[PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Matt Fleming]

Môshe reported the following warning triggered on his machine since
commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
data"),

  [    0.026936] ------------[ cut here ]------------
  [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
  [    0.026941] Modules linked in:
  [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
  [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
  [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
  [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
  [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
  [    0.026951] Call Trace:
  [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
  [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
  [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
  [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
  [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
  [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
  [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
  [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
  [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
  [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
  [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
  [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
  [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory

early_memremap() has an upper limit on the size of mapping it can
handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
much larger than that.

There's actually no reason to restrict ourselves to using the early_*
version of memremap() - the ACPI BGRT driver is invoked late enough in
boot that we can use the standard version, with the benefit that the
late version allows mappings of arbitrary size.

Reported-by: Môshe van der Sterre <me@moshe.nl>
Tested-by: Môshe van der Sterre <me@moshe.nl>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
---
 arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
index bf51f4c02562..b0970661870a 100644
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -72,14 +72,14 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
+	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image header memory\n");
 		return;
 	}
 
 	memcpy(&bmp_header, image, sizeof(bmp_header));
-	early_memunmap(image, sizeof(bmp_header));
+	memunmap(image);
 	bgrt_image_size = bmp_header.size;
 
 	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
@@ -89,7 +89,7 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, bmp_header.size);
+	image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image memory\n");
 		kfree(bgrt_image);
@@ -98,5 +98,5 @@ void __init efi_bgrt_init(void)
 	}
 
 	memcpy(bgrt_image, image, bgrt_image_size);
-	early_memunmap(image, bmp_header.size);
+	memunmap(image);
 }
-- 
2.6.2

[PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Matt Fleming]

Môshe reported the following warning triggered on his machine since
commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
data"),

  [    0.026936] ------------[ cut here ]------------
  [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
  [    0.026941] Modules linked in:
  [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
  [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
  [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
  [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
  [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
  [    0.026951] Call Trace:
  [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
  [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
  [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
  [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
  [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
  [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
  [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
  [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
  [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
  [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
  [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
  [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
  [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory

early_memremap() has an upper limit on the size of mapping it can
handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
much larger than that.

There's actually no reason to restrict ourselves to using the early_*
version of memremap() - the ACPI BGRT driver is invoked late enough in
boot that we can use the standard version, with the benefit that the
late version allows mappings of arbitrary size.

Reported-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
Tested-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
Cc: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Cc: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
Signed-off-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
---
 arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
index bf51f4c02562..b0970661870a 100644
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -72,14 +72,14 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
+	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image header memory\n");
 		return;
 	}
 
 	memcpy(&bmp_header, image, sizeof(bmp_header));
-	early_memunmap(image, sizeof(bmp_header));
+	memunmap(image);
 	bgrt_image_size = bmp_header.size;
 
 	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
@@ -89,7 +89,7 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, bmp_header.size);
+	image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image memory\n");
 		kfree(bgrt_image);
@@ -98,5 +98,5 @@ void __init efi_bgrt_init(void)
 	}
 
 	memcpy(bgrt_image, image, bgrt_image_size);
-	early_memunmap(image, bmp_header.size);
+	memunmap(image);
 }
-- 
2.6.2

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Josh Triplett]

On Mon, Dec 21, 2015 at 02:12:52PM +0000, Matt Fleming wrote:
> Môshe reported the following warning triggered on his machine since
> commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
> data"),
> 
>   [    0.026936] ------------[ cut here ]------------
>   [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
>   [    0.026941] Modules linked in:
>   [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
>   [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
>   [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
>   [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
>   [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
>   [    0.026951] Call Trace:
>   [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
>   [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
>   [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
>   [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
>   [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
>   [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
>   [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
>   [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
>   [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
>   [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
>   [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
>   [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
>   [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory
> 
> early_memremap() has an upper limit on the size of mapping it can
> handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
> much larger than that.
> 
> There's actually no reason to restrict ourselves to using the early_*
> version of memremap() - the ACPI BGRT driver is invoked late enough in
> boot that we can use the standard version, with the benefit that the
> late version allows mappings of arbitrary size.
> 
> Reported-by: Môshe van der Sterre <me@moshe.nl>
> Tested-by: Môshe van der Sterre <me@moshe.nl>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
> index bf51f4c02562..b0970661870a 100644
> --- a/arch/x86/platform/efi/efi-bgrt.c
> +++ b/arch/x86/platform/efi/efi-bgrt.c
> @@ -72,14 +72,14 @@ void __init efi_bgrt_init(void)
>  		return;
>  	}
>  
> -	image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
> +	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
>  	if (!image) {
>  		pr_err("Ignoring BGRT: failed to map image header memory\n");
>  		return;
>  	}
>  
>  	memcpy(&bmp_header, image, sizeof(bmp_header));
> -	early_memunmap(image, sizeof(bmp_header));
> +	memunmap(image);
>  	bgrt_image_size = bmp_header.size;
>  
>  	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
> @@ -89,7 +89,7 @@ void __init efi_bgrt_init(void)
>  		return;
>  	}
>  
> -	image = early_memremap(bgrt_tab->image_address, bmp_header.size);
> +	image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
>  	if (!image) {
>  		pr_err("Ignoring BGRT: failed to map image memory\n");
>  		kfree(bgrt_image);
> @@ -98,5 +98,5 @@ void __init efi_bgrt_init(void)
>  	}
>  
>  	memcpy(bgrt_image, image, bgrt_image_size);
> -	early_memunmap(image, bmp_header.size);
> +	memunmap(image);
>  }
> -- 
> 2.6.2
> 

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Josh Triplett]

On Mon, Dec 21, 2015 at 02:12:52PM +0000, Matt Fleming wrote:
> Môshe reported the following warning triggered on his machine since
> commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
> data"),
> 
>   [    0.026936] ------------[ cut here ]------------
>   [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
>   [    0.026941] Modules linked in:
>   [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
>   [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
>   [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
>   [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
>   [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
>   [    0.026951] Call Trace:
>   [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
>   [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
>   [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
>   [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
>   [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
>   [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
>   [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
>   [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
>   [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
>   [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
>   [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
>   [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
>   [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory
> 
> early_memremap() has an upper limit on the size of mapping it can
> handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
> much larger than that.
> 
> There's actually no reason to restrict ourselves to using the early_*
> version of memremap() - the ACPI BGRT driver is invoked late enough in
> boot that we can use the standard version, with the benefit that the
> late version allows mappings of arbitrary size.
> 
> Reported-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
> Tested-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
> Cc: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>
> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Cc: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> Signed-off-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>

Reviewed-by: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>

>  arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
> index bf51f4c02562..b0970661870a 100644
> --- a/arch/x86/platform/efi/efi-bgrt.c
> +++ b/arch/x86/platform/efi/efi-bgrt.c
> @@ -72,14 +72,14 @@ void __init efi_bgrt_init(void)
>  		return;
>  	}
>  
> -	image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
> +	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
>  	if (!image) {
>  		pr_err("Ignoring BGRT: failed to map image header memory\n");
>  		return;
>  	}
>  
>  	memcpy(&bmp_header, image, sizeof(bmp_header));
> -	early_memunmap(image, sizeof(bmp_header));
> +	memunmap(image);
>  	bgrt_image_size = bmp_header.size;
>  
>  	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
> @@ -89,7 +89,7 @@ void __init efi_bgrt_init(void)
>  		return;
>  	}
>  
> -	image = early_memremap(bgrt_tab->image_address, bmp_header.size);
> +	image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
>  	if (!image) {
>  		pr_err("Ignoring BGRT: failed to map image memory\n");
>  		kfree(bgrt_image);
> @@ -98,5 +98,5 @@ void __init efi_bgrt_init(void)
>  	}
>  
>  	memcpy(bgrt_image, image, bgrt_image_size);
> -	early_memunmap(image, bmp_header.size);
> +	memunmap(image);
>  }
> -- 
> 2.6.2
> 

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Matt Fleming]

On Mon, 21 Dec, at 02:12:52PM, Matt Fleming wrote:
> Môshe reported the following warning triggered on his machine since
> commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
> data"),
> 
>   [    0.026936] ------------[ cut here ]------------
>   [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
>   [    0.026941] Modules linked in:
>   [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
>   [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
>   [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
>   [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
>   [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
>   [    0.026951] Call Trace:
>   [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
>   [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
>   [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
>   [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
>   [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
>   [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
>   [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
>   [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
>   [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
>   [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
>   [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
>   [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
>   [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory
> 
> early_memremap() has an upper limit on the size of mapping it can
> handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
> much larger than that.
> 
> There's actually no reason to restrict ourselves to using the early_*
> version of memremap() - the ACPI BGRT driver is invoked late enough in
> boot that we can use the standard version, with the benefit that the
> late version allows mappings of arbitrary size.
> 
> Reported-by: Môshe van der Sterre <me@moshe.nl>
> Tested-by: Môshe van der Sterre <me@moshe.nl>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
> ---
>  arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Ping? Could someone please pick this up for the 'x86/efi' branch? It
fixes a bug in 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when
mapping BGRT data").

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Matt Fleming]

On Mon, 21 Dec, at 02:12:52PM, Matt Fleming wrote:
> Môshe reported the following warning triggered on his machine since
> commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
> data"),
> 
>   [    0.026936] ------------[ cut here ]------------
>   [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
>   [    0.026941] Modules linked in:
>   [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
>   [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
>   [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
>   [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
>   [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
>   [    0.026951] Call Trace:
>   [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
>   [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
>   [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
>   [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
>   [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
>   [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
>   [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
>   [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
>   [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
>   [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
>   [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
>   [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
>   [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory
> 
> early_memremap() has an upper limit on the size of mapping it can
> handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
> much larger than that.
> 
> There's actually no reason to restrict ourselves to using the early_*
> version of memremap() - the ACPI BGRT driver is invoked late enough in
> boot that we can use the standard version, with the benefit that the
> late version allows mappings of arbitrary size.
> 
> Reported-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
> Tested-by: Môshe van der Sterre <me-A/3C56C7qwM@public.gmane.org>
> Cc: Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>
> Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Cc: Borislav Petkov <bp-l3A5Bk7waGM@public.gmane.org>
> Signed-off-by: Matt Fleming <matt-mF/unelCI9GS6iBeEJttW/XRex20P6io@public.gmane.org>
> ---
>  arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Ping? Could someone please pick this up for the 'x86/efi' branch? It
fixes a bug in 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when
mapping BGRT data").

[tip:x86/efi] x86/efi-bgrt: Replace early_memremap() with memremap()

[tip-bot for Matt Fleming]

Commit-ID:  e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
Gitweb:     http://git.kernel.org/tip/e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
Author:     Matt Fleming <matt@codeblueprint.co.uk>
AuthorDate: Mon, 21 Dec 2015 14:12:52 +0000
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 6 Jan 2016 18:28:52 +0100

x86/efi-bgrt: Replace early_memremap() with memremap()

Môshe reported the following warning triggered on his machine since
commit 50a0cb565246 ("x86/efi-bgrt: Fix kernel panic when mapping BGRT
data"),

  [    0.026936] ------------[ cut here ]------------
  [    0.026941] WARNING: CPU: 0 PID: 0 at mm/early_ioremap.c:137 __early_ioremap+0x102/0x1bb()
  [    0.026941] Modules linked in:
  [    0.026944] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1 #2
  [    0.026945] Hardware name: Dell Inc. XPS 13 9343/09K8G1, BIOS A05 07/14/2015
  [    0.026946]  0000000000000000 900f03d5a116524d ffffffff81c03e60 ffffffff813a3fff
  [    0.026948]  0000000000000000 ffffffff81c03e98 ffffffff810a0852 00000000d7b76000
  [    0.026949]  0000000000000000 0000000000000001 0000000000000001 000000000000017c
  [    0.026951] Call Trace:
  [    0.026955]  [<ffffffff813a3fff>] dump_stack+0x44/0x55
  [    0.026958]  [<ffffffff810a0852>] warn_slowpath_common+0x82/0xc0
  [    0.026959]  [<ffffffff810a099a>] warn_slowpath_null+0x1a/0x20
  [    0.026961]  [<ffffffff81d8c395>] __early_ioremap+0x102/0x1bb
  [    0.026962]  [<ffffffff81d8c602>] early_memremap+0x13/0x15
  [    0.026964]  [<ffffffff81d78361>] efi_bgrt_init+0x162/0x1ad
  [    0.026966]  [<ffffffff81d778ec>] efi_late_init+0x9/0xb
  [    0.026968]  [<ffffffff81d58ff5>] start_kernel+0x46f/0x49f
  [    0.026970]  [<ffffffff81d58120>] ? early_idt_handler_array+0x120/0x120
  [    0.026972]  [<ffffffff81d58339>] x86_64_start_reservations+0x2a/0x2c
  [    0.026974]  [<ffffffff81d58485>] x86_64_start_kernel+0x14a/0x16d
  [    0.026977] ---[ end trace f9b3812eb8e24c58 ]---
  [    0.026978] efi_bgrt: Ignoring BGRT: failed to map image memory

early_memremap() has an upper limit on the size of mapping it can
handle which is ~200KB. Clearly the BGRT image on Môshe's machine is
much larger than that.

There's actually no reason to restrict ourselves to using the early_*
version of memremap() - the ACPI BGRT driver is invoked late enough in
boot that we can use the standard version, with the benefit that the
late version allows mappings of arbitrary size.

Reported-by: Môshe van der Sterre <me@moshe.nl>
Tested-by: Môshe van der Sterre <me@moshe.nl>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1450707172-12561-1-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/platform/efi/efi-bgrt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
index bf51f4c..b097066 100644
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -72,14 +72,14 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
+	image = memremap(bgrt_tab->image_address, sizeof(bmp_header), MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image header memory\n");
 		return;
 	}
 
 	memcpy(&bmp_header, image, sizeof(bmp_header));
-	early_memunmap(image, sizeof(bmp_header));
+	memunmap(image);
 	bgrt_image_size = bmp_header.size;
 
 	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
@@ -89,7 +89,7 @@ void __init efi_bgrt_init(void)
 		return;
 	}
 
-	image = early_memremap(bgrt_tab->image_address, bmp_header.size);
+	image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
 	if (!image) {
 		pr_err("Ignoring BGRT: failed to map image memory\n");
 		kfree(bgrt_image);
@@ -98,5 +98,5 @@ void __init efi_bgrt_init(void)
 	}
 
 	memcpy(bgrt_image, image, bgrt_image_size);
-	early_memunmap(image, bmp_header.size);
+	memunmap(image);
 }

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Greg KH]

On Fri, Dec 01, 2017 at 04:25:44PM +0000, Ghannam, Yazen wrote:
> > -----Original Message-----
> > From: Greg KH [mailto:gregkh@linuxfoundation.org]
> > Sent: Friday, December 1, 2017 11:16 AM
> > To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
> > Cc: stable@vger.kernel.org
> > Subject: Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with
> > memremap()
> > 
> > On Fri, Dec 01, 2017 at 08:35:52AM +0000, Ghannam, Yazen wrote:
> > > Upstream commit ID: e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
> > > Prerequisite commit: "50a0cb565246 x86/efi-bgrt: Fix kernel panic when
> > mapping BGRT data"
> > 
> > So apply both of these patches to 4.4?  Please be specific as I'm
> > confused here.
> > 
> 
> Yes, both.
> 
> The first commit is the fix, and the second commit is needed for the first to
> apply cleanly.
> 
> So cherry-pick
> 1) 50a0cb565246f20d59cdb161778531e4b19d35ac
> 2) e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
> 
> Sorry, I wasn't sure of the best way to describe this.

Both now applied, thanks.

greg k-h

RE: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Ghannam, Yazen]

> -----Original Message-----
> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> Sent: Friday, December 1, 2017 11:16 AM
> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
> Cc: stable@vger.kernel.org
> Subject: Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with
> memremap()
> 
> On Fri, Dec 01, 2017 at 08:35:52AM +0000, Ghannam, Yazen wrote:
> > Upstream commit ID: e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
> > Prerequisite commit: "50a0cb565246 x86/efi-bgrt: Fix kernel panic when
> mapping BGRT data"
> 
> So apply both of these patches to 4.4?  Please be specific as I'm
> confused here.
> 

Yes, both.

The first commit is the fix, and the second commit is needed for the first to
apply cleanly.

So cherry-pick
1) 50a0cb565246f20d59cdb161778531e4b19d35ac
2) e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f

Sorry, I wasn't sure of the best way to describe this.

Thanks,
Yazen

Re: [PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Greg KH]

On Fri, Dec 01, 2017 at 08:35:52AM +0000, Ghannam, Yazen wrote:
> Upstream commit ID: e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
> Prerequisite commit: "50a0cb565246 x86/efi-bgrt: Fix kernel panic when mapping BGRT data"

So apply both of these patches to 4.4?  Please be specific as I'm
confused here.

thanks,

greg k-h

[PATCH] x86/efi-bgrt: Replace early_memremap() with memremap()

[Ghannam, Yazen]

Upstream commit ID: e2c90dd7e11e3025b46719a79fb4bb1e7a5cef9f
Prerequisite commit: "50a0cb565246 x86/efi-bgrt: Fix kernel panic when mapping BGRT data"

Reason: Fixes the following call trace on AMD Fam17h systems.
[  +0.019604] ------------[ cut here ]------------
[  +0.000008] WARNING: CPU: 0 PID: 0 at /home/yghannam/linux-amd-yazen/mm/early_ioremap.c:122 __early_ioremap+0x9b/0x1bd()
[  +0.000006] Modules linked in:
[  +0.000006] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.103-HEAD #2
...
[  +0.000006]  0000000000000286 02cb38f113d2874f ffffffff81e03e50 ffffffff813e0767
[  +0.000007]  0000000000000000 ffffffff81c9e5f0 ffffffff81e03e88 ffffffff81080192
[  +0.000007]  0000000074d32018 0000000000000000 0000000000000001 0000000000000001
[  +0.000007] Call Trace:
[  +0.000007]  [<ffffffff813e0767>] dump_stack+0x63/0x8c
[  +0.000006]  [<ffffffff81080192>] warn_slowpath_common+0x82/0xc0
[  +0.000005]  [<ffffffff810802da>] warn_slowpath_null+0x1a/0x20
[  +0.000004]  [<ffffffff81fbb86e>] __early_ioremap+0x9b/0x1bd
[  +0.000006]  [<ffffffff81fa5476>] ? __early_set_fixmap+0x84/0x95
[  +0.000005]  [<ffffffff811adc75>] ? kmalloc_slab+0x5/0xa0
[  +0.000005]  [<ffffffff81fbbb66>] early_ioremap+0x13/0x15
[  +0.000005]  [<ffffffff81fa860b>] efi_bgrt_init+0x192/0x1ea
[  +0.000004]  [<ffffffff81fa7b68>] efi_late_init+0x9/0xb
[  +0.000006]  [<ffffffff81f88002>] start_kernel+0x46c/0x49c
[  +0.000005]  [<ffffffff81f87120>] ? early_idt_handler_array+0x120/0x120
[  +0.000005]  [<ffffffff81f8732d>] x86_64_start_reservations+0x2a/0x2c
[  +0.000004]  [<ffffffff81f8746a>] x86_64_start_kernel+0x13b/0x15e
[  +0.000009] ---[ end trace f9b2fbcd6a135369 ]---
[  +0.000004] Ignoring BGRT: failed to map image memory

Stable version to apply to: 4.4.x

Thanks,
Yazen