Re: [PATCH v4 2/3] ACPI / NUMA: Add warning message if the padding size for KASLR is not enough

[Masayoshi Mizuma <msys.mizuma@gmail.com>]

On Thu, Sep 27, 2018 at 11:14:25PM +0200, Borislav Petkov wrote:
> On Thu, Sep 27, 2018 at 04:31:45PM -0400, Masayoshi Mizuma wrote:
> > From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> > 
> > Add warning message if the padding size for KASLR,
> > rand_mem_physical_padding, is not enough. The message also
> > says the suitable padding size.
> > 
> > Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
> > ---
> >  arch/x86/include/asm/setup.h |  2 ++
> >  drivers/acpi/numa.c          | 14 ++++++++++++++
> >  2 files changed, 16 insertions(+)
> > 
> > diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
> > index ae13bc9..65a5bf8 100644
> > --- a/arch/x86/include/asm/setup.h
> > +++ b/arch/x86/include/asm/setup.h
> > @@ -80,6 +80,8 @@ static inline unsigned long kaslr_offset(void)
> >  	return (unsigned long)&_text - __START_KERNEL;
> >  }
> >  
> > +extern int rand_mem_physical_padding;
> > +
> >  /*
> >   * Do NOT EVER look at the BIOS memory size location.
> >   * It does not work on many machines.
> > diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> > index 8516760..9c3cc3c 100644
> > --- a/drivers/acpi/numa.c
> > +++ b/drivers/acpi/numa.c
> > @@ -32,6 +32,7 @@
> >  #include <linux/numa.h>
> >  #include <linux/nodemask.h>
> >  #include <linux/topology.h>
> > +#include <asm/setup.h>
> >  
> >  static nodemask_t nodes_found_map = NODE_MASK_NONE;
> >  
> > @@ -435,6 +436,8 @@ acpi_table_parse_srat(enum acpi_srat_type id,
> >  int __init acpi_numa_init(void)
> >  {
> >  	int cnt = 0;
> > +	u32 max_phys_addr_tb;
> > +	u64 max_phys_addr;
> >  
> >  	if (acpi_disabled)
> >  		return -EINVAL;
> > @@ -463,6 +466,17 @@ int __init acpi_numa_init(void)
> >  
> >  		cnt = acpi_table_parse_srat(ACPI_SRAT_TYPE_MEMORY_AFFINITY,
> >  					    acpi_parse_memory_affinity, 0);
> > +
> > +		if (parsed_numa_memblks && kaslr_enabled()) {
> > +			max_phys_addr = PFN_PHYS(max_possible_pfn);
> > +			max_phys_addr_tb = (roundup(max_phys_addr, 1ULL << 40)) >> 40;
> > +
> > +			if (max_phys_addr_tb > rand_mem_physical_padding)
> > +				pr_warn("Set 'rand_mem_physical_padding=%d' "
> > +					"as the kernel parameter. "
> > +					"Otherwise, memory hotadd may be failed.\n",
> > +					max_phys_addr_tb);
> 
> Please integrate scripts/checkpatch.pl into your patch creation
> workflow. Some of the warnings/errors *actually* make sense:
> 
> WARNING: quoted string split across lines
> #75: FILE: drivers/acpi/numa.c:476:
> +                               pr_warn("Set 'rand_mem_physical_padding=%d' "
> +                                       "as the kernel parameter. "
> 
> WARNING: quoted string split across lines
> #76: FILE: drivers/acpi/numa.c:477:
> +                                       "as the kernel parameter. "
> +                                       "Otherwise, memory hotadd may be failed.\n",
> 
> total: 0 errors, 2 warnings, 40 lines checked
> 
> Also, that sentence needs polishing:
> 
> 				pr_warn("Set 'rand_mem_physical_padding=%d' to avoid memory hotadd failure.\n",

Thank you for pointing it out.
I'll fix it.

Thnaks,
Masa

> 
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> Good mailing practices for 400: avoid top-posting and trim the reply.