From f6ab0b922c3423b88c0e6e3e2c5fc1e58d83055d Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 29 Oct 2007 12:05:18 +1100 Subject: [PATCH] [POWERPC] powerpc: Fix demotion of segments to 4K pages When demoting a process to use 4K HW pages (instead of 64K), which happens under various circumstances such as doing cache inhibited mappings on machines that do not support 64K CI pages, the assembly hash code calls back into the C function flush_hash_page(). This function prototype was recently changed to accomodate for 1T segments but the assembly call site was not updated, causing applications that do demotion to hang. In addition, when updating the per-CPU PACA for the new sizes, we didn't properly update the slice "map", thus causing the SLB miss code to re-insert segments for the wrong size. This fixes both and adds a warning comment next to the C implementation to try to avoid problems next time someone changes it. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/mm/hash_low_64.S | 5 +++-- arch/powerpc/mm/hash_utils_64.c | 6 ++++-- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/mm/hash_low_64.S b/arch/powerpc/mm/hash_low_64.S index ad253b959030..e935edd6b72b 100644 --- a/arch/powerpc/mm/hash_low_64.S +++ b/arch/powerpc/mm/hash_low_64.S @@ -331,7 +331,7 @@ htab_pte_insert_failure: *****************************************************************************/ /* _hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, - * pte_t *ptep, unsigned long trap, int local) + * pte_t *ptep, unsigned long trap, int local, int ssize) */ /* @@ -557,7 +557,8 @@ htab_inval_old_hpte: mr r4,r31 /* PTE.pte */ li r5,0 /* PTE.hidx */ li r6,MMU_PAGE_64K /* psize */ - ld r7,STK_PARM(r8)(r1) /* local */ + ld r7,STK_PARM(r9)(r1) /* ssize */ + ld r8,STK_PARM(r8)(r1) /* local */ bl .flush_hash_page b htab_insert_pte diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index c78dc912411f..c5a603fdb22d 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -791,8 +791,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap) } if (user_region) { if (psize != get_paca()->context.user_psize) { - get_paca()->context.user_psize = - mm->context.user_psize; + get_paca()->context = mm->context; slb_flush_and_rebolt(); } } else if (get_paca()->vmalloc_sllp != @@ -885,6 +884,9 @@ void hash_preload(struct mm_struct *mm, unsigned long ea, local_irq_restore(flags); } +/* WARNING: This is called from hash_low_64.S, if you change this prototype, + * do not forget to update the assembly call site ! + */ void flush_hash_page(unsigned long va, real_pte_t pte, int psize, int ssize, int local) { -- 2.20.1