From f00ec48fadf5e37e7889f14cff900aa70d18b644 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 4 Sep 2010 10:47:48 +0100 Subject: ARM: Allow SMP kernels to boot on UP systems UP systems do not implement all the instructions that SMP systems have, so in order to boot a SMP kernel on a UP system, we need to rewrite parts of the kernel. Do this using an 'alternatives' scheme, where the kernel code and data is modified prior to initialization to replace the SMP instructions, thereby rendering the problematical code ineffectual. We use the linker to generate a list of 32-bit word locations and their replacement values, and run through these replacements when we detect a UP system. Signed-off-by: Russell King --- arch/arm/kernel/setup.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index d5231ae7355a..5a82c39ca85e 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -36,6 +36,7 @@ #include #include #include +#include #include #include #include @@ -825,7 +826,8 @@ void __init setup_arch(char **cmdline_p) request_standard_resources(&meminfo, mdesc); #ifdef CONFIG_SMP - smp_init_cpus(); + if (is_smp()) + smp_init_cpus(); #endif reserve_crashkernel(); -- cgit v1.2.3 From 8925ec4c530094b878e7e28a1fd78e7122afd973 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 13 Sep 2010 16:18:30 +0100 Subject: ARM: 6385/1: setup: detect aliasing I-cache when D-cache is non-aliasing Currently, the Kernel assumes that if a CPU has a non-aliasing D-cache then the I-cache is also non-aliasing. This may not be true on ARM cores from v6 onwards, which may have aliasing I-caches but non-aliasing D-caches. This patch adds a cpu_has_aliasing_icache function, which is called from cacheid_init and adds CACHEID_VIPT_I_ALIASING to the cacheid when appropriate. A utility macro, icache_is_vipt_aliasing(), is also provided. Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/include/asm/cachetype.h | 8 ++++++-- arch/arm/kernel/setup.c | 39 ++++++++++++++++++++++++++++++++++++--- 2 files changed, 42 insertions(+), 5 deletions(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/include/asm/cachetype.h b/arch/arm/include/asm/cachetype.h index d3a4c2cb9f2f..c023db09fcc1 100644 --- a/arch/arm/include/asm/cachetype.h +++ b/arch/arm/include/asm/cachetype.h @@ -6,6 +6,7 @@ #define CACHEID_VIPT_ALIASING (1 << 2) #define CACHEID_VIPT (CACHEID_VIPT_ALIASING|CACHEID_VIPT_NONALIASING) #define CACHEID_ASID_TAGGED (1 << 3) +#define CACHEID_VIPT_I_ALIASING (1 << 4) extern unsigned int cacheid; @@ -14,15 +15,18 @@ extern unsigned int cacheid; #define cache_is_vipt_nonaliasing() cacheid_is(CACHEID_VIPT_NONALIASING) #define cache_is_vipt_aliasing() cacheid_is(CACHEID_VIPT_ALIASING) #define icache_is_vivt_asid_tagged() cacheid_is(CACHEID_ASID_TAGGED) +#define icache_is_vipt_aliasing() cacheid_is(CACHEID_VIPT_I_ALIASING) /* * __LINUX_ARM_ARCH__ is the minimum supported CPU architecture * Mask out support which will never be present on newer CPUs. * - v6+ is never VIVT - * - v7+ VIPT never aliases + * - v7+ VIPT never aliases on D-side */ #if __LINUX_ARM_ARCH__ >= 7 -#define __CACHEID_ARCH_MIN (CACHEID_VIPT_NONALIASING | CACHEID_ASID_TAGGED) +#define __CACHEID_ARCH_MIN (CACHEID_VIPT_NONALIASING |\ + CACHEID_ASID_TAGGED |\ + CACHEID_VIPT_I_ALIASING) #elif __LINUX_ARM_ARCH__ >= 6 #define __CACHEID_ARCH_MIN (~CACHEID_VIVT) #else diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index d5231ae7355a..9fc483393bae 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -238,6 +238,34 @@ int cpu_architecture(void) return cpu_arch; } +static int cpu_has_aliasing_icache(unsigned int arch) +{ + int aliasing_icache; + unsigned int id_reg, num_sets, line_size; + + /* arch specifies the register format */ + switch (arch) { + case CPU_ARCH_ARMv7: + asm("mcr p15, 2, %1, c0, c0, 0 @ set CSSELR\n" + "isb\n" + "mrc p15, 1, %0, c0, c0, 0 @ read CCSIDR" + : "=r" (id_reg) + : "r" (1)); + line_size = 4 << ((id_reg & 0x7) + 2); + num_sets = ((id_reg >> 13) & 0x7fff) + 1; + aliasing_icache = (line_size * num_sets) > PAGE_SIZE; + break; + case CPU_ARCH_ARMv6: + aliasing_icache = read_cpuid_cachetype() & (1 << 11); + break; + default: + /* I-cache aliases will be handled by D-cache aliasing code */ + aliasing_icache = 0; + } + + return aliasing_icache; +} + static void __init cacheid_init(void) { unsigned int cachetype = read_cpuid_cachetype(); @@ -249,10 +277,15 @@ static void __init cacheid_init(void) cacheid = CACHEID_VIPT_NONALIASING; if ((cachetype & (3 << 14)) == 1 << 14) cacheid |= CACHEID_ASID_TAGGED; - } else if (cachetype & (1 << 23)) + else if (cpu_has_aliasing_icache(CPU_ARCH_ARMv7)) + cacheid |= CACHEID_VIPT_I_ALIASING; + } else if (cachetype & (1 << 23)) { cacheid = CACHEID_VIPT_ALIASING; - else + } else { cacheid = CACHEID_VIPT_NONALIASING; + if (cpu_has_aliasing_icache(CPU_ARCH_ARMv6)) + cacheid |= CACHEID_VIPT_I_ALIASING; + } } else { cacheid = CACHEID_VIVT; } @@ -263,7 +296,7 @@ static void __init cacheid_init(void) cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown", cache_is_vivt() ? "VIVT" : icache_is_vivt_asid_tagged() ? "VIVT ASID tagged" : - cache_is_vipt_aliasing() ? "VIPT aliasing" : + icache_is_vipt_aliasing() ? "VIPT aliasing" : cache_is_vipt_nonaliasing() ? "VIPT nonaliasing" : "unknown"); } -- cgit v1.2.3 From 5fb31a96e1e0078f1e82736ccd72a61ecabe6a4f Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Wed, 6 Oct 2010 11:07:28 +0100 Subject: ARM: 6431/1: fix isb regression on CPU < v7 The kernel does not compile for my ARM926EJ-S system U300 due to the isb instruction inserted in generic assember statement from commit 8925ec4c530094b878e7e28a1fd78e7122afd973, "ARM: 6385/1: setup: detect aliasing I-cache when D-cache is non-aliasing" hey the isb is only available when assembling for v7 so let's use the generic isb() macro from setup.h instead. Acked-by: Will Deacon Signed-off-by: Linus Walleij Signed-off-by: Russell King --- arch/arm/kernel/setup.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 9fc483393bae..e0430d036cea 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -246,11 +246,12 @@ static int cpu_has_aliasing_icache(unsigned int arch) /* arch specifies the register format */ switch (arch) { case CPU_ARCH_ARMv7: - asm("mcr p15, 2, %1, c0, c0, 0 @ set CSSELR\n" - "isb\n" - "mrc p15, 1, %0, c0, c0, 0 @ read CCSIDR" - : "=r" (id_reg) + asm("mcr p15, 2, %0, c0, c0, 0 @ set CSSELR" + : /* No output operands */ : "r" (1)); + isb(); + asm("mrc p15, 1, %0, c0, c0, 0 @ read CCSIDR" + : "=r" (id_reg)); line_size = 4 << ((id_reg & 0x7) + 2); num_sets = ((id_reg >> 13) & 0x7fff) + 1; aliasing_icache = (line_size * num_sets) > PAGE_SIZE; -- cgit v1.2.3 From 842eab40b6920819fff5caeefdb709f07d3f8e23 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 1 Oct 2010 14:12:22 +0100 Subject: ARM: vmlinux.lds: Refer to start of .data using _sdata rather than _data Use _sdata as the start of the data section, rather than _data. Signed-off-by: Russell King --- arch/arm/kernel/head-common.S | 2 +- arch/arm/kernel/setup.c | 2 +- arch/arm/mm/init.c | 4 ++-- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/arm/kernel/setup.c') diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index b9505aa267c0..58a3e632b6d5 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S @@ -20,7 +20,7 @@ __switch_data: .long __mmap_switched .long __data_loc @ r4 - .long _data @ r5 + .long _sdata @ r5 .long __bss_start @ r6 .long _end @ r7 .long processor_id @ r4 diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index 5a82c39ca85e..f38917174b71 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -491,7 +491,7 @@ request_standard_resources(struct meminfo *mi, struct machine_desc *mdesc) kernel_code.start = virt_to_phys(_text); kernel_code.end = virt_to_phys(_etext - 1); - kernel_data.start = virt_to_phys(_data); + kernel_data.start = virt_to_phys(_sdata); kernel_data.end = virt_to_phys(_end - 1); for (i = 0; i < mi->nr_banks; i++) { diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c index 7185b00650fe..36c4553ffcce 100644 --- a/arch/arm/mm/init.c +++ b/arch/arm/mm/init.c @@ -277,7 +277,7 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc) /* Register the kernel text, kernel data and initrd with memblock. */ #ifdef CONFIG_XIP_KERNEL - memblock_reserve(__pa(_data), _end - _data); + memblock_reserve(__pa(_sdata), _end - _sdata); #else memblock_reserve(__pa(_stext), _end - _stext); #endif @@ -545,7 +545,7 @@ void __init mem_init(void) MLK_ROUNDUP(__init_begin, __init_end), MLK_ROUNDUP(_text, _etext), - MLK_ROUNDUP(_data, _edata)); + MLK_ROUNDUP(_sdata, _edata)); #undef MLK #undef MLM -- cgit v1.2.3