kernel/linux.git/arch/arm/mm/init.c, branch linux-4.16.y

ARM: 8737/1: mm: dump: add checking for writable and executable

2018-01-21T15:32:20+00:00

Page mappings with full RWX permissions are a security risk. x86, arm64 has an option to walk the page tables and dump any bad pages. (1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages")) Add a similar implementation for arm. Reviewed-by: Kees Cook Tested-by: Laura Abbott Reviewed-by: Laura Abbott Signed-off-by: Jinbum Park Signed-off-by: Russell King

Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm

2017-11-26T23:03:49+00:00

Pull ARM fixes from Russell King: - LPAE fixes for kernel-readonly regions - Fix for get_user_pages_fast on LPAE systems - avoid tying decompressor to a particular platform if DEBUG_LL is enabled - BUG if we attempt to return to userspace but the to-be-restored PSR value keeps us in privileged mode (defeating an issue that ftracetest found) * 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: BUG if jumping to usermode address in kernel mode ARM: 8722/1: mm: make STRICT_KERNEL_RWX effective for LPAE ARM: 8721/1: mm: dump: check hardware RO bit for LPAE ARM: make decompressor debug output user selectable ARM: fix get_user_pages_fast

ARM: 8722/1: mm: make STRICT_KERNEL_RWX effective for LPAE

2017-11-21T15:10:07+00:00

Currently, for ARM kernels with CONFIG_ARM_LPAE and CONFIG_STRICT_KERNEL_RWX enabled, the 2MiB pages mapping the kernel code and rodata are writable. They are marked read-only in a software bit (L_PMD_SECT_RDONLY) but the hardware read-only bit is not set (PMD_SECT_AP2). For user mappings, the logic that propagates the software bit to the hardware bit is in set_pmd_at(); but for the kernel, section_update() writes the PMDs directly, skipping this logic. The fix is to set PMD_SECT_AP2 for read-only sections in section_update(), at the same time as L_PMD_SECT_RDONLY. Fixes: 1e3479225acb ("ARM: 8275/1: mm: fix PMD_SECT_RDONLY undeclared compile error") Signed-off-by: Philip Derrin Reported-by: Neil Dick Tested-by: Neil Dick Tested-by: Laura Abbott Reviewed-by: Kees Cook Cc: stable@vger.kernel.org Signed-off-by: Russell King

ARM: 8696/1: mm: Remove dead code in mem_init()

2017-09-28T10:13:04+00:00

The code in question checks memory constrains to set default policy for overcommit; however we support page size of 4K only thus condition is always evaluated to false. Remove that dead code. Signed-off-by: Vladimir Murzin Signed-off-by: Russell King

ARM: 8672/1: mm: remove tasklist locking from update_sections_early()

2017-04-26T09:59:36+00:00

The below backtrace can be observed on -rt kernel with CONFIG_DEBUG_MODULE_RONX (4.9 kernel CONFIG_DEBUG_RODATA) option enabled: BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:993 in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0 1 lock held by migration/0/14: #0: (tasklist_lock){+.+...}, at: [] update_sections_early+0x24/0xdc irq event stamp: 38 hardirqs last enabled at (37): [] _raw_spin_unlock_irq+0x24/0x68 hardirqs last disabled at (38): [] multi_cpu_stop+0xd8/0x138 softirqs last enabled at (0): [] copy_process.part.5+0x238/0x1b64 softirqs last disabled at (0): [< (null)>] (null) Preemption disabled at: [] cpu_stopper_thread+0x80/0x10c CPU: 0 PID: 14 Comm: migration/0 Not tainted 4.9.21-rt16-02220-g49e319c #15 Hardware name: Generic DRA74X (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xa8/0xd4) [] (dump_stack) from [] (___might_sleep+0x1bc/0x2ac) [] (___might_sleep) from [] (__rt_spin_lock+0x1c/0x30) [] (__rt_spin_lock) from [] (rt_read_lock+0x54/0x68) [] (rt_read_lock) from [] (update_sections_early+0x24/0xdc) [] (update_sections_early) from [] (__fix_kernmem_perms+0x10/0x1c) [] (__fix_kernmem_perms) from [] (multi_cpu_stop+0x100/0x138) [] (multi_cpu_stop) from [] (cpu_stopper_thread+0x88/0x10c) [] (cpu_stopper_thread) from [] (smpboot_thread_fn+0x174/0x31c) [] (smpboot_thread_fn) from [] (kthread+0xf0/0x108) [] (kthread) from [] (ret_from_fork+0x14/0x3c) Freeing unused kernel memory: 1024K (c0d00000 - c0e00000) The stop_machine() is called with cpus = NULL from fix_kernmem_perms() and mark_rodata_ro() which means only one CPU will execute update_sections_early() while all other CPUs will spin and wait. Hence, it's safe to remove tasklist locking from update_sections_early(). As part of this change also mark functions which are local to this module as static. Signed-off-by: Grygorii Strashko Acked-by: Laura Abbott Acked-by: Kees Cook Signed-off-by: Russell King

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:35+00:00

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

2017-02-28T19:50:53+00:00

Pull ARM updates from Russell King: - nommu updates from Afzal Mohammed cleaning up the vectors support - allow DMA memory "mapping" for nommu Benjamin Gaignard - fixing a correctness issue with R_ARM_PREL31 relocations in the module linker - add strlen() prototype for the decompressor - support for DEBUG_VIRTUAL from Florian Fainelli - adjusting memory bounds after memory reservations have been registered - unipher cache handling updates from Masahiro Yamada - initrd and Thumb Kconfig cleanups * 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (23 commits) ARM: mm: round the initrd reservation to page boundaries ARM: mm: clean up initrd initialisation ARM: mm: move initrd init code out of arm_memblock_init() ARM: 8655/1: improve NOMMU definition of pgprot_*() ARM: 8654/1: decompressor: add strlen prototype ARM: 8652/1: cache-uniphier: clean up active way setup code ARM: 8651/1: cache-uniphier: include instead of ARM: 8650/1: module: handle negative R_ARM_PREL31 addends correctly ARM: 8649/2: nommu: remove Hivecs configuration is asm ARM: 8648/2: nommu: display vectors base ARM: 8647/2: nommu: dynamic exception base address setting ARM: 8646/1: mmu: decouple VECTORS_BASE from Kconfig ARM: 8644/1: Reduce "CPU: shutdown" message to debug level ARM: 8641/1: treewide: Replace uses of virt_to_phys with __pa_symbol ARM: 8640/1: Add support for CONFIG_DEBUG_VIRTUAL ARM: 8639/1: Define KERNEL_START and KERNEL_END ARM: 8638/1: mtd: lart: Rename partition defines to be prefixed with PART_ ARM: 8637/1: Adjust memory boundaries after reservations ARM: 8636/1: Cleanup sanity_check_meminfo ARM: add CPU_THUMB_CAPABLE to indicate possible Thumb support ...

ARM: mm: round the initrd reservation to page boundaries

2017-02-28T11:06:22+00:00

Round the initrd memblock reservation to page boundaries to prevent other data sharing the initrd pages. This prevents an allocation possibly overlapping with the initrd, which would later get trampled on in free_initrd_mem(). Signed-off-by: Russell King

ARM: mm: clean up initrd initialisation

2017-02-28T11:06:21+00:00

Rather than repeatedly testing phys_initrd_size to see if the initrd is still enabled, return from the new function to avoid executing the remaining initialisation. Signed-off-by: Russell King