Add support for SuperH/"sh" to nolibc. Only sh4 is tested for now.
The startup code is special:
__nolibc_entrypoint_epilogue() calls __builtin_unreachable() which emits a call to abort(). To make this work a function prologue is generated to set up a GOT pointer which corrupts "sp". __builtin_unreachable() is necessary for __attribute__((noreturn)). Also depending on compiler flags (for example -fPIC) even more prologue is generated.
Work around this by defining a nested function in asm.
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70216 Signed-off-by: Thomas Weißschuh linux@weissschuh.net --- tools/include/nolibc/arch-sh.h | 162 ++++++++++++++++++++++++++++ tools/include/nolibc/arch.h | 2 + tools/testing/selftests/nolibc/Makefile | 7 ++ tools/testing/selftests/nolibc/run-tests.sh | 3 +- 4 files changed, 173 insertions(+), 1 deletion(-)
diff --git a/tools/include/nolibc/arch-sh.h b/tools/include/nolibc/arch-sh.h new file mode 100644 index 0000000000000000000000000000000000000000..1ad006cba0f627f663eea36b41bc7399cca4addb --- /dev/null +++ b/tools/include/nolibc/arch-sh.h @@ -0,0 +1,162 @@ +/* SPDX-License-Identifier: LGPL-2.1 OR MIT */ +/* + * SuperH specific definitions for NOLIBC + * Copyright (C) 2025 Thomas Weißschuh linux@weissschuh.net + */ + +#ifndef _NOLIBC_ARCH_SH_H +#define _NOLIBC_ARCH_SH_H + +#include "compiler.h" +#include "crt.h" + +/* + * Syscalls for SuperH: + * - registers are 32bit wide + * - syscall number is passed in r3 + * - arguments are in r4, r5, r6, r7, r0, r1, r2 + * - the system call is performed by calling trapa #31 + * - syscall return value is in r0 + */ + +#define my_syscall0(num) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "+r"(_ret) \ + : "r"(_num) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall1(num, arg1) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall2(num, arg1, arg2) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + register long _arg2 __asm__ ("r5") = (long)(arg2); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1), "r"(_arg2) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall3(num, arg1, arg2, arg3) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + register long _arg2 __asm__ ("r5") = (long)(arg2); \ + register long _arg3 __asm__ ("r6") = (long)(arg3); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall4(num, arg1, arg2, arg3, arg4) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + register long _arg2 __asm__ ("r5") = (long)(arg2); \ + register long _arg3 __asm__ ("r6") = (long)(arg3); \ + register long _arg4 __asm__ ("r7") = (long)(arg4); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall5(num, arg1, arg2, arg3, arg4, arg5) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + register long _arg2 __asm__ ("r5") = (long)(arg2); \ + register long _arg3 __asm__ ("r6") = (long)(arg3); \ + register long _arg4 __asm__ ("r7") = (long)(arg4); \ + register long _arg5 __asm__ ("r0") = (long)(arg5); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ + "r"(_arg5) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +#define my_syscall6(num, arg1, arg2, arg3, arg4, arg5, arg6) \ +({ \ + register long _num __asm__ ("r3") = (num); \ + register long _ret __asm__ ("r0"); \ + register long _arg1 __asm__ ("r4") = (long)(arg1); \ + register long _arg2 __asm__ ("r5") = (long)(arg2); \ + register long _arg3 __asm__ ("r6") = (long)(arg3); \ + register long _arg4 __asm__ ("r7") = (long)(arg4); \ + register long _arg5 __asm__ ("r0") = (long)(arg5); \ + register long _arg6 __asm__ ("r1") = (long)(arg6); \ + \ + __asm__ volatile ( \ + "trapa #31" \ + : "=r"(_ret) \ + : "r"(_num), "r"(_arg1), "r"(_arg2), "r"(_arg3), "r"(_arg4), \ + "r"(_arg5), "r"(_arg6) \ + : "memory", "cc" \ + ); \ + _ret; \ +}) + +/* startup code */ +void _start_wrapper(void); +void __attribute__((weak,noreturn)) __nolibc_entrypoint __no_stack_protector _start_wrapper(void) +{ + __asm__ volatile ( + ".global _start\n" /* The C function will have a prologue, */ + ".type _start, @function\n" /* corrupting "sp" */ + ".weak _start\n" + "_start:\n" + + "mov sp, r4\n" /* save argc pointer to r4, as arg1 of _start_c */ + "bsr _start_c\n" /* transfer to c runtime */ + "nop\n" /* delay slot */ + + ".size _start, .-_start\n" + ); + __nolibc_entrypoint_epilogue(); +} + +#endif /* _NOLIBC_ARCH_SH_H */ diff --git a/tools/include/nolibc/arch.h b/tools/include/nolibc/arch.h index d20b2304aac21bf817f02a085653d5a170546072..4cd10ebf2addca9a2a1f5ab5bb691ac7dfd4aa29 100644 --- a/tools/include/nolibc/arch.h +++ b/tools/include/nolibc/arch.h @@ -37,6 +37,8 @@ #include "arch-sparc.h" #elif defined(__m68k__) #include "arch-m68k.h" +#elif defined(__sh__) +#include "arch-sh.h" #else #error Unsupported Architecture #endif diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile index 238acaa7bb06dcdbcadd9d3190c2de726e1a40b1..65a2442c6709241e410dd08af9ab6b0b0691e7a7 100644 --- a/tools/testing/selftests/nolibc/Makefile +++ b/tools/testing/selftests/nolibc/Makefile @@ -58,6 +58,7 @@ ARCH_riscv64 = riscv ARCH_s390x = s390 ARCH_sparc32 = sparc ARCH_sparc64 = sparc +ARCH_sh4 = sh ARCH := $(or $(ARCH_$(XARCH)),$(XARCH))
# kernel image names by architecture @@ -81,6 +82,7 @@ IMAGE_loongarch = arch/loongarch/boot/vmlinuz.efi IMAGE_sparc32 = arch/sparc/boot/image IMAGE_sparc64 = arch/sparc/boot/image IMAGE_m68k = vmlinux +IMAGE_sh4 = arch/sh/boot/zImage IMAGE = $(objtree)/$(IMAGE_$(XARCH)) IMAGE_NAME = $(notdir $(IMAGE))
@@ -105,11 +107,13 @@ DEFCONFIG_loongarch = defconfig DEFCONFIG_sparc32 = sparc32_defconfig DEFCONFIG_sparc64 = sparc64_defconfig DEFCONFIG_m68k = virt_defconfig +DEFCONFIG_sh4 = rts7751r2dplus_defconfig DEFCONFIG = $(DEFCONFIG_$(XARCH))
EXTRACONFIG_arm = -e CONFIG_NAMESPACES EXTRACONFIG_armthumb = -e CONFIG_NAMESPACES EXTRACONFIG_m68k = -e CONFIG_BLK_DEV_INITRD +EXTRACONFIG_sh4 = -e CONFIG_BLK_DEV_INITRD -e CONFIG_CMDLINE_FROM_BOOTLOADER EXTRACONFIG = $(EXTRACONFIG_$(XARCH))
# optional tests to run (default = all) @@ -136,6 +140,7 @@ QEMU_ARCH_loongarch = loongarch64 QEMU_ARCH_sparc32 = sparc QEMU_ARCH_sparc64 = sparc64 QEMU_ARCH_m68k = m68k +QEMU_ARCH_sh4 = sh4 QEMU_ARCH = $(QEMU_ARCH_$(XARCH))
QEMU_ARCH_USER_ppc64le = ppc64le @@ -169,6 +174,7 @@ QEMU_ARGS_loongarch = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=N QEMU_ARGS_sparc32 = -M SS-5 -m 256M -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)" QEMU_ARGS_sparc64 = -M sun4u -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)" QEMU_ARGS_m68k = -M virt -append "console=ttyGF0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)" +QEMU_ARGS_sh4 = -M r2d -serial file:/dev/stdout -append "console=ttySC1,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)" QEMU_ARGS = -m 1G $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_BIOS) $(QEMU_ARGS_EXTRA)
# OUTPUT is only set when run from the main makefile, otherwise @@ -192,6 +198,7 @@ CFLAGS_s390 = -m31 CFLAGS_mips32le = -EL -mabi=32 -fPIC CFLAGS_mips32be = -EB -mabi=32 CFLAGS_sparc32 = $(call cc-option,-m32) +CFLAGS_sh4 = -ml -m4 ifeq ($(origin XARCH),command line) CFLAGS_XARCH = $(CFLAGS_$(XARCH)) endif diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh index 8277599e6441a933d9c1ec5003acf49b06df226f..8f6addb01d22d9532e2ef367692168787c23dc1f 100755 --- a/tools/testing/selftests/nolibc/run-tests.sh +++ b/tools/testing/selftests/nolibc/run-tests.sh @@ -27,6 +27,7 @@ all_archs=( loongarch sparc32 sparc64 m68k + sh4 ) archs="${all_archs[@]}"
@@ -187,7 +188,7 @@ test_arch() { echo "Unsupported configuration" return fi - if [ "$arch" = "m68k" ] && [ "$llvm" = "1" ]; then + if [ "$arch" = "m68k" -o "$arch" = "sh4" ] && [ "$llvm" = "1" ]; then echo "Unsupported configuration" return fi