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powerpc: Add HWCAP2 aux entry

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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 <michael@neuling.org>
Signed-off-by: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Michael Neuling 2013-04-17 17:33:11 +00:00 • committed by Benjamin Herrenschmidt
commit 2171364d1a
5 changed files with 10 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

1
arch/powerpc/include/asm/cputable.h
View file

@ -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 */

1
arch/powerpc/include/asm/elf.h
View file

@ -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

3
fs/binfmt_elf.c
View file

@ -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,

8
fs/binfmt_elf_fdpic.c
View file

@ -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);

1
include/uapi/linux/auxvec.h
View file

@ -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 */