Re: [Xen-devel] [PATCH] idle/x86: remove the call to boot_init_stack_canary() from cpu_startup_entry()

[Christophe LEROY <christophe.leroy@xxxxxx>]

Le 19/10/2018 à 12:01, Juergen Gross a écrit :
> On 19/10/2018 11:29, Christophe Leroy wrote:
> > commit d7880812b359 ("idle: Add the stack canary init to
> > cpu_startup_entry()") added the call to boot_init_stack_canary()
> > in cpu_startup_entry() in an #ifdef CONFIG_X86 statement, with
> > the intention to remove that #ifdef later.
> >
> > While implementing stack protector for powerpc, it has been
> > observed that calling boot_init_stack_canary() is also needed
> > for powerpc which uses per task (TLS) stack canary like the X86.
> >
> > However, calling boot_init_stack_canary() would break arches
> > using global stack canary (ARM, SH, MIPS and XTENSA).
> >
> > Instead of adding modifying the #ifdef in a
> > implemented the call to boot_init_stack_canary() in the function
> > calling cpu_startup_entry()
> I can't parse this sentence.
Oops, git commit took the #if for a comment and droped it. Fixed in v2.

> > On x86, we have two functions calling cpu_startup_entry():
> > - start_secondary()
> > - cpu_bringup_and_idle()
> >
> > start_secondary() already calls boot_init_stack_canary().
> >
> > This patch adds the call to boot_init_stack_canary() in
> > cpu_bringup_and_idle() and removes it from cpu_startup_entry()
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> With the commit message made understandable you can add my
>
> Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
Thanks
Christophe

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