Date: Sat, 2 Jan 2016 22:31:14 +0000 (UTC) From: Ian Lepore <ian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r293063 - head/sys/arm/arm Message-ID: <201601022231.u02MVEb5037283@repo.freebsd.org>
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Author: ian Date: Sat Jan 2 22:31:14 2016 New Revision: 293063 URL: https://svnweb.freebsd.org/changeset/base/293063 Log: Work around problems that happen when there is ram at the end of the physical address space. Modified: head/sys/arm/arm/physmem.c Modified: head/sys/arm/arm/physmem.c ============================================================================== --- head/sys/arm/arm/physmem.c Sat Jan 2 22:04:37 2016 (r293062) +++ head/sys/arm/arm/physmem.c Sat Jan 2 22:31:14 2016 (r293063) @@ -280,10 +280,24 @@ arm_physmem_hardware_region(vm_paddr_t p /* * Filter out the page at PA 0x00000000. The VM can't handle it, as * pmap_extract() == 0 means failure. + * + * Also filter out the page at the end of the physical address space -- + * if addr is non-zero and addr+size is zero that means we wrapped to + * the next byte beyond what vm_paddr_t can express. The calculations + * in vm_page_startup() are going to have the same problem, so just work + * around it by leaving the last page out. + * + * XXX This just in: subtract out a whole megabyte, not just 1 page. + * Reducing the size by anything less than 1MB results in a NULL pointer + * deref in _vm_map_lock_read() very early in startup. Better to give + * up a whole megabyte than leave some folks with an unusable system + * while we investigate. */ if (pa == 0) { pa = PAGE_SIZE; sz -= PAGE_SIZE; + } else if (pa + sz == 0) { + sz -= 1024 * 1024; } /*
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