Merge tag 'linux_kselftest-nolibc-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

torvalds · torvalds · commit 395b15778e8f · 2024-09-17T16:47:17.000+02:00
Pull nolibc updates from Shuah Khan:
 "Highlights:

   - Clang support (including LTO)

  Other Changes:

   - stdbool.h support

   - argc/argv/envp arguments for constructors

   - Small #include ordering fix"

* tag 'linux_kselftest-nolibc-6.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (21 commits)
  tools/nolibc: x86_64: use local label in memcpy/memmove
  tools/nolibc: stackprotector: mark implicitly used symbols as used
  tools/nolibc: crt: mark _start_c() as used
  selftests/nolibc: run-tests.sh: allow building through LLVM
  selftests/nolibc: use correct clang target for s390/systemz
  selftests/nolibc: don't use libgcc when building with clang
  selftests/nolibc: run-tests.sh: avoid overwriting CFLAGS_EXTRA
  selftests/nolibc: add cc-option compatible with clang cross builds
  selftests/nolibc: add support for LLVM= parameter
  selftests/nolibc: determine $(srctree) first
  selftests/nolibc: avoid passing NULL to printf("%s")
  selftests/nolibc: report failure if no testcase passed
  tools/nolibc: compiler: use attribute((naked)) if available
  tools/nolibc: move entrypoint specifics to compiler.h
  tools/nolibc: compiler: introduce __nolibc_has_attribute()
  tools/nolibc: powerpc: limit stack-protector workaround to GCC
  tools/nolibc: mips: load current function to $t9
  tools/nolibc: arm: use clang-compatible asm syntax
  tools/nolibc: pass argc, argv and envp to constructors
  tools/nolibc: add stdbool.h header
  ...
diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
@@ -35,6 +35,7 @@ all_files := \
 		stackprotector.h \
 		std.h \
 		stdarg.h \
+		stdbool.h \
 		stdint.h \
 		stdlib.h \
 		string.h \
diff --git a/tools/include/nolibc/arch-aarch64.h b/tools/include/nolibc/arch-aarch64.h
@@ -142,13 +142,13 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"mov x0, sp\n"          /* save stack pointer to x0, as arg1 of _start_c */
 		"and sp, x0, -16\n"     /* sp must be 16-byte aligned in the callee      */
 		"bl  _start_c\n"        /* transfer to c runtime                         */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 #endif /* _NOLIBC_ARCH_AARCH64_H */
diff --git a/tools/include/nolibc/arch-arm.h b/tools/include/nolibc/arch-arm.h
@@ -185,15 +185,15 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
-		"mov %r0, sp\n"         /* save stack pointer to %r0, as arg1 of _start_c */
-		"and ip, %r0, #-8\n"    /* sp must be 8-byte aligned in the callee        */
+		"mov r0, sp\n"          /* save stack pointer to %r0, as arg1 of _start_c */
+		"and ip, r0, #-8\n"     /* sp must be 8-byte aligned in the callee        */
 		"mov sp, ip\n"
 		"bl  _start_c\n"        /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_ARM_H */
diff --git a/tools/include/nolibc/arch-i386.h b/tools/include/nolibc/arch-i386.h
@@ -162,7 +162,7 @@
  * 2) The deepest stack frame should be set to zero
  *
  */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"xor  %ebp, %ebp\n"       /* zero the stack frame                                */
@@ -174,7 +174,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"call _start_c\n"         /* transfer to c runtime                               */
 		"hlt\n"                   /* ensure it does not return                           */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_I386_H */
diff --git a/tools/include/nolibc/arch-loongarch.h b/tools/include/nolibc/arch-loongarch.h
@@ -149,14 +149,14 @@
 #endif
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"move          $a0, $sp\n"         /* save stack pointer to $a0, as arg1 of _start_c */
 		LONG_BSTRINS " $sp, $zero, 3, 0\n" /* $sp must be 16-byte aligned                    */
 		"bl            _start_c\n"         /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_LOONGARCH_H */
diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
@@ -179,7 +179,7 @@
 })
 
 /* startup code, note that it's called __start on MIPS */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector __start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector __start(void)
 {
 	__asm__ volatile (
 		".set push\n"
@@ -194,11 +194,13 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"li    $t0, -8\n"
 		"and   $sp, $sp, $t0\n"  /* $sp must be 8-byte aligned                     */
 		"addiu $sp, $sp, -16\n"  /* the callee expects to save a0..a3 there        */
-		"jal   _start_c\n"       /* transfer to c runtime                          */
+		"lui $t9, %hi(_start_c)\n" /* ABI requires current function address in $t9 */
+		"ori $t9, %lo(_start_c)\n"
+		"jalr $t9\n"             /* transfer to c runtime                          */
 		" nop\n"                 /* delayed slot                                   */
 		".set pop\n"
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_MIPS_H */
diff --git a/tools/include/nolibc/arch-powerpc.h b/tools/include/nolibc/arch-powerpc.h
@@ -172,7 +172,7 @@
 	_ret;                                                                \
 })
 
-#ifndef __powerpc64__
+#if !defined(__powerpc64__) && !defined(__clang__)
 /* 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")))
@@ -184,7 +184,7 @@
 #endif /* !__powerpc64__ */
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 #ifdef __powerpc64__
 #if _CALL_ELF == 2
@@ -215,7 +215,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"bl     _start_c\n"     /* transfer to c runtime                         */
 	);
 #endif
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_POWERPC_H */
diff --git a/tools/include/nolibc/arch-riscv.h b/tools/include/nolibc/arch-riscv.h
@@ -140,7 +140,7 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		".option push\n"
@@ -151,7 +151,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"andi sp, a0, -16\n"      /* sp must be 16-byte aligned                    */
 		"call _start_c\n"         /* transfer to c runtime                         */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #endif /* _NOLIBC_ARCH_RISCV_H */
diff --git a/tools/include/nolibc/arch-s390.h b/tools/include/nolibc/arch-s390.h
@@ -139,15 +139,15 @@
 })
 
 /* startup code */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"lgr	%r2, %r15\n"          /* save stack pointer to %r2, as arg1 of _start_c */
 		"aghi	%r15, -160\n"         /* allocate new stackframe                        */
 		"xc	0(8,%r15), 0(%r15)\n" /* clear backchain                                */
 		"brasl	%r14, _start_c\n"     /* transfer to c runtime                          */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 struct s390_mmap_arg_struct {
diff --git a/tools/include/nolibc/arch-x86_64.h b/tools/include/nolibc/arch-x86_64.h
@@ -161,7 +161,7 @@
  * 2) The deepest stack frame should be zero (the %rbp).
  *
  */
-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)
+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)
 {
 	__asm__ volatile (
 		"xor  %ebp, %ebp\n"       /* zero the stack frame                            */
@@ -170,7 +170,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_
 		"call _start_c\n"         /* transfer to c runtime                           */
 		"hlt\n"                   /* ensure it does not return                       */
 	);
-	__builtin_unreachable();
+	__nolibc_entrypoint_epilogue();
 }
 
 #define NOLIBC_ARCH_HAS_MEMMOVE
@@ -193,10 +193,10 @@ __asm__ (
 	"movq %rdi, %rdx\n\t"
 	"subq %rsi, %rdx\n\t"
 	"cmpq %rcx, %rdx\n\t"
-	"jb   .Lbackward_copy\n\t"
+	"jb   1f\n\t"
 	"rep movsb\n\t"
 	"retq\n"
-".Lbackward_copy:"
+"1:" /* backward copy */
 	"leaq -1(%rdi, %rcx, 1), %rdi\n\t"
 	"leaq -1(%rsi, %rcx, 1), %rsi\n\t"
 	"std\n\t"
diff --git a/tools/include/nolibc/compiler.h b/tools/include/nolibc/compiler.h
@@ -6,20 +6,30 @@
 #ifndef _NOLIBC_COMPILER_H
 #define _NOLIBC_COMPILER_H
 
+#if defined(__has_attribute)
+#  define __nolibc_has_attribute(attr) __has_attribute(attr)
+#else
+#  define __nolibc_has_attribute(attr) 0
+#endif
+
+#if __nolibc_has_attribute(naked)
+#  define __nolibc_entrypoint __attribute__((naked))
+#  define __nolibc_entrypoint_epilogue()
+#else
+#  define __nolibc_entrypoint __attribute__((optimize("Os", "omit-frame-pointer")))
+#  define __nolibc_entrypoint_epilogue() __builtin_unreachable()
+#endif /* __nolibc_has_attribute(naked) */
+
 #if defined(__SSP__) || defined(__SSP_STRONG__) || defined(__SSP_ALL__) || defined(__SSP_EXPLICIT__)
 
 #define _NOLIBC_STACKPROTECTOR
 
 #endif /* defined(__SSP__) ... */
 
-#if defined(__has_attribute)
-#  if __has_attribute(no_stack_protector)
-#    define __no_stack_protector __attribute__((no_stack_protector))
-#  else
-#    define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
-#  endif
+#if __nolibc_has_attribute(no_stack_protector)
+#  define __no_stack_protector __attribute__((no_stack_protector))
 #else
 #  define __no_stack_protector __attribute__((__optimize__("-fno-stack-protector")))
-#endif /* defined(__has_attribute) */
+#endif /* __nolibc_has_attribute(no_stack_protector) */
 
 #endif /* _NOLIBC_COMPILER_H */
diff --git a/tools/include/nolibc/crt.h b/tools/include/nolibc/crt.h
@@ -13,23 +13,24 @@ const unsigned long *_auxv __attribute__((weak));
 static void __stack_chk_init(void);
 static void exit(int);
 
-extern void (*const __preinit_array_start[])(void) __attribute__((weak));
-extern void (*const __preinit_array_end[])(void) __attribute__((weak));
+extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak));
+extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak));
 
-extern void (*const __init_array_start[])(void) __attribute__((weak));
-extern void (*const __init_array_end[])(void) __attribute__((weak));
+extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak));
+extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak));
 
 extern void (*const __fini_array_start[])(void) __attribute__((weak));
 extern void (*const __fini_array_end[])(void) __attribute__((weak));
 
-__attribute__((weak))
+__attribute__((weak,used))
 void _start_c(long *sp)
 {
 	long argc;
 	char **argv;
 	char **envp;
 	int exitcode;
-	void (* const *func)(void);
+	void (* const *ctor_func)(int, char **, char **);
+	void (* const *dtor_func)(void);
 	const unsigned long *auxv;
 	/* silence potential warning: conflicting types for 'main' */
 	int _nolibc_main(int, char **, char **) __asm__ ("main");
@@ -66,16 +67,16 @@ void _start_c(long *sp)
 		;
 	_auxv = auxv;
 
-	for (func = __preinit_array_start; func < __preinit_array_end; func++)
-		(*func)();
-	for (func = __init_array_start; func < __init_array_end; func++)
-		(*func)();
+	for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++)
+		(*ctor_func)(argc, argv, envp);
+	for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++)
+		(*ctor_func)(argc, argv, envp);
 
 	/* go to application */
 	exitcode = _nolibc_main(argc, argv, envp);
 
-	for (func = __fini_array_end; func > __fini_array_start;)
-		(*--func)();
+	for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;)
+		(*--dtor_func)();
 
 	exit(exitcode);
 }
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
@@ -74,7 +74,8 @@
  *            -I../nolibc -o hello hello.c -lgcc
  *
  * The available standard (but limited) include files are:
- *   ctype.h, errno.h, signal.h, stdarg.h, stdio.h, stdlib.h, string.h, time.h
+ *   ctype.h, errno.h, signal.h, stdarg.h, stdbool.h stdio.h, stdlib.h,
+ *   string.h, time.h
  *
  * In addition, the following ones are expected to be provided by the compiler:
  *   float.h, stddef.h
diff --git a/tools/include/nolibc/stackprotector.h b/tools/include/nolibc/stackprotector.h
@@ -18,7 +18,7 @@
  * triggering stack protector errors themselves
  */
 
-__attribute__((weak,noreturn,section(".text.nolibc_stack_chk")))
+__attribute__((weak,used,noreturn,section(".text.nolibc_stack_chk")))
 void __stack_chk_fail(void)
 {
 	pid_t pid;
@@ -34,7 +34,7 @@ void __stack_chk_fail_local(void)
 	__stack_chk_fail();
 }
 
-__attribute__((weak,section(".data.nolibc_stack_chk")))
+__attribute__((weak,used,section(".data.nolibc_stack_chk")))
 uintptr_t __stack_chk_guard;
 
 static __no_stack_protector void __stack_chk_init(void)
diff --git a/tools/include/nolibc/stdbool.h b/tools/include/nolibc/stdbool.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Boolean types support for NOLIBC
+ * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_STDBOOL_H
+#define _NOLIBC_STDBOOL_H
+
+#define bool _Bool
+#define true 1
+#define false 0
+
+#define __bool_true_false_are_defined 1
+
+#endif /* _NOLIBC_STDBOOL_H */
diff --git a/tools/include/nolibc/string.h b/tools/include/nolibc/string.h
@@ -7,6 +7,7 @@
 #ifndef _NOLIBC_STRING_H
 #define _NOLIBC_STRING_H
 
+#include "arch.h"
 #include "std.h"
 
 static void *malloc(size_t len);
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
diff --git a/tools/testing/selftests/nolibc/run-tests.sh b/tools/testing/selftests/nolibc/run-tests.sh

Original file line number	Diff line number	Diff line change
`@@ -162,7 +162,7 @@`
`162`	`162`	`* 2) The deepest stack frame should be set to zero`
`163`	`163`	`*`
`164`	`164`	`*/`
`165`		`-void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_stack_protector _start(void)`
	`165`	`+void __attribute__((weak, noreturn)) __nolibc_entrypoint __no_stack_protector _start(void)`
`166`	`166`	`{`
`167`	`167`	`__asm__ volatile (`
`168`	`168`	`"xor %ebp, %ebp\n" /* zero the stack frame */`
`@@ -174,7 +174,7 @@ void __attribute__((weak, noreturn, optimize("Os", "omit-frame-pointer"))) __no_`
`174`	`174`	`"call _start_c\n" /* transfer to c runtime */`
`175`	`175`	`"hlt\n" /* ensure it does not return */`
`176`	`176`	`);`
`177`		`- __builtin_unreachable();`
	`177`	`+ __nolibc_entrypoint_epilogue();`
`178`	`178`	`}`
`179`	`179`
`180`	`180`	`#endif /* _NOLIBC_ARCH_I386_H */`