Unverified Commit a4261d4b authored by Christian Brauner's avatar Christian Brauner
Browse files

sparc: share process creation helpers between sparc and sparc64 



As promised in the previous patch, this moves the process creation
helpers into a common process.c file that is shared between sparc and
sparc64. It allows us to get rid of quite a bit custom assembler and the
to remove the separe 32bit specific sparc_do_fork() call.

One thing to note, is that when clone() was called with a separate stack
for the child the assembler would align it. But copy_thread() has always
been doing that too so that line wasn't needed and can thus simply be
removed.

Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: linux-csky@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Link: https://lore.kernel.org/r/20200512171527.570109-3-christian.brauner@ubuntu.com
parent dcad2a62

arch/sparc/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ obj-y += irq_$(BITS).o 
obj-$(CONFIG_SPARC32)   += sun4m_irq.o sun4d_irq.o



obj-y                   += process_$(BITS).o

obj-y                   += process.o

obj-y                   += signal_$(BITS).o

obj-y                   += sigutil_$(BITS).o

obj-$(CONFIG_SPARC32)   += ioport.o

arch/sparc/kernel/entry.S

+7 −22
Original line number Diff line number Diff line
@@ -869,14 +869,11 @@ flush_patch_two: 
	ld	[%curptr + TI_TASK], %o4

	rd	%psr, %g4

	WRITE_PAUSE

	mov	SIGCHLD, %o0			! arg0:	clone flags

	rd	%wim, %g5

	WRITE_PAUSE

	mov	%fp, %o1			! arg1:	usp

	std	%g4, [%o4 + AOFF_task_thread + AOFF_thread_fork_kpsr]

	add	%sp, STACKFRAME_SZ, %o2		! arg2:	pt_regs ptr

	mov	0, %o3

	call	sparc_do_fork

	add	%sp, STACKFRAME_SZ, %o0

	call	sparc_fork

	 mov	%l5, %o7



	/* Whee, kernel threads! */
@@ -888,19 +885,11 @@ flush_patch_three: 
	ld	[%curptr + TI_TASK], %o4

	rd	%psr, %g4

	WRITE_PAUSE



	/* arg0,1: flags,usp  -- loaded already */

	cmp	%o1, 0x0			! Is new_usp NULL?

	rd	%wim, %g5

	WRITE_PAUSE

	be,a	1f

	 mov	%fp, %o1			! yes, use callers usp

	andn	%o1, 7, %o1			! no, align to 8 bytes

1:

	std	%g4, [%o4 + AOFF_task_thread + AOFF_thread_fork_kpsr]

	add	%sp, STACKFRAME_SZ, %o2		! arg2:	pt_regs ptr

	mov	0, %o3

	call	sparc_do_fork

	add	%sp, STACKFRAME_SZ, %o0

	call	sparc_clone

	 mov	%l5, %o7



	/* Whee, real vfork! */
@@ -914,13 +903,9 @@ flush_patch_four: 
	rd	%wim, %g5

	WRITE_PAUSE

	std	%g4, [%o4 + AOFF_task_thread + AOFF_thread_fork_kpsr]

	sethi	%hi(0x4000 | 0x0100 | SIGCHLD), %o0

	mov	%fp, %o1

	or	%o0, %lo(0x4000 | 0x0100 | SIGCHLD), %o0

	sethi	%hi(sparc_do_fork), %l1

	mov	0, %o3

	jmpl	%l1 + %lo(sparc_do_fork), %g0

	 add	%sp, STACKFRAME_SZ, %o2

	sethi	%hi(sparc_vfork), %l1

	jmpl	%l1 + %lo(sparc_vfork), %g0

	 add	%sp, STACKFRAME_SZ, %o0



        .align  4

linux_sparc_ni_syscall:

arch/sparc/kernel/kernel.h

+5 −6
Original line number Diff line number Diff line
@@ -14,6 +14,11 @@ extern const char *sparc_pmu_type; 
extern unsigned int fsr_storage;

extern int ncpus_probed;



/* process{_32,_64}.c */

asmlinkage long sparc_clone(struct pt_regs *regs);

asmlinkage long sparc_fork(struct pt_regs *regs);

asmlinkage long sparc_vfork(struct pt_regs *regs);



#ifdef CONFIG_SPARC64

/* setup_64.c */

struct seq_file;
@@ -153,12 +158,6 @@ void floppy_hardint(void); 
extern unsigned long sun4m_cpu_startup;

extern unsigned long sun4d_cpu_startup;



/* process_32.c */

asmlinkage int sparc_do_fork(unsigned long clone_flags,

                             unsigned long stack_start,

                             struct pt_regs *regs,

                             unsigned long stack_size);



/* signal_32.c */

asmlinkage void do_sigreturn(struct pt_regs *regs);

asmlinkage void do_rt_sigreturn(struct pt_regs *regs);

arch/sparc/kernel/process.c

0 → 100644
+110 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



/*

 * This file handles the architecture independent parts of process handling..

 */



#include <linux/compat.h>

#include <linux/errno.h>

#include <linux/kernel.h>

#include <linux/ptrace.h>

#include <linux/sched.h>

#include <linux/sched/task.h>

#include <linux/sched/task_stack.h>

#include <linux/signal.h>



#include "kernel.h"



asmlinkage long sparc_fork(struct pt_regs *regs)

{

	unsigned long orig_i1 = regs->u_regs[UREG_I1];

	long ret;

	struct kernel_clone_args args = {

		.exit_signal	= SIGCHLD,

		/* Reuse the parent's stack for the child. */

		.stack		= regs->u_regs[UREG_FP],

	};



	ret = _do_fork(&args);



	/* If we get an error and potentially restart the system

	 * call, we're screwed because copy_thread_tls() clobbered

	 * the parent's %o1.  So detect that case and restore it

	 * here.

	 */

	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)

		regs->u_regs[UREG_I1] = orig_i1;



	return ret;

}



asmlinkage long sparc_vfork(struct pt_regs *regs)

{

	unsigned long orig_i1 = regs->u_regs[UREG_I1];

	long ret;



	struct kernel_clone_args args = {

		.flags		= CLONE_VFORK | CLONE_VM,

		.exit_signal	= SIGCHLD,

		/* Reuse the parent's stack for the child. */

		.stack		= regs->u_regs[UREG_FP],

	};



	ret = _do_fork(&args);



	/* If we get an error and potentially restart the system

	 * call, we're screwed because copy_thread_tls() clobbered

	 * the parent's %o1.  So detect that case and restore it

	 * here.

	 */

	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)

		regs->u_regs[UREG_I1] = orig_i1;



	return ret;

}



asmlinkage long sparc_clone(struct pt_regs *regs)

{

	unsigned long orig_i1 = regs->u_regs[UREG_I1];

	unsigned int flags = lower_32_bits(regs->u_regs[UREG_I0]);

	long ret;



	struct kernel_clone_args args = {

		.flags		= (flags & ~CSIGNAL),

		.exit_signal	= (flags & CSIGNAL),

		.tls		= regs->u_regs[UREG_I3],

	};



#ifdef CONFIG_COMPAT

	if (test_thread_flag(TIF_32BIT)) {

		args.pidfd	= compat_ptr(regs->u_regs[UREG_I2]);

		args.child_tid	= compat_ptr(regs->u_regs[UREG_I4]);

		args.parent_tid	= compat_ptr(regs->u_regs[UREG_I2]);

	} else

#endif

	{

		args.pidfd	= (int __user *)regs->u_regs[UREG_I2];

		args.child_tid	= (int __user *)regs->u_regs[UREG_I4];

		args.parent_tid	= (int __user *)regs->u_regs[UREG_I2];

	}



	/* Did userspace give setup a separate stack for the child or are we

	 * reusing the parent's?

	 */

	if (regs->u_regs[UREG_I1])

		args.stack = regs->u_regs[UREG_I1];

	else

		args.stack = regs->u_regs[UREG_FP];



	ret = _do_fork(&args);



	/* If we get an error and potentially restart the system

	 * call, we're screwed because copy_thread_tls() clobbered

	 * the parent's %o1.  So detect that case and restore it

	 * here.

	 */

	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)

		regs->u_regs[UREG_I1] = orig_i1;



	return ret;

}

arch/sparc/kernel/process_32.c

+0 −27
Original line number Diff line number Diff line
@@ -257,33 +257,6 @@ clone_stackframe(struct sparc_stackf __user *dst, 
	return sp;

}



asmlinkage int sparc_do_fork(unsigned long clone_flags,

                             unsigned long stack_start,

                             struct pt_regs *regs,

                             unsigned long stack_size)

{

	unsigned long parent_tid_ptr, child_tid_ptr;

	unsigned long orig_i1 = regs->u_regs[UREG_I1];

	long ret;



	parent_tid_ptr = regs->u_regs[UREG_I2];

	child_tid_ptr = regs->u_regs[UREG_I4];



	ret = do_fork(clone_flags, stack_start, stack_size,

		      (int __user *) parent_tid_ptr,

		      (int __user *) child_tid_ptr);



	/* If we get an error and potentially restart the system

	 * call, we're screwed because copy_thread() clobbered

	 * the parent's %o1.  So detect that case and restore it

	 * here.

	 */

	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)

		regs->u_regs[UREG_I1] = orig_i1;



	return ret;

}



/* Copy a Sparc thread.  The fork() return value conventions

 * under SunOS are nothing short of bletcherous:

 * Parent -->  %o0 == childs  pid, %o1 == 0

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