Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.8 02/33] powerpc/mm: Fix lazy icache flush on pre-POWER5 | Date | Tue, 13 Dec 2016 09:16:03 -0800 |
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4.8-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
commit dd7b2f035ec41a409f7a7cec7aabc0ec0eacf476 upstream.
On 64-bit CPUs with no-execute support and non-snooping icache, such as 970 or POWER4, we have a software mechanism to ensure coherency of the cache (using exec faults when needed).
This was broken due to a logic error when the code was rewritten from assembly to C, previously the assembly code did:
BEGIN_FTR_SECTION mr r4,r30 mr r5,r7 bl hash_page_do_lazy_icache END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)
Which tests that: (cpu_features & (NOEXECUTE | COHERENT_ICACHE)) == NOEXECUTE
Which says that the current cpu does have NOEXECUTE, but does not have COHERENT_ICACHE.
Fixes: 91f1da99792a ("powerpc/mm: Convert 4k hash insert to C") Fixes: 89ff725051d1 ("powerpc/mm: Convert __hash_page_64K to C") Fixes: a43c0eb8364c ("powerpc/mm: Convert 4k insert from asm to C") Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> [mpe: Change log verbosification] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/powerpc/mm/hash64_4k.c | 2 +- arch/powerpc/mm/hash64_64k.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
--- a/arch/powerpc/mm/hash64_4k.c +++ b/arch/powerpc/mm/hash64_4k.c @@ -55,7 +55,7 @@ int __hash_page_4K(unsigned long ea, uns */ rflags = htab_convert_pte_flags(new_pte); - if (!cpu_has_feature(CPU_FTR_NOEXECUTE) && + if (cpu_has_feature(CPU_FTR_NOEXECUTE) && !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap); --- a/arch/powerpc/mm/hash64_64k.c +++ b/arch/powerpc/mm/hash64_64k.c @@ -87,7 +87,7 @@ int __hash_page_4K(unsigned long ea, uns subpg_pte = new_pte & ~subpg_prot; rflags = htab_convert_pte_flags(subpg_pte); - if (!cpu_has_feature(CPU_FTR_NOEXECUTE) && + if (cpu_has_feature(CPU_FTR_NOEXECUTE) && !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) { /* @@ -258,7 +258,7 @@ int __hash_page_64K(unsigned long ea, un rflags = htab_convert_pte_flags(new_pte); - if (!cpu_has_feature(CPU_FTR_NOEXECUTE) && + if (cpu_has_feature(CPU_FTR_NOEXECUTE) && !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
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