From mboxrd@z Thu Jan 1 00:00:00 1970 From: nico@fluxnic.net (Nicolas Pitre) Date: Wed, 04 Jan 2012 14:34:27 -0500 (EST) Subject: [PATCH] ARM: LPAE: Check the CPU support for the long descriptor format In-Reply-To: <1325696652-27367-1-git-send-email-catalin.marinas@arm.com> References: <1325696652-27367-1-git-send-email-catalin.marinas@arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 4 Jan 2012, Catalin Marinas wrote: > This patch adds a check for the presence of the LPAE feature during the > CPU initialisation. If not present, it reports an error when > CONFIG_DEBUG_LL is enabled. > > Signed-off-by: Catalin Marinas Acked-by: Nicolas Pitre > --- > arch/arm/kernel/head.S | 8 ++++++++ > 1 files changed, 8 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S > index 54fa641..b26291c 100644 > --- a/arch/arm/kernel/head.S > +++ b/arch/arm/kernel/head.S > @@ -99,6 +99,14 @@ ENTRY(stext) > THUMB( it eq ) @ force fixup-able long branch encoding > beq __error_p @ yes, error 'p' > > +#ifdef CONFIG_ARM_LPAE > + mrc p15, 0, r3, c0, c1, 4 @ read ID_MMFR0 > + and r3, r3, #0xf @ extract VMSA support > + cmp r3, #5 @ long-descriptor translation table format? > + THUMB( it lo ) @ force fixup-able long branch encoding > + blo __error_p @ only classic page table format > +#endif > + > #ifndef CONFIG_XIP_KERNEL > adr r3, 2f > ldmia r3, {r4, r8} > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >