Re: [PATCH v2 16/16] objtool/powerpc: Add --mcount specific implementation
From: Christophe Leroy <hidden>
Date: 2022-08-31 12:50:48
Also in:
lkml
Le 29/08/2022 à 07:52, Sathvika Vasireddy a écrit :
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This patch enables objtool --mcount on powerpc, and adds implementation specific to powerpc. Signed-off-by: Sathvika Vasireddy <redacted> --- arch/powerpc/Kconfig | 1 + tools/objtool/arch/powerpc/decode.c | 22 +++++++++++++++++++ tools/objtool/arch/powerpc/include/arch/elf.h | 2 ++ 3 files changed, 25 insertions(+)diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index dc05cd23c233..6be2e68fa9eb 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig@@ -238,6 +238,7 @@ config PPC select HAVE_NMI if PERF_EVENTS || (PPC64 && PPC_BOOK3S) select HAVE_OPTPROBES select HAVE_OBJTOOL if PPC32 || MPROFILE_KERNEL + select HAVE_OBJTOOL_MCOUNT if HAVE_OBJTOOL select HAVE_PERF_EVENTS select HAVE_PERF_EVENTS_NMI if PPC64 select HAVE_PERF_REGSdiff --git a/tools/objtool/arch/powerpc/decode.c b/tools/objtool/arch/powerpc/decode.c index 8b6a14680da7..b71c265ed503 100644 --- a/tools/objtool/arch/powerpc/decode.c +++ b/tools/objtool/arch/powerpc/decode.c@@ -9,6 +9,14 @@ #include <objtool/builtin.h> #include <objtool/endianness.h> +bool arch_ftrace_match(char *name) +{ + if (!strcmp(name, "_mcount")) + return true; + + return false; +} + unsigned long arch_dest_reloc_offset(int addend) { return addend;@@ -41,12 +49,26 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec struct list_head *ops_list) { u32 insn; + unsigned int opcode; *immediate = 0; insn = bswap_if_needed(file->elf, *(u32 *)(sec->data->d_buf + offset)); *len = 4; *type = INSN_OTHER; + opcode = insn >> 26; + + switch (opcode) { + case 18: /* bl */
case 18 is more than 'bl', it includes also 'b'. In both cases, the calculation of *immediate is the same. It would therefore be more correct to perform the calculation and setup of *immediate outside the 'if ((insn & 3) == 1)', that would avoid unnecessary churn the day we add support for branches without link.
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+ if ((insn & 3) == 1) { + *type = INSN_CALL; + *immediate = insn & 0x3fffffc; + if (*immediate & 0x2000000) + *immediate -= 0x4000000; + } + break; + } + return 0; }diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h b/tools/objtool/arch/powerpc/include/arch/elf.h index 3c8ebb7d2a6b..73f9ae172fe5 100644 --- a/tools/objtool/arch/powerpc/include/arch/elf.h +++ b/tools/objtool/arch/powerpc/include/arch/elf.h@@ -4,5 +4,7 @@ #define _OBJTOOL_ARCH_ELF #define R_NONE R_PPC_NONE +#define R_ABS64 R_PPC64_ADDR64 +#define R_ABS32 R_PPC_ADDR32 #endif /* _OBJTOOL_ARCH_ELF */