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2010-12-04ARM: 6511/1: ftrace: add ARM support for C version of recordmcountRabin Vincent
Depending on the compiler version, ARM GCC calls the mcount function either __gnu_mcount_nc or mcount. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-12-04ARM: 6509/1: ftrace: ignore any ftrace.o in C version of recordmcountRabin Vincent
arch/arm/kernel/ftrace.c references mcount like kernel/tracing/ftrace.c, so change the exclusion filter to match any ftrace.o. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-10-29ftrace/MIPS: Add module support for C version of recordmcountWu Zhangjin
Since MIPS modules' address space differs from the core kernel space, to access the _mcount in the core kernel, the kernel functions in modules must use long call (-mlong-calls): load the _mcount address into one register and jump to the address stored by the register: c: 3c030000 lui v1,0x0 <--------> b label c: R_MIPS_HI16 _mcount c: R_MIPS_NONE *ABS* c: R_MIPS_NONE *ABS* 10: 64630000 daddiu v1,v1,0 10: R_MIPS_LO16 _mcount 10: R_MIPS_NONE *ABS* 10: R_MIPS_NONE *ABS* 14: 03e0082d move at,ra 18: 0060f809 jalr v1 label: In the old Perl version of recordmcount, we only need to record the position of the 1st R_MIPS_HI16 type of _mcount, and later, in ftrace_make_nop(), replace the instruction in this position by a "b label" and in ftrace_make_call(), replace it back. But, the default C version of recordmcount records all of the _mcount symbols, so, we must filter the 2nd _mcount like the Perl version of recordmcount does. The C version of recordmcount copes with the symbols before they are linked, So It doesn't know the type of the symbols and therefore can not filter the symbols as the Perl version of recordmcount does. But as we can see above, the 2nd _mcount symbols of the long call alawys follows the 1st _mcount symbol of the same long call, which means the offset from the 1st to the 2nd is fixed, it is 0x10-0xc = 4 here, 4 is the length of the 1st load instruciton, for MIPS has fixed length of instructions, this offset is always 4. And as we know, the _mcount is inserted into the entry of every kernel function, the offset between the other _mcount's is expected to be always bigger than 4. So, to filter the 2ns _mcount symbol of the long call, we can simply check the offset between two _mcount symbols, If it is 4, then, filter the 2nd _mcount symbol. To avoid touching too much code, an 'empty' function fn_is_fake_mcount() is added for all of the archs, and the specific archs can override it via chaning the function pointer: is_fake_mcount in do_file() with the e_machine. e.g. This patch adds MIPS_is_fake_mcount() to override the default fn_is_fake_mcount() pointed by is_fake_mcount. This fn_is_fake_mcount() checks if the _mcount symbol is fake, e.g. the 2nd _mcount symbol of the long call is fake, for there are 2 _mcount symbols mapped to one real mcount call, so, one of them is fake and must be filtered. This fn_is_fake_mcount() is called in sift_rel_mcount() after finding the _mcount symbols and before adding the _mcount symbol into mrelp, so, it can prevent the fake mcount symbol going into the last __mcount_loc table. Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> LKML-Reference: <b866f0138224340a132d31861fa3f9300dee30ac.1288176026.git.wuzhangjin@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-10-29ftrace/MIPS: Add MIPS64 support for C version of recordmcountJohn Reiser
MIPS64 has 'weird' Elf64_Rel.r_info[1,2], which must be used instead of the generic Elf64_Rel.r_info, otherwise, the C version of recordmcount will not work for "segmentation fault". Usage of "union mips_r_info" and the functions MIPS64_r_sym() and MIPS64_r_info() written by Maciej W. Rozycki <macro@linux-mips.org> ---- [1] http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf [2] arch/mips/include/asm/module.h Tested-by: Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: John Reiser <jreiser@BitWagon.com> Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> LKML-Reference: <AANLkTinwXjLAYACUfhLYaocHD_vBbiErLN3NjwN8JqSy@mail.gmail.com> LKML-Reference: <910dc2d5ae1ed042df4f96815fe4a433078d1c2a.1288176026.git.wuzhangjin@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2010-10-15ftrace: Do not process kernel/trace/ftrace.o with C recordmcount programSteven Rostedt
The file kernel/trace/ftrace.c references the mcount() call to convert the mcount() callers to nops. But because it references mcount(), the mcount() address is placed in the relocation table. The C version of recordmcount reads the relocation table of all object files, and it will add all references to mcount to the __mcount_loc table that is used to find the places that call mcount() and change the call to a nop. When recordmcount finds the mcount reference in kernel/trace/ftrace.o, it saves that location even though the code is not a call, but references mcount as data. On boot up, when all calls are converted to nops, the code has a safety check to determine what op code it is actually replacing before it replaces it. If that op code at the address does not match, then a warning is printed and the function tracer is disabled. The reference to mcount in ftrace.c, causes this warning to trigger, since the reference is not a call to mcount(). The ftrace.c file is not compiled with the -pg flag, so no calls to mcount() should be expected. This patch simply makes recordmcount.c skip the kernel/trace/ftrace.c file. This was the same solution used by the perl version of recordmcount. Reported-by: Ingo Molnar <mingo@elte.hu> Cc: John Reiser <jreiser@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-14ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.cSteven Rostedt
The elf reader for recordmcount.c had duplicate functions for both 32 bit and 64 bit elf handling. This was due to the need of using the 32 and 64 bit elf structures. This patch consolidates the two by using macros to define the 32 and 64 bit names in a recordmcount.h file, and then by just defining a RECORD_MCOUNT_64 macro and including recordmcount.h twice we create the funtions for both the 32 bit version as well as the 64 bit version using one code source. Cc: John Reiser <jreiser@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-14ftrace: Add C version of recordmcount compile time codeJohn Reiser
Currently, the mcount callers are found with a perl script that does an objdump on every file in the kernel. This is a C version of that same code which should increase the performance time of compiling the kernel with dynamic ftrace enabled. Signed-off-by: John Reiser <jreiser@bitwagon.com> [ Updated the code to include .text.unlikely section as well as changing the format to follow Linux coding style. ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>