* [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-11 3:55 Add and use a generic copy_oldmem_page() Palmer Dabbelt
@ 2020-07-11 3:55 ` Palmer Dabbelt
2020-07-13 13:06 ` Christoph Hellwig
2020-07-11 3:55 ` [PATCH 2/3] arm: Use the new " Palmer Dabbelt
2020-07-11 3:55 ` [PATCH 3/3] arm64: " Palmer Dabbelt
2 siblings, 1 reply; 11+ messages in thread
From: Palmer Dabbelt @ 2020-07-11 3:55 UTC (permalink / raw)
To: mick
Cc: linux, catalin.marinas, will, Arnd Bergmann, rppt, akpm,
linus.walleij, mchehab+samsung, gregory.0xf0, masahiroy,
Nick Desaulniers, bgolaszewski, Palmer Dabbelt, mingo, ben-linux,
peterz, broonie, davem, rdunlap, uwe, dan.j.williams, mhiramat,
matti.vaittinen, zaslonko, willy, krzk, paulmck, pmladek,
brendanhiggins, keescook, glider, elver, davidgow, mark.rutland,
ardb, takahiro.akashi, linux-arm-kernel, linux-kernel,
kernel-team
From: Palmer Dabbelt <palmerdabbelt@google.com>
A version of this that is identical to the arm64 version was recently
copied into the RISC-V port while adding kexec() support. Instead I'd
like to put a shared copy in lib/ and use it from the various ports.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
lib/Kconfig | 3 +++
lib/Makefile | 2 ++
lib/copy_oldmem_page.c | 51 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 56 insertions(+)
create mode 100644 lib/copy_oldmem_page.c
diff --git a/lib/Kconfig b/lib/Kconfig
index df3f3da95990..25544abc9547 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -676,3 +676,6 @@ config GENERIC_LIB_CMPDI2
config GENERIC_LIB_UCMPDI2
bool
+
+config GENERIC_LIB_COPY_OLDMEM_PAGE
+ bool
diff --git a/lib/Makefile b/lib/Makefile
index b1c42c10073b..30d57d8b32b1 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -318,3 +318,5 @@ obj-$(CONFIG_OBJAGG) += objagg.o
# KUnit tests
obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+
+obj-$(CONFIG_GENERIC_LIB_COPY_OLDMEM_PAGE) += copy_oldmem_page.o
diff --git a/lib/copy_oldmem_page.c b/lib/copy_oldmem_page.c
new file mode 100644
index 000000000000..f0090027218a
--- /dev/null
+++ b/lib/copy_oldmem_page.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Routines for doing kexec-based kdump
+ *
+ * Originally part of arch/arm64/kernel/crash_dump.c
+ * Copyright (C) 2017 Linaro Limited
+ * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
+ */
+
+#include <linux/io.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+/**
+ * copy_oldmem_page() - copy one page from old kernel memory
+ * @pfn: page frame number to be copied
+ * @buf: buffer where the copied page is placed
+ * @csize: number of bytes to copy
+ * @offset: offset in bytes into the page
+ * @userbuf: if set, @buf is in a user address space
+ *
+ * This function copies one page from old kernel memory into buffer pointed by
+ * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
+ * copied or negative error in case of failure.
+ */
+ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
+ size_t csize, unsigned long offset,
+ int userbuf)
+{
+ void *vaddr;
+
+ if (!csize)
+ return 0;
+
+ vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
+ if (!vaddr)
+ return -ENOMEM;
+
+ if (userbuf) {
+ if (copy_to_user((char __user *)buf, vaddr + offset, csize)) {
+ memunmap(vaddr);
+ return -EFAULT;
+ }
+ } else {
+ memcpy(buf, vaddr + offset, csize);
+ }
+
+ memunmap(vaddr);
+
+ return csize;
+}
--
2.27.0.383.g050319c2ae-goog
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-11 3:55 ` [PATCH 1/3] lib: Add " Palmer Dabbelt
@ 2020-07-13 13:06 ` Christoph Hellwig
2020-07-13 13:39 ` Arnd Bergmann
2020-07-15 7:03 ` Ard Biesheuvel
0 siblings, 2 replies; 11+ messages in thread
From: Christoph Hellwig @ 2020-07-13 13:06 UTC (permalink / raw)
To: Palmer Dabbelt
Cc: mick, mark.rutland, gregory.0xf0, peterz, catalin.marinas,
linus.walleij, Palmer Dabbelt, brendanhiggins, elver, glider,
krzk, mchehab+samsung, will, mingo, uwe, takahiro.akashi, paulmck,
masahiroy, linux, willy, rppt, bgolaszewski, kernel-team, pmladek,
zaslonko, keescook, Arnd Bergmann, broonie, matti.vaittinen,
ben-linux, dan.j.williams, linux-arm-kernel, davidgow, rdunlap,
Nick Desaulniers, linux-kernel, mhiramat, ardb, akpm, davem
On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote:
> +ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> + size_t csize, unsigned long offset,
> + int userbuf)
> +{
> + void *vaddr;
> +
> + if (!csize)
> + return 0;
> +
> + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
> + if (!vaddr)
> + return -ENOMEM;
Doing a memremap for every page is very inefficient. Also I don't see
why you'd want to even do that. All memory is in the direct mapping
for RISC-V. For other architecture that support highmem kmap_atomic_pfn
would do the job, which is what I'd use in a generic version.
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-13 13:06 ` Christoph Hellwig
@ 2020-07-13 13:39 ` Arnd Bergmann
2020-07-14 11:05 ` Christoph Hellwig
2020-07-15 7:03 ` Ard Biesheuvel
1 sibling, 1 reply; 11+ messages in thread
From: Arnd Bergmann @ 2020-07-13 13:39 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Palmer Dabbelt, Nick Kossifidis, Mark Rutland, Gregory Fong,
Peter Zijlstra, Catalin Marinas, Linus Walleij, Palmer Dabbelt,
Brendan Higgins, Marco Elver, Alexander Potapenko,
Krzysztof Kozlowski, Mauro Carvalho Chehab, Will Deacon,
Ingo Molnar, Uwe Kleine-König, AKASHI Takahiro,
Paul E. McKenney, Masahiro Yamada, Russell King - ARM Linux,
Matthew Wilcox, Mike Rapoport, Bartosz Golaszewski,
Android Kernel Team, Petr Mladek, zaslonko, Kees Cook, Mark Brown,
Vaittinen, Matti, Ben Dooks, Dan Williams, Linux ARM, David Gow,
Randy Dunlap, Nick Desaulniers, linux-kernel@vger.kernel.org,
Masami Hiramatsu, Ard Biesheuvel, Andrew Morton, David Miller
On Mon, Jul 13, 2020 at 3:07 PM Christoph Hellwig <hch@infradead.org> wrote:
> On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote:
> > +ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> > + size_t csize, unsigned long offset,
> > + int userbuf)
> > +{
> > + void *vaddr;
> > +
> > + if (!csize)
> > + return 0;
> > +
> > + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
> > + if (!vaddr)
> > + return -ENOMEM;
>
> Doing a memremap for every page is very inefficient. Also I don't see
> why you'd want to even do that. All memory is in the direct mapping
> for RISC-V. For other architecture that support highmem kmap_atomic_pfn
> would do the job, which is what I'd use in a generic version.
I would expect the 'oldmem' data to not have a 'struct page', which would
be a problem at least for the generic implementation of kmap_atomic_pfn()
include/linux/highmem.h:#define kmap_atomic_pfn(pfn)
kmap_atomic(pfn_to_page(pfn))
kmap_atomic() might still work with a bogus page pointer if it
only transforms it back into a pfn, but some implementations just
have this one that cannot work:
static inline void *page_address(const struct page *page)
{
return page->virtual;
}
I have not checked how the crash dump code works though, maybe
it does work after all.
Arnd
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-13 13:39 ` Arnd Bergmann
@ 2020-07-14 11:05 ` Christoph Hellwig
2020-07-14 11:38 ` Arnd Bergmann
0 siblings, 1 reply; 11+ messages in thread
From: Christoph Hellwig @ 2020-07-14 11:05 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Christoph Hellwig, Palmer Dabbelt, Nick Kossifidis, Mark Rutland,
Gregory Fong, Peter Zijlstra, Catalin Marinas, Linus Walleij,
Palmer Dabbelt, Brendan Higgins, Marco Elver, Alexander Potapenko,
Krzysztof Kozlowski, Mauro Carvalho Chehab, Will Deacon,
Ingo Molnar, Uwe Kleine-K??nig, AKASHI Takahiro, Paul E. McKenney,
Masahiro Yamada, Russell King - ARM Linux, Matthew Wilcox,
Mike Rapoport, Bartosz Golaszewski, Android Kernel Team,
Petr Mladek, zaslonko, Kees Cook, Mark Brown, Vaittinen, Matti,
Ben Dooks, Dan Williams, Linux ARM, David Gow, Randy Dunlap,
Nick Desaulniers, linux-kernel@vger.kernel.org, Masami Hiramatsu,
Ard Biesheuvel, Andrew Morton, David Miller
On Mon, Jul 13, 2020 at 03:39:17PM +0200, Arnd Bergmann wrote:
> On Mon, Jul 13, 2020 at 3:07 PM Christoph Hellwig <hch@infradead.org> wrote:
> > On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote:
> > > +ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> > > + size_t csize, unsigned long offset,
> > > + int userbuf)
> > > +{
> > > + void *vaddr;
> > > +
> > > + if (!csize)
> > > + return 0;
> > > +
> > > + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
> > > + if (!vaddr)
> > > + return -ENOMEM;
> >
> > Doing a memremap for every page is very inefficient. Also I don't see
> > why you'd want to even do that. All memory is in the direct mapping
> > for RISC-V. For other architecture that support highmem kmap_atomic_pfn
> > would do the job, which is what I'd use in a generic version.
>
> I would expect the 'oldmem' data to not have a 'struct page', which would
> be a problem at least for the generic implementation of kmap_atomic_pfn()
Why do you expect it to not have a struct page?
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-14 11:05 ` Christoph Hellwig
@ 2020-07-14 11:38 ` Arnd Bergmann
0 siblings, 0 replies; 11+ messages in thread
From: Arnd Bergmann @ 2020-07-14 11:38 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Palmer Dabbelt, Nick Kossifidis, Mark Rutland, Gregory Fong,
Peter Zijlstra, Catalin Marinas, Linus Walleij, Palmer Dabbelt,
Brendan Higgins, Marco Elver, Alexander Potapenko,
Krzysztof Kozlowski, Mauro Carvalho Chehab, Will Deacon,
Ingo Molnar, Uwe Kleine-K??nig, AKASHI Takahiro, Paul E. McKenney,
Masahiro Yamada, Russell King - ARM Linux, Matthew Wilcox,
Mike Rapoport, Bartosz Golaszewski, Android Kernel Team,
Petr Mladek, zaslonko, Kees Cook, Mark Brown, Vaittinen, Matti,
Ben Dooks, Dan Williams, Linux ARM, David Gow, Randy Dunlap,
Nick Desaulniers, linux-kernel@vger.kernel.org, Masami Hiramatsu,
Ard Biesheuvel, Andrew Morton, David Miller
On Tue, Jul 14, 2020 at 1:06 PM Christoph Hellwig <hch@infradead.org> wrote:
> On Mon, Jul 13, 2020 at 03:39:17PM +0200, Arnd Bergmann wrote:
> > On Mon, Jul 13, 2020 at 3:07 PM Christoph Hellwig <hch@infradead.org> wrote:
> > > On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote:
> > > > +ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> > > > + size_t csize, unsigned long offset,
> > > > + int userbuf)
> > > > +{
> > > > + void *vaddr;
> > > > +
> > > > + if (!csize)
> > > > + return 0;
> > > > +
> > > > + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
> > > > + if (!vaddr)
> > > > + return -ENOMEM;
> > >
> > > Doing a memremap for every page is very inefficient. Also I don't see
> > > why you'd want to even do that. All memory is in the direct mapping
> > > for RISC-V. For other architecture that support highmem kmap_atomic_pfn
> > > would do the job, which is what I'd use in a generic version.
> >
> > I would expect the 'oldmem' data to not have a 'struct page', which would
> > be a problem at least for the generic implementation of kmap_atomic_pfn()
>
> Why do you expect it to not have a struct page?
I was under the impression that the kdump kernel only accesses a small
amount of memory itself and would allocate its mem_map to fit that but
not pages of that were used by the kernel it is dumping.
Arnd
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 1/3] lib: Add a generic copy_oldmem_page()
2020-07-13 13:06 ` Christoph Hellwig
2020-07-13 13:39 ` Arnd Bergmann
@ 2020-07-15 7:03 ` Ard Biesheuvel
1 sibling, 0 replies; 11+ messages in thread
From: Ard Biesheuvel @ 2020-07-15 7:03 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Palmer Dabbelt, mick, Mark Rutland, gregory.0xf0, Peter Zijlstra,
Catalin Marinas, Linus Walleij, Palmer Dabbelt, Brendan Higgins,
Marco Elver, Alexander Potapenko, Krzysztof Kozlowski,
Mauro Carvalho Chehab, Will Deacon, Ingo Molnar,
Uwe Kleine-König, takahiro.akashi, Paul E. McKenney,
Masahiro Yamada, Russell King, willy, Mike Rapoport,
Bartosz Golaszewski, Android Kernel Team, Petr Mladek,
Mikhail Zaslonko, Kees Cook, Arnd Bergmann, Mark Brown,
Matti Vaittinen, Ben Dooks, Dan Williams, Linux ARM, David Gow,
Randy Dunlap, Nick Desaulniers, Linux Kernel Mailing List,
Masami Hiramatsu, Andrew Morton, David S. Miller
On Mon, 13 Jul 2020 at 16:06, Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Jul 10, 2020 at 08:55:42PM -0700, Palmer Dabbelt wrote:
> > +ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
> > + size_t csize, unsigned long offset,
> > + int userbuf)
> > +{
> > + void *vaddr;
> > +
> > + if (!csize)
> > + return 0;
> > +
> > + vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
> > + if (!vaddr)
> > + return -ENOMEM;
>
> Doing a memremap for every page is very inefficient.
memremap(MEMREMAP_WB) will reuse the existing linear address if the PA
is covered by the linear mapping.
> Also I don't see
> why you'd want to even do that. All memory is in the direct mapping
> for RISC-V. For other architecture that support highmem kmap_atomic_pfn
> would do the job, which is what I'd use in a generic version.
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 2/3] arm: Use the new generic copy_oldmem_page()
2020-07-11 3:55 Add and use a generic copy_oldmem_page() Palmer Dabbelt
2020-07-11 3:55 ` [PATCH 1/3] lib: Add " Palmer Dabbelt
@ 2020-07-11 3:55 ` Palmer Dabbelt
2020-07-16 12:54 ` Linus Walleij
2020-07-11 3:55 ` [PATCH 3/3] arm64: " Palmer Dabbelt
2 siblings, 1 reply; 11+ messages in thread
From: Palmer Dabbelt @ 2020-07-11 3:55 UTC (permalink / raw)
To: mick
Cc: linux, catalin.marinas, will, Arnd Bergmann, rppt, akpm,
linus.walleij, mchehab+samsung, gregory.0xf0, masahiroy,
Nick Desaulniers, bgolaszewski, Palmer Dabbelt, mingo, ben-linux,
peterz, broonie, davem, rdunlap, uwe, dan.j.williams, mhiramat,
matti.vaittinen, zaslonko, willy, krzk, paulmck, pmladek,
brendanhiggins, keescook, glider, elver, davidgow, mark.rutland,
ardb, takahiro.akashi, linux-arm-kernel, linux-kernel,
kernel-team
From: Palmer Dabbelt <palmerdabbelt@google.com>
This is exactly the same as the arm64 code, which I just into lib/ to
avoid copying it into the RISC-V port. This builds with defconfig and with
CRASH_DUMP=y.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/arm/Kconfig | 1 +
arch/arm/kernel/Makefile | 1 -
arch/arm/kernel/crash_dump.c | 54 ------------------------------------
3 files changed, 1 insertion(+), 55 deletions(-)
delete mode 100644 arch/arm/kernel/crash_dump.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2ac74904a3ce..dfbeb14e9673 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1933,6 +1933,7 @@ config ATAGS_PROC
config CRASH_DUMP
bool "Build kdump crash kernel (EXPERIMENTAL)"
+ select GENERIC_LIB_COPY_OLDMEM_PAGE
help
Generate crash dump after being started by kexec. This should
be normally only set in special crash dump kernels which are
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 89e5d864e923..b5310a90dfe4 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -65,7 +65,6 @@ obj-$(CONFIG_KGDB) += kgdb.o patch.o
obj-$(CONFIG_ARM_UNWIND) += unwind.o
obj-$(CONFIG_HAVE_TCM) += tcm.o
obj-$(CONFIG_OF) += devtree.o
-obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_SWP_EMULATE) += swp_emulate.o
CFLAGS_swp_emulate.o := -Wa,-march=armv7-a
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c
deleted file mode 100644
index 53cb92435392..000000000000
--- a/arch/arm/kernel/crash_dump.c
+++ /dev/null
@@ -1,54 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * arch/arm/kernel/crash_dump.c
- *
- * Copyright (C) 2010 Nokia Corporation.
- * Author: Mika Westerberg
- *
- * This code is taken from arch/x86/kernel/crash_dump_64.c
- * Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
- * Copyright (C) IBM Corporation, 2004. All rights reserved
- */
-
-#include <linux/errno.h>
-#include <linux/crash_dump.h>
-#include <linux/uaccess.h>
-#include <linux/io.h>
-
-/**
- * copy_oldmem_page() - copy one page from old kernel memory
- * @pfn: page frame number to be copied
- * @buf: buffer where the copied page is placed
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page
- * @userbuf: if set, @buf is int he user address space
- *
- * This function copies one page from old kernel memory into buffer pointed by
- * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
- * copied or negative error in case of failure.
- */
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
- size_t csize, unsigned long offset,
- int userbuf)
-{
- void *vaddr;
-
- if (!csize)
- return 0;
-
- vaddr = ioremap(__pfn_to_phys(pfn), PAGE_SIZE);
- if (!vaddr)
- return -ENOMEM;
-
- if (userbuf) {
- if (copy_to_user(buf, vaddr + offset, csize)) {
- iounmap(vaddr);
- return -EFAULT;
- }
- } else {
- memcpy(buf, vaddr + offset, csize);
- }
-
- iounmap(vaddr);
- return csize;
-}
--
2.27.0.383.g050319c2ae-goog
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH 2/3] arm: Use the new generic copy_oldmem_page()
2020-07-11 3:55 ` [PATCH 2/3] arm: Use the new " Palmer Dabbelt
@ 2020-07-16 12:54 ` Linus Walleij
0 siblings, 0 replies; 11+ messages in thread
From: Linus Walleij @ 2020-07-16 12:54 UTC (permalink / raw)
To: Palmer Dabbelt
Cc: mick, Russell King, Catalin Marinas, Will Deacon, Arnd Bergmann,
Mike Rapoport, Andrew Morton, Mauro Carvalho Chehab, Gregory Fong,
masahiroy, Nick Desaulniers, Bartosz Golaszewski, Palmer Dabbelt,
Ingo Molnar, Ben Dooks, Peter Zijlstra, Mark Brown,
David S. Miller, Randy Dunlap, Uwe Kleine-König,
Dan Williams, Masami Hiramatsu, Matti Vaittinen, Mikhail Zaslonko,
willy, Krzysztof Kozlowski, paulmck, Petr Mladek, Brendan Higgins,
Kees Cook, Alexander Potapenko, elver, David Gow, Mark Rutland,
Ard Biesheuvel, Takahiro Akashi, Linux ARM,
linux-kernel@vger.kernel.org, kernel-team
On Sat, Jul 11, 2020 at 5:59 AM Palmer Dabbelt <palmer@dabbelt.com> wrote:
> From: Palmer Dabbelt <palmerdabbelt@google.com>
>
> This is exactly the same as the arm64 code, which I just into lib/ to
> avoid copying it into the RISC-V port. This builds with defconfig and with
> CRASH_DUMP=y.
>
> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Looks good to me.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Yours,
Linus Walleij
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 3/3] arm64: Use the new generic copy_oldmem_page()
2020-07-11 3:55 Add and use a generic copy_oldmem_page() Palmer Dabbelt
2020-07-11 3:55 ` [PATCH 1/3] lib: Add " Palmer Dabbelt
2020-07-11 3:55 ` [PATCH 2/3] arm: Use the new " Palmer Dabbelt
@ 2020-07-11 3:55 ` Palmer Dabbelt
2020-07-14 20:37 ` Catalin Marinas
2 siblings, 1 reply; 11+ messages in thread
From: Palmer Dabbelt @ 2020-07-11 3:55 UTC (permalink / raw)
To: mick
Cc: linux, catalin.marinas, will, Arnd Bergmann, rppt, akpm,
linus.walleij, mchehab+samsung, gregory.0xf0, masahiroy,
Nick Desaulniers, bgolaszewski, Palmer Dabbelt, mingo, ben-linux,
peterz, broonie, davem, rdunlap, uwe, dan.j.williams, mhiramat,
matti.vaittinen, zaslonko, willy, krzk, paulmck, pmladek,
brendanhiggins, keescook, glider, elver, davidgow, mark.rutland,
ardb, takahiro.akashi, linux-arm-kernel, linux-kernel,
kernel-team
From: Palmer Dabbelt <palmerdabbelt@google.com>
This is exactly the same as the arm64 code, which I just into lib/ to
avoid copying it into the RISC-V port. This builds with defconfig.
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/crash_dump.c | 39 ----------------------------------
2 files changed, 1 insertion(+), 39 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 66dc41fd49f2..55b27d56b163 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1109,6 +1109,7 @@ comment "Support for PE file signature verification disabled"
config CRASH_DUMP
bool "Build kdump crash kernel"
+ select GENERIC_LIB_COPY_OLDMEM_PAGE
help
Generate crash dump after being started by kexec. This should
be normally only set in special crash dump kernels which are
diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
index e6e284265f19..197b92c249ba 100644
--- a/arch/arm64/kernel/crash_dump.c
+++ b/arch/arm64/kernel/crash_dump.c
@@ -13,45 +13,6 @@
#include <linux/uaccess.h>
#include <asm/memory.h>
-/**
- * copy_oldmem_page() - copy one page from old kernel memory
- * @pfn: page frame number to be copied
- * @buf: buffer where the copied page is placed
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page
- * @userbuf: if set, @buf is in a user address space
- *
- * This function copies one page from old kernel memory into buffer pointed by
- * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
- * copied or negative error in case of failure.
- */
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
- size_t csize, unsigned long offset,
- int userbuf)
-{
- void *vaddr;
-
- if (!csize)
- return 0;
-
- vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB);
- if (!vaddr)
- return -ENOMEM;
-
- if (userbuf) {
- if (copy_to_user((char __user *)buf, vaddr + offset, csize)) {
- memunmap(vaddr);
- return -EFAULT;
- }
- } else {
- memcpy(buf, vaddr + offset, csize);
- }
-
- memunmap(vaddr);
-
- return csize;
-}
-
/**
* elfcorehdr_read - read from ELF core header
* @buf: buffer where the data is placed
--
2.27.0.383.g050319c2ae-goog
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH 3/3] arm64: Use the new generic copy_oldmem_page()
2020-07-11 3:55 ` [PATCH 3/3] arm64: " Palmer Dabbelt
@ 2020-07-14 20:37 ` Catalin Marinas
0 siblings, 0 replies; 11+ messages in thread
From: Catalin Marinas @ 2020-07-14 20:37 UTC (permalink / raw)
To: Palmer Dabbelt
Cc: mick, linux, will, Arnd Bergmann, rppt, akpm, linus.walleij,
mchehab+samsung, gregory.0xf0, masahiroy, Nick Desaulniers,
bgolaszewski, Palmer Dabbelt, mingo, ben-linux, peterz, broonie,
davem, rdunlap, uwe, dan.j.williams, mhiramat, matti.vaittinen,
zaslonko, willy, krzk, paulmck, pmladek, brendanhiggins, keescook,
glider, elver, davidgow, mark.rutland, ardb, takahiro.akashi,
linux-arm-kernel, linux-kernel, kernel-team
On Fri, Jul 10, 2020 at 08:55:44PM -0700, Palmer Dabbelt wrote:
> From: Palmer Dabbelt <palmerdabbelt@google.com>
>
> This is exactly the same as the arm64 code, which I just into lib/ to
> avoid copying it into the RISC-V port. This builds with defconfig.
>
> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
^ permalink raw reply [flat|nested] 11+ messages in thread