On 19/12/2019 11:49, Michael Ellerman wrote:

Steven Price [off-list ref] writes:

quoted

walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.

For powerpc p?d_is_leaf() functions already exist. Export them using the
new p?d_leaf() name.

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org
CC: kvm-ppc@vger.kernel.org
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 3 +++
 1 file changed, 3 insertions(+)

We have fallback versions of our pmd_is_leaf() etc. in
arch/powerpc/include/asm/pgtable.h, eg:

#ifndef pmd_is_leaf
#define pmd_is_leaf pmd_is_leaf
static inline bool pmd_is_leaf(pmd_t pmd)
{
	return false;
}
#endif

Because we support several different MMUs and most of them don't need to
do anything.

So we could put the compatibility #defines to your names along with the
fallback versions in asm/pgtable.h, rather than in
asm/book3s/64/pgtable.h

But I see you also have fallbacks for your versions, so it probably
doesn't matter either way.

So I'm OK with this version, unless you think there's a compelling
reason to do the compatibility #defines in our asm/pgtable.h

I was thinking that (assuming this series actually gets merged this
time), the p?d_is_leaf() versions could be removed and replaced by
p?d_leaf() in the future. Since the fallbacks are in the asm-generic
code it makes sense for the pmd_leaf() definitions to be next to the
non-fallback versions.

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

Thanks!

Steve

cheers

quoted

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index b01624e5c467..201a69e6a355 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -1355,18 +1355,21 @@ static inline bool is_pte_rw_upgrade(unsigned long old_val, unsigned long new_va
  * Like pmd_huge() and pmd_large(), but works regardless of config options
  */
 #define pmd_is_leaf pmd_is_leaf
+#define pmd_leaf pmd_is_leaf
 static inline bool pmd_is_leaf(pmd_t pmd)
 {
 	return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
 }
 
 #define pud_is_leaf pud_is_leaf
+#define pud_leaf pud_is_leaf
 static inline bool pud_is_leaf(pud_t pud)
 {
 	return !!(pud_raw(pud) & cpu_to_be64(_PAGE_PTE));
 }
 
 #define pgd_is_leaf pgd_is_leaf
+#define pgd_leaf pgd_is_leaf
 static inline bool pgd_is_leaf(pgd_t pgd)
 {
 	return !!(pgd_raw(pgd) & cpu_to_be64(_PAGE_PTE));

-- 
2.20.1

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