diff mbox series

[v18,01/17] x86/setup: Move CRASH_ALIGN and CRASH_ADDR_{LOW|HIGH}_MAX to asm/kexec.h

Message ID 20211222130820.1754-2-thunder.leizhen@huawei.com (mailing list archive)
State New, archived
Headers show
Series support reserving crashkernel above 4G on arm64 kdump | expand

Commit Message

Leizhen (ThunderTown) Dec. 22, 2021, 1:08 p.m. UTC 
From: Chen Zhou <chenzhou10@huawei.com>

We want to make function reserve_crashkernel[_low](), which is implemented
by X86, available to other architectures. It references macro CRASH_ALIGN
and will be moved to public crash_core.c. But the defined values of
CRASH_ALIGN may be different in different architectures. So moving the
definition of CRASH_ALIGN to asm/kexec.h is a good choice.

The reason for moving CRASH_ADDR_{LOW|HIGH}_MAX is the same as above.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Co-developed-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
 arch/x86/include/asm/kexec.h | 24 ++++++++++++++++++++++++
 arch/x86/kernel/setup.c      | 24 ------------------------
 2 files changed, 24 insertions(+), 24 deletions(-)

Comments

Borislav Petkov Dec. 22, 2021, 8:43 p.m. UTC | #1 
On Wed, Dec 22, 2021 at 09:08:04PM +0800, Zhen Lei wrote:
> From: Chen Zhou <chenzhou10@huawei.com>
> 
> We want to make function reserve_crashkernel[_low](), which is implemented
  ^^

Please use passive voice in your commit message: no "we" or "I", etc,
and describe your changes in imperative mood.

Also, pls read section "2) Describe your changes" in
Documentation/process/submitting-patches.rst for more details.

Bottom line is: personal pronouns are ambiguous in text, especially with
so many parties/companies/etc developing the kernel so let's avoid them
please.

> by X86, available to other architectures. It references macro CRASH_ALIGN

"x86"

> and will be moved to public crash_core.c. But the defined values of
> CRASH_ALIGN may be different in different architectures. So moving the
> definition of CRASH_ALIGN to asm/kexec.h is a good choice.
> 
> The reason for moving CRASH_ADDR_{LOW|HIGH}_MAX is the same as above.

This commit message needs to say something along the lines of:

"Move CRASH_ALIGN and ... to the arch-specific header in preparation
of making reserve_crashkernel[_low]() generic, used by other
architectures."

or so.
Leizhen (ThunderTown) Dec. 23, 2021, 2:09 a.m. UTC | #2 
On 2021/12/23 4:43, Borislav Petkov wrote:
> On Wed, Dec 22, 2021 at 09:08:04PM +0800, Zhen Lei wrote:
>> From: Chen Zhou <chenzhou10@huawei.com>
>>
>> We want to make function reserve_crashkernel[_low](), which is implemented
>   ^^
> 
> Please use passive voice in your commit message: no "we" or "I", etc,
> and describe your changes in imperative mood.

My bad language habits. I've made this mistake several times.

> 
> Also, pls read section "2) Describe your changes" in
> Documentation/process/submitting-patches.rst for more details.
> 
> Bottom line is: personal pronouns are ambiguous in text, especially with
> so many parties/companies/etc developing the kernel so let's avoid them
> please.

OK, I'll check the description of the other patches.

> 
>> by X86, available to other architectures. It references macro CRASH_ALIGN
> 
> "x86"

OK

> 
>> and will be moved to public crash_core.c. But the defined values of
>> CRASH_ALIGN may be different in different architectures. So moving the
>> definition of CRASH_ALIGN to asm/kexec.h is a good choice.
>>
>> The reason for moving CRASH_ADDR_{LOW|HIGH}_MAX is the same as above.
> 
> This commit message needs to say something along the lines of:
> 
> "Move CRASH_ALIGN and ... to the arch-specific header in preparation
> of making reserve_crashkernel[_low]() generic, used by other
> architectures."

OK, I will use this one, thanks.

By the way, patch 0004-0006 were written based on your suggestion. Can you
take a moment to review it? I think I forgot to add "Suggested-by".

> 
> or so.
>
diff mbox series

Patch

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 11b7c06e2828c30..a0223a6c0238a15 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -18,6 +18,30 @@ 
 
 # define KEXEC_CONTROL_CODE_MAX_SIZE	2048
 
+/* 16M alignment for crash kernel regions */
+#define CRASH_ALIGN		SZ_16M
+
+/*
+ * Keep the crash kernel below this limit.
+ *
+ * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
+ * due to mapping restrictions.
+ *
+ * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
+ * the upper limit of system RAM in 4-level paging mode. Since the kdump
+ * jump could be from 5-level paging to 4-level paging, the jump will fail if
+ * the kernel is put above 64 TB, and during the 1st kernel bootup there's
+ * no good way to detect the paging mode of the target kernel which will be
+ * loaded for dumping.
+ */
+#ifdef CONFIG_X86_32
+# define CRASH_ADDR_LOW_MAX	SZ_512M
+# define CRASH_ADDR_HIGH_MAX	SZ_512M
+#else
+# define CRASH_ADDR_LOW_MAX	SZ_4G
+# define CRASH_ADDR_HIGH_MAX	SZ_64T
+#endif
+
 #ifndef __ASSEMBLY__
 
 #include <linux/string.h>
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 6a190c7f4d71b05..ae8f63661363e25 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -392,30 +392,6 @@  static void __init memblock_x86_reserve_range_setup_data(void)
 
 #ifdef CONFIG_KEXEC_CORE
 
-/* 16M alignment for crash kernel regions */
-#define CRASH_ALIGN		SZ_16M
-
-/*
- * Keep the crash kernel below this limit.
- *
- * Earlier 32-bits kernels would limit the kernel to the low 512 MB range
- * due to mapping restrictions.
- *
- * 64-bit kdump kernels need to be restricted to be under 64 TB, which is
- * the upper limit of system RAM in 4-level paging mode. Since the kdump
- * jump could be from 5-level paging to 4-level paging, the jump will fail if
- * the kernel is put above 64 TB, and during the 1st kernel bootup there's
- * no good way to detect the paging mode of the target kernel which will be
- * loaded for dumping.
- */
-#ifdef CONFIG_X86_32
-# define CRASH_ADDR_LOW_MAX	SZ_512M
-# define CRASH_ADDR_HIGH_MAX	SZ_512M
-#else
-# define CRASH_ADDR_LOW_MAX	SZ_4G
-# define CRASH_ADDR_HIGH_MAX	SZ_64T
-#endif
-
 static int __init reserve_crashkernel_low(void)
 {
 #ifdef CONFIG_X86_64