[1/2] arm64: don't make early_*map() calls post paging_init()

Message ID 1420482835-6444-2-git-send-email-leif.lindholm@linaro.org
State New
Headers show

Commit Message

Leif Lindholm Jan. 5, 2015, 6:33 p.m.
arm64 early_ioremap/iounmap/memremap/memunmap are not supported beyond
the call to paging_init(), but arm64_enter_virtual_mode() (an early
initcall) makes one call to unmap the UEFI memory map.

Rearrange the code to unmap this region before paging_init().

Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
---
 arch/arm64/kernel/efi.c   | 12 +++---------
 arch/arm64/kernel/setup.c |  2 --
 2 files changed, 3 insertions(+), 11 deletions(-)

Comments

Ard Biesheuvel Jan. 6, 2015, 9:38 a.m. | #1
On 5 January 2015 at 18:33, Leif Lindholm <leif.lindholm@linaro.org> wrote:
> arm64 early_ioremap/iounmap/memremap/memunmap are not supported beyond
> the call to paging_init(), but arm64_enter_virtual_mode() (an early
> initcall) makes one call to unmap the UEFI memory map.
>
> Rearrange the code to unmap this region before paging_init().
>
> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
> ---
>  arch/arm64/kernel/efi.c   | 12 +++---------
>  arch/arm64/kernel/setup.c |  2 --
>  2 files changed, 3 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> index 6fac253..790adb5 100644
> --- a/arch/arm64/kernel/efi.c
> +++ b/arch/arm64/kernel/efi.c
> @@ -317,15 +317,8 @@ void __init efi_init(void)
>                 return;
>
>         reserve_regions();
> -}
> -
> -void __init efi_idmap_init(void)
> -{
> -       if (!efi_enabled(EFI_BOOT))
> -               return;
>
> -       /* boot time idmap_pg_dir is incomplete, so fill in missing parts */
> -       efi_setup_idmap();
> +       early_memunmap(memmap.map, params.mmap_size);
>  }
>
>  static int __init remap_region(efi_memory_desc_t *md, void **new)
> @@ -380,7 +373,6 @@ static int __init arm64_enter_virtual_mode(void)
>         }
>
>         mapsize = memmap.map_end - memmap.map;
> -       early_memunmap(memmap.map, mapsize);
>
>         if (efi_runtime_disabled()) {
>                 pr_info("EFI runtime services will be disabled.\n");
> @@ -393,6 +385,8 @@ static int __init arm64_enter_virtual_mode(void)
>                                                    mapsize);
>         memmap.map_end = memmap.map + mapsize;
>
> +       efi_setup_idmap();
> +

I think this is incorrect: we may call early_alloc() here which is
only allowed before paging_init()

>         efi.memmap = &memmap;
>
>         /* Map the runtime regions */
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index b809911..c7eb3c5 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -401,8 +401,6 @@ void __init setup_arch(char **cmdline_p)
>         paging_init();
>         request_standard_resources();
>
> -       efi_idmap_init();
> -
>         unflatten_device_tree();
>
>         psci_init();
> --
> 2.1.3
>
Leif Lindholm Jan. 6, 2015, 1:39 p.m. | #2
On Tue, Jan 06, 2015 at 09:38:24AM +0000, Ard Biesheuvel wrote:
> > diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> > index 6fac253..790adb5 100644
> > --- a/arch/arm64/kernel/efi.c
> > +++ b/arch/arm64/kernel/efi.c

> > @@ -393,6 +385,8 @@ static int __init arm64_enter_virtual_mode(void)
> >                                                    mapsize);
> >         memmap.map_end = memmap.map + mapsize;
> >
> > +       efi_setup_idmap();
> > +
> 
> I think this is incorrect: we may call early_alloc() here which is
> only allowed before paging_init()

Hmm...
Technically, the existing code is already breaking this restriction
then - but my patch moved that _way_ later in the boot process (early
initcall instead of setup_arch()).

I'll resend with an alternative solution that leaves the
efi_setup_idmap() ordering vs paging init() in its current state.
Since efi_setup_idmap() goes away with your "stable UEFI virtual
mappings for kexec" series, I don't want to make changes here and for
potential backports too invasive.

/
    Leif

Patch

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index 6fac253..790adb5 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -317,15 +317,8 @@  void __init efi_init(void)
 		return;
 
 	reserve_regions();
-}
-
-void __init efi_idmap_init(void)
-{
-	if (!efi_enabled(EFI_BOOT))
-		return;
 
-	/* boot time idmap_pg_dir is incomplete, so fill in missing parts */
-	efi_setup_idmap();
+	early_memunmap(memmap.map, params.mmap_size);
 }
 
 static int __init remap_region(efi_memory_desc_t *md, void **new)
@@ -380,7 +373,6 @@  static int __init arm64_enter_virtual_mode(void)
 	}
 
 	mapsize = memmap.map_end - memmap.map;
-	early_memunmap(memmap.map, mapsize);
 
 	if (efi_runtime_disabled()) {
 		pr_info("EFI runtime services will be disabled.\n");
@@ -393,6 +385,8 @@  static int __init arm64_enter_virtual_mode(void)
 						   mapsize);
 	memmap.map_end = memmap.map + mapsize;
 
+	efi_setup_idmap();
+
 	efi.memmap = &memmap;
 
 	/* Map the runtime regions */
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index b809911..c7eb3c5 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -401,8 +401,6 @@  void __init setup_arch(char **cmdline_p)
 	paging_init();
 	request_standard_resources();
 
-	efi_idmap_init();
-
 	unflatten_device_tree();
 
 	psci_init();