> +/* init_mm.page_table_lock must be held before calling! */
> +static void pram_page_writeable(unsigned long addr, int rw)
> +{
> + pgd_t *pgdp;
> + pud_t *pudp;
> + pmd_t *pmdp;
> + pte_t *ptep;
> +
> + pgdp = pgd_offset_k(addr);
> + if (!pgd_none(*pgdp)) {
> + pudp = pud_offset(pgdp, addr);
> + if (!pud_none(*pudp)) {
> + pmdp = pmd_offset(pudp, addr);
> + if (!pmd_none(*pmdp)) {
> + pte_t pte;
> + ptep = pte_offset_kernel(pmdp, addr);
> + pte = *ptep;
> + if (pte_present(pte)) {
> + pte = rw ? pte_mkwrite(pte) :
> + pte_wrprotect(pte);
> + set_pte(ptep, pte);
> + }
> + }
> + }
> + }
> +}
Wow. Don't we want to do this pte walking in mm/ someplace?
Do you really intend to protect just the PTE in question rather than
the entire physical page, regardless of which PTE is talking to it?
Maybe I'm missing something.
> +/* init_mm.page_table_lock must be held before calling! */
> +void pram_writeable(void *vaddr, unsigned long size, int rw)
> +{
> + unsigned long addr = (unsigned long)vaddr & PAGE_MASK;
> + unsigned long end = (unsigned long)vaddr + size;
> + unsigned long start = addr;
> +
> + do {
> + pram_page_writeable(addr, rw);
> + addr += PAGE_SIZE;
> + } while (addr && (addr < end));
> +
> +
> + /*
> + * NOTE: we will always flush just one page (one TLB
> + * entry) except possibly in one case: when a new
> + * filesystem is initialized at mount time, when pram_read_super
> + * calls pram_lock_range to make the super block, inode
> + * table, and bitmap writeable.
> + */
> +#if defined(CONFIG_ARM) || defined(CONFIG_M68K) || defined(CONFIG_H8300) || \
> + defined(CONFIG_BLACKFIN)
> + /*
> + * FIXME: so far only these archs have flush_tlb_kernel_page(),
> + * for the rest just use flush_tlb_kernel_range(). Not ideal
> + * to use _range() because many archs just flush the whole TLB.
> + */
> + if (end <= start + PAGE_SIZE)
> + flush_tlb_kernel_page(start);
> + else
> +#endif
> + flush_tlb_kernel_range(start, end);
> +}
Why not just fix flush_tlb_range()?
If an arch has a flush_tlb_kernel_page() that works then it stands to
reason that the flush_tlb_kernel_range() shouldn't work with minimal
effort, no?
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