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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/ia64/kernel
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/ia64/kernel')
-rw-r--r--arch/ia64/kernel/entry.S32
-rw-r--r--arch/ia64/kernel/process.c29
2 files changed, 36 insertions, 25 deletions
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index c5efac285bc3..e98e3dafffd8 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -112,19 +112,16 @@ GLOBAL_ENTRY(sys_clone2)
.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
alloc r16=ar.pfs,8,2,6,0
DO_SAVE_SWITCH_STACK
- adds r2=PT(R16)+IA64_SWITCH_STACK_SIZE+16,sp
mov loc0=rp
- mov loc1=r16 // save ar.pfs across do_fork
+ mov loc1=r16 // save ar.pfs across ia64_clone
.body
+ mov out0=in0
mov out1=in1
mov out2=in2
- tbit.nz p6,p0=in0,CLONE_SETTLS_BIT
- mov out3=in3 // parent_tidptr: valid only w/CLONE_PARENT_SETTID
- ;;
-(p6) st8 [r2]=in5 // store TLS in r16 for copy_thread()
- mov out4=in4 // child_tidptr: valid only w/CLONE_CHILD_SETTID or CLONE_CHILD_CLEARTID
- mov out0=in0 // out0 = clone_flags
- br.call.sptk.many rp=do_fork
+ mov out3=in3
+ mov out4=in4
+ mov out5=in5
+ br.call.sptk.many rp=ia64_clone
.ret1: .restore sp
adds sp=IA64_SWITCH_STACK_SIZE,sp // pop the switch stack
mov ar.pfs=loc1
@@ -143,19 +140,16 @@ GLOBAL_ENTRY(sys_clone)
.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8)
alloc r16=ar.pfs,8,2,6,0
DO_SAVE_SWITCH_STACK
- adds r2=PT(R16)+IA64_SWITCH_STACK_SIZE+16,sp
mov loc0=rp
- mov loc1=r16 // save ar.pfs across do_fork
+ mov loc1=r16 // save ar.pfs across ia64_clone
.body
+ mov out0=in0
mov out1=in1
mov out2=16 // stacksize (compensates for 16-byte scratch area)
- tbit.nz p6,p0=in0,CLONE_SETTLS_BIT
- mov out3=in2 // parent_tidptr: valid only w/CLONE_PARENT_SETTID
- ;;
-(p6) st8 [r2]=in4 // store TLS in r13 (tp)
- mov out4=in3 // child_tidptr: valid only w/CLONE_CHILD_SETTID or CLONE_CHILD_CLEARTID
- mov out0=in0 // out0 = clone_flags
- br.call.sptk.many rp=do_fork
+ mov out3=in3
+ mov out4=in4
+ mov out5=in5
+ br.call.sptk.many rp=ia64_clone
.ret2: .restore sp
adds sp=IA64_SWITCH_STACK_SIZE,sp // pop the switch stack
mov ar.pfs=loc1
@@ -590,7 +584,7 @@ GLOBAL_ENTRY(ia64_ret_from_clone)
nop.i 0
/*
* We need to call schedule_tail() to complete the scheduling process.
- * Called by ia64_switch_to() after do_fork()->copy_thread(). r8 contains the
+ * Called by ia64_switch_to() after ia64_clone()->copy_thread(). r8 contains the
* address of the previously executing task.
*/
br.call.sptk.many rp=ia64_invoke_schedule_tail
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index da55b41ae33e..7a4de9d994c5 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -296,7 +296,7 @@ ia64_load_extra (struct task_struct *task)
pfm_load_regs(task);
info = __this_cpu_read(pfm_syst_info);
- if (info & PFM_CPUINFO_SYST_WIDE)
+ if (info & PFM_CPUINFO_SYST_WIDE)
pfm_syst_wide_update_task(task, info, 1);
#endif
}
@@ -310,7 +310,7 @@ ia64_load_extra (struct task_struct *task)
*
* <clone syscall> <some kernel call frames>
* sys_clone :
- * do_fork do_fork
+ * _do_fork _do_fork
* copy_thread copy_thread
*
* This means that the stack layout is as follows:
@@ -333,9 +333,8 @@ ia64_load_extra (struct task_struct *task)
* so there is nothing to worry about.
*/
int
-copy_thread(unsigned long clone_flags,
- unsigned long user_stack_base, unsigned long user_stack_size,
- struct task_struct *p)
+copy_thread(unsigned long clone_flags, unsigned long user_stack_base,
+ unsigned long user_stack_size, struct task_struct *p, unsigned long tls)
{
extern char ia64_ret_from_clone;
struct switch_stack *child_stack, *stack;
@@ -416,7 +415,7 @@ copy_thread(unsigned long clone_flags,
rbs_size = stack->ar_bspstore - rbs;
memcpy((void *) child_rbs, (void *) rbs, rbs_size);
if (clone_flags & CLONE_SETTLS)
- child_ptregs->r13 = regs->r16; /* see sys_clone2() in entry.S */
+ child_ptregs->r13 = tls;
if (user_stack_base) {
child_ptregs->r12 = user_stack_base + user_stack_size - 16;
child_ptregs->ar_bspstore = user_stack_base;
@@ -441,6 +440,24 @@ copy_thread(unsigned long clone_flags,
return retval;
}
+asmlinkage long ia64_clone(unsigned long clone_flags, unsigned long stack_start,
+ unsigned long stack_size, unsigned long parent_tidptr,
+ unsigned long child_tidptr, unsigned long tls)
+{
+ struct kernel_clone_args args = {
+ .flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
+ .pidfd = (int __user *)parent_tidptr,
+ .child_tid = (int __user *)child_tidptr,
+ .parent_tid = (int __user *)parent_tidptr,
+ .exit_signal = (lower_32_bits(clone_flags) & CSIGNAL),
+ .stack = stack_start,
+ .stack_size = stack_size,
+ .tls = tls,
+ };
+
+ return _do_fork(&args);
+}
+
static void
do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info, void *arg)
{