This patch changes the __init_end address to a
page align address, so that free_initmem() can
free the whole .init section, because if the end
address is not page aligned, it will round down to
a page align address, then the tail unligned page
will not be freed.
Signed-off-by: wang <yalin.wang2010@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Commit 78d7530ac3 ("ARM: Clean up linker script using new linker script
macros.") modified the arm kernel linker script to use the STABS_DEBUG
macro, but left a .comment section definition. As STABS_DEBUG defines
the .comment section in an identical way, the second section definition
is redundant and can be removed.
This patch removes the redundant .comment section definition.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Use linker magic to create the vectors and vector stubs: we can tell the
linker to place them at an appropriate VMA, but keep the LMA within the
kernel. This gets rid of some unnecessary symbol manipulation, and
have the linker calculate the relocations appropriately.
Cc: <stable@vger.kernel.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We're about to move to an init procedure where we rely on the
fact that the init code fits in a single page. Make sure we
align the idmap text on a vector alignment, and that the code is
not bigger than a single page.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>
Add a method (hyp_idmap_setup) to populate a hyp pgd with an
identity mapping of the code contained in the .hyp.idmap.text
section.
Offer a method to drop this identity mapping through
hyp_idmap_teardown.
Make all the above depend on CONFIG_ARM_VIRT_EXT and CONFIG_ARM_LPAE.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
The .notes, being read-only data by nature, were placed between
read-write .data and .bss. This was harmful in case of the XIP
kernel, as being placed in the RAM range, most likely far
from the ROM address, was inflating the XIP images.
Moving the .notes at the end of the read-only section
(consisting of .text, .rodata and unwind info) fixes the problem.
Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add the ARM machine identifier to sortextable and select the
config option so that we can sort the exception table at compile
time. sortextable relies on a section named __ex_table existing
in the vmlinux, but ARM's linker script places the exception
table in the data section. Give the exception table its own
section so that sortextable can find it.
This allows us to skip the sorting step during boot.
Cc: David Daney <david.daney@cavium.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
ARM builds seem to be plagued by an occasional build error:
Inconsistent kallsyms data
This is a bug - please report about it
Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
The problem has to do with alignment of some sections by the linker.
The kallsyms data is built in two passes by first linking the kernel
without it, and then linking the kernel again with the symbols
included. Normally, this just shifts the symbols, without changing
their order, and the compression used by the kallsyms gives the same
result.
On non SMP, the per CPU data is empty. Depending on the where the
alignment ends up, it can come out as either:
+-------------------+
| last text segment |
+-------------------+
/* padding */
+-------------------+ <- L1_CACHE_BYTES alignemnt
| per cpu (empty) |
+-------------------+
__per_cpu_end:
/* padding */
__data_loc:
+-------------------+ <- THREAD_SIZE alignment
| data |
+-------------------+
or
+-------------------+
| last text segment |
+-------------------+
/* padding */
+-------------------+ <- L1_CACHE_BYTES alignemnt
| per cpu (empty) |
+-------------------+
__per_cpu_end:
/* no padding */
__data_loc:
+-------------------+ <- THREAD_SIZE alignment
| data |
+-------------------+
if the alignment satisfies both. Because symbols that have the same
address are sorted by 'nm -n', the second case will be in a different
order than the first case. This changes the compression, changing the
size of the kallsym data, causing the build failure.
The KALLSYMS_EXTRA_PASS=1 workaround usually works, but it is still
possible to have the alignment change between the second and third
pass. It's probably even possible for it to never reach a fixedpoint.
The problem only occurs on non-SMP, when the per-cpu data is empty,
and when the data segment has alignment (and immediately follows the
text segments). Fix this by only including the per_cpu section on
SMP, when it is not empty.
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
With an admittedly exotic choice of configuration options
(CC_OPTIMIZE_FOR_SIZE, THUMB2, some other size-minimizing ones)
and compiler, the proc_info table can end up being misaligned,
and the kernel being unbootable (Error: unrecognized/unsupported
processor variant).
Forcing the alignement to 4 bytes in the linker script fixes the
issue.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The exception fixup table is currently aligned to a 32-byte boundary.
Whilst this won't cause any problems, the exception_table_entry
structures contain only a pair of unsigned longs, so 4-byte alignment
is all that is required. If the table was walked from start to end,
cacheline alignment may bring some performance benefits, but since a
binary search is used, the access pattern is random and will not benefit
from a stricter alignment.
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The linker script assumes a cacheline size of 32 bytes when aligning
the .data..cacheline_aligned and .data..percpu sections.
This patch updates the script to use L1_CACHE_BYTES, which should be set
to 64 on platforms that require it.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
When disabling and re-enabling the MMU, it is necessary to take out an
identity mapping for the code that manipulates the SCTLR in order to
avoid it disappearing from under our feet. This is useful when soft
rebooting and returning from CPU suspend.
This patch allocates a set of page tables during boot and populates them
with an identity mapping for the .idmap.text section. This means that
users of the identity map do not need to manage their own pgd and can
instead annotate their functions with __idmap or, in the case of assembly
code, place them in the correct section.
Acked-by: Dave Martin <dave.martin@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
ARM uses its own BUG() handler which makes its output slightly different
from other archtectures.
One of the problems is that the ARM implementation doesn't report the function
with the BUG() in it, but always reports the PC being in __bug(). The generic
implementation doesn't have this problem.
Currently we get something like:
kernel BUG at fs/proc/breakme.c:35!
Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
PC is at __bug+0x20/0x2c
With this patch it displays:
kernel BUG at fs/proc/breakme.c:35!
Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP
...
PC is at write_breakme+0xd0/0x1b4
This implementation uses an undefined instruction to implement BUG, and sets up
a bug table containing the relevant information. Many versions of gcc do not
support %c properly for ARM (inserting a # when they shouldn't) so we work
around this using distasteful macro magic.
v1: Initial version to replace existing ARM BUG() implementation with something
more similar to other architectures.
v2: Add Thumb support, remove backtrace whitespace output changes. Change to
use macros instead of requiring the asm %d flag to work (thanks to
Dave Martin <dave.martin@linaro.org>)
v3: Remove old BUG() implementation in favor of this one.
Remove the Backtrace: message (will submit this separately).
Use ARM_EXIT_KEEP() so that some architectures can dump exit text at link time
thanks to Stephen Boyd <sboyd@codeaurora.org> (although since we always
define GENERIC_BUG this might be academic.)
Rebase to linux-2.6.git master.
v4: Allow BUGS in modules (these were not reported correctly in v3)
(thanks to Stephen Boyd <sboyd@codeaurora.org> for suggesting that.)
Remove __bug() as this is no longer needed.
v5: Add %progbits as the section flags.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
We are seeing linker errors caused by sections being discarded, despite
the linker script trying to keep them. The result is (eg):
`.exit.text' referenced in section `.alt.smp.init' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o
`.exit.text' referenced in section `.alt.smp.init' of net/built-in.o: defined in discarded section `.exit.text' of net/built-in.o
This is the relevent part of the linker script (reformatted to make it
clearer):
| SECTIONS
| {
| /*
| * unwind exit sections must be discarded before the rest of the
| * unwind sections get included.
| */
| /DISCARD/ : {
| *(.ARM.exidx.exit.text)
| *(.ARM.extab.exit.text)
| }
| ...
| .exit.text : {
| *(.exit.text)
| *(.memexit.text)
| }
| ...
| /DISCARD/ : {
| *(.exit.text)
| *(.memexit.text)
| *(.exit.data)
| *(.memexit.data)
| *(.memexit.rodata)
| *(.exitcall.exit)
| *(.discard)
| *(.discard.*)
| }
| }
Now, this is what the linker manual says about discarded output sections:
| The special output section name `/DISCARD/' may be used to discard
| input sections. Any input sections which are assigned to an output
| section named `/DISCARD/' are not included in the output file.
No questions, no exceptions. It doesn't say "unless they are listed
before the /DISCARD/ section." Now, this is what asn-generic/vmlinux.lds.S
says:
| /*
| * Default discarded sections.
| *
| * Some archs want to discard exit text/data at runtime rather than
| * link time due to cross-section references such as alt instructions,
| * bug table, eh_frame, etc. DISCARDS must be the last of output
| * section definitions so that such archs put those in earlier section
| * definitions.
| */
And guess what - the list _always_ includes .exit.text etc.
Now, what's actually happening is that the linker is reading the script,
and it finds the first /DISCARD/ output section at the beginning of the
script. It continues reading the script, and finds the 'DISCARD' macro
at the end, which having been postprocessed results in another
/DISCARD/ output section. As the linker already contains the earlier
/DISCARD/ output section, it adds it to that existing section, so it
effectively is placed at the start. This can be seen by using the -M
option to ld:
| Linker script and memory map
|
| 0xc037c080 jiffies = jiffies_64
|
| /DISCARD/
| *(.ARM.exidx.exit.text)
| *(.ARM.extab.exit.text)
| *(.exit.text)
| *(.memexit.text)
| *(.exit.data)
| *(.memexit.data)
| *(.memexit.rodata)
| *(.exitcall.exit)
| *(.discard)
| *(.discard.*)
|
| 0xc0008000 . = 0xc0008000
|
| .head.text 0xc0008000 0x1d0
| 0xc0008000 _text = .
| *(.head.text)
| .head.text 0xc0008000 0x1d0 arch/arm/kernel/head.o
| 0xc0008000 stext
|
| .text 0xc0008200 0x2d78d0
| 0xc0008200 _stext = .
| 0xc0008200 __exception_text_start = .
| *(.exception.text)
| .exception.text
| ...
As you can see, all the discarded sections are grouped together - and
as a result of it being the first output section, they all appear before
any other section.
The result is that not only is the unwind information discarded (as
intended), but also the .exit.text, despite us wanting to have the
.exit.text preserved.
We can't move the unwind information elsewhere, because it'll then be
included even when we do actually discard the .exit.text (and similar)
sections.
So, work around this by avoiding the generic DISCARDS macro, and instead
conditionalize the sections to be discarded ourselves. This avoids the
ambiguity in how the linker assigns input sections to output sections,
making our script less dependent on undocumented linker behaviour.
Reported-by: Rob Herring <robherring2@gmail.com>
Tested-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
x86 uses _text to mark the start of the kernel image including the
head text, and _stext to mark the start of the .text section. Change
our vmlinux.lds to conform. An audit of the places which use _stext
and _text in arch/arm indicates no users of either symbol are impacted
by this change. It does mean a slight change to /proc/iomem output.
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Place the init sections between the text and data sections. This
means all code is grouped together at the beginning of the kernel
image, and all data is at the end of the image. This avoids problems
with the 24-bit branch instruction relocations becoming invalid with
large initramfs images.
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Keep the various linker tables as separate output sections rather
than combining them together into one big .init section. This
makes the 'vmlinux' easier to see what is placed where.
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Percpu allocator honors alignment request upto PAGE_SIZE and both the
percpu addresses in the percpu address space and the translated kernel
addresses should be aligned accordingly. The calculation of the
former depends on the alignment of percpu output section in the kernel
image.
The linker script macros PERCPU_VADDR() and PERCPU() are used to
define this output section and the latter takes @align parameter.
Several architectures are using @align smaller than PAGE_SIZE breaking
percpu memory alignment.
This patch removes @align parameter from PERCPU(), renames it to
PERCPU_SECTION() and makes it always align to PAGE_SIZE. While at it,
add PCPU_SETUP_BUG_ON() checks such that alignment problems are
reliably detected and remove percpu alignment comment recently added
in workqueue.c as the condition would trigger BUG way before reaching
there.
For um, this patch raises the alignment of percpu area. As the area
is in .init, there shouldn't be any noticeable difference.
This problem was discovered by David Howells while debugging boot
failure on mn10300.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm: (91 commits)
ARM: 6806/1: irq: introduce entry and exit functions for chained handlers
ARM: 6781/1: Thumb-2: Work around buggy Thumb-2 short branch relocations in gas
ARM: 6747/1: P2V: Thumb2 support
ARM: 6798/1: aout-core: zero thread debug registers in a.out core dump
ARM: 6796/1: Footbridge: Fix I/O mappings for NOMMU mode
ARM: 6784/1: errata: no automatic Store Buffer drain on Cortex-A9
ARM: 6772/1: errata: possible fault MMU translations following an ASID switch
ARM: 6776/1: mach-ux500: activate fix for errata 753970
ARM: 6794/1: SPEAr: Append UL to device address macros.
ARM: 6793/1: SPEAr: Remove unused *_SIZE macros from spear*.h files
ARM: 6792/1: SPEAr: Replace SIZE macro's with SZ_4K macros
ARM: 6791/1: SPEAr3xx: Declare device structures after shirq code
ARM: 6790/1: SPEAr: Clock Framework: Rename usbd clock and align apb_clk entry
ARM: 6789/1: SPEAr3xx: Rename sdio to sdhci
ARM: 6788/1: SPEAr: Include mach/hardware.h instead of mach/spear.h
ARM: 6787/1: SPEAr: Reorder #includes in .h & .c files.
ARM: 6681/1: SPEAr: add debugfs support to clk API
ARM: 6703/1: SPEAr: update clk API support
ARM: 6679/1: SPEAr: make clk API functions more generic
ARM: 6737/1: SPEAr: formalized timer support
...
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu, x86: Add arch-specific this_cpu_cmpxchg_double() support
percpu: Generic support for this_cpu_cmpxchg_double()
alpha: use L1_CACHE_BYTES for cacheline size in the linker script
percpu: align percpu readmostly subsection to cacheline
Fix up trivial conflict in arch/x86/kernel/vmlinux.lds.S due to the
percpu alignment having changed ("x86: Reduce back the alignment of the
per-CPU data section")
