[POWERPC] Small fixes & cleanups in segment page size demotion
The code for demoting segments to 4K had some issues, like for example, when using _PAGE_4K_PFN flag, the first CPU to hit it would do the demotion, but other CPUs hitting the same page wouldn't properly flush their SLBs if mmu_ci_restriction isn't set. There are also potential issues with hash_preload not handling _PAGE_4K_PFN. All of these are non issues on current hardware but might bite us in the future. This patch thus fixes it by: - Taking the test comparing the mm and current CPU context page sizes to decide to flush SLBs out of the mmu_ci_restrictions test since that can also be triggered by _PAGE_4K_PFN pages - Due to the above being done all the time, demote_segment_4k doesn't need update the context and flush the SLB - demote_segment_4k can be static and doesn't need an EXPORT_SYMBOL - Making hash_preload ignore anything that has either _PAGE_4K_PFN or _PAGE_NO_CACHE set, thus avoiding duplication of the complicated logic in hash_page() (and possibly making hash_preload a little bit faster for the normal case). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
parent
b15f792faf
commit
16f1c74675
@ -596,22 +596,18 @@ unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap)
|
||||
* Demote a segment to using 4k pages.
|
||||
* For now this makes the whole process use 4k pages.
|
||||
*/
|
||||
void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
|
||||
{
|
||||
#ifdef CONFIG_PPC_64K_PAGES
|
||||
static void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
|
||||
{
|
||||
if (mm->context.user_psize == MMU_PAGE_4K)
|
||||
return;
|
||||
mm->context.user_psize = MMU_PAGE_4K;
|
||||
mm->context.sllp = SLB_VSID_USER | mmu_psize_defs[MMU_PAGE_4K].sllp;
|
||||
get_paca()->context = mm->context;
|
||||
slb_flush_and_rebolt();
|
||||
#ifdef CONFIG_SPE_BASE
|
||||
spu_flush_all_slbs(mm);
|
||||
#endif
|
||||
#endif
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(demote_segment_4k);
|
||||
#endif /* CONFIG_PPC_64K_PAGES */
|
||||
|
||||
/* Result code is:
|
||||
* 0 - handled
|
||||
@ -711,40 +707,42 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
|
||||
psize = MMU_PAGE_4K;
|
||||
}
|
||||
|
||||
if (mmu_ci_restrictions) {
|
||||
/* If this PTE is non-cacheable, switch to 4k */
|
||||
if (psize == MMU_PAGE_64K &&
|
||||
(pte_val(*ptep) & _PAGE_NO_CACHE)) {
|
||||
if (user_region) {
|
||||
demote_segment_4k(mm, ea);
|
||||
psize = MMU_PAGE_4K;
|
||||
} else if (ea < VMALLOC_END) {
|
||||
/*
|
||||
* some driver did a non-cacheable mapping
|
||||
* in vmalloc space, so switch vmalloc
|
||||
* to 4k pages
|
||||
*/
|
||||
printk(KERN_ALERT "Reducing vmalloc segment "
|
||||
"to 4kB pages because of "
|
||||
"non-cacheable mapping\n");
|
||||
psize = mmu_vmalloc_psize = MMU_PAGE_4K;
|
||||
}
|
||||
/* If this PTE is non-cacheable and we have restrictions on
|
||||
* using non cacheable large pages, then we switch to 4k
|
||||
*/
|
||||
if (mmu_ci_restrictions && psize == MMU_PAGE_64K &&
|
||||
(pte_val(*ptep) & _PAGE_NO_CACHE)) {
|
||||
if (user_region) {
|
||||
demote_segment_4k(mm, ea);
|
||||
psize = MMU_PAGE_4K;
|
||||
} else if (ea < VMALLOC_END) {
|
||||
/*
|
||||
* some driver did a non-cacheable mapping
|
||||
* in vmalloc space, so switch vmalloc
|
||||
* to 4k pages
|
||||
*/
|
||||
printk(KERN_ALERT "Reducing vmalloc segment "
|
||||
"to 4kB pages because of "
|
||||
"non-cacheable mapping\n");
|
||||
psize = mmu_vmalloc_psize = MMU_PAGE_4K;
|
||||
#ifdef CONFIG_SPE_BASE
|
||||
spu_flush_all_slbs(mm);
|
||||
#endif
|
||||
}
|
||||
if (user_region) {
|
||||
if (psize != get_paca()->context.user_psize) {
|
||||
get_paca()->context = mm->context;
|
||||
slb_flush_and_rebolt();
|
||||
}
|
||||
} else if (get_paca()->vmalloc_sllp !=
|
||||
mmu_psize_defs[mmu_vmalloc_psize].sllp) {
|
||||
get_paca()->vmalloc_sllp =
|
||||
mmu_psize_defs[mmu_vmalloc_psize].sllp;
|
||||
}
|
||||
if (user_region) {
|
||||
if (psize != get_paca()->context.user_psize) {
|
||||
get_paca()->context.user_psize =
|
||||
mm->context.user_psize;
|
||||
slb_flush_and_rebolt();
|
||||
}
|
||||
} else if (get_paca()->vmalloc_sllp !=
|
||||
mmu_psize_defs[mmu_vmalloc_psize].sllp) {
|
||||
get_paca()->vmalloc_sllp =
|
||||
mmu_psize_defs[mmu_vmalloc_psize].sllp;
|
||||
slb_flush_and_rebolt();
|
||||
}
|
||||
|
||||
if (psize == MMU_PAGE_64K)
|
||||
rc = __hash_page_64K(ea, access, vsid, ptep, trap, local);
|
||||
else
|
||||
@ -780,13 +778,26 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
|
||||
DBG_LOW("hash_preload(mm=%p, mm->pgdir=%p, ea=%016lx, access=%lx,"
|
||||
" trap=%lx\n", mm, mm->pgd, ea, access, trap);
|
||||
|
||||
/* Get PTE, VSID, access mask */
|
||||
/* Get Linux PTE if available */
|
||||
pgdir = mm->pgd;
|
||||
if (pgdir == NULL)
|
||||
return;
|
||||
ptep = find_linux_pte(pgdir, ea);
|
||||
if (!ptep)
|
||||
return;
|
||||
|
||||
#ifdef CONFIG_PPC_64K_PAGES
|
||||
/* If either _PAGE_4K_PFN or _PAGE_NO_CACHE is set (and we are on
|
||||
* a 64K kernel), then we don't preload, hash_page() will take
|
||||
* care of it once we actually try to access the page.
|
||||
* That way we don't have to duplicate all of the logic for segment
|
||||
* page size demotion here
|
||||
*/
|
||||
if (pte_val(*ptep) & (_PAGE_4K_PFN | _PAGE_NO_CACHE))
|
||||
return;
|
||||
#endif /* CONFIG_PPC_64K_PAGES */
|
||||
|
||||
/* Get VSID */
|
||||
vsid = get_vsid(mm->context.id, ea);
|
||||
|
||||
/* Hash it in */
|
||||
@ -797,12 +808,6 @@ void hash_preload(struct mm_struct *mm, unsigned long ea,
|
||||
#ifndef CONFIG_PPC_64K_PAGES
|
||||
__hash_page_4K(ea, access, vsid, ptep, trap, local);
|
||||
#else
|
||||
if (mmu_ci_restrictions) {
|
||||
/* If this PTE is non-cacheable, switch to 4k */
|
||||
if (mm->context.user_psize == MMU_PAGE_64K &&
|
||||
(pte_val(*ptep) & _PAGE_NO_CACHE))
|
||||
demote_segment_4k(mm, ea);
|
||||
}
|
||||
if (mm->context.user_psize == MMU_PAGE_64K)
|
||||
__hash_page_64K(ea, access, vsid, ptep, trap, local);
|
||||
else
|
||||
|
Loading…
Reference in New Issue
Block a user