[PATCH v2 09/17] powerpc/mm: Add new hash_page_mm()

Michael Neuling
2014-09-30T10:35:47Z

From: Ian Munsie <imunsie@au1.ibm.com>

This adds a new function hash_page_mm() based on the existing hash_page().
This version allows any struct mm to be passed in, rather than assuming
current. This is useful for servicing co-processor faults which are not in the
context of the current running process.

We need to be careful here as the current hash_page() assumes current in a few
places.

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
---
arch/powerpc/include/asm/mmu-hash64.h | 1 +
arch/powerpc/mm/hash_utils_64.c | 22 ++++++++++++++--------
2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h
index 6d0b7a2..f84e5a5 100644
--- a/arch/powerpc/include/asm/mmu-hash64.h
+++ b/arch/powerpc/include/asm/mmu-hash64.h
@@ -322,6 +322,7 @@ extern int __hash_page_64K(unsigned long ea, unsigned long access,
unsigned int local, int ssize);
struct mm_struct;
unsigned int hash_page_do_lazy_icache(unsigned int pp, pte_t pte, int trap);
+extern int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, unsigned long trap);
extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap);
int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
pte_t *ptep, unsigned long trap, int local, int ssize,
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index bbdb054..0a5c8c0 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -904,7 +904,7 @@ void demote_segment_4k(struct mm_struct *mm, unsigned long addr)
return;
slice_set_range_psize(mm, addr, 1, MMU_PAGE_4K);
copro_flush_all_slbs(mm);
- if (get_paca_psize(addr) != MMU_PAGE_4K) {
+ if ((get_paca_psize(addr) != MMU_PAGE_4K) && (current->mm == mm)) {
get_paca()->context = mm->context;
slb_flush_and_rebolt();
}
@@ -989,26 +989,24 @@ static void check_paca_psize(unsigned long ea, struct mm_struct *mm,
* -1 - critical hash insertion error
* -2 - access not permitted by subpage protection mechanism
*/
-int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
+int hash_page_mm(struct mm_struct *mm, unsigned long ea, unsigned long access, unsigned long trap)
{
enum ctx_state prev_state = exception_enter();
pgd_t *pgdir;
unsigned long vsid;
- struct mm_struct *mm;
pte_t *ptep;
unsigned hugeshift;
const struct cpumask *tmp;
int rc, user_region = 0, local = 0;
int psize, ssize;

- DBG_LOW("hash_page(ea=%016lx, access=%lx, trap=%lx\n",
- ea, access, trap);
+ DBG_LOW("%s(ea=%016lx, access=%lx, trap=%lx\n",
+ __func__, ea, access, trap);

/* Get region & vsid */
switch (REGION_ID(ea)) {
case USER_REGION_ID:
user_region = 1;
- mm = current->mm;
if (! mm) {
DBG_LOW(" user region with no mm !\n");
rc = 1;
@@ -1104,7 +1102,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
WARN_ON(1);
}
#endif
- check_paca_psize(ea, mm, psize, user_region);
+ if (current->mm == mm)
+ check_paca_psize(ea, mm, psize, user_region);

goto bail;
}
@@ -1145,7 +1144,8 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
}
}

- check_paca_psize(ea, mm, psize, user_region);
+ if (current->mm == mm)
+ check_paca_psize(ea, mm, psize, user_region);
#endif /* CONFIG_PPC_64K_PAGES */

#ifdef CONFIG_PPC_HAS_HASH_64K
@@ -1180,6 +1180,12 @@ bail:
exception_exit(prev_state);
return rc;
}
+EXPORT_SYMBOL_GPL(hash_page_mm);
+
+int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
+{
+ return hash_page_mm(current->mm, ea, access, trap);
+}
EXPORT_SYMBOL_GPL(hash_page);

void hash_preload(struct mm_struct *mm, unsigned long ea,
--
1.9.1