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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-05 00:47:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-05 00:47:45 +0300
commit9ba27414f2ec2bfb019d9e9170fd2308aebab63a (patch)
tree1ecbed91b2c68b4c28709fcb36689236eac7d304 /arch/sparc
parent0a72761b27fe3b10e3f336bf2f2aa22635504cdd (diff)
parent714acdbd1c94e7e3ab90f6b6938f1ccb27b662f0 (diff)
downloadlinux-9ba27414f2ec2bfb019d9e9170fd2308aebab63a.tar.xz
Merge tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull fork cleanups from Christian Brauner: "This is cleanup series from when we reworked a chunk of the process creation paths in the kernel and switched to struct {kernel_}clone_args. High-level this does two main things: - Remove the double export of both do_fork() and _do_fork() where do_fork() used the incosistent legacy clone calling convention. Now we only export _do_fork() which is based on struct kernel_clone_args. - Remove the copy_thread_tls()/copy_thread() split making the architecture specific HAVE_COYP_THREAD_TLS config option obsolete. This switches all remaining architectures to select HAVE_COPY_THREAD_TLS and thus to the copy_thread_tls() calling convention. The current split makes the process creation codepaths more convoluted than they need to be. Each architecture has their own copy_thread() function unless it selects HAVE_COPY_THREAD_TLS then it has a copy_thread_tls() function. The split is not needed anymore nowadays, all architectures support CLONE_SETTLS but quite a few of them never bothered to select HAVE_COPY_THREAD_TLS and instead simply continued to use copy_thread() and use the old calling convention. Removing this split cleans up the process creation codepaths and paves the way for implementing clone3() on such architectures since it requires the copy_thread_tls() calling convention. After having made each architectures support copy_thread_tls() this series simply renames that function back to copy_thread(). It also switches all architectures that call do_fork() directly over to _do_fork() and the struct kernel_clone_args calling convention. This is a corollary of switching the architectures that did not yet support it over to copy_thread_tls() since do_fork() is conditional on not supporting copy_thread_tls() (Mostly because it lacks a separate argument for tls which is trivial to fix but there's no need for this function to exist.). The do_fork() removal is in itself already useful as it allows to to remove the export of both do_fork() and _do_fork() we currently have in favor of only _do_fork(). This has already been discussed back when we added clone3(). The legacy clone() calling convention is - as is probably well-known - somewhat odd: # # ABI hall of shame # config CLONE_BACKWARDS config CLONE_BACKWARDS2 config CLONE_BACKWARDS3 that is aggravated by the fact that some architectures such as sparc follow the CLONE_BACKWARDSx calling convention but don't really select the corresponding config option since they call do_fork() directly. So do_fork() enforces a somewhat arbitrary calling convention in the first place that doesn't really help the individual architectures that deviate from it. They can thus simply be switched to _do_fork() enforcing a single calling convention. (I really hope that any new architectures will __not__ try to implement their own calling conventions...) Most architectures already have made a similar switch (m68k comes to mind). Overall this removes more code than it adds even with a good portion of added comments. It simplifies a chunk of arch specific assembly either by moving the code into C or by simply rewriting the assembly. Architectures that have been touched in non-trivial ways have all been actually boot and stress tested: sparc and ia64 have been tested with Debian 9 images. They are the two architectures which have been touched the most. All non-trivial changes to architectures have seen acks from the relevant maintainers. nios2 with a custom built buildroot image. h8300 I couldn't get something bootable to test on but the changes have been fairly automatic and I'm sure we'll hear people yell if I broke something there. All other architectures that have been touched in trivial ways have been compile tested for each single patch of the series via git rebase -x "make ..." v5.8-rc2. arm{64} and x86{_64} have been boot tested even though they have just been trivially touched (removal of the HAVE_COPY_THREAD_TLS macro from their Kconfig) because well they are basically "core architectures" and since it is trivial to get your hands on a useable image" * tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: arch: rename copy_thread_tls() back to copy_thread() arch: remove HAVE_COPY_THREAD_TLS unicore: switch to copy_thread_tls() sh: switch to copy_thread_tls() nds32: switch to copy_thread_tls() microblaze: switch to copy_thread_tls() hexagon: switch to copy_thread_tls() c6x: switch to copy_thread_tls() alpha: switch to copy_thread_tls() fork: remove do_fork() h8300: select HAVE_COPY_THREAD_TLS, switch to kernel_clone_args nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args ia64: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args sparc: unconditionally enable HAVE_COPY_THREAD_TLS sparc: share process creation helpers between sparc and sparc64 sparc64: enable HAVE_COPY_THREAD_TLS fork: fold legacy_clone_args_valid() into _do_fork()
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/include/asm/syscalls.h7
-rw-r--r--arch/sparc/kernel/Makefile1
-rw-r--r--arch/sparc/kernel/entry.S29
-rw-r--r--arch/sparc/kernel/kernel.h11
-rw-r--r--arch/sparc/kernel/process.c110
-rw-r--r--arch/sparc/kernel/process_32.c33
-rw-r--r--arch/sparc/kernel/process_64.c40
-rw-r--r--arch/sparc/kernel/syscalls.S23
8 files changed, 145 insertions, 109 deletions
diff --git a/arch/sparc/include/asm/syscalls.h b/arch/sparc/include/asm/syscalls.h
index 1d819f5e21da..35575fbfb9dc 100644
--- a/arch/sparc/include/asm/syscalls.h
+++ b/arch/sparc/include/asm/syscalls.h
@@ -4,9 +4,8 @@
struct pt_regs;
-asmlinkage long sparc_do_fork(unsigned long clone_flags,
- unsigned long stack_start,
- struct pt_regs *regs,
- unsigned long stack_size);
+asmlinkage long sparc_fork(struct pt_regs *regs);
+asmlinkage long sparc_vfork(struct pt_regs *regs);
+asmlinkage long sparc_clone(struct pt_regs *regs);
#endif /* _SPARC64_SYSCALLS_H */
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index 97c0e19263d1..d3a0e072ebe8 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -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
diff --git a/arch/sparc/kernel/entry.S b/arch/sparc/kernel/entry.S
index f636acf3312f..d58940280f8d 100644
--- a/arch/sparc/kernel/entry.S
+++ b/arch/sparc/kernel/entry.S
@@ -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:
diff --git a/arch/sparc/kernel/kernel.h b/arch/sparc/kernel/kernel.h
index f6f498ba3198..9cd09a3ef35f 100644
--- a/arch/sparc/kernel/kernel.h
+++ b/arch/sparc/kernel/kernel.h
@@ -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);
diff --git a/arch/sparc/kernel/process.c b/arch/sparc/kernel/process.c
new file mode 100644
index 000000000000..5234b5ccc0b9
--- /dev/null
+++ b/arch/sparc/kernel/process.c
@@ -0,0 +1,110 @@
+// 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() 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() 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() 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;
+}
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 13cb5638fab8..bd123f1de2e7 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -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
@@ -300,8 +273,8 @@ asmlinkage int sparc_do_fork(unsigned long clone_flags,
extern void ret_from_fork(void);
extern void ret_from_kernel_thread(void);
-int copy_thread(unsigned long clone_flags, unsigned long sp,
- unsigned long arg, struct task_struct *p)
+int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
+ struct task_struct *p, unsigned long tls)
{
struct thread_info *ti = task_thread_info(p);
struct pt_regs *childregs, *regs = current_pt_regs();
@@ -403,7 +376,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
regs->u_regs[UREG_I1] = 0;
if (clone_flags & CLONE_SETTLS)
- childregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
+ childregs->u_regs[UREG_G7] = tls;
return 0;
}
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 54945eacd3b5..04ef19b88632 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -572,47 +572,13 @@ barf:
force_sig(SIGSEGV);
}
-asmlinkage long sparc_do_fork(unsigned long clone_flags,
- unsigned long stack_start,
- struct pt_regs *regs,
- unsigned long stack_size)
-{
- int __user *parent_tid_ptr, *child_tid_ptr;
- unsigned long orig_i1 = regs->u_regs[UREG_I1];
- long ret;
-
-#ifdef CONFIG_COMPAT
- if (test_thread_flag(TIF_32BIT)) {
- parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
- child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
- } else
-#endif
- {
- parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
- child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
- }
-
- ret = do_fork(clone_flags, stack_start, stack_size,
- parent_tid_ptr, 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
* Child --> %o0 == parents pid, %o1 == 1
*/
-int copy_thread(unsigned long clone_flags, unsigned long sp,
- unsigned long arg, struct task_struct *p)
+int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
+ struct task_struct *p, unsigned long tls)
{
struct thread_info *t = task_thread_info(p);
struct pt_regs *regs = current_pt_regs();
@@ -670,7 +636,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
regs->u_regs[UREG_I1] = 0;
if (clone_flags & CLONE_SETTLS)
- t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
+ t->kregs->u_regs[UREG_G7] = tls;
return 0;
}
diff --git a/arch/sparc/kernel/syscalls.S b/arch/sparc/kernel/syscalls.S
index db42b4fb3708..0e8ab0602c36 100644
--- a/arch/sparc/kernel/syscalls.S
+++ b/arch/sparc/kernel/syscalls.S
@@ -86,19 +86,22 @@ sys32_rt_sigreturn:
* during system calls...
*/
.align 32
-sys_vfork: /* Under Linux, vfork and fork are just special cases of clone. */
- sethi %hi(0x4000 | 0x0100 | SIGCHLD), %o0
- or %o0, %lo(0x4000 | 0x0100 | SIGCHLD), %o0
- ba,pt %xcc, sys_clone
+sys_vfork:
+ flushw
+ ba,pt %xcc, sparc_vfork
+ add %sp, PTREGS_OFF, %o0
+
+ .align 32
sys_fork:
- clr %o1
- mov SIGCHLD, %o0
+ flushw
+ ba,pt %xcc, sparc_fork
+ add %sp, PTREGS_OFF, %o0
+
+ .align 32
sys_clone:
flushw
- movrz %o1, %fp, %o1
- mov 0, %o3
- ba,pt %xcc, sparc_do_fork
- add %sp, PTREGS_OFF, %o2
+ ba,pt %xcc, sparc_clone
+ add %sp, PTREGS_OFF, %o0
.globl ret_from_fork
ret_from_fork: