Commit 6fc5bae7 authored Dec 28, 2006 by David S. Miller

[SPARC64]: Fix "mem=xxx" handling.



We were not being careful enough.  When we trim the physical
memory areas, we have to make sure we don't remove the kernel
image or initial ramdisk image ranges.

Signed-off-by: David S. Miller <davem@davemloft.net>

parent bfff6e92

arch/sparc64/mm/init.c

+124 −23

Original line number	Diff line number	Diff line
		@@ -872,6 +872,115 @@ static unsigned long __init choose_bootmap_pfn(unsigned long start_pfn,
		prom_halt();
		}

		static void __init trim_pavail(unsigned long *cur_size_p,
		unsigned long *end_of_phys_p)
		{
		unsigned long to_trim = *cur_size_p - cmdline_memory_size;
		unsigned long avoid_start, avoid_end;
		int i;

		to_trim = PAGE_ALIGN(to_trim);

		avoid_start = avoid_end = 0;
		#ifdef CONFIG_BLK_DEV_INITRD
		avoid_start = initrd_start;
		avoid_end = PAGE_ALIGN(initrd_end);
		#endif

		/* Trim some pavail[] entries in order to satisfy the
		* requested "mem=xxx" kernel command line specification.
		*
		* We must not trim off the kernel image area nor the
		* initial ramdisk range (if any). Also, we must not trim
		* any pavail[] entry down to zero in order to preserve
		* the invariant that all pavail[] entries have a non-zero
		* size which is assumed by all of the code in here.
		*/
		for (i = 0; i < pavail_ents; i++) {
		unsigned long start, end, kern_end;
		unsigned long trim_low, trim_high, n;

		kern_end = PAGE_ALIGN(kern_base + kern_size);

		trim_low = start = pavail[i].phys_addr;
		trim_high = end = start + pavail[i].reg_size;

		if (kern_base >= start &&
		kern_base < end) {
		trim_low = kern_base;
		if (kern_end >= end)
		continue;
		}
		if (kern_end >= start &&
		kern_end < end) {
		trim_high = kern_end;
		}
		if (avoid_start &&
		avoid_start >= start &&
		avoid_start < end) {
		if (trim_low > avoid_start)
		trim_low = avoid_start;
		if (avoid_end >= end)
		continue;
		}
		if (avoid_end &&
		avoid_end >= start &&
		avoid_end < end) {
		if (trim_high < avoid_end)
		trim_high = avoid_end;
		}

		if (trim_high <= trim_low)
		continue;

		if (trim_low == start && trim_high == end) {
		/* Whole chunk is available for trimming.
		* Trim all except one page, in order to keep
		* entry non-empty.
		*/
		n = (end - start) - PAGE_SIZE;
		if (n > to_trim)
		n = to_trim;

		if (n) {
		pavail[i].phys_addr += n;
		pavail[i].reg_size -= n;
		to_trim -= n;
		}
		} else {
		n = (trim_low - start);
		if (n > to_trim)
		n = to_trim;

		if (n) {
		pavail[i].phys_addr += n;
		pavail[i].reg_size -= n;
		to_trim -= n;
		}
		if (to_trim) {
		n = end - trim_high;
		if (n > to_trim)
		n = to_trim;
		if (n) {
		pavail[i].reg_size -= n;
		to_trim -= n;
		}
		}
		}

		if (!to_trim)
		break;
		}

		/* Recalculate. */
		*cur_size_p = 0UL;
		for (i = 0; i < pavail_ents; i++) {
		*end_of_phys_p = pavail[i].phys_addr +
		pavail[i].reg_size;
		*cur_size_p += pavail[i].reg_size;
		}
		}

		static unsigned long __init bootmem_init(unsigned long *pages_avail,
		unsigned long phys_base)
		{
		@@ -889,31 +998,13 @@ static unsigned long __init bootmem_init(unsigned long *pages_avail,
		end_of_phys_memory = pavail[i].phys_addr +
		pavail[i].reg_size;
		bytes_avail += pavail[i].reg_size;
		if (cmdline_memory_size) {
		if (bytes_avail > cmdline_memory_size) {
		unsigned long slack = bytes_avail - cmdline_memory_size;

		bytes_avail -= slack;
		end_of_phys_memory -= slack;

		pavail[i].reg_size -= slack;
		if ((long)pavail[i].reg_size <= 0L) {
		pavail[i].phys_addr = 0xdeadbeefUL;
		pavail[i].reg_size = 0UL;
		pavail_ents = i;
		} else {
		pavail[i+1].reg_size = 0Ul;
		pavail[i+1].phys_addr = 0xdeadbeefUL;
		pavail_ents = i + 1;
		}
		break;
		}
		}
		}

		*pages_avail = bytes_avail >> PAGE_SHIFT;

		end_pfn = end_of_phys_memory >> PAGE_SHIFT;
		/* Determine the location of the initial ramdisk before trying
		* to honor the "mem=xxx" command line argument. We must know
		* where the kernel image and the ramdisk image are so that we
		* do not trim those two areas from the physical memory map.
		*/

		#ifdef CONFIG_BLK_DEV_INITRD
		/* Now have to check initial ramdisk, so that bootmap does not overwrite it */
		@@ -932,6 +1023,16 @@ static unsigned long __init bootmem_init(unsigned long *pages_avail,
		}
		}
		#endif

		if (cmdline_memory_size &&
		bytes_avail > cmdline_memory_size)
		trim_pavail(&bytes_avail,
		&end_of_phys_memory);

		*pages_avail = bytes_avail >> PAGE_SHIFT;

		end_pfn = end_of_phys_memory >> PAGE_SHIFT;

		/* Initialize the boot-time allocator. */
		max_pfn = max_low_pfn = end_pfn;
		min_low_pfn = (phys_base >> PAGE_SHIFT);