
 DEFCONFIG_riscv      = defconfig
 DEFCONFIG_s390       = defconfig
@@ -78,6 +81,7 @@ QEMU_ARCH_arm64      = aarch64
 QEMU_ARCH_arm        = arm
 QEMU_ARCH_mips       = mipsel  # works with malta_defconfig
 QEMU_ARCH_ppc        = ppc
+QEMU_ARCH_ppc64      = ppc64
 QEMU_ARCH_ppc64le    = ppc64le
 QEMU_ARCH_riscv      = riscv64
 QEMU_ARCH_s390       = s390x
@@ -92,6 +96,7 @@ QEMU_ARGS_arm64      = -M virt -cpu cortex-a53 -append "panic=-1 $(TEST:%=NOLIBC
 QEMU_ARGS_arm        = -M virt -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_ppc        = -M g3beige -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
+QEMU_ARGS_ppc64      = -M powernv -append "console=hvc0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_ppc64le    = -M powernv -append "console=hvc0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -109,6 +114,7 @@ Q=@
 endif
 
 CFLAGS_ppc = -m32 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
+CFLAGS_ppc64 = -m64 -mbig-endian -mno-vsx $(call cc-option,-mmultiple)
 CFLAGS_ppc64le = -m64 -mlittle-endian -mno-vsx $(call cc-option,-mabi=elfv2)
 CFLAGS_s390 = -m64
 CFLAGS_mips = -EL
-- 
2.25.1

[PATCH v6 7/8] selftests/nolibc: allow customize CROSS_COMPILE by architecture

[Zhangjin Wu]

Some cross compilers may not just be prefixed with ARCH, customize them
by architecture may simplify the test a lot, especially, when iterate
with ARCH.

After customizing this for every architecture, the minimal test argument
will be architecture itself, no CROSS_COMPILE required to be passed.

If the prefix of installed cross compiler is not the same as the one
customized, we can also pass CROSS_COMPILE as before or even pass
CROSS_COMPILE_<ARCH>.

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 452d8e424d28..45d231b9c5c2 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -55,6 +55,12 @@ IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
 IMAGE            = $(IMAGE_$(XARCH))
 IMAGE_NAME       = $(notdir $(IMAGE))
 
+# CROSS_COMPILE: cross toolchain prefix by architecture
+CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
+
+# make sure CC is prefixed with CROSS_COMPILE
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+
 # default kernel configurations that appear to be usable
 DEFCONFIG_i386       = defconfig
 DEFCONFIG_x86_64     = defconfig
-- 
2.25.1

[PATCH v6 8/8] selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

[Zhangjin Wu]

The little-endian powerpc64le compilers provided by Ubuntu and Fedora
are able to compile big endian kernel and big endian nolibc-test [1].

These default CROSS_COMPILE settings allow to test target architectures
with:

    $ cd /path/to/tools/testing/selftests/nolibc/

    $ for arch in ppc ppc64 ppc64le; do \
        make run-user XARCH=$arch | grep "status: "; \
      done

If want to use another cross compiler, please simply pass CROSS_COMPILE
or CC as before.

For example, it is able to build 64-bit nolibc-test with the big endian
powerpc64-linux-gcc crosstool from [2]:

    $ wget -c https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/13.1.0/x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
    $ tar xvf x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
    $ export PATH=$PWD/gcc-13.1.0-nolibc/powerpc64-linux/bin/:$PATH

    $ export CROSS_COMPILE_ppc=powerpc64-linux-
    $ export CROSS_COMPILE_ppc64=powerpc64-linux-
    $ export CROSS_COMPILE_ppc64le=powerpc64-linux-
    $ for arch in ppc ppc64 ppc64le; do \
        make run-user XARCH=$arch | grep "status: "; \
      done

Or specify CC directly with full path:

    $ export CC=$PWD/gcc-13.1.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc
    $ for arch in ppc ppc64 ppc64le; do \
        make run-user XARCH=$arch | grep "status: "; \
      done

[1]: https://github.com/open-power/skiboot
[2]: https://mirrors.edge.kernel.org/pub/tools/crosstool/

Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
---
 tools/testing/selftests/nolibc/Makefile | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index 45d231b9c5c2..b4171a754eb2 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -56,6 +56,9 @@ IMAGE            = $(IMAGE_$(XARCH))
 IMAGE_NAME       = $(notdir $(IMAGE))
 
 # CROSS_COMPILE: cross toolchain prefix by architecture
+CROSS_COMPILE_ppc       ?= powerpc-linux-gnu-
+CROSS_COMPILE_ppc64     ?= powerpc64le-linux-gnu-
+CROSS_COMPILE_ppc64le   ?= powerpc64le-linux-gnu-
 CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
 
 # make sure CC is prefixed with CROSS_COMPILE
-- 
2.25.1

Re: [PATCH v6 8/8] selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

[Willy Tarreau]

On Sun, Aug 06, 2023 at 02:47:09AM +0800, Zhangjin Wu wrote:
> The little-endian powerpc64le compilers provided by Ubuntu and Fedora
> are able to compile big endian kernel and big endian nolibc-test [1].

FWIW I'm wondering why focusing on these ones which have a different
naming from the other ones, when I think that most users rely on the
ones maintained by Arnd there:

   https://mirrors.edge.kernel.org/pub/tools/crosstool/

Yours is called powerpc64le while the one above is "powerpc64", it
requires to make an exception for this one, I find this a bit odd.

If someone wants to use their distro's cross toolchain, that's fine,
but I think that it will depend on distros anyway and some may not
even be provided (like loongarch) so I think it would make more sense
to adopt the canonical naming from Arnd's toolchains above.

It's not critical, but as you showed below, it makes building for ppc
a little bit cumbersome: those "export" lines could be dropped when
using the default names, and that's what we should document as the
recommended way to test:

> For example, it is able to build 64-bit nolibc-test with the big endian
> powerpc64-linux-gcc crosstool from [2]:
> 
>     $ wget -c https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/13.1.0/x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
>     $ tar xvf x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
>     $ export PATH=$PWD/gcc-13.1.0-nolibc/powerpc64-linux/bin/:$PATH
> 
>     $ export CROSS_COMPILE_ppc=powerpc64-linux-
>     $ export CROSS_COMPILE_ppc64=powerpc64-linux-
>     $ export CROSS_COMPILE_ppc64le=powerpc64-linux-
>     $ for arch in ppc ppc64 ppc64le; do \
>         make run-user XARCH=$arch | grep "status: "; \
>       done

Any opinion on this ?

Thanks,
Willy

Re: [PATCH v6 8/8] selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

[Zhangjin Wu]

Hi, Willy

> On Sun, Aug 06, 2023 at 02:47:09AM +0800, Zhangjin Wu wrote:
> > The little-endian powerpc64le compilers provided by Ubuntu and Fedora
> > are able to compile big endian kernel and big endian nolibc-test [1].
> 
> FWIW I'm wondering why focusing on these ones which have a different
> naming from the other ones, when I think that most users rely on the
> ones maintained by Arnd there:
> 
>    https://mirrors.edge.kernel.org/pub/tools/crosstool/
>

Arnd's toolchains may be a more distribution independent ones.

> Yours is called powerpc64le while the one above is "powerpc64", it
> requires to make an exception for this one, I find this a bit odd.
> 

Yes, one is little endian output by default, another may be big endian output
by default.

> If someone wants to use their distro's cross toolchain, that's fine,
> but I think that it will depend on distros anyway and some may not
> even be provided (like loongarch) so I think it would make more sense
> to adopt the canonical naming from Arnd's toolchains above.
>

Agree very much, let's switch to Arnd's toolchains.

> It's not critical, but as you showed below, it makes building for ppc
> a little bit cumbersome: those "export" lines could be dropped when
> using the default names, and that's what we should document as the
> recommended way to test:
> 
> > For example, it is able to build 64-bit nolibc-test with the big endian
> > powerpc64-linux-gcc crosstool from [2]:
> > 
> >     $ wget -c https://mirrors.edge.kernel.org/pub/tools/crosstool/files/bin/x86_64/13.1.0/x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
> >     $ tar xvf x86_64-gcc-13.1.0-nolibc-powerpc64-linux.tar.xz
> >     $ export PATH=$PWD/gcc-13.1.0-nolibc/powerpc64-linux/bin/:$PATH
> > 
> >     $ export CROSS_COMPILE_ppc=powerpc64-linux-
> >     $ export CROSS_COMPILE_ppc64=powerpc64-linux-
> >     $ export CROSS_COMPILE_ppc64le=powerpc64-linux-
> >     $ for arch in ppc ppc64 ppc64le; do \
> >         make run-user XARCH=$arch | grep "status: "; \
> >       done
> 
> Any opinion on this ?
>

Ok, let's go this way, if the others are ok for you, could you please
drop the last two CROSS_COMPILE patches from this v6 ppc series? Thanks.

I will send v2 CROSS_COMPILE series with them, with Arnd's toolchains, the
whole CROSS_COMPILE series will be unified and become very simple, although
they need to download the toolchains manually one by one, but it is possible to
write a common script, but that is another requirement.

BR,
Zhangjin
---
[1]: https://lore.kernel.org/lkml/cover.1691259983.git.falcon@tinylab.org/
[2]: https://lore.kernel.org/lkml/cover.1691263493.git.falcon@tinylab.org/

> Thanks,
> Willy

Re: [PATCH v6 8/8] selftests/nolibc: customize CROSS_COMPILE for 32/64-bit powerpc

[Willy Tarreau]

On Sun, Aug 06, 2023 at 11:11:25AM +0800, Zhangjin Wu wrote:
> > If someone wants to use their distro's cross toolchain, that's fine,
> > but I think that it will depend on distros anyway and some may not
> > even be provided (like loongarch) so I think it would make more sense
> > to adopt the canonical naming from Arnd's toolchains above.
> >
> 
> Agree very much, let's switch to Arnd's toolchains.

Fine!

> Ok, let's go this way, if the others are ok for you, could you please
> drop the last two CROSS_COMPILE patches from this v6 ppc series? Thanks.

Will do.

> I will send v2 CROSS_COMPILE series with them, with Arnd's toolchains, the
> whole CROSS_COMPILE series will be unified and become very simple, although
> they need to download the toolchains manually one by one, but it is possible to
> write a common script, but that is another requirement.

Or even wget -r or any such thing.

Cheers,
Willy

Re: [PATCH v6 7/8] selftests/nolibc: allow customize CROSS_COMPILE by architecture

[Willy Tarreau]

On Sun, Aug 06, 2023 at 02:46:03AM +0800, Zhangjin Wu wrote:
> Some cross compilers may not just be prefixed with ARCH, customize them
> by architecture may simplify the test a lot, especially, when iterate
> with ARCH.
> 
> After customizing this for every architecture, the minimal test argument
> will be architecture itself, no CROSS_COMPILE required to be passed.
> 
> If the prefix of installed cross compiler is not the same as the one
> customized, we can also pass CROSS_COMPILE as before or even pass
> CROSS_COMPILE_<ARCH>.
> 
> Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> ---
>  tools/testing/selftests/nolibc/Makefile | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> index 452d8e424d28..45d231b9c5c2 100644
> --- a/tools/testing/selftests/nolibc/Makefile
> +++ b/tools/testing/selftests/nolibc/Makefile
> @@ -55,6 +55,12 @@ IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
>  IMAGE            = $(IMAGE_$(XARCH))
>  IMAGE_NAME       = $(notdir $(IMAGE))
>  
> +# CROSS_COMPILE: cross toolchain prefix by architecture
> +CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
> +
> +# make sure CC is prefixed with CROSS_COMPILE
> +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> +

Note that I feared that it would break my "CC=gcc-5.5.0" and so on but
fortunately it did not. However I don't understand what it tries to do
nor the problem it tries to solve (even the commit message is quite
unclear to me). I'm leaving it aside anyway but I wanted to let you
know.

Willy

Re: [PATCH v6 7/8] selftests/nolibc: allow customize CROSS_COMPILE by architecture

[Zhangjin Wu]

Hi, Willy

> On Sun, Aug 06, 2023 at 02:46:03AM +0800, Zhangjin Wu wrote:
> > Some cross compilers may not just be prefixed with ARCH, customize them
> > by architecture may simplify the test a lot, especially, when iterate
> > with ARCH.
> > 
> > After customizing this for every architecture, the minimal test argument
> > will be architecture itself, no CROSS_COMPILE required to be passed.
> > 
> > If the prefix of installed cross compiler is not the same as the one
> > customized, we can also pass CROSS_COMPILE as before or even pass
> > CROSS_COMPILE_<ARCH>.
> > 
> > Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
> > ---
> >  tools/testing/selftests/nolibc/Makefile | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
> > index 452d8e424d28..45d231b9c5c2 100644
> > --- a/tools/testing/selftests/nolibc/Makefile
> > +++ b/tools/testing/selftests/nolibc/Makefile
> > @@ -55,6 +55,12 @@ IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
> >  IMAGE            = $(IMAGE_$(XARCH))
> >  IMAGE_NAME       = $(notdir $(IMAGE))
> >  
> > +# CROSS_COMPILE: cross toolchain prefix by architecture
> > +CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
> > +
> > +# make sure CC is prefixed with CROSS_COMPILE
> > +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> > +
> 
> Note that I feared that it would break my "CC=gcc-5.5.0" and so on but
> fortunately it did not. However I don't understand what it tries to do
> nor the problem it tries to solve (even the commit message is quite
> unclear to me). I'm leaving it aside anyway but I wanted to let you
> know.
>

Thanks you for this note, will add it as a test case in our v2.

These places require the '$(CC)' prefixed with $(CROSS_COMPILE):

    $ grep ")\$(CC)" tools/testing/selftests/nolibc/Makefile
	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
	$(QUIET_CC)$(CC) -o $@ $<

When CROSS_COMPILE come from command line, the first lines we included have
the CROSS_COMPILE knowledge and will add right prefix for CC:

   # Makefile for nolibc tests
   include ../../../scripts/Makefile.include

But the customized $(CROSS_COMPILE) must be added from the XARCH lines, then,
differs from the ones passed from command line, the above lines (before XARCH)
will have no CROSS_COMPILE knowledge, the CC therefore will have no prefix.

   CROSS_COMPILE=xxx                                 <= before, from command line

   include ../../../scripts/Makefile.include         <= CC get the right CROSS_COMPILE prefix

   XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH)) <= XARCH here

   CROSS_COMPILE    ?= $(CROSS_COMPILE_$(XARCH))     <= after, customize ourselves
   (call allow-override,CC,$(CROSS_COMPILE)gcc)      <= CC have no right prefix here 

   $(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \

So, we must add the prefix to CC ourselves after the CROSS_COMPILE lines we
customized, the 'allow-override' helper is also from
../../../scripts/Makefile.include.

But you did find a bug above, we should include it again here to avoid not
break the possibility of using llvm (still require to check if there are some
other regressions):

   include ../../../scripts/Makefile.include

And I have further found there is another cc-cross-prefix helper from:

    $ grep cc-cross-prefix -ur scripts/
    scripts/Makefile.compiler:# cc-cross-prefix
    scripts/Makefile.compiler:# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
    scripts/Makefile.compiler:cc-cross-prefix = $(firstword $(foreach c, $(1), \

So, we are able to search the toolchains from Arnd's, local toolchains and ...,
may not need to force users to use which one, I will do more tests on it.

Please don't merge this patch too, to avoid break anything, let's tune it
carefully in our v2 and delay the whole stuff to v6.7.

Thanks,
Zhangjin

> Willy

Re: [PATCH v6 7/8] selftests/nolibc: allow customize CROSS_COMPILE by architecture

[Willy Tarreau]

On Sun, Aug 06, 2023 at 05:39:21PM +0800, Zhangjin Wu wrote:
> > > +# CROSS_COMPILE: cross toolchain prefix by architecture
> > > +CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
> > > +
> > > +# make sure CC is prefixed with CROSS_COMPILE
> > > +$(call allow-override,CC,$(CROSS_COMPILE)gcc)
> > > +
> > 
> > Note that I feared that it would break my "CC=gcc-5.5.0" and so on but
> > fortunately it did not. However I don't understand what it tries to do
> > nor the problem it tries to solve (even the commit message is quite
> > unclear to me). I'm leaving it aside anyway but I wanted to let you
> > know.
> >
> 
> Thanks you for this note, will add it as a test case in our v2.
> 
> These places require the '$(CC)' prefixed with $(CROSS_COMPILE):
> 
>     $ grep ")\$(CC)" tools/testing/selftests/nolibc/Makefile
> 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
> 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
> 	$(QUIET_CC)$(CC) -o $@ $<
> 
> When CROSS_COMPILE come from command line, the first lines we included have
> the CROSS_COMPILE knowledge and will add right prefix for CC:
> 
>    # Makefile for nolibc tests
>    include ../../../scripts/Makefile.include
> 
> But the customized $(CROSS_COMPILE) must be added from the XARCH lines, then,
> differs from the ones passed from command line, the above lines (before XARCH)
> will have no CROSS_COMPILE knowledge, the CC therefore will have no prefix.
> 
>    CROSS_COMPILE=xxx                                 <= before, from command line
> 
>    include ../../../scripts/Makefile.include         <= CC get the right CROSS_COMPILE prefix
> 
>    XARCH            = $(or $(XARCH_$(ARCH)),$(ARCH)) <= XARCH here
> 
>    CROSS_COMPILE    ?= $(CROSS_COMPILE_$(XARCH))     <= after, customize ourselves
>    (call allow-override,CC,$(CROSS_COMPILE)gcc)      <= CC have no right prefix here 
> 
>    $(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
> 
> So, we must add the prefix to CC ourselves after the CROSS_COMPILE lines we
> customized, the 'allow-override' helper is also from
> ../../../scripts/Makefile.include.

OK, I feared it would overwrite the command-line one.

> But you did find a bug above, we should include it again here to avoid not
> break the possibility of using llvm (still require to check if there are some
> other regressions):
> 
>    include ../../../scripts/Makefile.include
> 
> And I have further found there is another cc-cross-prefix helper from:
> 
>     $ grep cc-cross-prefix -ur scripts/
>     scripts/Makefile.compiler:# cc-cross-prefix
>     scripts/Makefile.compiler:# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
>     scripts/Makefile.compiler:cc-cross-prefix = $(firstword $(foreach c, $(1), \
> 
> So, we are able to search the toolchains from Arnd's, local toolchains and ...,
> may not need to force users to use which one, I will do more tests on it.
> 
> Please don't merge this patch too, to avoid break anything, let's tune it
> carefully in our v2 and delay the whole stuff to v6.7.

OK. Note that in the end it might be less difficult to try to set
CROSS_COMPILE *before* including the general include instead of
after: we could preset CROSS_COMPILE based on the ARCH/XARCH we know
at this step, as this is not expected to rely on auto-detection.

Willy

Re: [PATCH v6 7/8] selftests/nolibc: allow customize CROSS_COMPILE by architecture

[Zhangjin Wu]

It uses 'eval $(1) = $(2)' style, no real 'override' as the name shows
;-)

> > But you did find a bug above, we should include it again here to avoid not
> > break the possibility of using llvm (still require to check if there are some
> > other regressions):
> > 
> >    include ../../../scripts/Makefile.include
> > 
> > And I have further found there is another cc-cross-prefix helper from:
> > 
> >     $ grep cc-cross-prefix -ur scripts/
> >     scripts/Makefile.compiler:# cc-cross-prefix
> >     scripts/Makefile.compiler:# Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
> >     scripts/Makefile.compiler:cc-cross-prefix = $(firstword $(foreach c, $(1), \
> > 
> > So, we are able to search the toolchains from Arnd's, local toolchains and ...,
> > may not need to force users to use which one, I will do more tests on it.
> > 
> > Please don't merge this patch too, to avoid break anything, let's tune it
> > carefully in our v2 and delay the whole stuff to v6.7.
> 
> OK. Note that in the end it might be less difficult to try to set
> CROSS_COMPILE *before* including the general include instead of
> after: we could preset CROSS_COMPILE based on the ARCH/XARCH we know
> at this step, as this is not expected to rely on auto-detection.
>

A simple tests shows, we are able to simply move the include after our
customize lines:

    diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
    index 1f7c36fbe083..ed21dc393dc0 100644
    --- a/tools/testing/selftests/nolibc/Makefile
    +++ b/tools/testing/selftests/nolibc/Makefile
    @@ -1,6 +1,4 @@
     # SPDX-License-Identifier: GPL-2.0
    -# Makefile for nolibc tests
    -include ../../../scripts/Makefile.include
     # We need this for the "cc-option" macro.
     include ../../../build/Build.include

    diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
    index 228a95e65113..91a2a546954c 100644
    --- a/tools/testing/selftests/nolibc/Makefile
    +++ b/tools/testing/selftests/nolibc/Makefile
    @@ -55,6 +55,12 @@ IMAGE_loongarch  = arch/loongarch/boot/vmlinuz.efi
     IMAGE            = $(IMAGE_$(XARCH))
     IMAGE_NAME       = $(notdir $(IMAGE))

    +# CROSS_COMPILE: cross toolchain prefix by architecture
    +CROSS_COMPILE           ?= $(CROSS_COMPILE_$(XARCH))
    +
    +# make sure CC is prefixed with CROSS_COMPILE
    +include ../../../scripts/Makefile.include

Thanks,
Zhangjin

> Willy