Re: [PATCH v6 2/7] powerpc/64s: mm: Introduce __pmdp_collapse_flush with mm_struct argument

On 15 Feb 2023, at 11:17 am, Rohan McLure [off-list ref] wrote:

quoted

On 14 Feb 2023, at 5:02 pm, Christophe Leroy [off-list ref] wrote:



Le 14/02/2023 à 02:59, Rohan McLure a écrit :

quoted

pmdp_collapse_flush has references in generic code with just three
parameters, due to the choice of mm context being implied by the vm_area
context parameter.

Define __pmdp_collapse_flush to accept an additional mm_struct *
parameter, with pmdp_collapse_flush a macro that unpacks the vma and
calls __pmdp_collapse_flush. The mm_struct * parameter is needed in a
future patch providing Page Table Check support, which is defined in
terms of mm context objects.

Signed-off-by: Rohan McLure <redacted>
---
v6: New patch
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index cb4c67bf45d7..9d8b4e25f5ed 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -1244,14 +1244,22 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
 return hash__pmdp_huge_get_and_clear(mm, addr, pmdp);

}

-static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmdp)
+static inline pmd_t __pmdp_collapse_flush(struct vm_area_struct *vma, struct mm_struct *mm,
+  unsigned long address, pmd_t *pmdp)
{
 if (radix_enabled())
 return radix__pmdp_collapse_flush(vma, address, pmdp);
 return hash__pmdp_collapse_flush(vma, address, pmdp);
}
-#define pmdp_collapse_flush pmdp_collapse_flush
+#define pmdp_collapse_flush(vma, addr, pmdp) \
+({ \
+ struct vm_area_struct *_vma = (vma); \
+ pmd_t _r; \
+ \
+ _r = __pmdp_collapse_flush(_vma, _vma->vm_mm, (addr), (pmdp)); \
+ \
+ _r; \
+})

Can you make it a static inline function instead of a ugly macro ?

Due to some header hell, it’s looking like this location only has access to
a prototype for struct vm_area_struct. Might have to remain a macro then.

Probably don’t need to expliclty declare a variable for the macro ‘return’
though.

It’s the same solution opted for by ptep_test_and_clear_young.

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define ptep_test_and_clear_young(__vma, __addr, __ptep)	\
({								\
	__ptep_test_and_clear_young((__vma)->vm_mm, __addr, __ptep); \
})

quoted

quoted

#define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL
pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma,