Add getauxval and cleanup libc startup

5 files changed, 9 insertions, 145 deletions

diff --git a/lib/libc/arch/x86_64/Kbuild b/lib/libc/arch/x86_64/Kbuild
index fc8a2d3f..830a1c5b 100644
--- a/lib/libc/arch/x86_64/Kbuild
+++ b/lib/libc/arch/x86_64/Kbuild
@@ -1,7 +1,5 @@
-obj-y += clock_gettime.o
-obj-y += crt0.o
+obj-y += _start.o
 obj-y += fenv.o
 obj-y += longjmp.o
 obj-y += setjmp.o
 obj-y += sigsetjmp.o
-obj-y += vdso_setup.o
diff --git a/lib/libc/arch/x86_64/_start.c b/lib/libc/arch/x86_64/_start.c
new file mode 100644
index 00000000..52b5c774
--- /dev/null
+++ b/lib/libc/arch/x86_64/_start.c
@@ -0,0 +1,8 @@
+#include <libc.h>
+#include <sys/cdefs.h>
+
+__dead __naked void _start(void)
+{
+	__asm__ __volatile__("mov %rsp, %rdi\n"
+			     "call __libc_main\n");
+}
diff --git a/lib/libc/arch/x86_64/clock_gettime.c b/lib/libc/arch/x86_64/clock_gettime.c
deleted file mode 100644
index c05926fa..00000000
--- a/lib/libc/arch/x86_64/clock_gettime.c
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "asm/unistd_64.h" // for __NR_clock_gettime
-
-#include <asm/vdso.h> // for __vdso_clock_gettime
-#include <syscall.h>  // for __syscall_2, syscall
-#include <time.h>     // for clock_gettime, clockid_t
-
-int clock_gettime(clockid_t clock_id, struct timespec *tp)
-{
-#if defined(__x86_64__)
-	if (__vdso_clock_gettime)
-		return __vdso_clock_gettime(clock_id, tp);
-#endif
-
-	return syscall(clock_gettime, clock_id, tp);
-}
diff --git a/lib/libc/arch/x86_64/crt0.c b/lib/libc/arch/x86_64/crt0.c
deleted file mode 100644
index c60239d3..00000000
--- a/lib/libc/arch/x86_64/crt0.c
+++ /dev/null
@@ -1,63 +0,0 @@
-#include "asm/auxvec.h" // for AT_SYSINFO_EHDR
-#include <io_uring.h>
-#include <linux/auxvec.h> // for AT_NULL
-#include <linux/elf.h>	  // for Elf64_Ehdr
-#include <stdint.h>	  // for uintptr_t
-#include <stdlib.h>	  // for exit
-
-#define weak_reference(old, new) \
-	extern __typeof(old) new __attribute__((__weak__, __alias__(#old)))
-
-extern int main(int, char *[]);
-char **environ;
-char *__progname;
-
-struct __attribute__((packed)) auxv_t {
-	uintptr_t a_type;
-	uintptr_t a_val;
-} *__auxv;
-
-static void __vdso_setup(Elf64_Ehdr *vdso_addr __attribute__((unused)))
-{
-}
-
-weak_reference(__vdso_setup, vdso_setup);
-
-static void __io_uring_setup_(void)
-{
-}
-weak_reference(__io_uring_setup_, __io_uring_setup);
-
-__attribute__((used)) void __libc_start(uintptr_t *sp)
-{
-	char **argv;
-	int argc;
-
-	argc = (int)(*sp);
-	argv = (char **)(++sp);
-	__progname = argv[0];
-	sp += argc;
-	environ = (char **)(++sp);
-
-	while (*sp)
-		sp++;
-
-	__auxv = (struct auxv_t *)(++sp);
-	while (__auxv->a_type != AT_NULL) {
-		if (__auxv->a_type == AT_SYSINFO_EHDR) {
-			vdso_setup((Elf64_Ehdr *)__auxv->a_val);
-		}
-
-		__auxv++;
-	}
-
-	__io_uring_setup_();
-
-	exit(main(argc, argv));
-}
-
-__attribute__((noreturn, naked)) void _start(void)
-{
-	__asm__ __volatile__("mov %rsp, %rdi\n"
-			     "call __libc_start\n");
-}
diff --git a/lib/libc/arch/x86_64/vdso_setup.c b/lib/libc/arch/x86_64/vdso_setup.c
deleted file mode 100644
index 059aa44a..00000000
--- a/lib/libc/arch/x86_64/vdso_setup.c
+++ /dev/null
@@ -1,64 +0,0 @@
-#include <linux/elf.h> // for Elf64_Sym, (anonymous struct)::(anonymous)
-#include "stddef.h"    // for NULL
-
-#include <string.h> // for strcmp
-
-struct timespec;
-
-int (*__vdso_clock_gettime)(int, struct timespec *) = NULL;
-int (*__vdso_getcpu)(unsigned *, unsigned *, void *) = NULL;
-int (*__vdso_time)(long *) = NULL;
-
-static __inline __attribute__((used)) void vdso_setup(Elf64_Ehdr *vdso_addr)
-{
-	Elf64_Phdr *phdr =
-		(Elf64_Phdr *)((char *)vdso_addr + vdso_addr->e_phoff);
-
-	for (int i = 0; i < vdso_addr->e_phnum; i++) {
-		if (phdr[i].p_type == PT_DYNAMIC) {
-			Elf64_Dyn *dyn = (Elf64_Dyn *)((char *)vdso_addr +
-						       phdr[i].p_offset);
-			const char *strtab = NULL;
-			Elf64_Sym *symtab = NULL;
-			for (; dyn->d_tag != DT_NULL; dyn++) {
-				if (dyn->d_tag == DT_STRTAB) {
-					strtab = (const char *)vdso_addr +
-						 dyn->d_un.d_ptr;
-				} else if (dyn->d_tag == DT_SYMTAB) {
-					symtab =
-						(Elf64_Sym *)((char *)vdso_addr +
-							      dyn->d_un.d_ptr);
-				}
-			}
-
-			if (strtab == NULL || symtab == NULL) {
-				return;
-			}
-
-			Elf64_Sym *sym = symtab;
-			while ((char *)sym < (char *)strtab) {
-				if (sym->st_name != 0 && sym->st_value != 0) {
-					const char *name =
-						strtab + sym->st_name;
-					if (strcmp(name,
-						   "__vdso_clock_gettime") == 0)
-						__vdso_clock_gettime =
-							(void *)(vdso_addr +
-								 sym->st_value);
-					else if (strcmp(name,
-							"__vdso_getcpu") == 0)
-						__vdso_getcpu =
-							(void *)(vdso_addr +
-								 sym->st_value);
-					else if (strcmp(name, "__vdso_time") ==
-						 0)
-						__vdso_time =
-							(void *)(vdso_addr +
-								 sym->st_value);
-				}
-				sym = (Elf64_Sym *)((char *)sym +
-						    sizeof(Elf64_Sym));
-			}
-		}
-	}
-}