From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754411AbZCLX73 (ORCPT ); Thu, 12 Mar 2009 19:59:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753070AbZCLX7O (ORCPT ); Thu, 12 Mar 2009 19:59:14 -0400 Received: from gw.goop.org ([64.81.55.164]:41974 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752682AbZCLX7N (ORCPT ); Thu, 12 Mar 2009 19:59:13 -0400 Message-ID: <49B9A1CD.5040704@goop.org> Date: Thu, 12 Mar 2009 16:59:09 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Yinghai Lu CC: "H. Peter Anvin" , Ingo Molnar , the arch/x86 maintainers , "Eric W. Biederman" , Linux Kernel Mailing List Subject: Re: [GIT PULL] x86: add brk allocator for very early allocations References: <49B7EDF4.7060904@goop.org> <49B800B8.2040009@kernel.org> In-Reply-To: <49B800B8.2040009@kernel.org> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yinghai Lu wrote: > could have more explanation about the 1M size. > because initial_pg_tables will sit in it. please consider to add something like > > in head_32.S > > LOW_PAGES = (KERNEL_IMAGE_SIZE + PAGE_SIZE_asm - 1)>>PAGE_SHIFT > > #if PTRS_PER_PMD > 1 > PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PMD) + PTRS_PER_PGD > #else > PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PGD) > #endif > ALLOCATOR_SLOP = 4 > OK, how does this look: The following changes since commit 21e8ba72daf5d7f0af33968f873499c85f96ccef: Jeremy Fitzhardinge (1): x86: use brk allocation for DMI are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git push/x86/brk Jeremy Fitzhardinge (1): x86: allow extend_brk users to reserve brk space Yinghai Lu (1): x86-32: compute initial mapping size more accurately arch/x86/include/asm/page_32_types.h | 5 +++++ arch/x86/include/asm/setup.h | 30 ++++++++++++++++++++++++++++++ arch/x86/kernel/head_32.S | 4 +++- arch/x86/kernel/setup.c | 2 ++ arch/x86/kernel/vmlinux_32.lds.S | 4 +++- arch/x86/kernel/vmlinux_64.lds.S | 4 +++- 6 files changed, 46 insertions(+), 3 deletions(-) git diff 21e8ba72daf5d7f0af33968f873499c85f96ccef..push/x86/brk diff --git a/arch/x86/include/asm/page_32_types.h b/arch/x86/include/asm/page_32_types.h index f1e4a79..0f915ae 100644 --- a/arch/x86/include/asm/page_32_types.h +++ b/arch/x86/include/asm/page_32_types.h @@ -39,6 +39,11 @@ #define __VIRTUAL_MASK_SHIFT 32 #endif /* CONFIG_X86_PAE */ +/* + * Kernel image size is limited to 512 MB (see in arch/x86/kernel/head_32.S) + */ +#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) + #ifndef __ASSEMBLY__ /* diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index 366d366..61b126b 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -104,6 +104,29 @@ extern struct boot_params boot_params; extern unsigned long _brk_end; void *extend_brk(size_t size, size_t align); +/* + * Reserve space in the brk section. The name must be unique within + * the file, and somewhat descriptive. The size is in bytes. Must be + * used at file scope. + * + * (This uses a temp function to wrap the asm so we can pass it the + * size parameter; otherwise we wouldn't be able to. We can't use a + * "section" attribute on a normal variable because it always ends up + * being @progbits, which ends up allocating space in the vmlinux + * executable.) + */ +#define RESERVE_BRK(name,sz) \ + static void __section(.discard) __used \ + __brk_reservation_fn_##name##__(void) { \ + asm volatile ( \ + ".pushsection .brk_reservation,\"aw\",@nobits;" \ + "__brk_reservation_" #name "__:" \ + " 1:.skip %c0;" \ + " .size __brk_reservation_" #name "__, . - 1b;" \ + " .popsection" \ + : : "i" (sz)); \ + } + #ifdef __i386__ void __init i386_start_kernel(void); @@ -115,6 +138,13 @@ void __init x86_64_start_reservations(char *real_mode_data); #endif /* __i386__ */ #endif /* _SETUP */ +#else +#define RESERVE_BRK(name,sz) \ + .pushsection .brk_reservation,"aw",@nobits; \ +__brk_reservation_##name##__: \ +1: .skip sz; \ + .size __brk_reservation_##name##__,.-1b; \ + .popsection #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index d243437..80dc05e 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -54,7 +54,7 @@ * * This should be a multiple of a page. */ -LOW_PAGES = 1<<(32-PAGE_SHIFT_asm) +LOW_PAGES = (KERNEL_IMAGE_SIZE + PAGE_SIZE_asm - 1)>>PAGE_SHIFT /* * To preserve the DMA pool in PAGEALLOC kernels, we'll allocate @@ -75,6 +75,8 @@ ALLOCATOR_SLOP = 4 INIT_MAP_BEYOND_END = BOOTBITMAP_SIZE + (PAGE_TABLE_SIZE + ALLOCATOR_SLOP)*PAGE_SIZE_asm +RESERVE_BRK(pagetables, PAGE_TABLE_SIZE * PAGE_SIZE) + /* * 32-bit kernel entrypoint; only used by the boot CPU. On entry, * %esi points to the real-mode code as a 32-bit pointer. diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b344908..d633958 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -112,6 +112,8 @@ #define ARCH_SETUP #endif +RESERVE_BRK(dmi_alloc, 65536); + unsigned int boot_cpu_id __read_mostly; static __initdata unsigned long _brk_start = (unsigned long)__brk_base; diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S index 1063fbe..4005279 100644 --- a/arch/x86/kernel/vmlinux_32.lds.S +++ b/arch/x86/kernel/vmlinux_32.lds.S @@ -192,7 +192,8 @@ SECTIONS . = ALIGN(PAGE_SIZE); __brk_base = . ; - . += 1024 * 1024 ; + . += 64 * 1024 ; /* 64k slop space */ + *(.brk_reservation) /* areas brk users have reserved */ __brk_limit = . ; _end = . ; @@ -201,6 +202,7 @@ SECTIONS /* Sections to be discarded */ /DISCARD/ : { *(.exitcall.exit) + *(.discard) } STABS_DEBUG diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S index b8b83e4..47deee3 100644 --- a/arch/x86/kernel/vmlinux_64.lds.S +++ b/arch/x86/kernel/vmlinux_64.lds.S @@ -250,7 +250,8 @@ SECTIONS . = ALIGN(PAGE_SIZE); __brk_base = . ; - . += 1024 * 1024 ; + . += 64 * 1024 ; /* 64k slop space */ + *(.brk_reservation) /* areas brk users have reserved */ __brk_limit = . ; } @@ -260,6 +261,7 @@ SECTIONS /DISCARD/ : { *(.exitcall.exit) *(.eh_frame) + *(.discard) } STABS_DEBUG