Commit e585b768 authored by YunQiang Su's avatar YunQiang Su Committed by Thomas Bogendoerfer
Browse files

Use ELF_BASE_PLATFORM to pass ISA level 



Some userland application/program runtime/dynamic loaded need to
know about the current ISA level to use the best runtime.
While kernel doesn't provides this info.

ELF_PLATFORM only provides some info about the CPU, with very few info,
for example, the value is "mips" for both 24Kc and P6600.

Currently ELF_BASE_PLATFORM is not used by MIPS (only by powerpc).
So we cant set its value as:
  mips2, mips3, mips4, mips5,
  mips32, mips32r2, mips32r6
  mips64, mips64r2, mips64r6
Then in userland, we can get it by:
  getauxval(AT_BASE_PLATFORM)

The only problem is that it seems has different defination than ppc:
  on ppc, it is the mircoarchitecture
while now we use it as ISA level on MIPS.

Signed-off-by: default avatarYunQiang Su <syq@debian.org>
Reviewed-by: default avatarJiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent be280764

arch/mips/include/asm/elf.h

+3 −0
Original line number Diff line number Diff line
@@ -445,6 +445,9 @@ extern unsigned int elf_hwcap; 
#define ELF_PLATFORM  __elf_platform

extern const char *__elf_platform;



#define ELF_BASE_PLATFORM  __elf_base_platform

extern const char *__elf_base_platform;



/*

 * See comments in asm-alpha/elf.h, this is the same thing

 * on the MIPS.

arch/mips/kernel/cpu-probe.c

+18 −0
Original line number Diff line number Diff line
@@ -513,6 +513,13 @@ static inline void set_elf_platform(int cpu, const char *plat) 
		__elf_platform = plat;

}



static inline void set_elf_base_platform(const char *plat)

{

	if (__elf_base_platform == NULL) {

		__elf_base_platform = plat;

	}

}



static inline void cpu_probe_vmbits(struct cpuinfo_mips *c)

{

#ifdef __NEED_VMBITS_PROBE
@@ -527,36 +534,46 @@ static void set_isa(struct cpuinfo_mips *c, unsigned int isa) 
	switch (isa) {

	case MIPS_CPU_ISA_M64R2:

		c->isa_level |= MIPS_CPU_ISA_M32R2 | MIPS_CPU_ISA_M64R2;

		set_elf_base_platform("mips64r2");

		/* fall through */

	case MIPS_CPU_ISA_M64R1:

		c->isa_level |= MIPS_CPU_ISA_M32R1 | MIPS_CPU_ISA_M64R1;

		set_elf_base_platform("mips64");

		/* fall through */

	case MIPS_CPU_ISA_V:

		c->isa_level |= MIPS_CPU_ISA_V;

		set_elf_base_platform("mips5");

		/* fall through */

	case MIPS_CPU_ISA_IV:

		c->isa_level |= MIPS_CPU_ISA_IV;

		set_elf_base_platform("mips4");

		/* fall through */

	case MIPS_CPU_ISA_III:

		c->isa_level |= MIPS_CPU_ISA_II | MIPS_CPU_ISA_III;

		set_elf_base_platform("mips3");

		break;



	/* R6 incompatible with everything else */

	case MIPS_CPU_ISA_M64R6:

		c->isa_level |= MIPS_CPU_ISA_M32R6 | MIPS_CPU_ISA_M64R6;

		set_elf_base_platform("mips64r6");

		/* fall through */

	case MIPS_CPU_ISA_M32R6:

		c->isa_level |= MIPS_CPU_ISA_M32R6;

		set_elf_base_platform("mips32r6");

		/* Break here so we don't add incompatible ISAs */

		break;

	case MIPS_CPU_ISA_M32R2:

		c->isa_level |= MIPS_CPU_ISA_M32R2;

		set_elf_base_platform("mips32r2");

		/* fall through */

	case MIPS_CPU_ISA_M32R1:

		c->isa_level |= MIPS_CPU_ISA_M32R1;

		set_elf_base_platform("mips32");

		/* fall through */

	case MIPS_CPU_ISA_II:

		c->isa_level |= MIPS_CPU_ISA_II;

		set_elf_base_platform("mips2");

		break;

	}

}
@@ -2113,6 +2130,7 @@ EXPORT_SYMBOL(__ua_limit); 


const char *__cpu_name[NR_CPUS];

const char *__elf_platform;

const char *__elf_base_platform;



void cpu_probe(void)

{