Commit a0a458fb authored by Qing Zhang's avatar Qing Zhang Committed by Huacai Chen
Browse files

LoongArch/ftrace: Add recordmcount support 



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 the 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 LoongArch specific definitions to identify such locations.
And on LoongArch, only the C version is used to build the kernel now that
CONFIG_HAVE_C_RECORDMCOUNT is on.

Acked-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarQing Zhang <zhangqing@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent dbe3ba30

arch/loongarch/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -85,11 +85,13 @@ config LOONGARCH 
	select HAVE_ARCH_TRANSPARENT_HUGEPAGE

	select HAVE_ASM_MODVERSIONS

	select HAVE_CONTEXT_TRACKING_USER

	select HAVE_C_RECORDMCOUNT

	select HAVE_DEBUG_STACKOVERFLOW

	select HAVE_DMA_CONTIGUOUS

	select HAVE_EBPF_JIT

	select HAVE_EXIT_THREAD

	select HAVE_FAST_GUP

	select HAVE_FTRACE_MCOUNT_RECORD

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_GENERIC_VDSO

scripts/recordmcount.c

+39 −0
Original line number Diff line number Diff line
@@ -38,6 +38,14 @@ 
#define R_AARCH64_ABS64	257

#endif



#ifndef EM_LOONGARCH

#define EM_LOONGARCH		258

#define R_LARCH_32			1

#define R_LARCH_64			2

#define R_LARCH_MARK_LA			20

#define R_LARCH_SOP_PUSH_PLT_PCREL	29

#endif



#define R_ARM_PC24		1

#define R_ARM_THM_CALL		10

#define R_ARM_CALL		28
@@ -441,6 +449,28 @@ static int arm64_is_fake_mcount(Elf64_Rel const *rp) 
	return ELF64_R_TYPE(w8(rp->r_info)) != R_AARCH64_CALL26;

}



static int LARCH32_is_fake_mcount(Elf32_Rel const *rp)

{

	switch (ELF64_R_TYPE(w(rp->r_info))) {

	case R_LARCH_MARK_LA:

	case R_LARCH_SOP_PUSH_PLT_PCREL:

		return 0;

	}



	return 1;

}



static int LARCH64_is_fake_mcount(Elf64_Rel const *rp)

{

	switch (ELF64_R_TYPE(w(rp->r_info))) {

	case R_LARCH_MARK_LA:

	case R_LARCH_SOP_PUSH_PLT_PCREL:

		return 0;

	}



	return 1;

}



/* 64-bit EM_MIPS has weird ELF64_Rela.r_info.

 * http://techpubs.sgi.com/library/manuals/4000/007-4658-001/pdf/007-4658-001.pdf

 * We interpret Table 29 Relocation Operation (Elf64_Rel, Elf64_Rela) [p.40]
@@ -558,6 +588,7 @@ static int do_file(char const *const fname) 
		break;

	case EM_IA_64:	reltype = R_IA64_IMM64; break;

	case EM_MIPS:	/* reltype: e_class    */ break;

	case EM_LOONGARCH:	/* reltype: e_class    */ break;

	case EM_PPC:	reltype = R_PPC_ADDR32; break;

	case EM_PPC64:	reltype = R_PPC64_ADDR64; break;

	case EM_S390:	/* reltype: e_class    */ break;
@@ -589,6 +620,10 @@ static int do_file(char const *const fname) 
			reltype = R_MIPS_32;

			is_fake_mcount32 = MIPS32_is_fake_mcount;

		}

		if (w2(ehdr->e_machine) == EM_LOONGARCH) {

			reltype = R_LARCH_32;

			is_fake_mcount32 = LARCH32_is_fake_mcount;

		}

		if (do32(ehdr, fname, reltype) < 0)

			goto out;

		break;
@@ -610,6 +645,10 @@ static int do_file(char const *const fname) 
			Elf64_r_info = MIPS64_r_info;

			is_fake_mcount64 = MIPS64_is_fake_mcount;

		}

		if (w2(ghdr->e_machine) == EM_LOONGARCH) {

			reltype = R_LARCH_64;

			is_fake_mcount64 = LARCH64_is_fake_mcount;

		}

		if (do64(ghdr, fname, reltype) < 0)

			goto out;

		break;