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authorLinus Torvalds <torvalds@linux-foundation.org>2019-10-09 09:27:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-10-09 09:27:22 -0700
commite60329c97b9cc07ce15e3c39fc42e57bf14add92 (patch)
tree292d55061b827e277433c67f6871d1bcd1ff75d2 /Documentation
parente3280b54afed870d531571212f1fc375df39b7d2 (diff)
parent3e7c93bd04edfb0cae7dad1215544c9350254b8f (diff)
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon: "A larger-than-usual batch of arm64 fixes for -rc3. The bulk of the fixes are dealing with a bunch of issues with the build system from the compat vDSO, which unfortunately led to some significant Makefile rework to manage the horrible combinations of toolchains that we can end up needing to drive simultaneously. We came close to disabling the thing entirely, but Vincenzo was quick to spin up some patches and I ended up picking up most of the bits that were left [*]. Future work will look at disentangling the header files properly. Other than that, we have some important fixes all over, including one papering over the miscompilation fallout from forcing CONFIG_OPTIMIZE_INLINING=y, which I'm still unhappy about. Harumph. We've still got a couple of open issues, so I'm expecting to have some more fixes later this cycle. Summary: - Numerous fixes to the compat vDSO build system, especially when combining gcc and clang - Fix parsing of PAR_EL1 in spurious kernel fault detection - Partial workaround for Neoverse-N1 erratum #1542419 - Fix IRQ priority masking on entry from compat syscalls - Fix advertisment of FRINT HWCAP to userspace - Attempt to workaround inlining breakage with '__always_inline' - Fix accidental freeing of parent SVE state on fork() error path - Add some missing NULL pointer checks in instruction emulation init - Some formatting and comment fixes" [*] Will's final fixes were Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com> but they were already in linux-next by then and he didn't rebase just to add those. * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (21 commits) arm64: armv8_deprecated: Checking return value for memory allocation arm64: Kconfig: Make CONFIG_COMPAT_VDSO a proper Kconfig option arm64: vdso32: Rename COMPATCC to CC_COMPAT arm64: vdso32: Pass '--target' option to clang via VDSO_CAFLAGS arm64: vdso32: Don't use KBUILD_CPPFLAGS unconditionally arm64: vdso32: Move definition of COMPATCC into vdso32/Makefile arm64: Default to building compat vDSO with clang when CONFIG_CC_IS_CLANG lib: vdso: Remove CROSS_COMPILE_COMPAT_VDSO arm64: vdso32: Remove jump label config option in Makefile arm64: vdso32: Detect binutils support for dmb ishld arm64: vdso: Remove stale files from old assembly implementation arm64: vdso32: Fix broken compat vDSO build warnings arm64: mm: fix spurious fault detection arm64: ftrace: Ensure synchronisation in PLT setup for Neoverse-N1 #1542419 arm64: Fix incorrect irqflag restore for priority masking for compat arm64: mm: avoid virt_to_phys(init_mm.pgd) arm64: cpufeature: Effectively expose FRINT capability to userspace arm64: Mark functions using explicit register variables as '__always_inline' docs: arm64: Fix indentation and doc formatting arm64/sve: Fix wrong free for task->thread.sve_state ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arm64/memory.rst9
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/arm64/memory.rst b/Documentation/arm64/memory.rst
index b040909e45f8..02e02175e6f5 100644
--- a/Documentation/arm64/memory.rst
+++ b/Documentation/arm64/memory.rst
@@ -154,11 +154,18 @@ return virtual addresses to userspace from a 48-bit range.
Software can "opt-in" to receiving VAs from a 52-bit space by
specifying an mmap hint parameter that is larger than 48-bit.
+
For example:
- maybe_high_address = mmap(~0UL, size, prot, flags,...);
+
+.. code-block:: c
+
+ maybe_high_address = mmap(~0UL, size, prot, flags,...);
It is also possible to build a debug kernel that returns addresses
from a 52-bit space by enabling the following kernel config options:
+
+.. code-block:: sh
+
CONFIG_EXPERT=y && CONFIG_ARM64_FORCE_52BIT=y
Note that this option is only intended for debugging applications