Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757771Ab3EOJF6 (ORCPT ); Wed, 15 May 2013 05:05:58 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:51870 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757193Ab3EOJFy (ORCPT ); Wed, 15 May 2013 05:05:54 -0400 From: HATAYAMA Daisuke Subject: [PATCH v6 2/8] vmcore: allocate buffer for ELF headers on page-size alignment To: vgoyal@redhat.com, ebiederm@xmission.com, akpm@linux-foundation.org Cc: cpw@sgi.com, kumagai-atsushi@mxc.nes.nec.co.jp, lisa.mitchell@hp.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, zhangyanfei@cn.fujitsu.com, jingbai.ma@hp.com, linux-mm@kvack.org, riel@redhat.com, walken@google.com, hughd@google.com, kosaki.motohiro@jp.fujitsu.com Date: Wed, 15 May 2013 18:05:51 +0900 Message-ID: <20130515090551.28109.73350.stgit@localhost6.localdomain6> In-Reply-To: <20130515090507.28109.28956.stgit@localhost6.localdomain6> References: <20130515090507.28109.28956.stgit@localhost6.localdomain6> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10492 Lines: 289 Allocate ELF headers on page-size boundary using __get_free_pages() instead of kmalloc(). Later patch will merge PT_NOTE entries into a single unique one and decrease the buffer size actually used. Keep original buffer size in variable elfcorebuf_sz_orig to kfree the buffer later and actually used buffer size with rounded up to page-size boundary in variable elfcorebuf_sz separately. The size of part of the ELF buffer exported from /proc/vmcore is elfcorebuf_sz. The merged, removed PT_NOTE entries, i.e. the range [elfcorebuf_sz, elfcorebuf_sz_orig], is filled with 0. Use size of the ELF headers as an initial offset value in set_vmcore_list_offsets_elf{64,32} and process_ptload_program_headers_elf{64,32} in order to indicate that the offset includes the holes towards the page boundary. Signed-off-by: HATAYAMA Daisuke --- fs/proc/vmcore.c | 80 ++++++++++++++++++++++++++++++------------------------ 1 files changed, 45 insertions(+), 35 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index ab0c92e..48886e6 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -32,6 +32,7 @@ static LIST_HEAD(vmcore_list); /* Stores the pointer to the buffer containing kernel elf core headers. */ static char *elfcorebuf; static size_t elfcorebuf_sz; +static size_t elfcorebuf_sz_orig; /* Total size of vmcore file. */ static u64 vmcore_size; @@ -186,7 +187,7 @@ static struct vmcore* __init get_new_element(void) return kzalloc(sizeof(struct vmcore), GFP_KERNEL); } -static u64 __init get_vmcore_size_elf64(char *elfptr) +static u64 __init get_vmcore_size_elf64(char *elfptr, size_t elfsz) { int i; u64 size; @@ -195,7 +196,7 @@ static u64 __init get_vmcore_size_elf64(char *elfptr) ehdr_ptr = (Elf64_Ehdr *)elfptr; phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); - size = sizeof(Elf64_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr)); + size = elfsz; for (i = 0; i < ehdr_ptr->e_phnum; i++) { size += phdr_ptr->p_memsz; phdr_ptr++; @@ -203,7 +204,7 @@ static u64 __init get_vmcore_size_elf64(char *elfptr) return size; } -static u64 __init get_vmcore_size_elf32(char *elfptr) +static u64 __init get_vmcore_size_elf32(char *elfptr, size_t elfsz) { int i; u64 size; @@ -212,7 +213,7 @@ static u64 __init get_vmcore_size_elf32(char *elfptr) ehdr_ptr = (Elf32_Ehdr *)elfptr; phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); - size = sizeof(Elf32_Ehdr) + ((ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr)); + size = elfsz; for (i = 0; i < ehdr_ptr->e_phnum; i++) { size += phdr_ptr->p_memsz; phdr_ptr++; @@ -280,7 +281,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, phdr.p_flags = 0; note_off = sizeof(Elf64_Ehdr) + (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr); - phdr.p_offset = note_off; + phdr.p_offset = roundup(note_off, PAGE_SIZE); phdr.p_vaddr = phdr.p_paddr = 0; phdr.p_filesz = phdr.p_memsz = phdr_sz; phdr.p_align = 0; @@ -294,6 +295,8 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz, i = (nr_ptnote - 1) * sizeof(Elf64_Phdr); *elfsz = *elfsz - i; memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf64_Ehdr)-sizeof(Elf64_Phdr))); + memset(elfptr + *elfsz, 0, i); + *elfsz = roundup(*elfsz, PAGE_SIZE); /* Modify e_phnum to reflect merged headers. */ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; @@ -361,7 +364,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz, phdr.p_flags = 0; note_off = sizeof(Elf32_Ehdr) + (ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf32_Phdr); - phdr.p_offset = note_off; + phdr.p_offset = roundup(note_off, PAGE_SIZE); phdr.p_vaddr = phdr.p_paddr = 0; phdr.p_filesz = phdr.p_memsz = phdr_sz; phdr.p_align = 0; @@ -375,6 +378,8 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz, i = (nr_ptnote - 1) * sizeof(Elf32_Phdr); *elfsz = *elfsz - i; memmove(tmp, tmp+i, ((*elfsz)-sizeof(Elf32_Ehdr)-sizeof(Elf32_Phdr))); + memset(elfptr + *elfsz, 0, i); + *elfsz = roundup(*elfsz, PAGE_SIZE); /* Modify e_phnum to reflect merged headers. */ ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1; @@ -398,9 +403,7 @@ static int __init process_ptload_program_headers_elf64(char *elfptr, phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */ /* First program header is PT_NOTE header. */ - vmcore_off = sizeof(Elf64_Ehdr) + - (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) + - phdr_ptr->p_memsz; /* Note sections */ + vmcore_off = elfsz + roundup(phdr_ptr->p_memsz, PAGE_SIZE); for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { if (phdr_ptr->p_type != PT_LOAD) @@ -435,9 +438,7 @@ static int __init process_ptload_program_headers_elf32(char *elfptr, phdr_ptr = (Elf32_Phdr*)(elfptr + sizeof(Elf32_Ehdr)); /* PT_NOTE hdr */ /* First program header is PT_NOTE header. */ - vmcore_off = sizeof(Elf32_Ehdr) + - (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr) + - phdr_ptr->p_memsz; /* Note sections */ + vmcore_off = elfsz + roundup(phdr_ptr->p_memsz, PAGE_SIZE); for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) { if (phdr_ptr->p_type != PT_LOAD) @@ -459,7 +460,7 @@ static int __init process_ptload_program_headers_elf32(char *elfptr, } /* Sets offset fields of vmcore elements. */ -static void __init set_vmcore_list_offsets_elf64(char *elfptr, +static void __init set_vmcore_list_offsets_elf64(char *elfptr, size_t elfsz, struct list_head *vc_list) { loff_t vmcore_off; @@ -469,8 +470,7 @@ static void __init set_vmcore_list_offsets_elf64(char *elfptr, ehdr_ptr = (Elf64_Ehdr *)elfptr; /* Skip Elf header and program headers. */ - vmcore_off = sizeof(Elf64_Ehdr) + - (ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr); + vmcore_off = elfsz; list_for_each_entry(m, vc_list, list) { m->offset = vmcore_off; @@ -479,7 +479,7 @@ static void __init set_vmcore_list_offsets_elf64(char *elfptr, } /* Sets offset fields of vmcore elements. */ -static void __init set_vmcore_list_offsets_elf32(char *elfptr, +static void __init set_vmcore_list_offsets_elf32(char *elfptr, size_t elfsz, struct list_head *vc_list) { loff_t vmcore_off; @@ -489,8 +489,7 @@ static void __init set_vmcore_list_offsets_elf32(char *elfptr, ehdr_ptr = (Elf32_Ehdr *)elfptr; /* Skip Elf header and program headers. */ - vmcore_off = sizeof(Elf32_Ehdr) + - (ehdr_ptr->e_phnum) * sizeof(Elf32_Phdr); + vmcore_off = elfsz; list_for_each_entry(m, vc_list, list) { m->offset = vmcore_off; @@ -526,30 +525,35 @@ static int __init parse_crash_elf64_headers(void) } /* Read in all elf headers. */ - elfcorebuf_sz = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); - elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL); + elfcorebuf_sz_orig = sizeof(Elf64_Ehdr) + ehdr.e_phnum * sizeof(Elf64_Phdr); + elfcorebuf_sz = elfcorebuf_sz_orig; + elfcorebuf = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, + get_order(elfcorebuf_sz_orig)); if (!elfcorebuf) return -ENOMEM; addr = elfcorehdr_addr; - rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0); + rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0); if (rc < 0) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } /* Merge all PT_NOTE headers into one. */ rc = merge_note_headers_elf64(elfcorebuf, &elfcorebuf_sz, &vmcore_list); if (rc) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } rc = process_ptload_program_headers_elf64(elfcorebuf, elfcorebuf_sz, &vmcore_list); if (rc) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } - set_vmcore_list_offsets_elf64(elfcorebuf, &vmcore_list); + set_vmcore_list_offsets_elf64(elfcorebuf, elfcorebuf_sz, &vmcore_list); return 0; } @@ -581,30 +585,35 @@ static int __init parse_crash_elf32_headers(void) } /* Read in all elf headers. */ - elfcorebuf_sz = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr); - elfcorebuf = kmalloc(elfcorebuf_sz, GFP_KERNEL); + elfcorebuf_sz_orig = sizeof(Elf32_Ehdr) + ehdr.e_phnum * sizeof(Elf32_Phdr); + elfcorebuf_sz = elfcorebuf_sz_orig; + elfcorebuf = (void *) __get_free_pages(GFP_KERNEL | __GFP_ZERO, + get_order(elfcorebuf_sz_orig)); if (!elfcorebuf) return -ENOMEM; addr = elfcorehdr_addr; - rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz, &addr, 0); + rc = read_from_oldmem(elfcorebuf, elfcorebuf_sz_orig, &addr, 0); if (rc < 0) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } /* Merge all PT_NOTE headers into one. */ rc = merge_note_headers_elf32(elfcorebuf, &elfcorebuf_sz, &vmcore_list); if (rc) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } rc = process_ptload_program_headers_elf32(elfcorebuf, elfcorebuf_sz, &vmcore_list); if (rc) { - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); return rc; } - set_vmcore_list_offsets_elf32(elfcorebuf, &vmcore_list); + set_vmcore_list_offsets_elf32(elfcorebuf, elfcorebuf_sz, &vmcore_list); return 0; } @@ -629,14 +638,14 @@ static int __init parse_crash_elf_headers(void) return rc; /* Determine vmcore size. */ - vmcore_size = get_vmcore_size_elf64(elfcorebuf); + vmcore_size = get_vmcore_size_elf64(elfcorebuf, elfcorebuf_sz); } else if (e_ident[EI_CLASS] == ELFCLASS32) { rc = parse_crash_elf32_headers(); if (rc) return rc; /* Determine vmcore size. */ - vmcore_size = get_vmcore_size_elf32(elfcorebuf); + vmcore_size = get_vmcore_size_elf32(elfcorebuf, elfcorebuf_sz); } else { pr_warn("Warning: Core image elf header is not sane\n"); return -EINVAL; @@ -683,7 +692,8 @@ void vmcore_cleanup(void) list_del(&m->list); kfree(m); } - kfree(elfcorebuf); + free_pages((unsigned long)elfcorebuf, + get_order(elfcorebuf_sz_orig)); elfcorebuf = NULL; } EXPORT_SYMBOL_GPL(vmcore_cleanup); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/