| Message ID | 20200302022209.82874-1-syq@debian.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] Use ELF_BASE_PLATFORM to pass ISA level | expand |
On Mon, Mar 02, 2020 at 10:22:10AM +0800, YunQiang Su wrote: > 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. while I see how this could be used, it feels incomplete to me. What about implemented ASEs ? Can't you just use information already present in /proc/cpuinfo ? > 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 > @@ -2113,6 +2130,7 @@ EXPORT_SYMBOL(__ua_limit); > > const char *__cpu_name[NR_CPUS]; > const char *__elf_platform; > +const char *__elf_base_platform = NULL; no need to init static data with 0 Thomas.
Thomas Bogendoerfer <tsbogend@alpha.franken.de> 于2020年3月6日周五 下午9:49写道： > > On Mon, Mar 02, 2020 at 10:22:10AM +0800, YunQiang Su wrote: > > 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. > > while I see how this could be used, it feels incomplete to me. What > about implemented ASEs ? Can't you just use information already present ASEs can be get by hwcap thu getauxval in userland. > in /proc/cpuinfo ? cpuinfo is not always available, for example in some chroot env. Lot's of userland projects doesn't like to the way to parse cpuinfo, they prefer to get the info by a more elegant way. > > > 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 > > @@ -2113,6 +2130,7 @@ EXPORT_SYMBOL(__ua_limit); > > > > const char *__cpu_name[NR_CPUS]; > > const char *__elf_platform; > > +const char *__elf_base_platform = NULL; > > no need to init static data with 0 > > Thomas. > > -- > Crap can work. Given enough thrust pigs will fly, but it's not necessarily a > good idea. [ RFC1925, 2.3 ]
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..925cc1c9bb04 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 = NULL; void cpu_probe(void) {