Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932486AbaFKONY (ORCPT ); Wed, 11 Jun 2014 10:13:24 -0400 Received: from mail.skyhub.de ([78.46.96.112]:51851 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755646AbaFKONX (ORCPT ); Wed, 11 Jun 2014 10:13:23 -0400 Date: Wed, 11 Jun 2014 16:13:20 +0200 From: Borislav Petkov To: Vivek Goyal Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, ebiederm@xmission.com, hpa@zytor.com, mjg59@srcf.ucam.org, greg@kroah.com, jkosina@suse.cz, dyoung@redhat.com, chaowang@redhat.com, bhe@redhat.com, akpm@linux-foundation.org Subject: Re: [PATCH 07/13] kexec: Implementation of new syscall kexec_file_load Message-ID: <20140611141320.GA30685@nazgul.tnic> References: <1401800822-27425-1-git-send-email-vgoyal@redhat.com> <1401800822-27425-8-git-send-email-vgoyal@redhat.com> <20140605111535.GB16642@pd.tnic> <20140605201732.GF14083@redhat.com> <20140606021133.GB27257@pd.tnic> <20140606180214.GH1526@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20140606180214.GH1526@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 06, 2014 at 02:02:14PM -0400, Vivek Goyal wrote: > > If you want to make it more explicit, you could do > > > > #define RES_OK 0 > > #define RES_ERR 1 > > #define RES_STOP 2 > > You are saying that called back function should return this to walk_* > functions? But then we lose the actual error code which should be > passed to parent function which actually called walk_* function. Well, RES_STOP could implicitly mean stop and no error. Also, if you really want to return back the retval, you could slice it into bitfields: retval = [ ... 8 | 7 ... 0] where [7:0] is the return value and bits from 8 onwards contain different flags like RES_STOP. I did it just for the fun of it and it looks like below. I honestly can't say that I'm crazy about it though. -- Index: b/kernel/resource.c =================================================================== --- a/kernel/resource.c 2014-06-11 14:49:35.865426300 +0200 +++ b/kernel/resource.c 2014-06-11 15:37:50.050299684 +0200 @@ -371,7 +371,7 @@ static int find_next_iomem_res(struct re } int walk_ram_res(char *name, unsigned long flags, u64 start, u64 end, - void *arg, int (*func)(u64, u64, void *)) + void *arg, int (*func)(u64, u64, void *)) { struct resource res; u64 orig_end; @@ -384,12 +384,12 @@ int walk_ram_res(char *name, unsigned lo while ((res.start < res.end) && (find_next_iomem_res(&res, name) >= 0)) { ret = (*func)(res.start, res.end, arg); - if (ret) + if (ret & RES_STOP) break; res.start = res.end + 1; res.end = orig_end; } - return ret; + return RETVAL(ret); } /* @@ -441,7 +441,7 @@ static int find_next_system_ram(struct r * with pfn can truncate ranges. */ int walk_system_ram_res(u64 start, u64 end, void *arg, - int (*func)(u64, u64, void *)) + int (*func)(u64, u64, void *)) { struct resource res; u64 orig_end; @@ -454,12 +454,13 @@ int walk_system_ram_res(u64 start, u64 e while ((res.start < res.end) && (find_next_system_ram(&res, "System RAM") >= 0)) { ret = (*func)(res.start, res.end, arg); - if (ret) + if (ret & RES_STOP) break; res.start = res.end + 1; res.end = orig_end; } - return ret; + + return RETVAL(ret); } #if !defined(CONFIG_ARCH_HAS_WALK_MEMORY) Index: b/kernel/kexec.c =================================================================== --- a/kernel/kexec.c 2014-06-11 14:49:35.865426300 +0200 +++ b/kernel/kexec.c 2014-06-11 16:03:26.264232477 +0200 @@ -2063,8 +2063,9 @@ static int __kexec_add_segment(struct ki } static int locate_mem_hole_top_down(unsigned long start, unsigned long end, - struct kexec_buf *kbuf) + struct kexec_buf *kbuf) { + int ret = 0; struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; @@ -2076,7 +2077,7 @@ static int locate_mem_hole_top_down(unsi temp_start = temp_start & (~(kbuf->buf_align - 1)); if (temp_start < start || temp_start < kbuf->buf_min) - return 0; + return EADDRNOTAVAIL; temp_end = temp_start + kbuf->memsz - 1; @@ -2098,12 +2099,15 @@ static int locate_mem_hole_top_down(unsi kbuf->memsz); /* Stop navigating through remaining System RAM ranges */ - return 1; + ret |= RES_STOP; + + return ret; } static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, - struct kexec_buf *kbuf) + struct kexec_buf *kbuf) { + int ret = 0; struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; @@ -2114,7 +2118,7 @@ static int locate_mem_hole_bottom_up(uns temp_end = temp_start + kbuf->memsz - 1; if (temp_end > end || temp_end > kbuf->buf_max) - return 0; + return EADDRNOTAVAIL; /* * Make sure this does not conflict with any of existing * segments @@ -2133,7 +2137,9 @@ static int locate_mem_hole_bottom_up(uns kbuf->memsz); /* Stop navigating through remaining System RAM ranges */ - return 1; + ret |= RES_STOP; + + return ret; } static int walk_ram_range_callback(u64 start, u64 end, void *arg) @@ -2141,12 +2147,11 @@ static int walk_ram_range_callback(u64 s struct kexec_buf *kbuf = (struct kexec_buf *)arg; unsigned long sz = end - start + 1; - /* Returning 0 will take to next memory range */ if (sz < kbuf->memsz) - return 0; + return EADDRNOTAVAIL; if (end < kbuf->buf_min || start > kbuf->buf_max) - return 0; + return EADDRNOTAVAIL; /* * Allocate memory top down with-in ram range. Otherwise bottom up @@ -2168,15 +2173,15 @@ int kexec_add_buffer(struct kimage *imag unsigned long buf_max, bool top_down, unsigned long *load_addr) { - unsigned long nr_segments = image->nr_segments, new_nr_segments; struct kexec_segment *ksegment; struct kexec_buf buf, *kbuf; + int ret; /* Currently adding segment this way is allowed only in file mode */ if (!image->file_mode) return -EINVAL; - if (nr_segments >= KEXEC_SEGMENT_MAX) + if (image->nr_segments >= KEXEC_SEGMENT_MAX) return -EINVAL; /* @@ -2208,25 +2213,18 @@ int kexec_add_buffer(struct kimage *imag /* Walk the RAM ranges and allocate a suitable range for the buffer */ if (image->type == KEXEC_TYPE_CRASH) - walk_ram_res("Crash kernel", IORESOURCE_MEM | IORESOURCE_BUSY, - crashk_res.start, crashk_res.end, kbuf, - walk_ram_range_callback); + ret = walk_ram_res("Crash kernel", + IORESOURCE_MEM | IORESOURCE_BUSY, + crashk_res.start, crashk_res.end, kbuf, + walk_ram_range_callback); else - walk_system_ram_res(0, -1, kbuf, walk_ram_range_callback); - - /* - * If range could be found successfully, it would have incremented - * the nr_segments value. - */ - new_nr_segments = image->nr_segments; + ret = walk_system_ram_res(0, -1, kbuf, walk_ram_range_callback); - /* A suitable memory range could not be found for buffer */ - if (new_nr_segments == nr_segments) + if (ret) return -EADDRNOTAVAIL; /* Found a suitable memory range */ - - ksegment = &image->segment[new_nr_segments - 1]; + ksegment = &image->segment[image->nr_segments - 1]; *load_addr = ksegment->mem; return 0; } Index: b/include/linux/ioport.h =================================================================== --- a/include/linux/ioport.h 2014-06-11 14:49:35.865426300 +0200 +++ b/include/linux/ioport.h 2014-06-11 16:02:12.775235692 +0200 @@ -237,6 +237,16 @@ extern int iomem_is_exclusive(u64 addr); extern int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages, void *arg, int (*func)(unsigned long, unsigned long, void *)); + +#define RET_BITS 8 +#define RET_MASK ((1U << RET_BITS) - 1) +#define RETVAL(r) (-((r) & RET_MASK)) + +#define RET_OK 0 +#define RET_ERR 1 + +#define RES_STOP BIT(0 + RET_BITS) + extern int walk_system_ram_res(u64 start, u64 end, void *arg, int (*func)(u64, u64, void *)); -- 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/