Re: [PATCH 08/15] powerpc/mm: Add new hash_page_mm()
From: Aneesh Kumar K.V <hidden>
Date: 2014-09-29 08:51:05
Also in:
lkml
Michael Neuling [off-list ref] writes:
From: Ian Munsie <redacted> 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.
Can you also explain calling semantics. ie, why would we want to call
this with anything other than current ? Should we flush slb now or
should it be skipped ? so what would happen if the new hash page can
result in segment demotion ? You don't put that under if (mm ==
current->mm). is that ok ?
if ((pte_val(*ptep) & _PAGE_4K_PFN) && psize == MMU_PAGE_64K) {
demote_segment_4k(mm, ea);
psize = MMU_PAGE_4K;
}
We also update paca context there
if (get_paca_psize(addr) != MMU_PAGE_4K) {
get_paca()->context = mm->context;
slb_flush_and_rebolt();
}
You also added code to handle KERNEL_REGION_ID in
[PATCH 02/15] powerpc/cell: Move data segment faulting code out of cell
platform. do we need to handle that here ?
quoted hunk ↗ jump to hunk
Signed-off-by: Ian Munsie <redacted> Signed-off-by: Michael Neuling <redacted> --- arch/powerpc/include/asm/mmu-hash64.h | 1 + arch/powerpc/mm/hash_utils_64.c | 20 +++++++++++++------- 2 files changed, 14 insertions(+), 7 deletions(-)diff --git a/arch/powerpc/include/asm/mmu-hash64.h b/arch/powerpc/include/asm/mmu-hash64.h index fd19a53..a3b85e9 100644 --- a/arch/powerpc/include/asm/mmu-hash64.h +++ b/arch/powerpc/include/asm/mmu-hash64.h@@ -319,6 +319,7 @@ 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 0f73367..66071af 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c@@ -991,26 +991,24 @@ 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;@@ -1106,7 +1104,8 @@ 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; }@@ -1149,7 +1148,8 @@ 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@@ -1184,6 +1184,12 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/