E820 reserved ranges is useful in kdump kernel, it has been added in
kexec-tools code.
One reason is PCI mmconf (extended mode) requires reserved region otherwise
it falls back to legacy mode.
Furthermore, when AMD SME kdump support, it needs to map dmi table area as
decrypted. For normal boot, these ranges sit in e820 reserved ranges, thus
the early ioremap code naturally map them as decrypted. If it also has same
e820 reserve setup in kdump kernel then it will just work like normal
kernel.
Kdump uses walk_iomem_res_desc to iterate resources, then adds matched desc
to e820 table for the kdump kernel.
But IORES_DESC_NONE resource type includes several different e820 types, we
need add exact e820 type to the kdump kernel e820 table, thus it also needs
an extra checking in memmap_entry_callback() to match the e820 type and
resource name.
Changes since v1:
1. Modified the value of flags to "0", when walking through the whole
tree for e820 reserved ranges.
Changes since v2:
1. Modified the value of flags to "0", when walking through the whole
tree for e820 reserved ranges.
2. Modified the invalid SOB chain issue.
Changes since v3:
1. Dropped [PATCH 1/3 v3] resource: fix an error which walks through iomem
resources. Please refer to this commit <010a93bf97c7> "resource: Fix
find_next_iomem_res() iteration issue"
Note:
1. The patches are made based on this branch:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
2. And you need to apply the follow patch before test kdump file_load,
otherwise these patches won't work.
commit <010a93bf97c7> "resource: Fix find_next_iomem_res() iteration
issue"
Lianbo Jiang (2):
x86/kexec_file: add e820 entry in case e820 type string matches to io
resource name
x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table
arch/x86/include/asm/e820/api.h | 2 ++
arch/x86/kernel/crash.c | 10 +++++++++-
arch/x86/kernel/e820.c | 2 +-
kernel/resource.c | 1 +
4 files changed, 13 insertions(+), 2 deletions(-)
--
2.17.1
E820 reserved ranges is useful in kdump kernel, it has been added in
kexec-tools code.
One reason is PCI mmconf (extended mode) requires reserved region otherwise
it falls back to legacy mode.
When AMD SME kdump support, it needs to map dmi table area as decrypted.
For normal boot, these ranges sit in e820 reserved ranges, thus the early
ioremap code naturally map them as decrypted. If it also has same e820
reserve setup in kdump kernel then it will just work like normal kernel.
Suggested-by: Dave Young <[email protected]>
Signed-off-by: Lianbo Jiang <[email protected]>
---
arch/x86/kernel/crash.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index ae724a6e0a5f..d3167125800e 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -384,6 +384,10 @@ int crash_setup_memmap_entries(struct kimage *image, struct boot_params *params)
walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1, &cmd,
memmap_entry_callback);
+ cmd.type = E820_TYPE_RESERVED;
+ walk_iomem_res_desc(IORES_DESC_NONE, 0, 0, -1, &cmd,
+ memmap_entry_callback);
+
/* Add crashk_low_res region */
if (crashk_low_res.end) {
ei.addr = crashk_low_res.start;
--
2.17.1
kdump uses walk_iomem_res_desc() to iterate io resources, then adds matched
desc to e820 table for kdump kernel.
But IORES_DESC_NONE resource type includes several different e820 types,
we need add exact e820 type to kdump kernel e820 table, thus it also needs
an extra checking in memmap_entry_callback() to match the e820 type and
resource name.
Suggested-by: Dave Young <[email protected]>
Signed-off-by: Lianbo Jiang <[email protected]>
---
arch/x86/include/asm/e820/api.h | 2 ++
arch/x86/kernel/crash.c | 6 +++++-
arch/x86/kernel/e820.c | 2 +-
kernel/resource.c | 1 +
4 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h
index 62be73b23d5c..6d5451b36e80 100644
--- a/arch/x86/include/asm/e820/api.h
+++ b/arch/x86/include/asm/e820/api.h
@@ -42,6 +42,8 @@ extern void e820__register_nosave_regions(unsigned long limit_pfn);
extern int e820__get_entry_type(u64 start, u64 end);
+extern const char *e820_type_to_string(struct e820_entry *entry);
+
/*
* Returns true iff the specified range [start,end) is completely contained inside
* the ISA region.
diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c
index f631a3f15587..ae724a6e0a5f 100644
--- a/arch/x86/kernel/crash.c
+++ b/arch/x86/kernel/crash.c
@@ -37,6 +37,7 @@
#include <asm/reboot.h>
#include <asm/virtext.h>
#include <asm/intel_pt.h>
+#include <asm/e820/api.h>
/* Used while preparing memory map entries for second kernel */
struct crash_memmap_data {
@@ -314,11 +315,14 @@ static int memmap_entry_callback(struct resource *res, void *arg)
struct crash_memmap_data *cmd = arg;
struct boot_params *params = cmd->params;
struct e820_entry ei;
+ const char *name;
ei.addr = res->start;
ei.size = resource_size(res);
ei.type = cmd->type;
- add_e820_entry(params, &ei);
+ name = e820_type_to_string(&ei);
+ if (res->name && !strcmp(name, res->name))
+ add_e820_entry(params, &ei);
return 0;
}
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index c88c23c658c1..f9761b2f7abb 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1012,7 +1012,7 @@ void __init e820__finish_early_params(void)
}
}
-static const char *__init e820_type_to_string(struct e820_entry *entry)
+const char *e820_type_to_string(struct e820_entry *entry)
{
switch (entry->type) {
case E820_TYPE_RESERVED_KERN: /* Fall-through: */
diff --git a/kernel/resource.c b/kernel/resource.c
index b3a3a1fc499e..6285a6b4de6c 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -366,6 +366,7 @@ static int find_next_iomem_res(resource_size_t start, resource_size_t end,
res->end = min(end, p->end);
res->flags = p->flags;
res->desc = p->desc;
+ res->name = p->name;
return 0;
}
--
2.17.1
On 10/22/18 at 03:47pm, Lianbo Jiang wrote:
> E820 reserved ranges is useful in kdump kernel, it has been added in
> kexec-tools code.
>
> One reason is PCI mmconf (extended mode) requires reserved region otherwise
> it falls back to legacy mode.
>
> Furthermore, when AMD SME kdump support, it needs to map dmi table area as
> decrypted. For normal boot, these ranges sit in e820 reserved ranges, thus
> the early ioremap code naturally map them as decrypted. If it also has same
> e820 reserve setup in kdump kernel then it will just work like normal
> kernel.
>
> Kdump uses walk_iomem_res_desc to iterate resources, then adds matched desc
> to e820 table for the kdump kernel.
>
> But IORES_DESC_NONE resource type includes several different e820 types, we
> need add exact e820 type to the kdump kernel e820 table, thus it also needs
> an extra checking in memmap_entry_callback() to match the e820 type and
> resource name.
>
> Changes since v1:
> 1. Modified the value of flags to "0", when walking through the whole
> tree for e820 reserved ranges.
>
> Changes since v2:
> 1. Modified the value of flags to "0", when walking through the whole
> tree for e820 reserved ranges.
> 2. Modified the invalid SOB chain issue.
>
> Changes since v3:
> 1. Dropped [PATCH 1/3 v3] resource: fix an error which walks through iomem
> resources. Please refer to this commit <010a93bf97c7> "resource: Fix
> find_next_iomem_res() iteration issue"
>
> Note:
> 1. The patches are made based on this branch:
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git
>
> 2. And you need to apply the follow patch before test kdump file_load,
> otherwise these patches won't work.
> commit <010a93bf97c7> "resource: Fix find_next_iomem_res() iteration
> issue"
>
> Lianbo Jiang (2):
> x86/kexec_file: add e820 entry in case e820 type string matches to io
> resource name
> x86/kexec_file: add reserved e820 ranges to kdump kernel e820 table
>
> arch/x86/include/asm/e820/api.h | 2 ++
> arch/x86/kernel/crash.c | 10 +++++++++-
> arch/x86/kernel/e820.c | 2 +-
> kernel/resource.c | 1 +
> 4 files changed, 13 insertions(+), 2 deletions(-)
>
> --
> 2.17.1
>
Lianbo, thank you for the update, added Andrew in cc.
Acked-by: Dave Young <[email protected]>
Thanks
Dave