Messages in this thread Patch in this message | | | Date | Thu, 1 Sep 2022 20:53:19 +0800 | Subject | Re: [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug | From | Victor Hassan <> |
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On 2022/8/31 20:37, Victor Hassan wrote: > On 8/31/2022 7:52 PM, Marek Szyprowski wrote: >> 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 > > Dear Marek, > Thank you for the notice. I'll figure it out and feed back to you as > soon as possible. > > Regards, > Victor
Hi Marek,
Sorry, didn't take into account that console_drivers is NULL when earlycon is not used.
Here is the patch-v2. Please review:
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index a49f0b9..a240f38 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> @@ -1730,6 +1731,10 @@ pmd_clear(fixmap_pmd(va)); local_flush_tlb_kernel_page(va);
+#ifdef CONFIG_FIX_EARLYCON_MEM + if (console_drivers) + console_stop(console_drivers); +#endif for (i = 0; i < __end_of_permanent_fixed_addresses; i++) { pte_t *pte; struct map_desc map; @@ -1748,6 +1753,10 @@
create_mapping(&map); } +#ifdef CONFIG_FIX_EARLYCON_MEM + if (console_drivers) + console_start(console_drivers); +#endif }
BTW, should I resend the patch-v2 through the site (https://www.armlinux.org.uk/developer/patches/add.php), or should I send the patch-v2 through E-mail to Linux-Mainline?
Thanks you. Regards, Victor
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