From 8164f7af88d9ad3a757bd14f634b23997ee77f6b Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Mon, 18 Mar 2013 19:44:15 +0100 Subject: ARM: 7680/1: Detect support for SDIV/UDIV from ISAR0 register 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. Acked-by: Will Deacon Cc: Stepan Moskovchenko Signed-off-by: Stephen Boyd Signed-off-by: Russell King --- arch/arm/kernel/setup.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index e2c8bbffb0b1..f3ac13f69b7a 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 cpuid_init_hwcaps(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; + + cpuid_init_hwcaps(); + #ifndef CONFIG_ARM_THUMB elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT); #endif -- cgit v1.2.3