10 Aug, 2020
1 commit
-
Commit ea0eada45632 leads to the following build failure on powerpc:
HOSTCC scripts/recordmcount
scripts/recordmcount.c: In function 'arm64_is_fake_mcount':
scripts/recordmcount.c:440: error: 'R_AARCH64_CALL26' undeclared (first use in this function)
scripts/recordmcount.c:440: error: (Each undeclared identifier is reported only once
scripts/recordmcount.c:440: error: for each function it appears in.)
make[2]: *** [scripts/recordmcount] Error 1Make sure R_AARCH64_CALL26 is always defined.
Fixes: ea0eada45632 ("recordmcount: only record relocation of type R_AARCH64_CALL26 on arm64.")
Signed-off-by: Christophe Leroy
Acked-by: Steven Rostedt (VMware)
Acked-by: Gregory Herrero
Cc: Gregory Herrero
Link: https://lore.kernel.org/r/5ca1be21fa6ebf73203b45fd9aadd2bafb5e6b15.1597049145.git.christophe.leroy@csgroup.eu
Signed-off-by: Catalin Marinas
24 Jul, 2020
1 commit
-
Currently, if a section has a relocation to '_mcount' symbol, a new
__mcount_loc entry will be added whatever the relocation type is.
This is problematic when a relocation to '_mcount' is in the middle of a
section and is not a call for ftrace use.Such relocation could be generated with below code for example:
bool is_mcount(unsigned long addr)
{
return (target == (unsigned long) &_mcount);
}With this snippet of code, ftrace will try to patch the mcount location
generated by this code on module load and fail with:Call trace:
ftrace_bug+0xa0/0x28c
ftrace_process_locs+0x2f4/0x430
ftrace_module_init+0x30/0x38
load_module+0x14f0/0x1e78
__do_sys_finit_module+0x100/0x11c
__arm64_sys_finit_module+0x28/0x34
el0_svc_common+0x88/0x194
el0_svc_handler+0x38/0x8c
el0_svc+0x8/0xc
---[ end trace d828d06b36ad9d59 ]---
ftrace failed to modify
[] 0xffffa2dbf3a3a41c
actual: 66:a9:3c:90
Initializing ftrace call sites
ftrace record flags: 2000000
(0)
expected tramp: ffffa2dc6cf66724So Limit the relocation type to R_AARCH64_CALL26 as in perl version of
recordmcount.Fixes: af64d2aa872a ("ftrace: Add arm64 support to recordmcount")
Signed-off-by: Gregory Herrero
Acked-by: Steven Rostedt (VMware)
Link: https://lore.kernel.org/r/20200717143338.19302-1-gregory.herrero@oracle.com
Signed-off-by: Catalin Marinas
20 Jan, 2020
1 commit
-
Scenario 1, ARMv7
=================If code in arch/arm/kernel/ftrace.c would operate on mcount() pointer
the following may be generated:00000230 :
230: b5f8 push {r3, r4, r5, r6, r7, lr}
232: b500 push {lr}
234: f7ff fffe bl 0
234: R_ARM_THM_CALL __gnu_mcount_nc
238: f240 0600 movw r6, #0
238: R_ARM_THM_MOVW_ABS_NC __gnu_mcount_nc
23c: f8d0 1180 ldr.w r1, [r0, #384] ; 0x180FTRACE currently is not able to deal with it:
WARNING: CPU: 0 PID: 0 at .../kernel/trace/ftrace.c:1979 ftrace_bug+0x1ad/0x230()
...
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.116-... #1
...
[] (unwind_backtrace) from [] (show_stack+0x11/0x14)
[] (show_stack) from [] (dump_stack+0x81/0xa8)
[] (dump_stack) from [] (warn_slowpath_common+0x69/0x90)
[] (warn_slowpath_common) from [] (warn_slowpath_null+0x17/0x1c)
[] (warn_slowpath_null) from [] (ftrace_bug+0x1ad/0x230)
[] (ftrace_bug) from [] (ftrace_process_locs+0x27d/0x444)
[] (ftrace_process_locs) from [] (ftrace_init+0x91/0xe8)
[] (ftrace_init) from [] (start_kernel+0x34b/0x358)
[] (start_kernel) from [] (0x308095)
---[ end trace cb88537fdc8fa200 ]---
ftrace failed to modify [] prealloc_fixed_plts+0x8/0x60
actual: 44:f2:e1:36
ftrace record flags: 0
(0) expected tramp: c03143e9Scenario 2, ARMv4T
==================ftrace: allocating 14435 entries in 43 pages
------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at kernel/trace/ftrace.c:2029 ftrace_bug+0x204/0x310
CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.5 #1
Hardware name: Cirrus Logic EDB9302 Evaluation Board
[] (unwind_backtrace) from [] (show_stack+0x20/0x2c)
[] (show_stack) from [] (dump_stack+0x20/0x30)
[] (dump_stack) from [] (__warn+0xdc/0x104)
[] (__warn) from [] (warn_slowpath_null+0x4c/0x5c)
[] (warn_slowpath_null) from [] (ftrace_bug+0x204/0x310)
[] (ftrace_bug) from [] (ftrace_init+0x3b4/0x4d4)
[] (ftrace_init) from [] (start_kernel+0x20c/0x410)
[] (start_kernel) from [] ( (null))
---[ end trace 0506a2f5dae6b341 ]---
ftrace failed to modify
[] perf_trace_sys_exit+0x5c/0xe8
actual: 1e:ff:2f:e1
Initializing ftrace call sites
ftrace record flags: 0
(0)
expected tramp: c000fb24The analysis for this problem has been already performed previously,
refer to the link below.Fix the above problems by allowing only selected reloc types in
__mcount_loc. The list itself comes from the legacy recordmcount.pl
script.Link: https://lore.kernel.org/lkml/56961010.6000806@pengutronix.de/
Cc: stable@vger.kernel.org
Fixes: ed60453fa8f8 ("ARM: 6511/1: ftrace: add ARM support for C version of recordmcount")
Signed-off-by: Alexander Sverdlin
Acked-by: Steven Rostedt (VMware)
Signed-off-by: Russell King
01 Sep, 2019
8 commits
-
cleanup() mostly frees/unmaps the malloc'd/privately-mapped
copy of the ELF file recordmcount is working on, which is
set up in mmap_file(). It also deals with positioning within
the pseduo prive-mapping of the file and appending to the ELF
file.Split into two steps:
mmap_cleanup() for the mapping itself
file_append_cleanup() for allocations storing the
appended ELF data.Also, move the global variable initializations out of the main,
per-object-file loop and nearer to the alloc/init (mmap_file())
and two cleanup functions so we can more clearly see how they're
related.Link: http://lkml.kernel.org/r/2a387ac86d133d22c68f57b9933c32bab1d09a2d.1564596289.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
Redundant cleanup calls were introduced when transitioning from
the old error/success handling via setjmp/longjmp -- the longjmp
ensured the cleanup() call only happened once but replacing
the success_file()/fail_file() calls with cleanup() meant that
multiple cleanup() calls can happen as we return from function
calls.In do_file(), looking just before and after the "goto out" jumps we
can see that multiple cleanups() are being performed. We remove
cleanup() calls from the nested functions because it makes the code
easier to review -- the resources being cleaned up are generally
allocated and initialized in the callers so freeing them there
makes more sense.Other redundant cleanup() calls:
mmap_file() is only called from do_file() and, if mmap_file() fails,
then we goto out and do cleanup() there too.write_file() is only called from do_file() and do_file()
calls cleanup() unconditionally after returning from write_file()
therefore the cleanup() calls in write_file() are not necessary.find_secsym_ndx(), called from do_func()'s for-loop, when we are
cleaning up here it's obvious that we break out of the loop and
do another cleanup().__has_rel_mcount() is called from two parts of do_func()
and calls cleanup(). In theory we move them into do_func(), however
these in turn prove redundant so another simplification step
removes them as well.Link: http://lkml.kernel.org/r/de197e17fc5426623a847ea7cf3a1560a7402a4b.1564596289.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
Fix up the whitespace irregularity in the ELF switch
blocks.Swapping the initial value of gpfx allows us to
simplify all but one of the one-line switch cases even
further.Link: http://lkml.kernel.org/r/647f21f43723d3e831cedd3238c893db03eea6f0.1564596289.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
The uwrite() and ulseek() functions are formatted inconsistently
with the rest of the file and the kernel overall. While we're
making other changes here let's fix this.Link: http://lkml.kernel.org/r/4c67698f734be9867a2aba7035fe0ce59e1e4423.1564596289.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
Recordmcount uses setjmp/longjmp to manage control flow as
it reads and then writes the ELF file. This unusual control
flow is hard to follow and check in addition to being unlike
kernel coding style.So we rewrite these paths to use regular return values to
indicate error/success. When an error or previously-completed object
file is found we return an error code following kernel
coding conventions -- negative error values and 0 for success when
we're not returning a pointer. We return NULL for those that fail
and return non-NULL pointers otherwise.One oddity is already_has_rel_mcount -- there we use pointer comparison
rather than string comparison to differentiate between
previously-processed object files and returning the name of a text
section.Link: http://lkml.kernel.org/r/8ba8633d4afe444931f363c8d924bf9565b89a86.1564596289.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
uwrite() works within the pseudo-mapping and extends it as necessary
without needing the file descriptor (fd) parameter passed to it.
Similarly, ulseek() doesn't need its fd parameter. These parameters
were only added because the functions bear a conceptual resemblance
to write() and lseek(). Worse, they obscure the fact that at the time
uwrite() and ulseek() are called fd_map is not a valid file descriptor.Remove the unused file descriptor parameters that make it look like
fd_map is still valid.Link: http://lkml.kernel.org/r/2a136e820ee208469d375265c7b8eb28570749a0.1563992889.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
uread() is only used to initialize the ELF file's pseudo
private-memory mapping while uwrite() and ulseek() work within
the pseudo-mapping and extend it as necessary. Thus it is not
a complementary function to uwrite() and ulseek(). It also makes
no sense to do cleanups inside uread() when its only caller,
mmap_file(), is doing the relevant allocations and associated
initializations.Therefore it's clearer to use a plain read() call to initialize the
data in mmap_file() and remove uread().Link: http://lkml.kernel.org/r/31a87c22b19150cec1c8dc800c8b0873a2741703.1563992889.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware) -
The strcmp is unnecessary since .text is already accepted as a
prefix in the strncmp().Link: http://lkml.kernel.org/r/358e590b49adbe4185e161a8b364e323f3d52857.1563992889.git.mhelsley@vmware.com
Signed-off-by: Matt Helsley
Signed-off-by: Steven Rostedt (VMware)
05 Jun, 2019
1 commit
-
Based on 1 normalized pattern(s):
licensed under the gnu general public license version 2 gplv2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 5 file(s).
Signed-off-by: Thomas Gleixner
Reviewed-by: Kate Stewart
Reviewed-by: Armijn Hemel
Reviewed-by: Allison Randal
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531081036.993848054@linutronix.de
Signed-off-by: Greg Kroah-Hartman
09 Dec, 2018
1 commit
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When building with -ffunction-sections, the compiler will place each
function into its own ELF section, prefixed with ".text". For example,
a simple test module with functions test_module_do_work() and
test_module_wq_func():% objdump --section-headers test_module.o | awk '/\.text/{print $2}'
.text
.text.test_module_do_work
.text.test_module_wq_func
.init.text
.exit.textAdjust the recordmcount scripts to look for ".text" as a section name
prefix. This will ensure that those functions will be included in the
__mcount_loc relocations:% objdump --reloc --section __mcount_loc test_module.o
OFFSET TYPE VALUE
0000000000000000 R_X86_64_64 .text.test_module_do_work
0000000000000008 R_X86_64_64 .text.test_module_wq_func
0000000000000010 R_X86_64_64 .init.textLink: http://lkml.kernel.org/r/1542745158-25392-2-git-send-email-joe.lawrence@redhat.com
Signed-off-by: Joe Lawrence
Signed-off-by: Steven Rostedt (VMware)
29 May, 2018
1 commit
-
scripts/kallsyms.c: function write_src:
"printf", the #1 format specifier "d" need arg type "int",
but the according arg "table_cnt" has type "unsigned int"scripts/recordmcount.c: function do_file:
"fprintf", the #1 format specifier "d" need arg type "int",
but the according arg "(*w2)(ehdr->e_machine)" has type "unsigned int"scripts/recordmcount.h: function find_secsym_ndx:
"fprintf", the #1 format specifier "d" need arg type "int",
but the according arg "txtndx" has type "unsigned int"Signed-off-by: nixiaoming
Acked-by: Steven Rostedt (VMware)
Signed-off-by: Masahiro Yamada
23 Feb, 2018
1 commit
-
Now that arch/metag/ has been removed, drop a bunch of metag references
in various codes across the whole tree:
- VM_GROWSUP and __VM_ARCH_SPECIFIC_1.
- MT_METAG_* ELF note types.
- METAG Kconfig dependencies (FRAME_POINTER) and ranges
(MAX_STACK_SIZE_MB).
- metag cases in tools (checkstack.pl, recordmcount.c, perf).Signed-off-by: James Hogan
Acked-by: Steven Rostedt (VMware)
Acked-by: Peter Zijlstra (Intel)
Reviewed-by: Guenter Roeck
Cc: Ingo Molnar
Cc: Arnaldo Carvalho de Melo
Cc: Alexander Shishkin
Cc: Jiri Olsa
Cc: Namhyung Kim
Cc: linux-mm@kvack.org
Cc: linux-metag@vger.kernel.org
25 Mar, 2017
1 commit
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Adding a hook into free_reserve_area() that informs ftrace that boot up init
text is being free, lets ftrace safely remove those init functions from its
records, which keeps ftrace from trying to modify text that no longer
exists.Note, this still does not allow for tracing .init text of modules, as
modules require different work for freeing its init code.Link: http://lkml.kernel.org/r/1488502497.7212.24.camel@linux.intel.com
Cc: linux-mm@kvack.org
Cc: Vlastimil Babka
Cc: Mel Gorman
Cc: Peter Zijlstra
Requested-by: Todd Brandt
Signed-off-by: Steven Rostedt (VMware)
15 Nov, 2016
1 commit
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In similar spirit to x86 and arm64 support, add a make_nop_arm()
to replace calls to mcount with a nop in sections that aren't
traced.Link: http://lkml.kernel.org/r/20161018234200.5804-1-sboyd@codeaurora.org
Acked-by: Russell King
Acked-by: Rabin Vincent
Signed-off-by: Stephen Boyd
Signed-off-by: Steven Rostedt
08 Oct, 2016
1 commit
-
When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative. Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf
Acked-by: Peter Zijlstra (Intel)
Tested-by: Peter Zijlstra (Intel)
Tested-by: Daniel Thompson [arm]
Tested-by: Petr Mladek
Cc: Aaron Tomlin
Cc: Peter Zijlstra (Intel)
Cc: "Rafael J. Wysocki"
Cc: Russell King
Cc: Thomas Gleixner
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
29 Sep, 2016
1 commit
-
be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into
separate sections") added .softirqentry.text section, but it was not added
to recordmcount. So functions in the section are untracable. Add the
section to scripts/recordmcount.c and scripts/recordmcount.pl.Fixes: be7635e7287e ("arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections")
Link: http://lkml.kernel.org/r/1474902626-73468-1-git-send-email-dvyukov@google.com
Signed-off-by: Dmitry Vyukov
Acked-by: Steve Rostedt
Cc: [4.6+]
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
03 Aug, 2016
1 commit
-
glibc recently did a sync up (94e73c95d9b5 "elf.h: Sync with the gabi
webpage") that added a #define for EM_METAG but did not add relocationsThis triggers build errors:
scripts/recordmcount.c: In function 'do_file':
scripts/recordmcount.c:466:28: error: 'R_METAG_ADDR32' undeclared (first use in this function)
case EM_METAG: reltype = R_METAG_ADDR32;
^~~~~~~~~~~~~~
scripts/recordmcount.c:466:28: note: each undeclared identifier is reported only once for each function it appears in
scripts/recordmcount.c:468:20: error: 'R_METAG_NONE' undeclared (first use in this function)
rel_type_nop = R_METAG_NONE;
^~~~~~~~~~~~Work around this change with some more #ifdefery for the relocations.
Fedora Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1354034
Link: http://lkml.kernel.org/r/1468005530-14757-1-git-send-email-labbott@redhat.com
Cc: stable@vger.kernel.org # v3.9+
Cc: James Hogan
Fixes: 00512bdd4573 ("metag: ftrace support")
Reported-by: Ross Burton
Signed-off-by: Laura Abbott
Signed-off-by: Steven Rostedt
05 Jan, 2016
1 commit
-
Fix build warning:
scripts/recordmcount.c:589:4: warning: format not a string
literal and no format arguments [-Wformat-security]
sprintf("%s: failed\n", file);Fixes: a50bd43935586 ("ftrace/scripts: Have recordmcount copy the object file")
Link: http://lkml.kernel.org/r/1451516801-16951-1-git-send-email-colin.king@canonical.comCc: Li Bin
Cc: Russell King
Cc: Will Deacon
Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Colin Ian King
Signed-off-by: Steven Rostedt
17 Dec, 2015
1 commit
-
Russell King found that he had weird side effects when compiling the kernel
with hard linked ccache. The reason was that recordmcount modified the
kernel in place via mmap, and when a file gets modified twice by
recordmcount, it will complain about it. To fix this issue, Russell wrote a
patch that checked if the file was hard linked more than once and would
unlink it if it was.Linus Torvalds was not happy with the fact that recordmcount does this in
place modification. Instead of doing the unlink only if the file has two or
more hard links, it does the unlink all the time. In otherwords, it always
does a copy if it changed something. That is, it does the write out if a
change was made.Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Steven Rostedt
16 Dec, 2015
1 commit
-
recordmcount edits the file in-place, which can cause problems when
using ccache in hardlink mode. Arrange for recordmcount to break a
hardlinked object.Link: http://lkml.kernel.org/r/E1a7MVT-0000et-62@rmk-PC.arm.linux.org.uk
Cc: stable@vger.kernel.org # 2.6.37+
Signed-off-by: Russell King
Signed-off-by: Steven Rostedt
03 Nov, 2015
2 commits
-
By now, the recordmcount only records the function that in
following sections:
.text/.ref.text/.sched.text/.spinlock.text/.irqentry.text/
.kprobes.text/.text.unlikelyFor the function that not in these sections, the call mcount
will be in place and not be replaced when kernel boot up. And
it will bring performance overhead, such as do_mem_abort (in
.exception.text section). This patch make the call mcount to
nop for this case in recordmcount.Link: http://lkml.kernel.org/r/1446019445-14421-1-git-send-email-huawei.libin@huawei.com
Link: http://lkml.kernel.org/r/1446193864-24593-4-git-send-email-huawei.libin@huawei.comCc:
Cc:
Cc:
Cc: # 3.18+
Acked-by: Will Deacon
Signed-off-by: Li Bin
Signed-off-by: Steven Rostedt -
Although, the default value of rel_type_nop is zero, and the value
of R_386_NONE/R_X86_64_NONE is zero too, but it should be assigned
a meaningful value explicitly, otherwise it looks confused.Assign R_386_NONE to rel_type_nop for 386, assign R_X86_64_NONE
to rel_type_nop for x86_64.Link: http://lkml.kernel.org/r/1446020606-16352-1-git-send-email-huawei.libin@huawei.com
Signed-off-by: Li Bin
Signed-off-by: Steven Rostedt
27 Oct, 2014
1 commit
-
If the function tracer is enabled, allow to set kprobes on the first
instruction of a function (which is the function trace caller):If no kprobe is set handling of enabling and disabling function tracing
of a function simply patches the first instruction. Either it is a nop
(right now it's an unconditional branch, which skips the mcount block),
or it's a branch to the ftrace_caller() function.If a kprobe is being placed on a function tracer calling instruction
we encode if we actually have a nop or branch in the remaining bytes
after the breakpoint instruction (illegal opcode).
This is possible, since the size of the instruction used for the nop
and branch is six bytes, while the size of the breakpoint is only
two bytes.
Therefore the first two bytes contain the illegal opcode and the last
four bytes contain either "0" for nop or "1" for branch. The kprobes
code will then execute/simulate the correct instruction.Instruction patching for kprobes and function tracer is always done
with stop_machine(). Therefore we don't have any races where an
instruction is patched concurrently on a different cpu.
Besides that also the program check handler which executes the function
trace caller instruction won't be executed concurrently to any
stop_machine() execution.This allows to keep full fault based kprobes handling which generates
correct pt_regs contents automatically.Signed-off-by: Heiko Carstens
Signed-off-by: Martin Schwidefsky
09 Oct, 2014
1 commit
-
31 bit and 64 bit diverge more and more and it is rather painful
to keep both parts running.
To make things simpler just remove the 31 bit support which nobody
uses anyway.Signed-off-by: Heiko Carstens
Signed-off-by: Martin Schwidefsky
13 Jun, 2014
1 commit
-
Pull kbuild misc updates from Michal Marek:
"This is the non-critical part of kbuild for v3.16-rc1:
- make deb-pkg can do s390x and arm64
- new patterns in scripts/tags.sh
- scripts/tags.sh skips userspace tools' sources (which sometimes
have copies of kernel structures) and symlinks
- improvements to the objdiff tool
- two new coccinelle patches
- other minor fixes"* 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
scripts: objdiff: support directories for the augument of record command
scripts: objdiff: fix a comment
scripts: objdiff: change the extension of disassembly from .o to .dis
scripts: objdiff: improve path flexibility for record command
scripts: objdiff: remove unnecessary code
scripts: objdiff: direct error messages to stderr
scripts: objdiff: get the path to .tmp_objdiff more simply
deb-pkg: Add automatic support for s390x architecture
coccicheck: Add unneeded return variable test
kbuild: Fix a typo in documentation
kbuild: trivial - use tabs for code indent where possible
kbuild: trivial - remove trailing empty lines
coccinelle: Check for missing NULL terminators in of_device_id tables
scripts/tags.sh: ignore symlink'ed source files
scripts/tags.sh: add regular expression replacement pattern for memcg
builddeb: add arm64 in the supported architectures
builddeb: use $OBJCOPY variable instead of objcopy
scripts/tags.sh: ignore code of user space tools
scripts/tags.sh: add pattern for DEFINE_HASHTABLE
.gitignore: ignore Module.symvers in all directories
10 Jun, 2014
1 commit
-
Signed-off-by: Masahiro Yamada
29 May, 2014
1 commit
-
Recordmcount utility under scripts is run, after compiling each object,
to find out all the locations of calling _mcount() and put them into
specific seciton named __mcount_loc.
Then linker collects all such information into a table in the kernel image
(between __start_mcount_loc and __stop_mcount_loc) for later use by ftrace.This patch adds arm64 specific definitions to identify such locations.
There are two types of implementation, C and Perl. On arm64, only C version
is used to build the kernel now that CONFIG_HAVE_C_RECORDMCOUNT is on.
But Perl version is also maintained.This patch also contains a workaround just in case where a header file,
elf.h, on host machine doesn't have definitions of EM_AARCH64 nor
R_AARCH64_ABS64. Without them, compiling C version of recordmcount will
fail.Acked-by: Will Deacon
Signed-off-by: AKASHI Takahiro
Signed-off-by: Will Deacon
03 Mar, 2013
1 commit
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Add ftrace support for metag.
Signed-off-by: James Hogan
Cc: Frederic Weisbecker
Cc: Ingo Molnar
Reviewed-by: Steven Rostedt
17 May, 2011
7 commits
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Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch]
at compile time and not in ftrace_call_adjust at run time.Signed-off-by: Martin Schwidefsky
Signed-off-by: Steven Rostedt -
Do the mcount offset adjustment in the recordmcount.pl/recordmcount.[ch]
at compile time and not in ftrace_call_adjust at run time.Signed-off-by: Martin Schwidefsky
Signed-off-by: Steven Rostedt -
There's some sections that should not have mcount recorded and should not have
modifications to the that code. But currently they waste some time by calling
mcount anyway (which simply returns). As the real answer should be to
either whitelist the section or have gcc ignore it fully.This change adds a option to recordmcount to warn when it finds a section
that is ignored by ftrace but still contains mcount callers. This is not on
by default as developers may not know if the section should be completely
ignored or added to the whitelist.Cc: John Reiser
Link: http://lkml.kernel.org/r/20110421023738.476989377@goodmis.org
Signed-off-by: Steven Rostedt -
There are sections that are ignored by ftrace for the function tracing because
the text is in a section that can be removed without notice. The mcount calls
in these sections are ignored and ftrace never sees them. The downside of this
is that the functions in these sections still call mcount. Although the mcount
function is defined in assembly simply as a return, this added overhead is
unnecessary.The solution is to convert these callers into nops at compile time.
A better solution is to add 'notrace' to the section markers, but as new sections
come up all the time, it would be nice that they are delt with when they
are created.Later patches will deal with finding these sections and doing the proper solution.
Thanks to H. Peter Anvin for giving me the right nops to use for x86.
Cc: "H. Peter Anvin"
Cc: John Reiser
Link: http://lkml.kernel.org/r/20110421023738.237101176@goodmis.org
Signed-off-by: Steven Rostedt -
The .kprobe.text section is safe to modify mcount to nop and tracing.
Add it to the whitelist in recordmcount.c and recordmcount.pl.Cc: John Reiser
Cc: Masami Hiramatsu
Link: http://lkml.kernel.org/r/20110421023737.743350547@goodmis.org
Signed-off-by: Steven Rostedt -
The Linux style for switch statements is:
switch (var) {
case x:
[...]
break;
}Not:
switch (var) {
case x: {
[...]
} break;Cc: John Reiser
Link: http://lkml.kernel.org/r/20110421023737.523968644@goodmis.org
Signed-off-by: Steven Rostedt -
The Linux ftrace subsystem style for comparing is:
var == 1
var > 0and not:
1 == var
0 < varIt is considered that Linux developers are smart enough not to do the
if (var = 1)
mistake.
Cc: John Reiser
Link: http://lkml.kernel.org/r/20110421023737.290712238@goodmis.org
Signed-off-by: Steven Rostedt
10 Mar, 2011
1 commit
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The section .ref.text will not go away unexpectedly and is
safe to trace. Add it to the safe list of sections to allow
tracing.Signed-off-by: Steven Rostedt
04 Dec, 2010
1 commit
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Depending on the compiler version, ARM GCC calls the mcount function
either __gnu_mcount_nc or mcount.Acked-by: Steven Rostedt
Signed-off-by: Rabin Vincent
Signed-off-by: Russell King
