From e585b768da111f2c2d413de6214e83bbdfee8f22 Mon Sep 17 00:00:00 2001 From: YunQiang Su Date: Sat, 7 Mar 2020 10:39:45 +0800 Subject: [PATCH] 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: YunQiang Su Reviewed-by: Jiaxun Yang Signed-off-by: Thomas Bogendoerfer --- arch/mips/include/asm/elf.h | 3 +++ arch/mips/kernel/cpu-probe.c | 18 ++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h index f8f44b1a6cbb..5aa29ced6970 100644 --- a/arch/mips/include/asm/elf.h +++ b/arch/mips/include/asm/elf.h @@ -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. diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c index 6ab6b03d35ba..f21a2304401f 100644 --- a/arch/mips/kernel/cpu-probe.c +++ b/arch/mips/kernel/cpu-probe.c @@ -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) {