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Subject[PATCH] m68k: Implement copy_thread_tls()
Date
This is required for clone3(), which passes the TLS value through a
struct rather than a register.

As do_fork() is only available if CONFIG_HAVE_COPY_THREAD_TLS is set,
m68k_clone() must be changed to call _do_fork() directly.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
This is a dependency for the combination of commits
e8bb2a2a1d51511e ("m68k: Wire up clone3() syscall") in m68k/for-next,
dd499f7a7e342702 ("clone3: ensure copy_thread_tls is implemented") in
v5.5-rc6.
---
arch/m68k/Kconfig | 1 +
arch/m68k/kernel/process.c | 31 ++++++++++++++++++++++---------
2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 6663f1741798e83f..6ad6cdac74b3dc42 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -14,6 +14,7 @@ config M68K
select HAVE_AOUT if MMU
select HAVE_ASM_MODVERSIONS
select HAVE_DEBUG_BUGVERBOSE
+ select HAVE_COPY_THREAD_TLS
select GENERIC_IRQ_SHOW
select GENERIC_ATOMIC64
select HAVE_UID16
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index 22e6b8f4f9582aa4..8f0d9140700f09ad 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -108,16 +108,28 @@ void flush_thread(void)
* on top of pt_regs, which means that sys_clone() arguments would be
* buried. We could, of course, copy them, but it's too costly for no
* good reason - generic clone() would have to copy them *again* for
- * do_fork() anyway. So in this case it's actually better to pass pt_regs *
- * and extract arguments for do_fork() from there. Eventually we might
- * go for calling do_fork() directly from the wrapper, but only after we
- * are finished with do_fork() prototype conversion.
+ * _do_fork() anyway. So in this case it's actually better to pass pt_regs *
+ * and extract arguments for _do_fork() from there. Eventually we might
+ * go for calling _do_fork() directly from the wrapper, but only after we
+ * are finished with _do_fork() prototype conversion.
*/
asmlinkage int m68k_clone(struct pt_regs *regs)
{
/* regs will be equal to current_pt_regs() */
- return do_fork(regs->d1, regs->d2, 0,
- (int __user *)regs->d3, (int __user *)regs->d4);
+ struct kernel_clone_args args = {
+ .flags = regs->d1 & ~CSIGNAL,
+ .pidfd = (int __user *)regs->d3,
+ .child_tid = (int __user *)regs->d4,
+ .parent_tid = (int __user *)regs->d3,
+ .exit_signal = regs->d1 & CSIGNAL,
+ .stack = regs->d2,
+ .tls = regs->d5,
+ };
+
+ if (!legacy_clone_args_valid(&args))
+ return -EINVAL;
+
+ return _do_fork(&args);
}

/*
@@ -130,8 +142,9 @@ asmlinkage int m68k_clone3(struct pt_regs *regs)
return sys_clone3((struct clone_args __user *)regs->d1, regs->d2);
}

-int copy_thread(unsigned long clone_flags, unsigned long usp,
- unsigned long arg, struct task_struct *p)
+int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
+ unsigned long arg, struct task_struct *p,
+ unsigned long tls)
{
struct fork_frame {
struct switch_stack sw;
@@ -166,7 +179,7 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
p->thread.usp = usp ?: rdusp();

if (clone_flags & CLONE_SETTLS)
- task_thread_info(p)->tp_value = frame->regs.d5;
+ task_thread_info(p)->tp_value = tls;

#ifdef CONFIG_FPU
if (!FPU_IS_EMU) {
--
2.17.1
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