On Thu, 2013-04-18 at 13:41 +1000, Michael Neuling wrote:
> akpm,
>
> If you're happy with this, is it something you can take in your tree?
Andrew ? Or give me an ack ? :-) I'm happy to carry this, we need that
rather urgently and we have the glibc folks on board.
Cheers,
Ben.
> Mikey
>
> Michael Neuling <mi...@neuling.org> wrote:
> > We are currently out of free bits in AT_HWCAP. With POWER8, we have
> > several hardware features that we need to advertise.
> >
> > Tested on POWER and x86.
> >
> > Signed-off-by: Michael Neuling <mich...@neuling.org>
> > Signed-off-by: Nishanth Aravamudan <n...@linux.vnet.ibm.com>
> > ---
> >
> > > Wouldn't it be safer to not emit AT_HWCAP2 unless it is defined by the
> > > arch?
> > >
> > > That way the change would only impact powerpc.
> >
> > Should be addressed with this version.
> >
> > Mikey
> >
> > diff --git a/arch/powerpc/include/asm/cputable.h
> > b/arch/powerpc/include/asm/cputable.h
> > index fb3245e..ccadad6 100644
> > --- a/arch/powerpc/include/asm/cputable.h
> > +++ b/arch/powerpc/include/asm/cputable.h
> > @@ -52,6 +52,7 @@ struct cpu_spec {
> > char *cpu_name;
> > unsigned long cpu_features; /* Kernel features */
> > unsigned int cpu_user_features; /* Userland features */
> > + unsigned int cpu_user_features2; /* Userland features v2 */
> > unsigned int mmu_features; /* MMU features */
> >
> > /* cache line sizes */
> > diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h
> > index ac9790f..cc0655a 100644
> > --- a/arch/powerpc/include/asm/elf.h
> > +++ b/arch/powerpc/include/asm/elf.h
> > @@ -61,6 +61,7 @@ typedef elf_vrregset_t elf_fpxregset_t;
> > instruction set this cpu supports. This could be done in userspace,
> > but it's not easy, and we've already done it here. */
> > # define ELF_HWCAP (cur_cpu_spec->cpu_user_features)
> > +# define ELF_HWCAP2 (cur_cpu_spec->cpu_user_features2)
> >
> > /* This yields a string that ld.so will use to load implementation
> > specific libraries for optimization. This is more specific in
> > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
> > index 3939829..1f8b5d5 100644
> > --- a/fs/binfmt_elf.c
> > +++ b/fs/binfmt_elf.c
> > @@ -240,6 +240,9 @@ create_elf_tables(struct linux_binprm *bprm, struct
> > elfhdr *exec,
> > NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
> > NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
> > NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
> > +#ifdef ELF_HWCAP2
> > + NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
> > +#endif
> > NEW_AUX_ENT(AT_EXECFN, bprm->exec);
> > if (k_platform) {
> > NEW_AUX_ENT(AT_PLATFORM,
> > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
> > index 9c13e02..bf2381d 100644
> > --- a/fs/binfmt_elf_fdpic.c
> > +++ b/fs/binfmt_elf_fdpic.c
> > @@ -483,7 +483,6 @@ static int create_elf_fdpic_tables(struct linux_binprm
> > *bprm,
> > size_t platform_len = 0, len;
> > char *k_platform, *k_base_platform;
> > char __user *u_platform, *u_base_platform, *p;
> > - long hwcap;
> > int loop;
> > int nr; /* reset for each csp adjustment */
> >
> > @@ -502,8 +501,6 @@ static int create_elf_fdpic_tables(struct linux_binprm
> > *bprm,
> > return -EFAULT;
> > #endif
> >
> > - hwcap = ELF_HWCAP;
> > -
> > /*
> > * If this architecture has a platform capability string, copy it
> > * to userspace. In some cases (Sparc), this info is impossible
> > @@ -617,7 +614,10 @@ static int create_elf_fdpic_tables(struct linux_binprm
> > *bprm,
> >
> > nr = 0;
> > csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long);
> > - NEW_AUX_ENT(AT_HWCAP, hwcap);
> > + NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
> > +#ifdef ELF_HWCAP2
> > + NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
> > +#endif
> > NEW_AUX_ENT(AT_PAGESZ, PAGE_SIZE);
> > NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
> > NEW_AUX_ENT(AT_PHDR, exec_params->ph_addr);
> > diff --git a/include/uapi/linux/auxvec.h b/include/uapi/linux/auxvec.h
> > index 61594d5..835c065 100644
> > --- a/include/uapi/linux/auxvec.h
> > +++ b/include/uapi/linux/auxvec.h
> > @@ -28,6 +28,7 @@
> > #define AT_BASE_PLATFORM 24 /* string identifying real platform, may
> > * differ from AT_PLATFORM. */
> > #define AT_RANDOM 25 /* address of 16 random bytes */
> > +#define AT_HWCAP2 26 /* extension of AT_HWCAP */
> >
> > #define AT_EXECFN 31 /* filename of program */
> >
> > _______________________________________________
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> > Linuxppc-dev@lists.ozlabs.org
> > https://lists.ozlabs.org/listinfo/linuxppc-dev
> >
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