* Re: [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment
2018-11-01 15:53 [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment Borislav Petkov
@ 2018-11-01 17:09 ` Thomas Gleixner
2018-11-05 13:39 ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Thomas Gleixner @ 2018-11-01 17:09 UTC (permalink / raw)
To: Borislav Petkov; +Cc: X86 ML, Mike Rapoport, LKML
On Thu, 1 Nov 2018, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> ... to actually explain what the function is trying to do.
>
> Reported-by: Mike Rapoport <rppt@linux.ibm.com>
> Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
^ permalink raw reply [flat|nested] 6+ messages in thread* [tip:x86/cleanups] x86/gart: Rewrite early_gart_iommu_check() comment
2018-11-01 15:53 [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment Borislav Petkov
2018-11-01 17:09 ` Thomas Gleixner
@ 2018-11-05 13:39 ` tip-bot for Borislav Petkov
2018-11-05 15:35 ` [PATCH] " Ingo Molnar
2018-11-05 20:24 ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Borislav Petkov @ 2018-11-05 13:39 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, bp, tglx, hpa, x86, rppt, mingo
Commit-ID: 59d130cc9b92b92feaada94a0802fa747038d17f
Gitweb: https://git.kernel.org/tip/59d130cc9b92b92feaada94a0802fa747038d17f
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Thu, 1 Nov 2018 16:24:43 +0100
Committer: Borislav Petkov <bp@suse.de>
CommitDate: Mon, 5 Nov 2018 14:35:10 +0100
x86/gart: Rewrite early_gart_iommu_check() comment
... to actually explain what the function is trying to do.
Reported-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <x86@kernel.org>
Link: http://lkml.kernel.org/r/20181101155314.30690-1-bp@alien8.de
---
arch/x86/kernel/aperture_64.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 2c4d5ece7456..4fb4b7f53568 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -264,18 +264,23 @@ static int __init parse_gart_mem(char *p)
}
early_param("gart_fix_e820", parse_gart_mem);
+/*
+ * With kexec/kdump, if the first kernel doesn't shutdown the GART and the
+ * second kernel allocates a different GART region, there might be two
+ * overlapping GART regions present:
+ *
+ * - the first still used by the GART initialized in the first kernel.
+ * - (sub-)set of it used as normal RAM by the second kernel.
+ *
+ * which leads to memory corruptions and a kernel panic eventually.
+ *
+ * This can also happen if the BIOS has forgotten to mark the GART region
+ * as reserved.
+ *
+ * Try to update the e820 map to mark that new region as reserved.
+ */
void __init early_gart_iommu_check(void)
{
- /*
- * in case it is enabled before, esp for kexec/kdump,
- * previous kernel already enable that. memset called
- * by allocate_aperture/__alloc_bootmem_nopanic cause restart.
- * or second kernel have different position for GART hole. and new
- * kernel could use hole as RAM that is still used by GART set by
- * first kernel
- * or BIOS forget to put that in reserved.
- * try to update e820 to make that region as reserved.
- */
u32 agp_aper_order = 0;
int i, fix, slot, valid_agp = 0;
u32 ctl;
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment
2018-11-01 15:53 [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment Borislav Petkov
2018-11-01 17:09 ` Thomas Gleixner
2018-11-05 13:39 ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
@ 2018-11-05 15:35 ` Ingo Molnar
2018-11-05 20:20 ` Borislav Petkov
2018-11-05 20:24 ` [tip:x86/cleanups] " tip-bot for Borislav Petkov
3 siblings, 1 reply; 6+ messages in thread
From: Ingo Molnar @ 2018-11-05 15:35 UTC (permalink / raw)
To: Borislav Petkov; +Cc: X86 ML, Mike Rapoport, LKML
* Borislav Petkov <bp@alien8.de> wrote:
> From: Borislav Petkov <bp@suse.de>
>
> ... to actually explain what the function is trying to do.
>
> Reported-by: Mike Rapoport <rppt@linux.ibm.com>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> ---
> arch/x86/kernel/aperture_64.c | 25 +++++++++++++++----------
> 1 file changed, 15 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
> index 2c4d5ece7456..4fb4b7f53568 100644
> --- a/arch/x86/kernel/aperture_64.c
> +++ b/arch/x86/kernel/aperture_64.c
> @@ -264,18 +264,23 @@ static int __init parse_gart_mem(char *p)
> }
> early_param("gart_fix_e820", parse_gart_mem);
>
> +/*
> + * With kexec/kdump, if the first kernel doesn't shutdown the GART and the
> + * second kernel allocates a different GART region, there might be two
> + * overlapping GART regions present:
s/shutdown
/shut down
Thanks,
Ingo
^ permalink raw reply [flat|nested] 6+ messages in thread* [tip:x86/cleanups] x86/gart: Rewrite early_gart_iommu_check() comment
2018-11-01 15:53 [PATCH] x86/gart: Rewrite early_gart_iommu_check() comment Borislav Petkov
` (2 preceding siblings ...)
2018-11-05 15:35 ` [PATCH] " Ingo Molnar
@ 2018-11-05 20:24 ` tip-bot for Borislav Petkov
3 siblings, 0 replies; 6+ messages in thread
From: tip-bot for Borislav Petkov @ 2018-11-05 20:24 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, rppt, bp, tglx, hpa, mingo, x86
Commit-ID: 63ecd3b13d5cf07959a2315ec62a7c62e20df114
Gitweb: https://git.kernel.org/tip/63ecd3b13d5cf07959a2315ec62a7c62e20df114
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Thu, 1 Nov 2018 16:24:43 +0100
Committer: Borislav Petkov <bp@suse.de>
CommitDate: Mon, 5 Nov 2018 21:18:31 +0100
x86/gart: Rewrite early_gart_iommu_check() comment
... to actually explain what the function is trying to do.
Reported-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <x86@kernel.org>
Link: http://lkml.kernel.org/r/20181101155314.30690-1-bp@alien8.de
---
arch/x86/kernel/aperture_64.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
index 2c4d5ece7456..58176b56354e 100644
--- a/arch/x86/kernel/aperture_64.c
+++ b/arch/x86/kernel/aperture_64.c
@@ -264,18 +264,23 @@ static int __init parse_gart_mem(char *p)
}
early_param("gart_fix_e820", parse_gart_mem);
+/*
+ * With kexec/kdump, if the first kernel doesn't shut down the GART and the
+ * second kernel allocates a different GART region, there might be two
+ * overlapping GART regions present:
+ *
+ * - the first still used by the GART initialized in the first kernel.
+ * - (sub-)set of it used as normal RAM by the second kernel.
+ *
+ * which leads to memory corruptions and a kernel panic eventually.
+ *
+ * This can also happen if the BIOS has forgotten to mark the GART region
+ * as reserved.
+ *
+ * Try to update the e820 map to mark that new region as reserved.
+ */
void __init early_gart_iommu_check(void)
{
- /*
- * in case it is enabled before, esp for kexec/kdump,
- * previous kernel already enable that. memset called
- * by allocate_aperture/__alloc_bootmem_nopanic cause restart.
- * or second kernel have different position for GART hole. and new
- * kernel could use hole as RAM that is still used by GART set by
- * first kernel
- * or BIOS forget to put that in reserved.
- * try to update e820 to make that region as reserved.
- */
u32 agp_aper_order = 0;
int i, fix, slot, valid_agp = 0;
u32 ctl;
^ permalink raw reply related [flat|nested] 6+ messages in thread