user/sven/linux.git/scripts/recordmcount.c, branch v4.4.294

scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

2021-03-17T15:07:21Z

commit 9c8e2f6d3d361439cc6744a094f1c15681b55269 upstream. 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.text Adjust 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.text Link: 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) [Manoj: Resolve conflict on 4.4.y/4.9.y because of missing 42c269c88dc1] Signed-off-by: Manoj Gupta Signed-off-by: Greg Kroah-Hartman

ARM: 8950/1: ftrace/recordmcount: filter relocation types

2020-01-29T09:21:51Z

commit 927d780ee371d7e121cea4fc7812f6ef2cea461c upstream. 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 <__gnu_mcount_nc> 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] ; 0x180 FTRACE 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 [<00308095>] (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: c03143e9 Scenario 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 [<00000000>] ( (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: c000fb24 The 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 Signed-off-by: Greg Kroah-Hartman

ftrace/recordmcount: Work around for addition of metag magic but not relocations

2016-08-20T16:09:23Z

commit b2e1c26f0b62531636509fbcb6dab65617ed8331 upstream. 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 relocations This 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: James Hogan Fixes: 00512bdd4573 ("metag: ftrace support") Reported-by: Ross Burton Signed-off-by: Laura Abbott Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman

ftrace/scripts: Fix incorrect use of sprintf in recordmcount

2016-01-04T16:13:16Z

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.com Cc: 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

ftrace/scripts: Have recordmcount copy the object file

2015-12-16T20:46:07Z

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

scripts: recordmcount: break hardlinks

2015-12-16T14:28:23Z

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

recordmcount: arm64: Replace the ignored mcount call into nop

2015-11-03T15:50:29Z

By now, the recordmcount only records the function that in following sections: .text/.ref.text/.sched.text/.spinlock.text/.irqentry.text/ .kprobes.text/.text.unlikely For 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.com Cc: Cc: Cc: Cc: # 3.18+ Acked-by: Will Deacon Signed-off-by: Li Bin Signed-off-by: Steven Rostedt

recordmcount: x86: Assign a meaningful value to rel_type_nop

2015-11-02T18:34:32Z

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

s390/ftrace,kprobes: allow to patch first instruction

2014-10-27T12:27:27Z

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

s390/ftrace: remove 31 bit ftrace support

2014-10-09T07:14:18Z

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