From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben.dooks@codethink.co.uk (Ben Dooks) Date: Mon, 11 Feb 2013 19:11:58 +0000 Subject: [PATCH 05/17] ARM: fixup_pv_table bug when CPU_ENDIAN_BE8 In-Reply-To: References: <1360365467-25056-1-git-send-email-ben.dooks@codethink.co.uk> <1360365467-25056-6-git-send-email-ben.dooks@codethink.co.uk> Message-ID: <5119427E.3000502@codethink.co.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 09/02/13 03:40, Nicolas Pitre wrote: > On Fri, 8 Feb 2013, Ben Dooks wrote: > >> The fixup_pv_table assumes that the instructions are in the same >> endian configuration as the data, but when the CPU is running in >> BE8 the instructions stay in little-endian format. >> >> Make sure if CONFIG_CPU_ENDIAN_BE8 is set that we do all the >> alterations to the instructions taking in to account the LDR/STR >> will be swapping the data endian-ness. >> >> Since the code is only modifying a byte, we avoid dual-swapping >> the data, and just change the bits we clear and ORR in. >> >> Note, not tested against an actual bug, it looked wrong. > > You are missing the CONFIG_THUMB2_KERNEL counterpart. Sorry, I will have a look into that, although I may need some help on that as I don't have any experience with CONFIG_THUMB2_KERNEL or a userland to test with. >> Signed-off-by: Ben Dooks >> --- >> arch/arm/kernel/head.S | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S >> index f1ab279..aafb151 100644 >> --- a/arch/arm/kernel/head.S >> +++ b/arch/arm/kernel/head.S >> @@ -579,8 +579,14 @@ __fixup_a_pv_table: >> #else >> b 2f >> 1: ldr ip, [r7, r3] >> +#ifdef CONFIG_CPU_ENDIAN_BE8 >> + @ in BE8, we load data in BE, but instructions still in LE >> + bic ip, ip, #0xff000000 >> + orr ip, ip, r6, lsl#24 >> +#else >> bic ip, ip, #0x000000ff >> orr ip, ip, r6 @ mask in offset bits 31-24 >> +#endif >> str ip, [r7, r3] >> 2: cmp r4, r5 >> ldrcc r7, [r4], #4 @ use branch for delay slot >> -- >> 1.7.10.4 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel at lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius