From mboxrd@z Thu Jan 1 00:00:00 1970 From: rmk@arm.linux.org.uk (Russell King) Date: Mon, 06 Jun 2016 17:59:44 +0100 Subject: [PATCH kexec-tools v2 12/32] kexec: add helper to exlude a region from a set of memory ranges In-Reply-To: <20160606164129.GM1041@n2100.armlinux.org.uk> References: <20160606164129.GM1041@n2100.armlinux.org.uk> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Add a helper to exclude a region from a set of memory ranges. Signed-off-by: Russell King --- kexec/mem_regions.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++ kexec/mem_regions.h | 4 +++ 2 files changed, 75 insertions(+) diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c index 804984a..b01a5c8 100644 --- a/kexec/mem_regions.c +++ b/kexec/mem_regions.c @@ -55,3 +55,74 @@ int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, return 0; } +static void mem_regions_remove(struct memory_ranges *ranges, int index) +{ + int tail_entries; + + /* we are assured to have at least one entry */ + ranges->size -= 1; + + /* if we have following entries, shuffle them down one place */ + tail_entries = ranges->size - index; + if (tail_entries) + memmove(ranges->ranges + index, ranges->ranges + index + 1, + tail_entries * sizeof(*ranges->ranges)); + + /* zero the new tail entry */ + memset(ranges->ranges + ranges->size, 0, sizeof(*ranges->ranges)); +} + +/** + * mem_regions_exclude() - excludes a memory region from a set of memory ranges + * @ranges: memory ranges to exclude the region from + * @range: memory range to exclude + * + * Exclude a memory region from a set of memory ranges. We assume that + * the region to be excluded is either wholely located within one of the + * memory ranges, or not at all. + */ +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range) +{ + int i, ret; + + for (i = 0; i < ranges->size; i++) { + struct memory_range *r = ranges->ranges + i; + + /* + * We assume that crash area is fully contained in + * some larger memory area. + */ + if (r->start <= range->start && r->end >= range->end) { + if (r->start == range->start) { + if (r->end == range->end) + /* Remove this entry */ + mem_regions_remove(ranges, i); + else + /* Shrink the start of this memory range */ + r->start = range->end + 1; + } else if (r->end == range->end) { + /* Shrink the end of this memory range */ + r->end = range->start - 1; + } else { + /* + * Split this area into 2 smaller ones and + * remove excluded range from between. First + * create new entry for the remaining area. + */ + ret = mem_regions_add(ranges, range->end + 1, + r->end - range->end, 0); + if (ret < 0) + return ret; + + /* + * Update this area to end before excluded + * range. + */ + r->end = range->start - 1; + break; + } + } + } + return 0; +} diff --git a/kexec/mem_regions.h b/kexec/mem_regions.h index da7b5e8..ae9e972 100644 --- a/kexec/mem_regions.h +++ b/kexec/mem_regions.h @@ -2,9 +2,13 @@ #define MEM_REGIONS_H struct memory_ranges; +struct memory_range; void mem_regions_sort(struct memory_ranges *ranges); +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range); + int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, unsigned long long length, int type); -- 1.9.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1b9y3d-0007qr-Bg for kexec@lists.infradead.org; Mon, 06 Jun 2016 17:11:27 +0000 In-Reply-To: <20160606164129.GM1041@n2100.armlinux.org.uk> References: <20160606164129.GM1041@n2100.armlinux.org.uk> From: Russell King Subject: [PATCH kexec-tools v2 12/32] kexec: add helper to exlude a region from a set of memory ranges MIME-Version: 1.0 Content-Disposition: inline Message-Id: Date: Mon, 06 Jun 2016 17:59:44 +0100 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org Cc: Pratyush Anand , Baoquan He Add a helper to exclude a region from a set of memory ranges. Signed-off-by: Russell King --- kexec/mem_regions.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++ kexec/mem_regions.h | 4 +++ 2 files changed, 75 insertions(+) diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c index 804984a..b01a5c8 100644 --- a/kexec/mem_regions.c +++ b/kexec/mem_regions.c @@ -55,3 +55,74 @@ int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, return 0; } +static void mem_regions_remove(struct memory_ranges *ranges, int index) +{ + int tail_entries; + + /* we are assured to have at least one entry */ + ranges->size -= 1; + + /* if we have following entries, shuffle them down one place */ + tail_entries = ranges->size - index; + if (tail_entries) + memmove(ranges->ranges + index, ranges->ranges + index + 1, + tail_entries * sizeof(*ranges->ranges)); + + /* zero the new tail entry */ + memset(ranges->ranges + ranges->size, 0, sizeof(*ranges->ranges)); +} + +/** + * mem_regions_exclude() - excludes a memory region from a set of memory ranges + * @ranges: memory ranges to exclude the region from + * @range: memory range to exclude + * + * Exclude a memory region from a set of memory ranges. We assume that + * the region to be excluded is either wholely located within one of the + * memory ranges, or not at all. + */ +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range) +{ + int i, ret; + + for (i = 0; i < ranges->size; i++) { + struct memory_range *r = ranges->ranges + i; + + /* + * We assume that crash area is fully contained in + * some larger memory area. + */ + if (r->start <= range->start && r->end >= range->end) { + if (r->start == range->start) { + if (r->end == range->end) + /* Remove this entry */ + mem_regions_remove(ranges, i); + else + /* Shrink the start of this memory range */ + r->start = range->end + 1; + } else if (r->end == range->end) { + /* Shrink the end of this memory range */ + r->end = range->start - 1; + } else { + /* + * Split this area into 2 smaller ones and + * remove excluded range from between. First + * create new entry for the remaining area. + */ + ret = mem_regions_add(ranges, range->end + 1, + r->end - range->end, 0); + if (ret < 0) + return ret; + + /* + * Update this area to end before excluded + * range. + */ + r->end = range->start - 1; + break; + } + } + } + return 0; +} diff --git a/kexec/mem_regions.h b/kexec/mem_regions.h index da7b5e8..ae9e972 100644 --- a/kexec/mem_regions.h +++ b/kexec/mem_regions.h @@ -2,9 +2,13 @@ #define MEM_REGIONS_H struct memory_ranges; +struct memory_range; void mem_regions_sort(struct memory_ranges *ranges); +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range); + int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, unsigned long long length, int type); -- 1.9.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec