From b2a3c5be4d6df3b04781f430c2201cbbc9900f66 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Fri, 22 Jan 2016 10:58:25 +0000 Subject: [PATCH] MIPS: c-r4k: Sync icache when it fills from dcache It is still necessary to handle icache coherency in flush_cache_range() and copy_to_user_page() when the icache fills from the dcache, even though the dcache does not need to be written back. However when this handling was added in commit 2eaa7ec286db ("[MIPS] Handle I-cache coherency in flush_cache_range()"), it did not do any icache flushing when it fills from dcache. Therefore fix r4k_flush_cache_range() to run local_r4k_flush_cache_range() without taking into account whether icache fills from dcache, so that the icache coherency gets handled. Checks are also added in local_r4k_flush_cache_range() so that the dcache blast doesn't take place when icache fills from dcache. A test to mmap a page PROT_READ|PROT_WRITE, modify code in it, and mprotect it to VM_READ|VM_EXEC (similar to case described in above commit) can hit this case quite easily to verify the fix. A similar check was added in commit f8829caee311 ("[MIPS] Fix aliasing bug in copy_to_user_page / copy_from_user_page"), so also fix copy_to_user_page() similarly, to call flush_cache_page() without taking into account whether icache fills from dcache, since flush_cache_page() already takes that into account to avoid performing a dcache flush. Signed-off-by: James Hogan Cc: Leonid Yegoshin Cc: Manuel Lauss Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/12179/ Signed-off-by: Ralf Baechle --- arch/mips/mm/c-r4k.c | 11 +++++++++-- arch/mips/mm/init.c | 2 +- 2 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index caac3d7..fc7289d 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -492,7 +492,14 @@ static inline void local_r4k_flush_cache_range(void * args) if (!(has_valid_asid(vma->vm_mm))) return; - r4k_blast_dcache(); + /* + * If dcache can alias, we must blast it since mapping is changing. + * If executable, we must ensure any dirty lines are written back far + * enough to be visible to icache. + */ + if (cpu_has_dc_aliases || (exec && !cpu_has_ic_fills_f_dc)) + r4k_blast_dcache(); + /* If executable, blast stale lines from icache */ if (exec) r4k_blast_icache(); } @@ -502,7 +509,7 @@ static void r4k_flush_cache_range(struct vm_area_struct *vma, { int exec = vma->vm_flags & VM_EXEC; - if (cpu_has_dc_aliases || (exec && !cpu_has_ic_fills_f_dc)) + if (cpu_has_dc_aliases || exec) r4k_on_each_cpu(local_r4k_flush_cache_range, vma); } diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 7e5fa09..6c6a843 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -196,7 +196,7 @@ void copy_to_user_page(struct vm_area_struct *vma, if (cpu_has_dc_aliases) SetPageDcacheDirty(page); } - if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc) + if (vma->vm_flags & VM_EXEC) flush_cache_page(vma, vaddr, page_to_pfn(page)); } -- 2.7.4