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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-04 14:47:45 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-04 14:47:45 -0700
commit9ba27414f2ec2bfb019d9e9170fd2308aebab63a (patch)
tree1ecbed91b2c68b4c28709fcb36689236eac7d304 /arch/openrisc
parent0a72761b27fe3b10e3f336bf2f2aa22635504cdd (diff)
parent714acdbd1c94e7e3ab90f6b6938f1ccb27b662f0 (diff)
downloadlinux-9ba27414f2ec2bfb019d9e9170fd2308aebab63a.tar.bz2
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/openrisc')
-rw-r--r--arch/openrisc/Kconfig1
-rw-r--r--arch/openrisc/kernel/process.c6
2 files changed, 3 insertions, 4 deletions
diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
index 8588996165ae..7e94fe37cb2f 100644
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -16,7 +16,6 @@ config OPENRISC
select HANDLE_DOMAIN_IRQ
select GPIOLIB
select HAVE_ARCH_TRACEHOOK
- select HAVE_COPY_THREAD_TLS
select SPARSE_IRQ
select GENERIC_IRQ_CHIP
select GENERIC_IRQ_PROBE
diff --git a/arch/openrisc/kernel/process.c b/arch/openrisc/kernel/process.c
index d7010e72450c..848f74c2c47a 100644
--- a/arch/openrisc/kernel/process.c
+++ b/arch/openrisc/kernel/process.c
@@ -116,7 +116,7 @@ void release_thread(struct task_struct *dead_task)
extern asmlinkage void ret_from_fork(void);
/*
- * copy_thread_tls
+ * copy_thread
* @clone_flags: flags
* @usp: user stack pointer or fn for kernel thread
* @arg: arg to fn for kernel thread; always NULL for userspace thread
@@ -147,8 +147,8 @@ extern asmlinkage void ret_from_fork(void);
*/
int
-copy_thread_tls(unsigned long clone_flags, unsigned long usp,
- unsigned long arg, struct task_struct *p, unsigned long tls)
+copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long arg,
+ struct task_struct *p, unsigned long tls)
{
struct pt_regs *userregs;
struct pt_regs *kregs;