linux-kernel - Re: [PATCH v3 4/4] arm64: apply __ro_after

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Message-ID: <20160815145303.71628c8b@xhacker>
Date:	Mon, 15 Aug 2016 14:53:03 +0800
From:	Jisheng Zhang <jszhang@...vell.com>
To:	Mark Rutland <mark.rutland@....com>
CC:	<catalin.marinas@....com>, <will.deacon@....com>,
	<lorenzo.pieralisi@....com>, <keescook@...omium.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 4/4] arm64: apply __ro_after_init to some objects

Hi Mark,

On Fri, 12 Aug 2016 13:43:45 +0100 Mark Rutland wrote:

> Hi,
> 
> There are still a few missing includes as of this patch, and I have a
> small nit about one file as commented below.
> 
> Please fix up the includes.
> 
> On Fri, Aug 12, 2016 at 04:01:11PM +0800, Jisheng Zhang wrote:
> > diff --git a/arch/arm64/kernel/cpu_ops.c b/arch/arm64/kernel/cpu_ops.c
> > index c7cfb8f..6d32d1a 100644
> > --- a/arch/arm64/kernel/cpu_ops.c
> > +++ b/arch/arm64/kernel/cpu_ops.c
> > @@ -28,7 +28,7 @@ extern const struct cpu_operations smp_spin_table_ops;
> >  extern const struct cpu_operations acpi_parking_protocol_ops;
> >  extern const struct cpu_operations cpu_psci_ops;
> >  
> > -const struct cpu_operations *cpu_ops[NR_CPUS];
> > +const struct cpu_operations *cpu_ops[NR_CPUS] __ro_after_init;  
> 
> This file is missing a <linux/cache.h> include for __ro_after_init.
> 
> >  static const struct cpu_operations *dt_supported_cpu_ops[] __initconst = {
> >  	&smp_spin_table_ops,
> > diff --git a/arch/arm64/kernel/kaslr.c b/arch/arm64/kernel/kaslr.c
> > index 8ebabc4..93c47e1 100644
> > --- a/arch/arm64/kernel/kaslr.c
> > +++ b/arch/arm64/kernel/kaslr.c
> > @@ -20,7 +20,7 @@
> >  #include <asm/pgtable.h>
> >  #include <asm/sections.h>
> >  
> > -u64 module_alloc_base __read_mostly;
> > +u64 module_alloc_base __ro_after_init;  
> 
> Likewise.
> 
> >  u16 memstart_offset_seed __initdata;
> >  
> >  static __init u64 get_kaslr_seed(void *fdt)
> > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> > index 10ad8ab..c1ff7c2 100644
> > --- a/arch/arm64/kernel/vdso.c
> > +++ b/arch/arm64/kernel/vdso.c
> > @@ -19,6 +19,7 @@
> >   */
> >  
> >  #include <linux/kernel.h>
> > +#include <linux/cache.h>
> >  #include <linux/clocksource.h>
> >  #include <linux/elf.h>
> >  #include <linux/err.h>  
> 
> Nit: Could you please sort this list? Everything but <linux/kernel.h> is
> already in order.
> 
> > diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
> > index c4284c4..59d44e7 100644
> > --- a/arch/arm64/mm/dma-mapping.c
> > +++ b/arch/arm64/mm/dma-mapping.c
> > @@ -30,7 +30,7 @@
> >  
> >  #include <asm/cacheflush.h>
> >  
> > -static int swiotlb __read_mostly;
> > +static int swiotlb __ro_after_init;  
> 
> This file is missing a <linux/cache.h> include for __ro_after_init.
> 
> >  
> >  static pgprot_t __get_dma_pgprot(unsigned long attrs, pgprot_t prot,
> >  				 bool coherent)
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index bbb7ee7..e8b81ea 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -55,8 +55,8 @@
> >   * executes, which assigns it its actual value. So use a default value
> >   * that cannot be mistaken for a real physical address.
> >   */
> > -s64 memstart_addr __read_mostly = -1;
> > -phys_addr_t arm64_dma_phys_limit __read_mostly;
> > +s64 memstart_addr __ro_after_init = -1;
> > +phys_addr_t arm64_dma_phys_limit __ro_after_init;  
> 
> Likewise.
> 
> >  #ifdef CONFIG_BLK_DEV_INITRD
> >  static int __init early_initrd(char *p)
> > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> > index 4989948..6029bed 100644
> > --- a/arch/arm64/mm/mmu.c
> > +++ b/arch/arm64/mm/mmu.c
> > @@ -46,7 +46,7 @@
> >  
> >  u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
> >  
> > -u64 kimage_voffset __read_mostly;
> > +u64 kimage_voffset __ro_after_init;  
> 
> Likewise.
> 

Thanks a lot, all comments are addressed in v4.

the headers in vdso.c is sorted now. However, the headers in mmu.c,
dma-mapping.c, init.c aren't, for I dunno whether it's acceptable
to do so. Or we could add one separate patch to make them sorted before
applying __ro_after_init

Thanks,
Jisheng