| Message ID | 1389950591-4212-2-git-send-email-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Ard, On Fri, Jan 17, 2014 at 09:23:07AM +0000, Ard Biesheuvel wrote: > This enables AT_HWCAP2 for ARM. The generic support for this > new ELF auxv entry was added in commit 2171364d1a9 (powerpc: > Add HWCAP2 aux entry) Does this require a corresponding change in libc so that the entry is actually used by the dynamic linker? Will
On 17 January 2014 16:07, Will Deacon <will.deacon@arm.com> wrote: > Hi Ard, > > On Fri, Jan 17, 2014 at 09:23:07AM +0000, Ard Biesheuvel wrote: >> This enables AT_HWCAP2 for ARM. The generic support for this >> new ELF auxv entry was added in commit 2171364d1a9 (powerpc: >> Add HWCAP2 aux entry) > > Does this require a corresponding change in libc so that the entry is > actually used by the dynamic linker? > The auxv entry itself is already wired up [this includes getauxval()] https://sourceware.org/git/?p=glibc.git;a=commit;h=1ae8bfe07c1a The only thing that is lacking is a way to hook up ifunc relocation, as the current prototype passes a single 32-bit quantity. So either we change the prototype to (hwcap, hwcap2) or we need to rely on getauxval() in ifunc selectors if they need to inspect hwcap2
diff --git a/arch/arm/include/asm/hwcap.h b/arch/arm/include/asm/hwcap.h index 6ff56eca3f1f..6e183fd269fb 100644 --- a/arch/arm/include/asm/hwcap.h +++ b/arch/arm/include/asm/hwcap.h @@ -9,6 +9,7 @@ * instruction set this cpu supports. */ #define ELF_HWCAP (elf_hwcap) -extern unsigned int elf_hwcap; +#define ELF_HWCAP2 (elf_hwcap2) +extern unsigned int elf_hwcap, elf_hwcap2; #endif #endif diff --git a/arch/arm/include/uapi/asm/hwcap.h b/arch/arm/include/uapi/asm/hwcap.h index 7dcc10d67253..87768b5cffd1 100644 --- a/arch/arm/include/uapi/asm/hwcap.h +++ b/arch/arm/include/uapi/asm/hwcap.h @@ -28,4 +28,8 @@ #define HWCAP_LPAE (1 << 20) #define HWCAP_EVTSTRM (1 << 21) +/* + * HWCAP2 flags - for elf_hwcap2 (in kernel) and AT_HWCAP2 + */ + #endif /* _UAPI__ASMARM_HWCAP_H */ diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 987a7f5bce5f..ce3049c89c18 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -100,6 +100,9 @@ EXPORT_SYMBOL(system_serial_high); unsigned int elf_hwcap __read_mostly; EXPORT_SYMBOL(elf_hwcap); +unsigned int elf_hwcap2 __read_mostly; +EXPORT_SYMBOL(elf_hwcap2); + #ifdef MULTI_CPU struct processor processor __read_mostly; @@ -992,6 +995,10 @@ static const char *hwcap_str[] = { NULL }; +static const char *hwcap2_str[] = { + NULL +}; + static int c_show(struct seq_file *m, void *v) { int i, j; @@ -1015,6 +1022,10 @@ static int c_show(struct seq_file *m, void *v) if (elf_hwcap & (1 << j)) seq_printf(m, "%s ", hwcap_str[j]); + for (j = 0; hwcap2_str[j]; j++) + if (elf_hwcap2 & (1 << j)) + seq_printf(m, "%s ", hwcap2_str[j]); + seq_printf(m, "\nCPU implementer\t: 0x%02x\n", cpuid >> 24); seq_printf(m, "CPU architecture: %s\n", proc_arch[cpu_architecture()]);
This enables AT_HWCAP2 for ARM. The generic support for this new ELF auxv entry was added in commit 2171364d1a9 (powerpc: Add HWCAP2 aux entry) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- arch/arm/include/asm/hwcap.h | 3 ++- arch/arm/include/uapi/asm/hwcap.h | 4 ++++ arch/arm/kernel/setup.c | 11 +++++++++++ 3 files changed, 17 insertions(+), 1 deletion(-)