From 4756dcbfd37819a8359d3c69a22be2ee41666d0f Mon Sep 17 00:00:00 2001 From: Cyril Chemparathy Date: Sat, 21 Jul 2012 15:55:04 -0400 Subject: ARM: LPAE: accomodate >32-bit addresses for page table base This patch redefines the early boot time use of the R4 register to steal a few low order bits (ARCH_PGD_SHIFT bits) on LPAE systems. This allows for up to 38-bit physical addresses. Signed-off-by: Cyril Chemparathy Signed-off-by: Vitaly Andrianov Acked-by: Nicolas Pitre Tested-by: Santosh Shilimkar Tested-by: Subash Patel Signed-off-by: Will Deacon --- arch/arm/kernel/head.S | 10 ++++------ arch/arm/kernel/smp.c | 11 +++++++++-- 2 files changed, 13 insertions(+), 8 deletions(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 8bac553fe213..45e8935cae4e 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -156,7 +156,7 @@ ENDPROC(stext) * * Returns: * r0, r3, r5-r7 corrupted - * r4 = physical page table address + * r4 = page table (see ARCH_PGD_SHIFT in asm/memory.h) */ __create_page_tables: pgtbl r4, r8 @ page table address @@ -331,6 +331,7 @@ __create_page_tables: #endif #ifdef CONFIG_ARM_LPAE sub r4, r4, #0x1000 @ point to the PGD table + mov r4, r4, lsr #ARCH_PGD_SHIFT #endif mov pc, lr ENDPROC(__create_page_tables) @@ -408,7 +409,7 @@ __secondary_data: * r0 = cp#15 control register * r1 = machine ID * r2 = atags or dtb pointer - * r4 = page table pointer + * r4 = page table (see ARCH_PGD_SHIFT in asm/memory.h) * r9 = processor ID * r13 = *virtual* address to jump to upon completion */ @@ -427,10 +428,7 @@ __enable_mmu: #ifdef CONFIG_CPU_ICACHE_DISABLE bic r0, r0, #CR_I #endif -#ifdef CONFIG_ARM_LPAE - mov r5, #0 - mcrr p15, 0, r4, r5, c2 @ load TTBR0 -#else +#ifndef CONFIG_ARM_LPAE mov r5, #(domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \ domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \ domain_val(DOMAIN_TABLE, DOMAIN_MANAGER) | \ diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 550d63cef68e..217b755aadd4 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -78,6 +78,13 @@ void __init smp_set_ops(struct smp_operations *ops) smp_ops = *ops; }; +static unsigned long get_arch_pgd(pgd_t *pgd) +{ + phys_addr_t pgdir = virt_to_phys(pgd); + BUG_ON(pgdir & ARCH_PGD_MASK); + return pgdir >> ARCH_PGD_SHIFT; +} + int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) { int ret; @@ -87,8 +94,8 @@ int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle) * its stack and the page tables. */ secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; - secondary_data.pgdir = virt_to_phys(idmap_pgd); - secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir); + secondary_data.pgdir = get_arch_pgd(idmap_pgd); + secondary_data.swapper_pg_dir = get_arch_pgd(swapper_pg_dir); __cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data)); outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1)); -- cgit v1.2.3 From a469abd0f868c902b75532579bf87553dcf1b360 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 8 Apr 2013 17:13:12 +0100 Subject: ARM: elf: add new hwcap for identifying atomic ldrd/strd instructions CPUs implementing LPAE have atomic ldrd/strd instructions, meaning that userspace software can avoid having to use the exclusive variants of these instructions if they wish. This patch advertises the atomicity of these instructions via the hwcaps, so userspace can detect this CPU feature. Reported-by: Vladimir Danushevsky Signed-off-by: Will Deacon --- arch/arm/kernel/setup.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/arm/kernel') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 1522c7ae31b0..bdcd4dd13230 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -355,7 +355,7 @@ void __init early_print(const char *str, ...) static void __init cpuid_init_hwcaps(void) { - unsigned int divide_instrs; + unsigned int divide_instrs, vmsa; if (cpu_architecture() < CPU_ARCH_ARMv7) return; @@ -368,6 +368,11 @@ static void __init cpuid_init_hwcaps(void) case 1: elf_hwcap |= HWCAP_IDIVT; } + + /* LPAE implies atomic ldrd/strd instructions */ + vmsa = (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xf) >> 0; + if (vmsa >= 5) + elf_hwcap |= HWCAP_LPAE; } static void __init feat_v6_fixup(void) @@ -872,6 +877,7 @@ static const char *hwcap_str[] = { "vfpv4", "idiva", "idivt", + "lpae", NULL }; -- cgit v1.2.3