From: Amit Daniel Kachhap <amit.kachhap@arm.com>
To: linux-kernel@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>,
Vincenzo Frascino <Vincenzo.Frascino@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
kexec <kexec@lists.infradead.org>,
Amit Daniel Kachhap <amit.kachhap@arm.com>,
Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>
Subject: [RFC PATCH 03/14] fs/proc/vmcore: Update copy_oldmem_page() for user buffer
Date: Fri, 3 Dec 2021 16:12:20 +0530 [thread overview]
Message-ID: <20211203104231.17597-4-amit.kachhap@arm.com> (raw)
In-Reply-To: <20211203104231.17597-1-amit.kachhap@arm.com>
The exported interface copy_oldmem_page passes user pointer without
__user annotation and does unnecessary user/kernel pointer
conversions during the pointer propagation.
Hence it is modified to have a new parameter for user pointer. However
instead of updating it directly a new interface copy_oldmem_page_buf()
is added as copy_oldmem_page() is used across different archs. This old
interface copy_oldmem_page() will be deleted after all the archs are
modified to use the new interface.
The weak implementation of both copy_oldmem_page() and
copy_oldmem_page_buf() are added temporarily to keep the kernel building
for the subsequent patches. As a consequence, crash dump is temporarily
broken for the archs till the patch where it implements its own
copy_oldmem_page_buf().
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: kexec <kexec@lists.infradead.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
---
fs/proc/vmcore.c | 27 +++++++++++++++++----------
include/linux/crash_dump.h | 3 +++
2 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index fa4492ef6124..d01b85c043dd 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -172,12 +172,9 @@ ssize_t read_from_oldmem(char __user *ubuf, char *kbuf, size_t count,
tmp = copy_oldmem_page_encrypted(pfn, ubuf,
kbuf, nr_bytes,
offset);
- else if (ubuf)
- tmp = copy_oldmem_page(pfn, (__force char *)ubuf,
- nr_bytes, offset, 1);
else
- tmp = copy_oldmem_page(pfn, kbuf, nr_bytes,
- offset, 0);
+ tmp = copy_oldmem_page_buf(pfn, ubuf, kbuf,
+ nr_bytes, offset);
}
if (tmp < 0) {
up_read(&vmcore_cb_rwsem);
@@ -244,11 +241,21 @@ ssize_t __weak
copy_oldmem_page_encrypted(unsigned long pfn, char __user *ubuf, char *kbuf,
size_t csize, unsigned long offset)
{
- if (ubuf)
- return copy_oldmem_page(pfn, (__force char *)ubuf, csize,
- offset, 1);
- else
- return copy_oldmem_page(pfn, kbuf, csize, offset, 0);
+ return copy_oldmem_page_buf(pfn, ubuf, kbuf, csize, offset);
+}
+
+ssize_t __weak
+copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf,
+ size_t csize, unsigned long offset)
+{
+ return -EOPNOTSUPP;
+}
+
+ssize_t __weak
+copy_oldmem_page(unsigned long pfn, char *ubuf, size_t csize,
+ unsigned long offset, int userbuf)
+{
+ return -EOPNOTSUPP;
}
/*
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index 36a7f08f4ad2..725c4e053ecf 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -26,6 +26,9 @@ extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
unsigned long, int);
+extern ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf,
+ char *kbuf, size_t csize,
+ unsigned long offset);
extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn,
char __user *ubuf, char *kbuf,
size_t csize, unsigned long offset);
--
2.17.1
next prev parent reply other threads:[~2021-12-03 10:43 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-03 10:42 [RFC PATCH 00/14] fs/proc/vmcore: Remove unnecessary user pointer conversions Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 01/14] fs/proc/vmcore: Update read_from_oldmem() for user pointer Amit Daniel Kachhap
2021-12-06 14:04 ` Christoph Hellwig
2021-12-06 14:17 ` Matthew Wilcox
2021-12-06 14:54 ` Christoph Hellwig
2021-12-06 15:07 ` Matthew Wilcox
2021-12-07 11:15 ` Christoph Hellwig
2021-12-07 7:11 ` Amit Kachhap
2021-12-03 10:42 ` [RFC PATCH 02/14] fs/proc/vmcore: Update copy_oldmem_page_encrypted() for user buffer Amit Daniel Kachhap
2021-12-03 10:42 ` Amit Daniel Kachhap [this message]
2021-12-03 10:42 ` [RFC PATCH 04/14] x86/crash_dump_64: Use the new interface copy_oldmem_page_buf Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 05/14] x86/crash_dump_32: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 06/14] arm64/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 07/14] arm/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 08/14] mips/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 09/14] sh/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 10/14] riscv/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 11/14] powerpc/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 12/14] ia64/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 13/14] s390/crash_dump: " Amit Daniel Kachhap
2021-12-03 10:42 ` [RFC PATCH 14/14] fs/proc/vmcore: Remove the unused old interface copy_oldmem_page Amit Daniel Kachhap
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