[PATCH v6 3/7] ftrace: Add arm64 support to recordmcount
From: Will Deacon <hidden>
Date: 2014-03-13 12:41:33
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lkml
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.
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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?
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+ 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)? Will