On Fri, Jun 10, 2011 at 15:09, Mathias Krause <[email protected]> wrote:
> The address limit is already set in flush_old_exec() so those calls to
> set_fs(USER_DS) are redundant.
>
> Signed-off-by: Mathias Krause <[email protected]>
> Cc: Greg Ungerer <[email protected]>
> ---
>
> Note: I'm not sure about the assignment to current->thread.fs in
> flush_thread() -- shouldn't this be done in set_fs() itself?
set_fs() is used to temporary set the address space to be used from the
kernel.
current->thread.fs is the address space that will be used when the
thread returns
to userspace.
So I think it's correct.
For nommu, thread.fs is set, but not really used.
> arch/m68k/include/asm/processor.h | 4 ----
> arch/m68k/kernel/process_mm.c | 2 +-
> arch/m68k/kernel/process_no.c | 2 +-
> 3 files changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/arch/m68k/include/asm/processor.h
> b/arch/m68k/include/asm/processor.h
> index f111b02..d8ef53a 100644
> --- a/arch/m68k/include/asm/processor.h
> +++ b/arch/m68k/include/asm/processor.h
> @@ -105,9 +105,6 @@ struct thread_struct {
> static inline void start_thread(struct pt_regs * regs, unsigned long pc,
> unsigned long usp)
> {
> - /* reads from user space */
> - set_fs(USER_DS);
> -
> regs->pc = pc;
> regs->sr &= ~0x2000;
> wrusp(usp);
> @@ -129,7 +126,6 @@ extern int handle_kernel_fault(struct pt_regs *regs);
>
> #define start_thread(_regs, _pc, _usp) \
> do { \
> - set_fs(USER_DS); /* reads from user space */ \
> (_regs)->pc = (_pc); \
> ((struct switch_stack *)(_regs))[-1].a6 = 0; \
> reformat(_regs); \
> diff --git a/arch/m68k/kernel/process_mm.c b/arch/m68k/kernel/process_mm.c
> index c2a1fc2..1bc223a 100644
> --- a/arch/m68k/kernel/process_mm.c
> +++ b/arch/m68k/kernel/process_mm.c
> @@ -185,7 +185,7 @@ EXPORT_SYMBOL(kernel_thread);
> void flush_thread(void)
> {
> unsigned long zero = 0;
> - set_fs(USER_DS);
> +
> current->thread.fs = __USER_DS;
> if (!FPU_IS_EMU)
> asm volatile (".chip 68k/68881\n\t"
> diff --git a/arch/m68k/kernel/process_no.c b/arch/m68k/kernel/process_no.c
> index 9b86ad1..69c1803 100644
> --- a/arch/m68k/kernel/process_no.c
> +++ b/arch/m68k/kernel/process_no.c
> @@ -158,7 +158,7 @@ void flush_thread(void)
> #ifdef CONFIG_FPU
> unsigned long zero = 0;
> #endif
> - set_fs(USER_DS);
> +
> current->thread.fs = __USER_DS;
> #ifdef CONFIG_FPU
> if (!FPU_IS_EMU)
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
--
To unsubscribe from this list: send the line "unsubscribe linux-m68k" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
