[PATCH v7 7/7] powerpc/32: use set_memory_attr()

[Russell Currey]

On Tue, 2020-03-31 at 11:56 +0200, Christophe Leroy wrote:
> 
> Le 31/03/2020 à 06:48, Russell Currey a écrit :
> > From: Christophe Leroy <christophe.leroy at c-s.fr>
> > 
> > Use set_memory_attr() instead of the PPC32 specific
> > change_page_attr()
> > 
> > change_page_attr() was checking that the address was not mapped by
> > blocks and was handling highmem, but that's unneeded because the
> > affected pages can't be in highmem and block mapping verification
> > is already done by the callers.
> > 
> > Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
> > ---
> >   arch/powerpc/mm/pgtable_32.c | 95 ++++---------------------------
> > -----
> >   1 file changed, 10 insertions(+), 85 deletions(-)
> > 
> > diff --git a/arch/powerpc/mm/pgtable_32.c
> > b/arch/powerpc/mm/pgtable_32.c
> > index 5fb90edd865e..3d92eaf3ee2f 100644
> > --- a/arch/powerpc/mm/pgtable_32.c
> > +++ b/arch/powerpc/mm/pgtable_32.c
> > @@ -23,6 +23,7 @@
> >   #include <linux/highmem.h>
> >   #include <linux/memblock.h>
> >   #include <linux/slab.h>
> > +#include <linux/set_memory.h>
> >   
> >   #include <asm/pgtable.h>
> >   #include <asm/pgalloc.h>
> > @@ -121,99 +122,20 @@ void __init mapin_ram(void)
> >   	}
> >   }
> >   
> > -/* Scan the real Linux page tables and return a PTE pointer for
> > - * a virtual address in a context.
> > - * Returns true (1) if PTE was found, zero otherwise.  The pointer
> > to
> > - * the PTE pointer is unmodified if PTE is not found.
> > - */
> > -static int
> > -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
> > pmd_t **pmdp)
> 
> This will conflict, get_pteptr() is gone now, see 
> https://github.com/linuxppc/linux/commit/2efc7c085f05870eda6f29ac71eeb83f3bd54415
> 
> Christophe

OK cool, so I can just drop that hunk?  Will try that and make sure it
rebases on powerpc/next

- Russell

> 
> 
> > -{
> > -        pgd_t	*pgd;
> > -	pud_t	*pud;
> > -        pmd_t	*pmd;
> > -        pte_t	*pte;
> > -        int     retval = 0;
> > -
> > -        pgd = pgd_offset(mm, addr & PAGE_MASK);
> > -        if (pgd) {
> > -		pud = pud_offset(pgd, addr & PAGE_MASK);
> > -		if (pud && pud_present(*pud)) {
> > -			pmd = pmd_offset(pud, addr & PAGE_MASK);
> > -			if (pmd_present(*pmd)) {
> > -				pte = pte_offset_map(pmd, addr &
> > PAGE_MASK);
> > -				if (pte) {
> > -					retval = 1;
> > -					*ptep = pte;
> > -					if (pmdp)
> > -						*pmdp = pmd;
> > -					/* XXX caller needs to do
> > pte_unmap, yuck */
> > -				}
> > -			}
> > -		}
> > -        }
> > -        return(retval);
> > -}
> > -
> > -static int __change_page_attr_noflush(struct page *page, pgprot_t
> > prot)
> > -{
> > -	pte_t *kpte;
> > -	pmd_t *kpmd;
> > -	unsigned long address;
> > -
> > -	BUG_ON(PageHighMem(page));
> > -	address = (unsigned long)page_address(page);
> > -
> > -	if (v_block_mapped(address))
> > -		return 0;
> > -	if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
> > -		return -EINVAL;
> > -	__set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
> > -	pte_unmap(kpte);
> > -
> > -	return 0;
> > -}
> > -
> > -/*
> > - * Change the page attributes of an page in the linear mapping.
> > - *
> > - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
> > - */
> > -static int change_page_attr(struct page *page, int numpages,
> > pgprot_t prot)
> > -{
> > -	int i, err = 0;
> > -	unsigned long flags;
> > -	struct page *start = page;
> > -
> > -	local_irq_save(flags);
> > -	for (i = 0; i < numpages; i++, page++) {
> > -		err = __change_page_attr_noflush(page, prot);
> > -		if (err)
> > -			break;
> > -	}
> > -	wmb();
> > -	local_irq_restore(flags);
> > -	flush_tlb_kernel_range((unsigned long)page_address(start),
> > -			       (unsigned long)page_address(page));
> > -	return err;
> > -}
> > -
> >   void mark_initmem_nx(void)
> >   {
> > -	struct page *page = virt_to_page(_sinittext);
> >   	unsigned long numpages = PFN_UP((unsigned long)_einittext) -
> >   				 PFN_DOWN((unsigned long)_sinittext);
> >   
> >   	if (v_block_mapped((unsigned long)_stext + 1))
> >   		mmu_mark_initmem_nx();
> >   	else
> > -		change_page_attr(page, numpages, PAGE_KERNEL);
> > +		set_memory_attr((unsigned long)_sinittext, numpages,
> > PAGE_KERNEL);
> >   }
> >   
> >   #ifdef CONFIG_STRICT_KERNEL_RWX
> >   void mark_rodata_ro(void)
> >   {
> > -	struct page *page;
> >   	unsigned long numpages;
> >   
> >   	if (v_block_mapped((unsigned long)_sinittext)) {
> > @@ -222,20 +144,18 @@ void mark_rodata_ro(void)
> >   		return;
> >   	}
> >   
> > -	page = virt_to_page(_stext);
> >   	numpages = PFN_UP((unsigned long)_etext) -
> >   		   PFN_DOWN((unsigned long)_stext);
> >   
> > -	change_page_attr(page, numpages, PAGE_KERNEL_ROX);
> > +	set_memory_attr((unsigned long)_stext, numpages,
> > PAGE_KERNEL_ROX);
> >   	/*
> >   	 * mark .rodata as read only. Use __init_begin rather than
> > __end_rodata
> >   	 * to cover NOTES and EXCEPTION_TABLE.
> >   	 */
> > -	page = virt_to_page(__start_rodata);
> >   	numpages = PFN_UP((unsigned long)__init_begin) -
> >   		   PFN_DOWN((unsigned long)__start_rodata);
> >   
> > -	change_page_attr(page, numpages, PAGE_KERNEL_RO);
> > +	set_memory_attr((unsigned long)__start_rodata, numpages,
> > PAGE_KERNEL_RO);
> >   
> >   	// mark_initmem_nx() should have already run by now
> >   	ptdump_check_wx();
> > @@ -245,9 +165,14 @@ void mark_rodata_ro(void)
> >   #ifdef CONFIG_DEBUG_PAGEALLOC
> >   void __kernel_map_pages(struct page *page, int numpages, int
> > enable)
> >   {
> > +	unsigned long addr = (unsigned long)page_address(page);
> > +
> >   	if (PageHighMem(page))
> >   		return;
> >   
> > -	change_page_attr(page, numpages, enable ? PAGE_KERNEL :
> > __pgprot(0));
> > +	if (enable)
> > +		set_memory_attr(addr, numpages, PAGE_KERNEL);
> > +	else
> > +		set_memory_attr(addr, numpages, __pgprot(0));
> >   }
> >   #endif /* CONFIG_DEBUG_PAGEALLOC */
> >