2020-01-13 10:32:34

by Geert Uytterhoeven

[permalink] [raw]
Subject: [PATCH] m68k: Implement copy_thread_tls()

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 <[email protected]>
---
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


2020-01-13 10:40:53

by Christian Brauner

[permalink] [raw]
Subject: Re: [PATCH] m68k: Implement copy_thread_tls()

On Mon, Jan 13, 2020 at 11:30:40AM +0100, Geert Uytterhoeven wrote:
> 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 <[email protected]>

Thanks!
Acked-by: Christian Brauner <[email protected]>

2020-01-14 03:11:56

by Greg Ungerer

[permalink] [raw]
Subject: Re: [PATCH] m68k: Implement copy_thread_tls()

Hi Geert,

On 13/1/20 8:30 pm, Geert Uytterhoeven wrote:
> 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 <[email protected]>

Looks good for ColdFire too. I compiled for both MMU and non-MMU
targets and no regressions (I did not test clone3() itself though).

Acked-by: Greg Ungerer <[email protected]>

Regards
Greg


> ---
> 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) {
>

2020-01-14 09:52:45

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH] m68k: Implement copy_thread_tls()

On Mon, Jan 13, 2020 at 11:30 AM Geert Uytterhoeven
<[email protected]> wrote:
> 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 <[email protected]>
> ---
> 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.

Applied and queued for v5.6.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds