From: Yinghai Lu Date: Wed, 30 Jan 2008 12:33:32 +0000 (+0100) Subject: x86_32: trim memory by updating e820 X-Git-Tag: v2.6.25-rc1~1143^2~192 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=093af8d7f0ba3c6be1485973508584ef081e9f93;p=linux-2.6 x86_32: trim memory by updating e820 when MTRRs are not covering the whole e820 table, we need to trim the RAM and need to update e820. reuse some code on 64-bit as well. here need to add early_get_cap and use it in early_cpu_detect, and move mtrr_bp_init early. The code successfully trimmed the memory map on Justin's system: from: [ 0.000000] BIOS-e820: 0000000100000000 - 000000022c000000 (usable) to: [ 0.000000] modified: 0000000100000000 - 0000000228000000 (usable) [ 0.000000] modified: 0000000228000000 - 000000022c000000 (reserved) According to Justin it makes quite a difference: | When I boot the box without any trimming it acts like a 286 or 386, | takes about 10 minutes to boot (using raptor disks). Signed-off-by: Yinghai Lu Tested-by: Justin Piszcz Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 50d564dabb..fe3031d564 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -583,7 +583,7 @@ and is between 256 and 4096 characters. It is defined in the file See drivers/char/README.epca and Documentation/digiepca.txt. - disable_mtrr_trim [X86-64, Intel only] + disable_mtrr_trim [X86, Intel and AMD only] By default the kernel will trim any uncacheable memory out of your available memory pool based on MTRR settings. This parameter disables that behavior, diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 56cc341cc5..bba850b05d 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -278,6 +278,33 @@ void __init cpu_detect(struct cpuinfo_x86 *c) c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8; } } +static void __cpuinit early_get_cap(struct cpuinfo_x86 *c) +{ + u32 tfms, xlvl; + int ebx; + + memset(&c->x86_capability, 0, sizeof c->x86_capability); + if (have_cpuid_p()) { + /* Intel-defined flags: level 0x00000001 */ + if (c->cpuid_level >= 0x00000001) { + u32 capability, excap; + cpuid(0x00000001, &tfms, &ebx, &excap, &capability); + c->x86_capability[0] = capability; + c->x86_capability[4] = excap; + } + + /* AMD-defined flags: level 0x80000001 */ + xlvl = cpuid_eax(0x80000000); + if ((xlvl & 0xffff0000) == 0x80000000) { + if (xlvl >= 0x80000001) { + c->x86_capability[1] = cpuid_edx(0x80000001); + c->x86_capability[6] = cpuid_ecx(0x80000001); + } + } + + } + +} /* Do minimum CPU detection early. Fields really needed: vendor, cpuid_level, family, model, mask, cache alignment. @@ -306,6 +333,8 @@ static void __init early_cpu_detect(void) early_init_intel(c); break; } + + early_get_cap(c); } static void __cpuinit generic_identify(struct cpuinfo_x86 * c) @@ -485,7 +514,6 @@ void __init identify_boot_cpu(void) identify_cpu(&boot_cpu_data); sysenter_setup(); enable_sep_cpu(); - mtrr_bp_init(); } void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c) diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c index ccd36ed218..ac4b6338f3 100644 --- a/arch/x86/kernel/cpu/mtrr/main.c +++ b/arch/x86/kernel/cpu/mtrr/main.c @@ -624,7 +624,6 @@ static struct sysdev_driver mtrr_sysdev_driver = { .resume = mtrr_restore, }; -#ifdef CONFIG_X86_64 static int disable_mtrr_trim; static int __init disable_mtrr_trim_setup(char *str) @@ -643,13 +642,10 @@ early_param("disable_mtrr_trim", disable_mtrr_trim_setup); #define Tom2Enabled (1U << 21) #define Tom2ForceMemTypeWB (1U << 22) -static __init int amd_special_default_mtrr(unsigned long end_pfn) +static __init int amd_special_default_mtrr(void) { u32 l, h; - /* Doesn't apply to memory < 4GB */ - if (end_pfn <= (0xffffffff >> PAGE_SHIFT)) - return 0; if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD) return 0; if (boot_cpu_data.x86 < 0xf || boot_cpu_data.x86 > 0x11) @@ -687,9 +683,14 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn) * Make sure we only trim uncachable memory on machines that * support the Intel MTRR architecture: */ + if (!is_cpu(INTEL) || disable_mtrr_trim) + return 0; rdmsr(MTRRdefType_MSR, def, dummy); def &= 0xff; - if (!is_cpu(INTEL) || disable_mtrr_trim || def != MTRR_TYPE_UNCACHABLE) + if (def != MTRR_TYPE_UNCACHABLE) + return 0; + + if (amd_special_default_mtrr()) return 0; /* Find highest cached pfn */ @@ -703,8 +704,14 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn) highest_addr = base + size; } - if (amd_special_default_mtrr(end_pfn)) + /* kvm/qemu doesn't have mtrr set right, don't trim them all */ + if (!highest_addr) { + printk(KERN_WARNING "***************\n"); + printk(KERN_WARNING "**** WARNING: likely strange cpu\n"); + printk(KERN_WARNING "**** MTRRs all blank, cpu in qemu?\n"); + printk(KERN_WARNING "***************\n"); return 0; + } if ((highest_addr >> PAGE_SHIFT) < end_pfn) { printk(KERN_WARNING "***************\n"); @@ -726,7 +733,6 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn) return 0; } -#endif /** * mtrr_bp_init - initialize mtrrs on the boot CPU diff --git a/arch/x86/kernel/e820_32.c b/arch/x86/kernel/e820_32.c index 931934a7b3..4e16ef4a26 100644 --- a/arch/x86/kernel/e820_32.c +++ b/arch/x86/kernel/e820_32.c @@ -749,3 +749,14 @@ static int __init parse_memmap(char *arg) return 0; } early_param("memmap", parse_memmap); +void __init update_e820(void) +{ + u8 nr_map; + + nr_map = e820.nr_map; + if (sanitize_e820_map(e820.map, &nr_map)) + return; + e820.nr_map = nr_map; + printk(KERN_INFO "modified physical RAM map:\n"); + print_memory_map("modified"); +} diff --git a/arch/x86/kernel/setup_32.c b/arch/x86/kernel/setup_32.c index 26a56f714d..83ba3ca5f4 100644 --- a/arch/x86/kernel/setup_32.c +++ b/arch/x86/kernel/setup_32.c @@ -48,6 +48,7 @@ #include