On 03/17/13 07:36, Will Deacon wrote:
> On Wed, Mar 13, 2013 at 01:32:00AM +0000, Stephen Boyd wrote:
>> The ISAR0 register indicates support for the SDIV and UDIV
>> instructions in both the Thumb and ARM instruction set. Read the
>> register to detect the supported instructions and update the
>> elf_hwcap mask as appropriate. This is better than adding more
>> and more cpuid checks in proc-v7.S for each new cpu variant that
>> supports these instructions.
>>
>> Cc: Will Deacon <will.dea...@arm.com>
>> Cc: Stepan Moskovchenko <step...@codeaurora.org>
>> Signed-off-by: Stephen Boyd <sb...@codeaurora.org>
>> ---
>> arch/arm/kernel/setup.c | 20 ++++++++++++++++++++
>> arch/arm/mm/proc-v7.S | 4 ++--
>> 2 files changed, 22 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
>> index e2c8bbf..bd27a70 100644
>> --- a/arch/arm/kernel/setup.c
>> +++ b/arch/arm/kernel/setup.c
>> @@ -353,6 +353,23 @@ void __init early_print(const char *str, ...)
>> printk("%s", buf);
>> }
>>
>> +static void __init idiv_setup(void)
>> +{
>> + unsigned int divide_instrs;
>> +
>> + if (cpu_architecture() < CPU_ARCH_ARMv7)
>> + return;
>> +
>> + divide_instrs = (read_cpuid_ext(CPUID_EXT_ISAR0) & 0x0f000000) >> 24;
>> +
>> + switch (divide_instrs) {
>> + case 2:
>> + elf_hwcap |= HWCAP_IDIVA;
>> + case 1:
>> + elf_hwcap |= HWCAP_IDIVT;
>> + }
>> +}
>> +
>> static void __init feat_v6_fixup(void)
>> {
>> int id = read_cpuid_id();
>> @@ -483,6 +500,9 @@ static void __init setup_processor(void)
>> snprintf(elf_platform, ELF_PLATFORM_SIZE, "%s%c",
>> list->elf_name, ENDIANNESS);
>> elf_hwcap = list->elf_hwcap;
>> +
>> + idiv_setup();
> Perhaps give this a more generic name (cpuid_init_hwcaps) so we can add more
> probing later on (we could probe swp, for example).
No problem. Thanks for the review.
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