Re: [PATCH v2 1/3] arm64/ras: support sea error recovery

From: Borislav Petkov
Date: Wed Sep 06 2017 - 06:13:43 EST

On Tue, Sep 05, 2017 at 07:06:04PM +0800, Xie XiuQi wrote:
> With ARM v8.2 RAS Extension, SEA are usually triggered when memory errors
> are consumed. In some cases, if the error address is in a clean page or a
> read-only page, there is a chance to recover. Such as error occurs in a
> instruction page, we can reread this page from disk instead of killing process.
>
> Because memory_failure() may sleep, we can not call it directly in SEA exception
> context. So we saved faulting physical address associated with a process in the
> ghes handler and set __TIF_SEA_NOTIFY. When we return from SEA exception context
> and get into do_notify_resume() before the process running, we could check it
> and call memory_failure() to do recovery. It's safe, because we are in process
> context.
>
> Signed-off-by: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
> Signed-off-by: Wang Xiongfeng <wangxiongfeng2@xxxxxxxxxx>
> ---
> arch/arm64/Kconfig | 11 +++
> arch/arm64/include/asm/ras.h | 36 +++++++++
> arch/arm64/include/asm/thread_info.h | 4 +-
> arch/arm64/kernel/Makefile | 1 +
> arch/arm64/kernel/ras.c | 143 +++++++++++++++++++++++++++++++++++
> arch/arm64/kernel/signal.c | 8 ++
> arch/arm64/mm/fault.c | 27 +++++--
> drivers/acpi/apei/ghes.c | 4 +-
> 8 files changed, 223 insertions(+), 11 deletions(-)
> create mode 100644 arch/arm64/include/asm/ras.h
> create mode 100644 arch/arm64/kernel/ras.c

Please integrate scripts/checkpatch.pl into your patch creation workflow
and run all patches through it before submitting:

ERROR: code indent should use tabs where possible
#200: FILE: arch/arm64/kernel/ras.c:42:
+ atomic_t inuse;$

WARNING: please, no spaces at the start of a line
#200: FILE: arch/arm64/kernel/ras.c:42:
+ atomic_t inuse;$

ERROR: code indent should use tabs where possible
#201: FILE: arch/arm64/kernel/ras.c:43:
+ struct task_struct *t;$

WARNING: please, no spaces at the start of a line
#201: FILE: arch/arm64/kernel/ras.c:43:
+ struct task_struct *t;$

ERROR: code indent should use tabs where possible
#202: FILE: arch/arm64/kernel/ras.c:44:
+ __u64 paddr;$

WARNING: please, no spaces at the start of a line
#202: FILE: arch/arm64/kernel/ras.c:44:
+ __u64 paddr;$

ERROR: code indent should use tabs where possible
#207: FILE: arch/arm64/kernel/ras.c:49:
+ struct sea_info *si;$

WARNING: please, no spaces at the start of a line
#207: FILE: arch/arm64/kernel/ras.c:49:
+ struct sea_info *si;$

ERROR: code indent should use tabs where possible
#209: FILE: arch/arm64/kernel/ras.c:51:
+ for (si = sea_info; si < &sea_info[SEA_INFO_MAX]; si++) {$

WARNING: please, no spaces at the start of a line
#209: FILE: arch/arm64/kernel/ras.c:51:
+ for (si = sea_info; si < &sea_info[SEA_INFO_MAX]; si++) {$

ERROR: code indent should use tabs where possible
#210: FILE: arch/arm64/kernel/ras.c:52:
+ if (atomic_cmpxchg(&si->inuse, 0, 1) == 0) {$

WARNING: please, no spaces at the start of a line
#210: FILE: arch/arm64/kernel/ras.c:52:
+ if (atomic_cmpxchg(&si->inuse, 0, 1) == 0) {$

ERROR: code indent should use tabs where possible
#211: FILE: arch/arm64/kernel/ras.c:53:
+ si->t = current;$

WARNING: please, no spaces at the start of a line
#211: FILE: arch/arm64/kernel/ras.c:53:
+ si->t = current;$

ERROR: code indent should use tabs where possible
#212: FILE: arch/arm64/kernel/ras.c:54:
+ si->paddr = addr;$

WARNING: please, no spaces at the start of a line
#212: FILE: arch/arm64/kernel/ras.c:54:
+ si->paddr = addr;$

ERROR: code indent should use tabs where possible
#213: FILE: arch/arm64/kernel/ras.c:55:
+ return true;$

WARNING: please, no spaces at the start of a line
#213: FILE: arch/arm64/kernel/ras.c:55:
+ return true;$

ERROR: code indent should use tabs where possible
#214: FILE: arch/arm64/kernel/ras.c:56:
+ }$

WARNING: please, no spaces at the start of a line
#214: FILE: arch/arm64/kernel/ras.c:56:
+ }$

ERROR: code indent should use tabs where possible
#215: FILE: arch/arm64/kernel/ras.c:57:
+ }$

WARNING: please, no spaces at the start of a line
#215: FILE: arch/arm64/kernel/ras.c:57:
+ }$

ERROR: code indent should use tabs where possible
#223: FILE: arch/arm64/kernel/ras.c:65:
+ struct sea_info *si;$

WARNING: please, no spaces at the start of a line
#223: FILE: arch/arm64/kernel/ras.c:65:
+ struct sea_info *si;$

ERROR: code indent should use tabs where possible
#225: FILE: arch/arm64/kernel/ras.c:67:
+ for (si = sea_info; si < &sea_info[SEA_INFO_MAX]; si++)$

WARNING: please, no spaces at the start of a line
#225: FILE: arch/arm64/kernel/ras.c:67:
+ for (si = sea_info; si < &sea_info[SEA_INFO_MAX]; si++)$

ERROR: code indent should use tabs where possible
#226: FILE: arch/arm64/kernel/ras.c:68:
+ if (atomic_read(&si->inuse) && si->t == current)$

WARNING: please, no spaces at the start of a line
#226: FILE: arch/arm64/kernel/ras.c:68:
+ if (atomic_read(&si->inuse) && si->t == current)$

ERROR: code indent should use tabs where possible
#227: FILE: arch/arm64/kernel/ras.c:69:
+ return si;$

WARNING: please, no spaces at the start of a line
#227: FILE: arch/arm64/kernel/ras.c:69:
+ return si;$

ERROR: code indent should use tabs where possible
#228: FILE: arch/arm64/kernel/ras.c:70:
+ return NULL;$

WARNING: please, no spaces at the start of a line
#228: FILE: arch/arm64/kernel/ras.c:70:
+ return NULL;$

ERROR: code indent should use tabs where possible
#233: FILE: arch/arm64/kernel/ras.c:75:
+ atomic_set(&si->inuse, 0);$

WARNING: please, no spaces at the start of a line
#233: FILE: arch/arm64/kernel/ras.c:75:
+ atomic_set(&si->inuse, 0);$

WARNING: braces {} are not necessary for single statement blocks
#265: FILE: arch/arm64/kernel/ras.c:107:
+ if (memory_failure(pfn, 0, flags) < 0) {
+ fail++;
+ }

WARNING: braces {} are not necessary for single statement blocks
#293: FILE: arch/arm64/kernel/ras.c:135:
+ if (err_info->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR) {
+ info_saved |= sea_save_info(err_info->physical_fault_addr);
+ }

total: 17 errors, 21 warnings, 299 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
mechanically convert to the typical style using --fix or --fix-inplace.

NOTE: Whitespace errors detected.
You may wish to use scripts/cleanpatch or scripts/cleanfile

Your patch has style problems, please review.

NOTE: If any of the errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.

--
Regards/Gruss,
Boris.

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