Messages in this thread | | | Date | Thu, 13 Mar 2014 23:57:58 +0900 | From | AKASHI Takahiro <> | Subject | Re: [PATCH v6 3/7] ftrace: Add arm64 support to recordmcount |
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On 03/13/2014 09:38 PM, Will Deacon wrote: > On Thu, Mar 13, 2014 at 10:13:46AM +0000, AKASHI Takahiro wrote: >> 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. > > [...] > >> diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c >> index 9c22317..047c8cd 100644 >> --- a/scripts/recordmcount.c >> +++ b/scripts/recordmcount.c >> @@ -40,6 +40,11 @@ >> #define R_METAG_NONE 3 >> #endif >> >> +#ifndef EM_AARCH64 >> +#define EM_AARCH64 183 >> +#define R_AARCH64_ABS64 257 >> +#endif >> + >> static int fd_map; /* File descriptor for file being modified. */ >> static int mmap_failed; /* Boolean flag. */ >> static void *ehdr_curr; /* current ElfXX_Ehdr * for resource cleanup */ >> @@ -347,6 +352,10 @@ do_file(char const *const fname) >> case EM_ARM: reltype = R_ARM_ABS32; >> altmcount = "__gnu_mcount_nc"; >> break; >> + case EM_AARCH64: >> + reltype = R_AARCH64_ABS64; >> + altmcount = "_mcount"; > > Shouldn't you be setting gpfx = '_' instead of overriding altmcount like > this?
Yep. Fix it.
>> + break; >> case EM_IA_64: reltype = R_IA64_IMM64; gpfx = '_'; break; >> case EM_METAG: reltype = R_METAG_ADDR32; >> altmcount = "_mcount_wrapper"; >> diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl >> index 91280b8..397b6b8 100755 >> --- a/scripts/recordmcount.pl >> +++ b/scripts/recordmcount.pl >> @@ -279,6 +279,11 @@ if ($arch eq "x86_64") { >> $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_ARM_(CALL|PC24|THM_CALL)" . >> "\\s+(__gnu_mcount_nc|mcount)\$"; >> >> +} elsif ($arch eq "arm64") { >> + $alignment = 3; >> + $section_type = '%progbits'; >> + $mcount_regex = "^\\s*([0-9a-fA-F]+):\\s*R_AARCH64_CALL26\\s+_mcount\$"; > > What about "mcount" (i.e. no underscore)?
I don't think it works since such regex doesn't match to "CALL26 _mcount".
Thanks, -Takahiro AKASHI
> Will >
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