Messages in this thread Patch in this message | | | Date | Wed, 31 Aug 2022 13:52:57 +0200 | Subject | Re: [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug | From | Marek Szyprowski <> |
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Hi Victor,
On 16.03.2022 03:33, Victor Hassan wrote: > earlycon uses fixmap to create a memory map, > So we need to close earlycon before closing fixmap, > otherwise printk will access illegal addresses. > After creating a new memory map, we open earlycon again. > > Signed-off-by: Victor Hassan <victor@allwinnertech.com>
This patch landed in linux next-20220831 as commit a76886d117cb ("ARM: 9223/1: mmu: fix access to illegal address when using earlycon & memblock=debug"). Unfortunately it breaks booting of all my test boards which *do not* use earlycon. It can be easily reproduced even with QEMU.
With kernel compiled from multi_v7_defconfig the following setup boots:
$ qemu-system-arm -nographic -kernel arch/arm/boot/zImage -append "console=ttyAMA0 earlycon" -M virt -smp 2 -m 512
while this one doesn't:
$ qemu-system-arm -nographic -kernel arch/arm/boot/zImage -append "console=ttyAMA0" -M virt -smp 2 -m 512
> --- > arch/arm/mm/mmu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c > index 274e4f73fd33..f3511f07a7d0 100644 > --- a/arch/arm/mm/mmu.c > +++ b/arch/arm/mm/mmu.c > @@ -14,6 +14,7 @@ > #include <linux/fs.h> > #include <linux/vmalloc.h> > #include <linux/sizes.h> > +#include <linux/console.h> > > #include <asm/cp15.h> > #include <asm/cputype.h> > @@ -1695,6 +1696,9 @@ static void __init early_fixmap_shutdown(void) > pmd_clear(fixmap_pmd(va)); > local_flush_tlb_kernel_page(va); > > +#ifdef CONFIG_FIX_EARLYCON_MEM > + console_stop(console_drivers); > +#endif > for (i = 0; i < __end_of_permanent_fixed_addresses; i++) { > pte_t *pte; > struct map_desc map; > @@ -1713,6 +1717,9 @@ static void __init early_fixmap_shutdown(void) > > create_mapping(&map); > } > +#ifdef CONFIG_FIX_EARLYCON_MEM > + console_start(console_drivers); > +#endif > } > > /*
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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