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sparc: Add architecture support for clone3

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Add support for the clone3 system call to the SPARC architectures.

The implementation follows the pattern of the original clone syscall.
However, instead of explicitly calling kernel_clone, the clone3
handler calls the generic sys_clone3 handler in kernel/fork.
In case no stack is provided, the parents stack is reused.

The return value convention for clone3 follows the regular kernel return
value convention (in contrast to the original clone/fork on SPARC).

Closes: https://github.com/sparclinux/issues/issues/10
Signed-off-by: Ludwig Rydberg <ludwig.rydberg@gaisler.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Link: https://lore.kernel.org/r/20260119144753.27945-3-ludwig.rydberg@gaisler.com
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
This commit is contained in:
Ludwig Rydberg 2026-01-19 15:47:53 +01:00 • committed by Andreas Larsson
parent e38eba3b77
commit 2153b2e891
9 changed files with 78 additions and 15 deletions
Download patch file Download diff file Expand all files Collapse all files

1
arch/sparc/include/asm/syscalls.h
View file

@ -7,5 +7,6 @@ struct pt_regs;
asmlinkage long sparc_fork(struct pt_regs *regs);
asmlinkage long sparc_vfork(struct pt_regs *regs);
asmlinkage long sparc_clone(struct pt_regs *regs);
asmlinkage long sparc_clone3(struct pt_regs *regs);
#endif /* _SPARC64_SYSCALLS_H */

2
arch/sparc/include/asm/unistd.h
View file

@ -49,8 +49,6 @@
#define __ARCH_WANT_COMPAT_STAT
#endif
#define __ARCH_BROKEN_SYS_CLONE3
#ifdef __32bit_syscall_numbers__
/* Sparc 32-bit only has the "setresuid32", "getresuid32" variants,
* it never had the plain ones and there is no value to adding those

15
arch/sparc/kernel/entry.S
View file

@ -907,6 +907,21 @@ flush_patch_four:
jmpl %l1 + %lo(sparc_vfork), %g0
add %sp, STACKFRAME_SZ, %o0
.globl __sys_clone3, flush_patch_five
__sys_clone3:
mov %o7, %l5
flush_patch_five:
FLUSH_ALL_KERNEL_WINDOWS;
ld [%curptr + TI_TASK], %o4
rd %psr, %g4
WRITE_PAUSE
rd %wim, %g5
WRITE_PAUSE
std %g4, [%o4 + AOFF_task_thread + AOFF_thread_fork_kpsr]
add %sp, STACKFRAME_SZ, %o0
call sparc_clone3
mov %l5, %o7
.align 4
linux_sparc_ni_syscall:
sethi %hi(sys_ni_syscall), %l7

1
arch/sparc/kernel/kernel.h
View file

@ -18,6 +18,7 @@ extern int ncpus_probed;
asmlinkage long sparc_clone(struct pt_regs *regs);
asmlinkage long sparc_fork(struct pt_regs *regs);
asmlinkage long sparc_vfork(struct pt_regs *regs);
asmlinkage long sparc_clone3(struct pt_regs *regs);
#ifdef CONFIG_SPARC64
/* setup_64.c */

14
arch/sparc/kernel/process.c
View file

@ -12,6 +12,7 @@
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include "kernel.h"
@ -118,3 +119,16 @@ asmlinkage long sparc_clone(struct pt_regs *regs)
return ret;
}
asmlinkage long sparc_clone3(struct pt_regs *regs)
{
unsigned long sz;
struct clone_args __user *cl_args;
synchronize_user_stack();
cl_args = (struct clone_args __user *)regs->u_regs[UREG_I0];
sz = regs->u_regs[UREG_I1];
return sys_clone3(cl_args, sz);
}

23
arch/sparc/kernel/process_32.c
View file

@ -247,6 +247,8 @@ clone_stackframe(struct sparc_stackf __user *dst,
* Parent --> %o0 == childs pid, %o1 == 0
* Child --> %o0 == parents pid, %o1 == 1
*
* clone3() - Uses regular kernel return value conventions
*
* NOTE: We have a separate fork kpsr/kwim because
* the parent could change these values between
* sys_fork invocation and when we reach here
@ -261,11 +263,11 @@ extern void ret_from_kernel_thread(void);
int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
u64 clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long tls = args->tls;
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs, *regs = current_pt_regs();
char *new_stack;
unsigned long sp = args->stack ? args->stack : regs->u_regs[UREG_FP];
#ifndef CONFIG_SMP
if(last_task_used_math == current) {
@ -350,13 +352,22 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
childregs->psr &= ~PSR_EF;
clear_tsk_thread_flag(p, TIF_USEDFPU);
#endif
/* Handle return value conventions */
if (regs->u_regs[UREG_G1] == __NR_clone3) {
/* clone3() - use regular kernel return value convention */
/* Set the return value for the child. */
childregs->u_regs[UREG_I0] = current->pid;
childregs->u_regs[UREG_I1] = 1;
/* Set the return value for the child. */
childregs->u_regs[UREG_I0] = 0;
} else {
/* clone()/fork() - use SunOS return value convention */
/* Set the return value for the parent. */
regs->u_regs[UREG_I1] = 0;
/* Set the return value for the child. */
childregs->u_regs[UREG_I0] = current->pid;
childregs->u_regs[UREG_I1] = 1;
/* Set the return value for the parent. */
regs->u_regs[UREG_I1] = 0;
}
if (clone_flags & CLONE_SETTLS)
childregs->u_regs[UREG_G7] = tls;

27
arch/sparc/kernel/process_64.c
View file

@ -564,17 +564,19 @@ barf:
* under SunOS are nothing short of bletcherous:
* Parent --> %o0 == childs pid, %o1 == 0
* Child --> %o0 == parents pid, %o1 == 1
*
* clone3() - Uses regular kernel return value conventions
*/
int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
{
u64 clone_flags = args->flags;
unsigned long sp = args->stack;
unsigned long tls = args->tls;
struct thread_info *t = task_thread_info(p);
struct pt_regs *regs = current_pt_regs();
struct sparc_stackf *parent_sf;
unsigned long child_stack_sz;
char *child_trap_frame;
unsigned long sp = args->stack ? args->stack : regs->u_regs[UREG_FP];
/* Calculate offset to stack_frame & pt_regs */
child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
@ -616,12 +618,25 @@ int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
if (t->utraps)
t->utraps[0]++;
/* Set the return value for the child. */
t->kregs->u_regs[UREG_I0] = current->pid;
t->kregs->u_regs[UREG_I1] = 1;
/* Handle return value conventions */
if (regs->u_regs[UREG_G1] == __NR_clone3) {
/* clone3() - use regular kernel return value convention */
/* Set the second return value for the parent. */
regs->u_regs[UREG_I1] = 0;
/* Set the return value for the child. */
t->kregs->u_regs[UREG_I0] = 0;
/* Clear g1 to indicate user thread */
t->kregs->u_regs[UREG_G1] = 0;
} else {
/* clone()/fork() - use SunOS return value convention */
/* Set the return value for the child. */
t->kregs->u_regs[UREG_I0] = current->pid;
t->kregs->u_regs[UREG_I1] = 1;
/* Set the second return value for the parent. */
regs->u_regs[UREG_I1] = 0;
}
if (clone_flags & CLONE_SETTLS)
t->kregs->u_regs[UREG_G7] = tls;

8
arch/sparc/kernel/syscalls.S
View file

@ -103,6 +103,12 @@ sys_clone:
ba,pt %xcc, sparc_clone
add %sp, PTREGS_OFF, %o0
.align 32
__sys_clone3:
flushw
ba,pt %xcc, sparc_clone3
add %sp, PTREGS_OFF, %o0
.globl ret_from_fork
ret_from_fork:
/* Clear current_thread_info()->new_child. */
@ -113,6 +119,8 @@ ret_from_fork:
brnz,pt %o0, ret_sys_call
ldx [%g6 + TI_FLAGS], %l0
ldx [%sp + PTREGS_OFF + PT_V9_G1], %l1
brz,pt %l1, ret_sys_call
nop
call %l1
ldx [%sp + PTREGS_OFF + PT_V9_G2], %o0
ba,pt %xcc, ret_sys_call

2
arch/sparc/kernel/syscalls/syscall.tbl
View file

@ -480,7 +480,7 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
# 435 reserved for clone3
435 common clone3 __sys_clone3
436 common close_range sys_close_range
437 common openat2 sys_openat2
438 common pidfd_getfd sys_pidfd_getfd