quoted

quoted

quoted

After creating a new memory map, we open earlycon again.

Signed-off-by: Victor Hassan <redacted>

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

quoted

---
   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

+#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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