Commit Graph

93 Commits

Author SHA1 Message Date
Linus Torvalds
be092017b6 arm64 updates for 4.7:
- virt_to_page/page_address optimisations
 
 - Support for NUMA systems described using device-tree
 
 - Support for hibernate/suspend-to-disk
 
 - Proper support for maxcpus= command line parameter
 
 - Detection and graceful handling of AArch64-only CPUs
 
 - Miscellaneous cleanups and non-critical fixes
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:

 - virt_to_page/page_address optimisations

 - support for NUMA systems described using device-tree

 - support for hibernate/suspend-to-disk

 - proper support for maxcpus= command line parameter

 - detection and graceful handling of AArch64-only CPUs

 - miscellaneous cleanups and non-critical fixes

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (92 commits)
  arm64: do not enforce strict 16 byte alignment to stack pointer
  arm64: kernel: Fix incorrect brk randomization
  arm64: cpuinfo: Missing NULL terminator in compat_hwcap_str
  arm64: secondary_start_kernel: Remove unnecessary barrier
  arm64: Ensure pmd_present() returns false after pmd_mknotpresent()
  arm64: Replace hard-coded values in the pmd/pud_bad() macros
  arm64: Implement pmdp_set_access_flags() for hardware AF/DBM
  arm64: Fix typo in the pmdp_huge_get_and_clear() definition
  arm64: mm: remove unnecessary EXPORT_SYMBOL_GPL
  arm64: always use STRICT_MM_TYPECHECKS
  arm64: kvm: Fix kvm teardown for systems using the extended idmap
  arm64: kaslr: increase randomization granularity
  arm64: kconfig: drop CONFIG_RTC_LIB dependency
  arm64: make ARCH_SUPPORTS_DEBUG_PAGEALLOC depend on !HIBERNATION
  arm64: hibernate: Refuse to hibernate if the boot cpu is offline
  arm64: kernel: Add support for hibernate/suspend-to-disk
  PM / Hibernate: Call flush_icache_range() on pages restored in-place
  arm64: Add new asm macro copy_page
  arm64: Promote KERNEL_START/KERNEL_END definitions to a header file
  arm64: kernel: Include _AC definition in page.h
  ...
2016-05-16 17:17:24 -07:00
James Morse
28c7258330 arm64: Promote KERNEL_START/KERNEL_END definitions to a header file
KERNEL_START and KERNEL_END are useful outside head.S, move them to a
header file.

Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-28 12:05:46 +01:00
James Morse
cabe1c81ea arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va
By enabling the MMU early in cpu_resume(), the sleep_save_sp and stack can
be accessed by VA, which avoids the need to convert-addresses and clean to
PoC on the suspend path.

MMU setup is shared with the boot path, meaning the swapper_pg_dir is
restored directly: ttbr1_el1 is no longer saved/restored.

struct sleep_save_sp is removed, replacing it with a single array of
pointers.

cpu_do_{suspend,resume} could be further reduced to not restore: cpacr_el1,
mdscr_el1, tcr_el1, vbar_el1 and sctlr_el1, all of which are set by
__cpu_setup(). However these values all contain res0 bits that may be used
to enable future features.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-28 12:05:46 +01:00
Ard Biesheuvel
08cdac619c arm64: relocatable: deal with physically misaligned kernel images
When booting a relocatable kernel image, there is no practical reason
to refuse an image whose load address is not exactly TEXT_OFFSET bytes
above a 2 MB aligned base address, as long as the physical and virtual
misalignment with respect to the swapper block size are equal, and are
both aligned to THREAD_SIZE.

Since the virtual misalignment is under our control when we first enter
the kernel proper, we can simply choose its value to be equal to the
physical misalignment.

So treat the misalignment of the physical load address as the initial
KASLR offset, and fix up the remaining code to deal with that.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:23:28 +01:00
Ard Biesheuvel
18b9c0d641 arm64: don't map TEXT_OFFSET bytes below the kernel if we can avoid it
For historical reasons, the kernel Image must be loaded into physical
memory at a 512 KB offset above a 2 MB aligned base address. The region
between the base address and the start of the kernel Image has no
significance to the kernel itself, but it is currently mapped explicitly
into the early kernel VMA range for all translation granules.

In some cases (i.e., 4 KB granule), this is unavoidable, due to the 2 MB
granularity of the early kernel mappings. However, in other cases, e.g.,
when running with larger page sizes, or in the future, with more granular
KASLR, there is no reason to map it explicitly like we do currently.

So update the logic so that the region is mapped only if that happens as
a side effect of rounding the start address of the kernel to swapper block
size, and leave it unmapped otherwise.

Since the symbol kernel_img_size now simply resolves to the memory
footprint of the kernel Image, we can drop its definition from image.h
and opencode its calculation.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:23:25 +01:00
Ard Biesheuvel
b03cc88532 arm64: kernel: replace early 64-bit literal loads with move-immediates
When building a relocatable kernel, we currently rely on the fact that
early 64-bit literal loads need to be deferred to after the relocation
has been performed only if they involve symbol references, and not if
they involve assemble time constants. While this is not an unreasonable
assumption to make, it is better to switch to movk/movz sequences, since
these are guaranteed to be resolved at link time, simply because there are
no dynamic relocation types to describe them.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:23:21 +01:00
Ard Biesheuvel
0cd3defe0a arm64: kernel: perform relocation processing from ID map
Refactor the relocation processing so that the code executes from the
ID map while accessing the relocation tables via the virtual mapping.
This way, we can use literals containing virtual addresses as before,
instead of having to use convoluted absolute expressions.

For symmetry with the secondary code path, the relocation code and the
subsequent jump to the virtual entry point are implemented in a function
called __primary_switch(), and __mmap_switched() is renamed to
__primary_switched(). Also, the call sequence in stext() is aligned with
the one in secondary_startup(), by replacing the awkward 'adr_l lr' and
'b cpu_setup' sequence with a simple branch and link.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:21:54 +01:00
Ard Biesheuvel
e5ebeec879 arm64: kernel: use literal for relocated address of __secondary_switched
We can simply use a relocated 64-bit literal to store the address of
__secondary_switched(), and the relocation code will ensure that it
holds the correct value at secondary entry time, as long as we make sure
that the literal is not dereferenced until after we have enabled the MMU.

So jump via a small __secondary_switch() function covered by the ID map
that performs the literal load and branch-to-register.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:19:55 +01:00
Ard Biesheuvel
190c056fc3 arm64: kernel: don't export local symbols from head.S
This unexports some symbols from head.S that are only used locally.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-26 12:19:22 +01:00
Dave Martin
882416c1e4 arm64: Fix EL1/EL2 early init inconsistencies with VHE
When using the Virtualisation Host Extensions, EL1 is not used in
the host and requires no separate configuration.

In addition, with VHE enabled, non-hyp-specific EL2 configuration
that does not need to be done early will be done anyway in
__cpu_setup via the _EL1 system register aliases.  In particular,
the layout and definition of CPTR_EL2 are changed by enabling VHE
so that they resemble CPACR_EL1, so existing code to initialise
CPTR_EL2 becomes architecturally wrong in this case.

This patch simply skips the affected initialisation code in the
non-VHE case.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-04-21 18:34:23 +01:00
Ard Biesheuvel
adb4907007 arm64: fix invalidation of wrong __early_cpu_boot_status cacheline
In head.S, the str_l macro, which takes a source register, a symbol name
and a temp register, is used to store a status value to the variable
__early_cpu_boot_status. Subsequently, the value of the temp register is
reused to invalidate any cachelines covering this variable.

However, since str_l resolves to

      adrp    \tmp, \sym
      str     \src, [\tmp, :lo12:\sym]

the temp register never actually holds the address of the variable but
only of the 4 KB window that covers it, and reusing it leads to the
wrong cacheline being invalidated. So instead, take the address
explicitly before doing the store, and reuse that value to perform
the cache invalidation.

Fixes: bb9052744f ("arm64: Handle early CPU boot failures")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-04-18 16:23:24 +01:00
Ard Biesheuvel
546c8c44f0 arm64: move early boot code to the .init segment
Apart from the arm64/linux and EFI header data structures, there is nothing
in the .head.text section that must reside at the beginning of the Image.
So let's move it to the .init section where it belongs.

Note that this involves some minor tweaking of the EFI header, primarily
because the address of 'stext' no longer coincides with the start of the
.text section. It also requires a couple of relocated symbol references
to be slightly rewritten or their definition moved to the linker script.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-04-14 18:11:30 +01:00
Linus Torvalds
9d854607f9 2nd set of arm64 updates for 4.6:
- KASLR bug fixes: use callee-saved register, boot-time I-cache
   maintenance
 - inv_entry asm macro fix (EL0 check typo)
 - pr_notice("Virtual kernel memory layout...") splitting
 - Clean-ups: use p?d_set_huge consistently, allow preemption around
   copy_to_user_page, remove unused __local_flush_icache_all()
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull second set of arm64 updates from Catalin Marinas:

 - KASLR bug fixes: use callee-saved register, boot-time I-cache
   maintenance

 - inv_entry asm macro fix (EL0 check typo)

 - pr_notice("Virtual kernel memory layout...") splitting

 - Clean-ups: use p?d_set_huge consistently, allow preemption around
   copy_to_user_page, remove unused __local_flush_icache_all()

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: allow preemption in copy_to_user_page
  arm64: consistently use p?d_set_huge
  arm64: kaslr: use callee saved register to preserve SCTLR across C call
  arm64: Split pr_notice("Virtual kernel memory layout...") into multiple pr_cont()
  arm64: drop unused __local_flush_icache_all()
  arm64: fix KASLR boot-time I-cache maintenance
  arm64/kernel: fix incorrect EL0 check in inv_entry macro
2016-03-24 19:13:59 -07:00
Ard Biesheuvel
d5e5743797 arm64: kaslr: use callee saved register to preserve SCTLR across C call
The KASLR code incorrectly expects the contents of x18 to be preserved
across a call into C code, and uses it to stash the contents of SCTLR_EL1
before enabling the MMU. If the MMU needs to be disabled again to create
the randomized kernel mapping, x18 is written back to SCTLR_EL1, which is
likely to crash the system if x18 has been clobbered by kasan_early_init()
or kaslr_early_init(). So use x22 instead, which is not in use so far in
head.S

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-03-24 16:19:24 +00:00
Mark Rutland
b90b4a608e arm64: fix KASLR boot-time I-cache maintenance
Commit f80fb3a3d5 ("arm64: add support for kernel ASLR") missed a
DSB necessary to complete I-cache maintenance in the primary boot path,
and hence stale instructions may still be present in the I-cache and may
be executed until the I-cache maintenance naturally completes.

Since commit 8ec4198743 ("arm64: mm: ensure patched kernel text is
fetched from PoU"), all CPUs invalidate their I-caches after their MMU
is enabled. Prior a CPU's MMU having been enabled, arbitrary lines may
have been fetched from the PoC into I-caches. We never patch text
expected to be executed with the MMU off. Thus, it is unnecessary to
perform broadcast I-cache maintenance in the primary boot path.

This patch reduces the scope of the I-cache maintenance to the local
CPU, and adds the missing DSB with similar scope, matching prior
maintenance in the primary boot path.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesehvuel <ard.biesheuvel@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-03-21 12:08:50 +00:00
Linus Torvalds
588ab3f9af arm64 updates for 4.6:
- Initial page table creation reworked to avoid breaking large block
   mappings (huge pages) into smaller ones. The ARM architecture requires
   break-before-make in such cases to avoid TLB conflicts but that's not
   always possible on live page tables
 
 - Kernel virtual memory layout: the kernel image is no longer linked to
   the bottom of the linear mapping (PAGE_OFFSET) but at the bottom of
   the vmalloc space, allowing the kernel to be loaded (nearly) anywhere
   in physical RAM
 
 - Kernel ASLR: position independent kernel Image and modules being
   randomly mapped in the vmalloc space with the randomness is provided
   by UEFI (efi_get_random_bytes() patches merged via the arm64 tree,
   acked by Matt Fleming)
 
 - Implement relative exception tables for arm64, required by KASLR
   (initial code for ARCH_HAS_RELATIVE_EXTABLE added to lib/extable.c but
   actual x86 conversion to deferred to 4.7 because of the merge
   dependencies)
 
 - Support for the User Access Override feature of ARMv8.2: this allows
   uaccess functions (get_user etc.) to be implemented using LDTR/STTR
   instructions. Such instructions, when run by the kernel, perform
   unprivileged accesses adding an extra level of protection. The
   set_fs() macro is used to "upgrade" such instruction to privileged
   accesses via the UAO bit
 
 - Half-precision floating point support (part of ARMv8.2)
 
 - Optimisations for CPUs with or without a hardware prefetcher (using
   run-time code patching)
 
 - copy_page performance improvement to deal with 128 bytes at a time
 
 - Sanity checks on the CPU capabilities (via CPUID) to prevent
   incompatible secondary CPUs from being brought up (e.g. weird
   big.LITTLE configurations)
 
 - valid_user_regs() reworked for better sanity check of the sigcontext
   information (restored pstate information)
 
 - ACPI parking protocol implementation
 
 - CONFIG_DEBUG_RODATA enabled by default
 
 - VDSO code marked as read-only
 
 - DEBUG_PAGEALLOC support
 
 - ARCH_HAS_UBSAN_SANITIZE_ALL enabled
 
 - Erratum workaround Cavium ThunderX SoC
 
 - set_pte_at() fix for PROT_NONE mappings
 
 - Code clean-ups
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 "Here are the main arm64 updates for 4.6.  There are some relatively
  intrusive changes to support KASLR, the reworking of the kernel
  virtual memory layout and initial page table creation.

  Summary:

   - Initial page table creation reworked to avoid breaking large block
     mappings (huge pages) into smaller ones.  The ARM architecture
     requires break-before-make in such cases to avoid TLB conflicts but
     that's not always possible on live page tables

   - Kernel virtual memory layout: the kernel image is no longer linked
     to the bottom of the linear mapping (PAGE_OFFSET) but at the bottom
     of the vmalloc space, allowing the kernel to be loaded (nearly)
     anywhere in physical RAM

   - Kernel ASLR: position independent kernel Image and modules being
     randomly mapped in the vmalloc space with the randomness is
     provided by UEFI (efi_get_random_bytes() patches merged via the
     arm64 tree, acked by Matt Fleming)

   - Implement relative exception tables for arm64, required by KASLR
     (initial code for ARCH_HAS_RELATIVE_EXTABLE added to lib/extable.c
     but actual x86 conversion to deferred to 4.7 because of the merge
     dependencies)

   - Support for the User Access Override feature of ARMv8.2: this
     allows uaccess functions (get_user etc.) to be implemented using
     LDTR/STTR instructions.  Such instructions, when run by the kernel,
     perform unprivileged accesses adding an extra level of protection.
     The set_fs() macro is used to "upgrade" such instruction to
     privileged accesses via the UAO bit

   - Half-precision floating point support (part of ARMv8.2)

   - Optimisations for CPUs with or without a hardware prefetcher (using
     run-time code patching)

   - copy_page performance improvement to deal with 128 bytes at a time

   - Sanity checks on the CPU capabilities (via CPUID) to prevent
     incompatible secondary CPUs from being brought up (e.g.  weird
     big.LITTLE configurations)

   - valid_user_regs() reworked for better sanity check of the
     sigcontext information (restored pstate information)

   - ACPI parking protocol implementation

   - CONFIG_DEBUG_RODATA enabled by default

   - VDSO code marked as read-only

   - DEBUG_PAGEALLOC support

   - ARCH_HAS_UBSAN_SANITIZE_ALL enabled

   - Erratum workaround Cavium ThunderX SoC

   - set_pte_at() fix for PROT_NONE mappings

   - Code clean-ups"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (99 commits)
  arm64: kasan: Fix zero shadow mapping overriding kernel image shadow
  arm64: kasan: Use actual memory node when populating the kernel image shadow
  arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission
  arm64: Fix misspellings in comments.
  arm64: efi: add missing frame pointer assignment
  arm64: make mrs_s prefixing implicit in read_cpuid
  arm64: enable CONFIG_DEBUG_RODATA by default
  arm64: Rework valid_user_regs
  arm64: mm: check at build time that PAGE_OFFSET divides the VA space evenly
  arm64: KVM: Move kvm_call_hyp back to its original localtion
  arm64: mm: treat memstart_addr as a signed quantity
  arm64: mm: list kernel sections in order
  arm64: lse: deal with clobbered IP registers after branch via PLT
  arm64: mm: dump: Use VA_START directly instead of private LOWEST_ADDR
  arm64: kconfig: add submenu for 8.2 architectural features
  arm64: kernel: acpi: fix ioremap in ACPI parking protocol cpu_postboot
  arm64: Add support for Half precision floating point
  arm64: Remove fixmap include fragility
  arm64: Add workaround for Cavium erratum 27456
  arm64: mm: Mark .rodata as RO
  ...
2016-03-17 20:03:47 -07:00
Marc Zyngier
1f364c8c48 arm64: VHE: Add support for running Linux in EL2 mode
With ARMv8.1 VHE, the architecture is able to (almost) transparently
run the kernel at EL2, despite being written for EL1.

This patch takes care of the "almost" part, mostly preventing the kernel
from dropping from EL2 to EL1, and setting up the HYP configuration.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2016-02-29 18:34:18 +00:00
Suzuki K Poulose
bb9052744f arm64: Handle early CPU boot failures
A secondary CPU could fail to come online due to insufficient
capabilities and could simply die or loop in the kernel.
e.g, a CPU with no support for the selected kernel PAGE_SIZE
loops in kernel with MMU turned off.
or a hotplugged CPU which doesn't have one of the advertised
system capability will die during the activation.

There is no way to synchronise the status of the failing CPU
back to the master. This patch solves the issue by adding a
field to the secondary_data which can be updated by the failing
CPU. If the secondary CPU fails even before turning the MMU on,
it updates the status in a special variable reserved in the head.txt
section to make sure that the update can be cache invalidated safely
without possible sharing of cache write back granule.

Here are the possible states :

 -1. CPU_MMU_OFF - Initial value set by the master CPU, this value
indicates that the CPU could not turn the MMU on, hence the status
could not be reliably updated in the secondary_data. Instead, the
CPU has updated the status @ __early_cpu_boot_status.

 0. CPU_BOOT_SUCCESS - CPU has booted successfully.

 1. CPU_KILL_ME - CPU has invoked cpu_ops->die, indicating the
master CPU to synchronise by issuing a cpu_ops->cpu_kill.

 2. CPU_STUCK_IN_KERNEL - CPU couldn't invoke die(), instead is
looping in the kernel. This information could be used by say,
kexec to check if it is really safe to do a kexec reboot.

 3. CPU_PANIC_KERNEL - CPU detected some serious issues which
requires kernel to crash immediately. The secondary CPU cannot
call panic() until it has initialised the GIC. This flag can
be used to instruct the master to do so.

Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
[catalin.marinas@arm.com: conflict resolution]
[catalin.marinas@arm.com: converted "status" from int to long]
[catalin.marinas@arm.com: updated update_early_cpu_boot_status to use str_l]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-25 10:32:23 +00:00
Ard Biesheuvel
f80fb3a3d5 arm64: add support for kernel ASLR
This adds support for KASLR is implemented, based on entropy provided by
the bootloader in the /chosen/kaslr-seed DT property. Depending on the size
of the address space (VA_BITS) and the page size, the entropy in the
virtual displacement is up to 13 bits (16k/2 levels) and up to 25 bits (all
4 levels), with the sidenote that displacements that result in the kernel
image straddling a 1GB/32MB/512MB alignment boundary (for 4KB/16KB/64KB
granule kernels, respectively) are not allowed, and will be rounded up to
an acceptable value.

If CONFIG_RANDOMIZE_MODULE_REGION_FULL is enabled, the module region is
randomized independently from the core kernel. This makes it less likely
that the location of core kernel data structures can be determined by an
adversary, but causes all function calls from modules into the core kernel
to be resolved via entries in the module PLTs.

If CONFIG_RANDOMIZE_MODULE_REGION_FULL is not enabled, the module region is
randomized by choosing a page aligned 128 MB region inside the interval
[_etext - 128 MB, _stext + 128 MB). This gives between 10 and 14 bits of
entropy (depending on page size), independently of the kernel randomization,
but still guarantees that modules are within the range of relative branch
and jump instructions (with the caveat that, since the module region is
shared with other uses of the vmalloc area, modules may need to be loaded
further away if the module region is exhausted)

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:27 +00:00
Ard Biesheuvel
1e48ef7fcc arm64: add support for building vmlinux as a relocatable PIE binary
This implements CONFIG_RELOCATABLE, which links the final vmlinux
image with a dynamic relocation section, allowing the early boot code
to perform a relocation to a different virtual address at runtime.

This is a prerequisite for KASLR (CONFIG_RANDOMIZE_BASE).

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:27 +00:00
Ard Biesheuvel
2bf31a4a05 arm64: avoid dynamic relocations in early boot code
Before implementing KASLR for arm64 by building a self-relocating PIE
executable, we have to ensure that values we use before the relocation
routine is executed are not subject to dynamic relocation themselves.
This applies not only to virtual addresses, but also to values that are
supplied by the linker at build time and relocated using R_AARCH64_ABS64
relocations.

So instead, use assemble time constants, or force the use of static
relocations by folding the constants into the instructions.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:25 +00:00
Ard Biesheuvel
6ad1fe5d90 arm64: avoid R_AARCH64_ABS64 relocations for Image header fields
Unfortunately, the current way of using the linker to emit build time
constants into the Image header will no longer work once we switch to
the use of PIE executables. The reason is that such constants are emitted
into the binary using R_AARCH64_ABS64 relocations, which are resolved at
runtime, not at build time, and the places targeted by those relocations
will contain zeroes before that.

So refactor the endian swapping linker script constant generation code so
that it emits the upper and lower 32-bit words separately.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-24 14:57:25 +00:00
Ard Biesheuvel
a7f8de168a arm64: allow kernel Image to be loaded anywhere in physical memory
This relaxes the kernel Image placement requirements, so that it
may be placed at any 2 MB aligned offset in physical memory.

This is accomplished by ignoring PHYS_OFFSET when installing
memblocks, and accounting for the apparent virtual offset of
the kernel Image. As a result, virtual address references
below PAGE_OFFSET are correctly mapped onto physical references
into the kernel Image regardless of where it sits in memory.

Special care needs to be taken for dealing with memory limits passed
via mem=, since the generic implementation clips memory top down, which
may clip the kernel image itself if it is loaded high up in memory. To
deal with this case, we simply add back the memory covering the kernel
image, which may result in more memory to be retained than was passed
as a mem= parameter.

Since mem= should not be considered a production feature, a panic notifier
handler is installed that dumps the memory limit at panic time if one was
set.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-18 18:16:53 +00:00
Ard Biesheuvel
ab893fb9f1 arm64: introduce KIMAGE_VADDR as the virtual base of the kernel region
This introduces the preprocessor symbol KIMAGE_VADDR which will serve as
the symbolic virtual base of the kernel region, i.e., the kernel's virtual
offset will be KIMAGE_VADDR + TEXT_OFFSET. For now, we define it as being
equal to PAGE_OFFSET, but in the future, it will be moved below it once
we move the kernel virtual mapping out of the linear mapping.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-18 18:16:27 +00:00
Mark Rutland
5227cfa71f arm64: mm: place empty_zero_page in bss
Currently the zero page is set up in paging_init, and thus we cannot use
the zero page earlier. We use the zero page as a reserved TTBR value
from which no TLB entries may be allocated (e.g. when uninstalling the
idmap). To enable such usage earlier (as may be required for invasive
changes to the kernel page tables), and to minimise the time that the
idmap is active, we need to be able to use the zero page before
paging_init.

This patch follows the example set by x86, by allocating the zero page
at compile time, in .bss. This means that the zero page itself is
available immediately upon entry to start_kernel (as we zero .bss before
this), and also means that the zero page takes up no space in the raw
Image binary. The associated struct page is allocated in bootmem_init,
and remains unavailable until this time.

Outside of arch code, the only users of empty_zero_page assume that the
empty_zero_page symbol refers to the zeroed memory itself, and that
ZERO_PAGE(x) must be used to acquire the associated struct page,
following the example of x86. This patch also brings arm64 inline with
these assumptions.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2016-02-16 15:10:44 +00:00
Lorenzo Pieralisi
f436b2ac90 arm64: kernel: fix architected PMU registers unconditional access
The Performance Monitors extension is an optional feature of the
AArch64 architecture, therefore, in order to access Performance
Monitors registers safely, the kernel should detect the architected
PMU unit presence through the ID_AA64DFR0_EL1 register PMUVer field
before accessing them.

This patch implements a guard by reading the ID_AA64DFR0_EL1 register
PMUVer field to detect the architected PMU presence and prevent accessing
PMU system registers if the Performance Monitors extension is not
implemented in the core.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Fixes: 60792ad349 ("arm64: kernel: enforce pmuserenr_el0 initialization and restore")
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-01-25 11:09:06 +00:00
Mark Rutland
2a803c4db6 arm64: head.S: use memset to clear BSS
Currently we use an open-coded memzero to clear the BSS. As it is a
trivial implementation, it is sub-optimal.

Our optimised memset doesn't use the stack, is position-independent, and
for the memzero case can use of DC ZVA to clear large blocks
efficiently. In __mmap_switched the MMU is on and there are no live
caller-saved registers, so we can safely call an uninstrumented memset.

This patch changes __mmap_switched to use memset when clearing the BSS.
We use the __pi_memset alias so as to avoid any instrumentation in all
kernel configurations.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2016-01-06 16:00:56 +00:00
Jungseok Lee
6cdf9c7ca6 arm64: Store struct thread_info in sp_el0
There is need for figuring out how to manage struct thread_info data when
IRQ stack is introduced. struct thread_info information should be copied
to IRQ stack under the current thread_info calculation logic whenever
context switching is invoked. This is too expensive to keep supporting
the approach.

Instead, this patch pays attention to sp_el0 which is an unused scratch
register in EL1 context. sp_el0 utilization not only simplifies the
management, but also prevents text section size from being increased
largely due to static allocated IRQ stack as removing masking operation
using THREAD_SIZE in many places.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-12-08 11:40:48 +00:00
Linus Torvalds
2dc10ad81f arm64 updates for 4.4:
- "genirq: Introduce generic irq migration for cpu hotunplugged" patch
   merged from tip/irq/for-arm to allow the arm64-specific part to be
   upstreamed via the arm64 tree
 
 - CPU feature detection reworked to cope with heterogeneous systems
   where CPUs may not have exactly the same features. The features
   reported by the kernel via internal data structures or ELF_HWCAP are
   delayed until all the CPUs are up (and before user space starts)
 
 - Support for 16KB pages, with the additional bonus of a 36-bit VA
   space, though the latter only depending on EXPERT
 
 - Implement native {relaxed, acquire, release} atomics for arm64
 
 - New ASID allocation algorithm which avoids IPI on roll-over, together
   with TLB invalidation optimisations (using local vs global where
   feasible)
 
 - KASan support for arm64
 
 - EFI_STUB clean-up and isolation for the kernel proper (required by
   KASan)
 
 - copy_{to,from,in}_user optimisations (sharing the memcpy template)
 
 - perf: moving arm64 to the arm32/64 shared PMU framework
 
 - L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware
 
 - Support for the contiguous PTE hint on kernel mapping (16 consecutive
   entries may be able to use a single TLB entry)
 
 - Generic CONFIG_HZ now used on arm64
 
 - defconfig updates
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:

 - "genirq: Introduce generic irq migration for cpu hotunplugged" patch
   merged from tip/irq/for-arm to allow the arm64-specific part to be
   upstreamed via the arm64 tree

 - CPU feature detection reworked to cope with heterogeneous systems
   where CPUs may not have exactly the same features.  The features
   reported by the kernel via internal data structures or ELF_HWCAP are
   delayed until all the CPUs are up (and before user space starts)

 - Support for 16KB pages, with the additional bonus of a 36-bit VA
   space, though the latter only depending on EXPERT

 - Implement native {relaxed, acquire, release} atomics for arm64

 - New ASID allocation algorithm which avoids IPI on roll-over, together
   with TLB invalidation optimisations (using local vs global where
   feasible)

 - KASan support for arm64

 - EFI_STUB clean-up and isolation for the kernel proper (required by
   KASan)

 - copy_{to,from,in}_user optimisations (sharing the memcpy template)

 - perf: moving arm64 to the arm32/64 shared PMU framework

 - L1_CACHE_BYTES increased to 128 to accommodate Cavium hardware

 - Support for the contiguous PTE hint on kernel mapping (16 consecutive
   entries may be able to use a single TLB entry)

 - Generic CONFIG_HZ now used on arm64

 - defconfig updates

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (91 commits)
  arm64/efi: fix libstub build under CONFIG_MODVERSIONS
  ARM64: Enable multi-core scheduler support by default
  arm64/efi: move arm64 specific stub C code to libstub
  arm64: page-align sections for DEBUG_RODATA
  arm64: Fix build with CONFIG_ZONE_DMA=n
  arm64: Fix compat register mappings
  arm64: Increase the max granular size
  arm64: remove bogus TASK_SIZE_64 check
  arm64: make Timer Interrupt Frequency selectable
  arm64/mm: use PAGE_ALIGNED instead of IS_ALIGNED
  arm64: cachetype: fix definitions of ICACHEF_* flags
  arm64: cpufeature: declare enable_cpu_capabilities as static
  genirq: Make the cpuhotplug migration code less noisy
  arm64: Constify hwcap name string arrays
  arm64/kvm: Make use of the system wide safe values
  arm64/debug: Make use of the system wide safe value
  arm64: Move FP/ASIMD hwcap handling to common code
  arm64/HWCAP: Use system wide safe values
  arm64/capabilities: Make use of system wide safe value
  arm64: Delay cpu feature capability checks
  ...
2015-11-04 14:47:13 -08:00
Suzuki K. Poulose
4bf8b96ed3 arm64: Check for selected granule support
Ensure that the selected page size is supported by the CPU(s). If it doesn't
park it.

Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-19 17:54:34 +01:00
Suzuki K. Poulose
6a3fd4026c arm64: Handle 4 level page table for swapper
At the moment, we only support maximum of 3-level page table for
swapper. With 48bit VA, 64K has only 3 levels and 4K uses section
mapping. Add support for 4-level page table for swapper, needed
by 16K pages.

Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-19 17:53:41 +01:00
Suzuki K. Poulose
87d1587bef arm64: Move swapper pagetable definitions
Move the kernel pagetable (both swapper and idmap) definitions
from the generic asm/page.h to a new file, asm/kernel-pgtable.h.

This is mostly a cosmetic change, to clean up the asm/page.h to
get rid of the arch specific details which are not needed by the
generic code.

Also renames the symbols to prevent conflicts. e.g,
 	BLOCK_SHIFT => SWAPPER_BLOCK_SHIFT

Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-19 17:52:14 +01:00
Andrey Ryabinin
39d114ddc6 arm64: add KASAN support
This patch adds arch specific code for kernel address sanitizer
(see Documentation/kasan.txt).

1/8 of kernel addresses reserved for shadow memory. There was no
big enough hole for this, so virtual addresses for shadow were
stolen from vmalloc area.

At early boot stage the whole shadow region populated with just
one physical page (kasan_zero_page). Later, this page reused
as readonly zero shadow for some memory that KASan currently
don't track (vmalloc).
After mapping the physical memory, pages for shadow memory are
allocated and mapped.

Functions like memset/memmove/memcpy do a lot of memory accesses.
If bad pointer passed to one of these function it is important
to catch this. Compiler's instrumentation cannot do this since
these functions are written in assembly.
KASan replaces memory functions with manually instrumented variants.
Original functions declared as weak symbols so strong definitions
in mm/kasan/kasan.c could replace them. Original functions have aliases
with '__' prefix in name, so we could call non-instrumented variant
if needed.
Some files built without kasan instrumentation (e.g. mm/slub.c).
Original mem* function replaced (via #define) with prefixed variants
to disable memory access checks for such files.

Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 17:46:36 +01:00
Ard Biesheuvel
e8f3010f73 arm64/efi: isolate EFI stub from the kernel proper
Since arm64 does not use a builtin decompressor, the EFI stub is built
into the kernel proper. So far, this has been working fine, but actually,
since the stub is in fact a PE/COFF relocatable binary that is executed
at an unknown offset in the 1:1 mapping provided by the UEFI firmware, we
should not be seamlessly sharing code with the kernel proper, which is a
position dependent executable linked at a high virtual offset.

So instead, separate the contents of libstub and its dependencies, by
putting them into their own namespace by prefixing all of its symbols
with __efistub. This way, we have tight control over what parts of the
kernel proper are referenced by the stub.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-12 16:20:12 +01:00
Marc Zyngier
d271976dbb arm64: el2_setup: Make sure ICC_SRE_EL2.SRE sticks before using GICv3 sysregs
Contrary to what was originally expected, EL3 firmware can (for whatever
reason) disable GICv3 system register access. In this case, the kernel
explodes very early.

Work around this by testing if the SRE bit sticks or not. If it doesn't,
abort the GICv3 setup, and pray that the firmware has passed a DT that
doesn't contain a GICv3 node.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2015-10-09 22:16:51 +01:00
Will Deacon
d10bcd4733 arm64: head.S: initialise mdcr_el2 in el2_setup
When entering the kernel at EL2, we fail to initialise the MDCR_EL2
register which controls debug access and PMU capabilities at EL1.

This patch ensures that the register is initialised so that all traps
are disabled and all the PMU counters are available to the host. When a
guest is scheduled, KVM takes care to configure trapping appropriately.

Cc: <stable@vger.kernel.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-09-15 15:50:01 +01:00
Will Deacon
8ec4198743 arm64: mm: ensure patched kernel text is fetched from PoU
The arm64 booting document requires that the bootloader has cleaned the
kernel image to the PoC. However, when a CPU re-enters the kernel due to
either a CPU hotplug "on" event or resuming from a low-power state (e.g.
cpuidle), the kernel text may in-fact be dirty at the PoU due to things
like alternative patching or even module loading.

Thanks to I-cache speculation with the MMU off, stale instructions could
be fetched prior to enabling the MMU, potentially leading to crashes
when executing regions of code that have been modified at runtime.

This patch addresses the issue by ensuring that the local I-cache is
invalidated immediately after a CPU has enabled its MMU but before
jumping out of the identity mapping. Any stale instructions fetched from
the PoC will then be discarded and refetched correctly from the PoU.
Patching kernel text executed prior to the MMU being enabled is
prohibited, so the early entry code will always be clean.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-08-05 10:05:20 +01:00
Will Deacon
4b3dc9679c arm64: force CONFIG_SMP=y and remove redundant #ifdefs
Nobody seems to be producing !SMP systems anymore, so this is just
becoming a source of kernel bugs, particularly if people want to use
coherent DMA with non-shared pages.

This patch forces CONFIG_SMP=y for arm64, removing a modest amount of
code in the process.

Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-07-27 11:08:40 +01:00
Ard Biesheuvel
5dfe9d7d23 arm64: reduce ID map to a single page
Commit ea8c2e1124 ("arm64: Extend the idmap to the whole kernel
image") changed the early page table code so that the entire kernel
Image is covered by the identity map. This allows functions that
need to enable or disable the MMU to reside anywhere in the kernel
Image.

However, this change has the unfortunate side effect that the Image
cannot cross a physical 512 MB alignment boundary anymore, since the
early page table code cannot deal with the Image crossing a /virtual/
512 MB alignment boundary.

So instead, reduce the ID map to a single page, that is populated by
the contents of the .idmap.text section. Only three functions reside
there at the moment: __enable_mmu(), cpu_resume_mmu() and cpu_reset().
If new code is introduced that needs to manipulate the MMU state, it
should be added to this section as well.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-06-02 17:44:51 +01:00
Ard Biesheuvel
61bd93ce80 arm64: use fixmap region for permanent FDT mapping
Currently, the FDT blob needs to be in the same 512 MB region as
the kernel, so that it can be mapped into the kernel virtual memory
space very early on using a minimal set of statically allocated
translation tables.

Now that we have early fixmap support, we can relax this restriction,
by moving the permanent FDT mapping to the fixmap region instead.
This way, the FDT blob may be anywhere in memory.

This also moves the vetting of the FDT to mmu.c, since the early
init code in head.S does not handle mapping of the FDT anymore.
At the same time, fix up some comments in head.S that have gone stale.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-06-02 16:31:33 +01:00
Mark Rutland
0c20856c26 arm64: head.S: ensure idmap_t0sz is visible
We write idmap_t0sz with SCTLR_EL1.{C,M} clear, but we only have the
guarnatee that the kernel Image is clean, not invalid in the caches, and
therefore we might read a stale value once the MMU is enabled.

This patch ensures we invalidate the corresponding cacheline after the
write as we do for all other data written before we set SCTLR_EL1.{C.M},
guaranteeing that the value will be visible later. We rely on the DSBs
in __create_page_tables to complete the maintenance.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-24 15:13:58 +00:00
Mark Rutland
91d57155dc arm64: head.S: ensure visibility of page tables
After writing the page tables, we use __inval_cache_range to invalidate
any stale cache entries. Strongly Ordered memory accesses are not
ordered w.r.t. cache maintenance instructions, and hence explicit memory
barriers are required to provide this ordering. However,
__inval_cache_range was written to be used on Normal Cacheable memory
once the MMU and caches are on, and does not have any barriers prior to
the DC instructions.

This patch adds a DMB between the page tables being written and the
corresponding cachelines being invalidated, ensuring that the
invalidation makes the new data visible to subsequent cacheable
accesses. A barrier is not required before the prior invalidate as we do
not access the page table memory area prior to this, and earlier
barriers in preserve_boot_args and set_cpu_boot_mode_flag ensures
ordering w.r.t. any stores performed prior to entering Linux.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: c218bca74e ("arm64: Relax the kernel cache requirements for boot")
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-24 14:36:35 +00:00
Ard Biesheuvel
dd006da216 arm64: mm: increase VA range of identity map
The page size and the number of translation levels, and hence the supported
virtual address range, are build-time configurables on arm64 whose optimal
values are use case dependent. However, in the current implementation, if
the system's RAM is located at a very high offset, the virtual address range
needs to reflect that merely because the identity mapping, which is only used
to enable or disable the MMU, requires the extended virtual range to map the
physical memory at an equal virtual offset.

This patch relaxes that requirement, by increasing the number of translation
levels for the identity mapping only, and only when actually needed, i.e.,
when system RAM's offset is found to be out of reach at runtime.

Tested-by: Laura Abbott <lauraa@codeaurora.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-23 11:35:29 +00:00
Ard Biesheuvel
da9c177de8 arm64: enforce x1|x2|x3 == 0 upon kernel entry as per boot protocol
According to the arm64 boot protocol, registers x1 to x3 should be
zero upon kernel entry, and non-zero values are reserved for future
use. This future use is going to be problematic if we never enforce
the current rules, so start enforcing them now, by emitting a warning
if non-zero values are detected.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:02 +00:00
Ard Biesheuvel
6f4d57fa70 arm64: remove __calc_phys_offset
This removes the function __calc_phys_offset and all open coded
virtual to physical address translations using the offset kept
in x28.

Instead, just use absolute or PC-relative symbol references as
appropriate when referring to virtual or physical addresses,
respectively.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:02 +00:00
Ard Biesheuvel
8b0a95753a arm64: merge __enable_mmu and __turn_mmu_on
Enabling of the MMU is split into two functions, with an align and
a branch in the middle. On arm64, the entire kernel Image is ID mapped
so this is really not necessary, and we can just merge it into a
single function.

Also replaces an open coded adrp/add reference to __enable_mmu pair
with adr_l.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:02 +00:00
Ard Biesheuvel
b1c98297fe arm64: use PC-relative reference for secondary_holding_pen_release
Replace the confusing virtual/physical address arithmetic with a simple
PC-relative reference.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:01 +00:00
Ard Biesheuvel
a871d354f7 arm64: remove __switch_data object from head.S
This removes the confusing __switch_data object from head.S,
and replaces it with standard PC-relative references to the
various symbols it encapsulates.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:01 +00:00
Ard Biesheuvel
a44ef51799 arm64: remove processor_id
The global processor_id is assigned the MIDR_EL1 value of the boot
CPU in the early init code, but is never referenced afterwards.

As the relevance of the MIDR_EL1 value of the boot CPU is debatable
anyway, especially under big.LITTLE, let's remove it before anyone
starts using it.

Tested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:01 +00:00
Marc Zyngier
a591ede4cd arm64: Get rid of struct cpu_table
struct cpu_table is an artifact left from the (very) early days of
the arm64 port, and its only real use is to allow the most beautiful
"AArch64 Processor" string to be displayed at boot time.

Really? Yes, really.

Let's get rid of it. In order to avoid another BogoMips-gate, the
aforementioned string is preserved.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2015-03-19 19:46:00 +00:00