From a6335fa11e08fc386740557b2a4c1b7ff34bc499 Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin <alexander.sverdlin@nokia.com> Date: Thu, 2 Jul 2015 17:16:01 +0200 Subject: [PATCH] MIPS: bootmem: Don't use memory holes for page bitmap Commit f9a7febd leads to a fact that mapstart and therefore a page bitmap for bootmem allocator immediately follows initrd_end. This doesn't always work well on Octeon, where there are holes in PFN ranges (refer to 5b3b1688 and 4MB-aligned PFN allocation). Depending on the inird location it could happen, that mapstart would be in an area not allocated by plat_mem_setup() in arch/mips/cavium-octeon/setup.c, but in the alignment hole between initrd and the next PFN area. Later on this memory will be unconditionally made available to buddy allocator at the end of free_all_bootmem_core() (mm/bootmem.c). All of this results in Linux using the memory not designated for Linux in Octeon's plat_mem_setup(), which in turn means corruption of the memory used by another OS/baremetal code on the same SoC. It doesn't look to me as a problem of Octeon platform code, but rather as an inability of f9a7febd to deal correctly with the fragmented memory-mappings. Proposed fix moves the check for initrd address to the same calculation-loop in bootmem_init() (arch/mips/kernel/setup.c), which also accounts for kernel code location. This should result in mapstart located starting from the first PFN area after kernel code AND initrd. Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Cc: linux-mips@linux-mips.org Cc: David Daney <david.daney@cavium.com> Cc: Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com> Cc: Huacai Chen <chenhc@lemote.com> Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com> Cc: Joe Perches <joe@perches.com> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: Yusuf Khan <yusuf.khan@nokia.com> Cc: Michael Kreuzer <michael.kreuzer@nokia.com> Cc: Aaro Koskinen <aaro.koskinen@iki.fi> Patchwork: https://patchwork.linux-mips.org/patch/10594/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> --- arch/mips/kernel/setup.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c index be73c491182bca..008b3378653a00 100644 --- a/arch/mips/kernel/setup.c +++ b/arch/mips/kernel/setup.c @@ -337,6 +337,11 @@ static void __init bootmem_init(void) min_low_pfn = start; if (end <= reserved_end) continue; +#ifdef CONFIG_BLK_DEV_INITRD + /* mapstart should be after initrd_end */ + if (initrd_end && end <= (unsigned long)PFN_UP(__pa(initrd_end))) + continue; +#endif if (start >= mapstart) continue; mapstart = max(reserved_end, start); @@ -366,14 +371,6 @@ static void __init bootmem_init(void) max_low_pfn = PFN_DOWN(HIGHMEM_START); } -#ifdef CONFIG_BLK_DEV_INITRD - /* - * mapstart should be after initrd_end - */ - if (initrd_end) - mapstart = max(mapstart, (unsigned long)PFN_UP(__pa(initrd_end))); -#endif - /* * Initialize the boot-time allocator with low memory only. */ -- GitLab