On Wed, May 31, 2023 at 02:40:13PM +0200, Ahmad Fatoum wrote: > On 31.05.23 14:38, Sascha Hauer wrote: > > On Wed, May 31, 2023 at 01:58:33PM +0200, Ahmad Fatoum wrote: > >>> From b6e5c92682467496bd9c57918996f1feffda2dd6 Mon Sep 17 00:00:00 2001 > >>> From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > >>> Date: Wed, 31 May 2023 11:58:51 +0200 > >>> Subject: [PATCH] ARM: mmu_32: fix setting up zero page when it is in SDRAM > >>> > >>> We used to skip setting the zero page to faulting when SDRAM starts at > >>> 0x0. As bootm code now explicitly sets the zero page accessible before > >>> copying ATAGs there this should no longer be necessary, so > >>> unconditionally set the zero page to faulting during MMU startup. This > >>> also moves the zero page and vector table setup after the point the > >>> SDRAM has been mapped cachable, because otherwise the zero page and > >>> possibly the vector table mapping would be overwritten. > >>> > >>> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> > >>> --- > >>> arch/arm/cpu/mmu_32.c | 23 +++++++++-------------- > >>> 1 file changed, 9 insertions(+), 14 deletions(-) > >>> > >>> diff --git a/arch/arm/cpu/mmu_32.c b/arch/arm/cpu/mmu_32.c > >>> index c4e5a3bb0a..14775768a3 100644 > >>> --- a/arch/arm/cpu/mmu_32.c > >>> +++ b/arch/arm/cpu/mmu_32.c > >>> @@ -461,19 +461,14 @@ static int set_vector_table(unsigned long adr) > >>> > >>> static void create_zero_page(void) > >> > >> Is this commit incomplete? Vectors should be set up unconditionally and > >> create_zero_page should be called after it. > > > > Vectors are set up unconditionally and create_zero_page() is called the > > same way as before. > > So zero page is requested first and then on platforms with vector at > address 0 requesting fails and we are left without configured IVT? I think you are misreading the patch. Please look at it again. create_zero_page() is called only when the vector table is not at 0x0. It has been like that without this patch, the patch doesn't change anything here. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |