Commit a2d49358 authored by John Reiser's avatar John Reiser Committed by Ralf Baechle
Browse files

ftrace/MIPS: Add MIPS64 support for C version of recordmcount 

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: default avatarWu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: default avatarJohn Reiser <jreiser@BitWagon.com>
Signed-off-by: default avatarMaciej W. Rozycki <macro@linux-mips.org>
LKML-Reference: <AANLkTinwXjLAYACUfhLYaocHD_vBbiErLN3NjwN8JqSy@mail.gmail.com>
LKML-Reference: <910dc2d5ae1ed042df4f96815fe4a433078d1c2a.1288176026.git.wuzhangjin@gmail.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 949e51be

scripts/recordmcount.c

+41 −0
Original line number Diff line number Diff line
@@ -217,6 +217,39 @@ is_mcounted_section_name(char const *const txtname) 
#define RECORD_MCOUNT_64

#include "recordmcount.h"



/* 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]

 * to imply the order of the members; the spec does not say so.

 *	typedef unsigned char Elf64_Byte;

 * fails on MIPS64 because their <elf.h> already has it!

 */



typedef uint8_t myElf64_Byte;		/* Type for a 8-bit quantity.  */



union mips_r_info {

	Elf64_Xword r_info;

	struct {

		Elf64_Word r_sym;		/* Symbol index.  */

		myElf64_Byte r_ssym;		/* Special symbol.  */

		myElf64_Byte r_type3;		/* Third relocation.  */

		myElf64_Byte r_type2;		/* Second relocation.  */

		myElf64_Byte r_type;		/* First relocation.  */

	} r_mips;

};



static uint64_t MIPS64_r_sym(Elf64_Rel const *rp)

{

	return w(((union mips_r_info){ .r_info = rp->r_info }).r_mips.r_sym);

}



static void MIPS64_r_info(Elf64_Rel *const rp, unsigned sym, unsigned type)

{

	rp->r_info = ((union mips_r_info){

		.r_mips = { .r_sym = w(sym), .r_type = type }

	}).r_info;

}



static void

do_file(char const *const fname)

{
@@ -268,6 +301,7 @@ do_file(char const *const fname) 
	case EM_386:	 reltype = R_386_32;                   break;

	case EM_ARM:	 reltype = R_ARM_ABS32;                break;

	case EM_IA_64:	 reltype = R_IA64_IMM64;   gpfx = '_'; break;

	case EM_MIPS:	 /* reltype: e_class    */ gpfx = '_'; break;

	case EM_PPC:	 reltype = R_PPC_ADDR32;   gpfx = '_'; break;

	case EM_PPC64:	 reltype = R_PPC64_ADDR64; gpfx = '_'; break;

	case EM_S390:    /* reltype: e_class    */ gpfx = '_'; break;
@@ -291,6 +325,8 @@ do_file(char const *const fname) 
		}

		if (EM_S390 == w2(ehdr->e_machine))

			reltype = R_390_32;

		if (EM_MIPS == w2(ehdr->e_machine))

			reltype = R_MIPS_32;

		do32(ehdr, fname, reltype);

	} break;

	case ELFCLASS64: {
@@ -303,6 +339,11 @@ do_file(char const *const fname) 
		}

		if (EM_S390 == w2(ghdr->e_machine))

			reltype = R_390_64;

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

			reltype = R_MIPS_64;

			Elf64_r_sym = MIPS64_r_sym;

			Elf64_r_info = MIPS64_r_info;

		}

		do64(ghdr, fname, reltype);

	} break;

	}  /* end switch */

scripts/recordmcount.h

+30 −4
Original line number Diff line number Diff line
@@ -31,8 +31,12 @@ 
#undef Elf_Rela

#undef Elf_Sym

#undef ELF_R_SYM

#undef Elf_r_sym

#undef ELF_R_INFO

#undef Elf_r_info

#undef ELF_ST_BIND

#undef fn_ELF_R_SYM

#undef fn_ELF_R_INFO

#undef uint_t

#undef _w

#undef _align
@@ -52,8 +56,12 @@ 
# define Elf_Rela		Elf64_Rela

# define Elf_Sym		Elf64_Sym

# define ELF_R_SYM		ELF64_R_SYM

# define Elf_r_sym		Elf64_r_sym

# define ELF_R_INFO		ELF64_R_INFO

# define Elf_r_info		Elf64_r_info

# define ELF_ST_BIND		ELF64_ST_BIND

# define fn_ELF_R_SYM		fn_ELF64_R_SYM

# define fn_ELF_R_INFO		fn_ELF64_R_INFO

# define uint_t			uint64_t

# define _w			w8

# define _align			7u
@@ -72,14 +80,32 @@ 
# define Elf_Rela		Elf32_Rela

# define Elf_Sym		Elf32_Sym

# define ELF_R_SYM		ELF32_R_SYM

# define Elf_r_sym		Elf32_r_sym

# define ELF_R_INFO		ELF32_R_INFO

# define Elf_r_info		Elf32_r_info

# define ELF_ST_BIND		ELF32_ST_BIND

# define fn_ELF_R_SYM		fn_ELF32_R_SYM

# define fn_ELF_R_INFO		fn_ELF32_R_INFO

# define uint_t			uint32_t

# define _w			w

# define _align			3u

# define _size			4

#endif



/* Functions and pointers that 64-bit EM_MIPS can override. */

static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)

{

	return ELF_R_SYM(_w(rp->r_info));

}

static uint_t (*Elf_r_sym)(Elf_Rel const *rp) = fn_ELF_R_SYM;



static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)

{

	rp->r_info = ELF_R_INFO(sym, type);

}

static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;





/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */

static void append_func(Elf_Ehdr *const ehdr,

			Elf_Shdr *const shstr,
@@ -197,22 +223,22 @@ static uint_t *sift_rel_mcount(uint_t *mlocp, 
	for (t = nrel; t; --t) {

		if (!mcountsym) {

			Elf_Sym const *const symp =

				&sym0[ELF_R_SYM(_w(relp->r_info))];

				&sym0[Elf_r_sym(relp)];

			char const *symname = &str0[w(symp->st_name)];



			if ('.' == symname[0])

				++symname;  /* ppc64 hack */

			if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),

					symname))

				mcountsym = ELF_R_SYM(_w(relp->r_info));

				mcountsym = Elf_r_sym(relp);

		}



		if (mcountsym == ELF_R_SYM(_w(relp->r_info))) {

		if (mcountsym == Elf_r_sym(relp)) {

			uint_t const addend = _w(_w(relp->r_offset) - recval);



			mrelp->r_offset = _w(offbase

				+ ((void *)mlocp - (void *)mloc0));

			mrelp->r_info = _w(ELF_R_INFO(recsym, reltype));

			Elf_r_info(mrelp, recsym, reltype);

			if (sizeof(Elf_Rela) == rel_entsize) {

				((Elf_Rela *)mrelp)->r_addend = addend;

				*mlocp++ = 0;

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