--- /dev/null
+/* The clone3 syscall wrapper. Linux/powerpc64 version.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#define _ERRNO_H 1
+#include <bits/errno.h>
+
+/* The userland implementation is:
+ int clone3 (struct clone_args *cl_args, size_t size,
+ int (*func)(void *arg), void *arg);
+
+ the kernel entry is:
+ int clone3 (struct clone_args *cl_args, size_t size);
+
+ The parameters are passed in registers from userland:
+ r3: cl_args
+ r4: size
+ r5: func
+ r6: arg */
+
+#ifdef USE_PPC_SCV
+/* This is equivalent to DO_CALL_SCV, but we cannot use the macro here
+ because it uses CFI directives and we just called cfi_endproc. */
+# define DO_CLONE3_SVC_CALL(jumpfalse) \
+ CHECK_SCV_SUPPORT r28 jumpfalse; \
+ mflr r9; \
+ std r9, FRAME_LR_SAVE(r1); \
+ .machine "push"; \
+ .machine "power9"; \
+ scv 0; \
+ .machine "pop"; \
+ ld r9, FRAME_LR_SAVE(r1); \
+ mtlr r9; \
+ /* With scv an, an error is a value -4095 <= x < 0. */ \
+ cmpdi cr1, r3, 0; \
+ b 1f;
+#else
+# define DO_CLONE3_SVC_CALL(fail_branch)
+#endif
+
+ .text
+ENTRY(__clone3)
+ CALL_MCOUNT 4
+
+ /* Sanity checks args. */
+ cmpdi cr0, r3, 0
+ cmpdi cr1, r5, 0
+ cror cr0*4+eq, cr1*4+eq, cr0*4+eq
+ beq cr0,L(badargs)
+
+ /* Save some regs in the "red zone". */
+#ifdef USE_PPC_SCV
+ std r28, -24(r1)
+ cfi_offset (r28, -24)
+#endif
+ std r29, -16(r1)
+ std r30, -8(r1)
+ cfi_offset (r29, -16)
+ cfi_offset (r30, -8)
+
+ /* Save func and arg across syscall. */
+ mr r30, r5 /* Function in r30. */
+ mr r29, r6 /* Argument in r29. */
+
+ /* End FDE now, because in the child the unwind info will be
+ wrong. */
+ cfi_endproc
+
+ /* Setup a minimum stack frame for child. It needs to first calculate
+ the effective stack address, write the start empty backchain pointer,
+ and update the frame size in the input cl_args. */
+ ld r7, 40(r3) /* Load stack value. */
+ ld r8, 48(r3) /* Load stack_size value. */
+ li r10, 0
+ add r7, r7, r8 /* Calculate effective stack address. */
+ std r10, -FRAME_MIN_SIZE_PARM(r7)
+ addi r8, r8, -FRAME_MIN_SIZE_PARM
+ std r8, 48(r3)
+
+ /* Do the system call, the kernel expects:
+ r0: system call numer
+ r3: cl_args
+ r4: size */
+ li r0, SYS_ify(clone3)
+ DO_CLONE3_SVC_CALL (0f)
+0: DO_CALL_SC
+
+ /* With sc, error is indicated by cr0.SO. */
+ cmpdi cr1, r3, 0
+ crandc cr1*4+eq, cr1*4+eq, cr0*4+so
+
+1: bne- cr1,L(parent)
+
+ /* Child, load the function and arguments. */
+ std r2, FRAME_TOC_SAVE(r1)
+ PPC64_LOAD_FUNCPTR r30
+ mr r3, r29
+ bctrl
+ ld r2, FRAME_TOC_SAVE(r1)
+
+ li r0, SYS_ify(exit)
+ DO_CLONE3_SVC_CALL (2f)
+2: DO_CALL_SC
+ /* We won't ever get here but provide a nop so that the linker
+ will insert a toc adjusting stub if necessary. */
+ nop
+
+L(badargs):
+ cfi_startproc
+ li r3, EINVAL
+ TAIL_CALL_SYSCALL_ERROR
+
+L(parent):
+ /* Check if scv is available. */
+ cmpdi cr1, r28, 0
+
+ /* Parent. Restore registers & return. */
+#ifdef USE_PPC_SCV
+ cfi_offset (r28, -24)
+ ld r28, -24(r1)
+ cfi_restore (r28)
+#endif
+ cfi_offset (r29,-16)
+ cfi_offset (r30,-8)
+ ld r29, -16(r1)
+ ld r30, -8(r1)
+ cfi_restore (r29)
+ cfi_restore (r30)
+
+#ifdef USE_PPC_SCV
+ beq cr1, 0f
+ RET_SCV
+ b 1f
+#endif
+0: RET_SC
+1: TAIL_CALL_SYSCALL_ERROR
+
+PSEUDO_END (__clone3)
+
+libc_hidden_def (__clone3)
+weak_alias (__clone3, clone3)
projects / thirdparty / glibc.git / commitdiff
