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CONFIG_VFPv3 set
commit 39141ddfb63a664f26d3f42f64ee386e879b492c upstream.
After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix
saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board
started crashing during boot with omap2plus_defconfig:
[ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB
[ 3.915954] mmcblk0: p1
[ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM
[ 4.093719] Modules linked in:
[ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570)
[ 4.103149] PC is at vfp_reload_hw+0x1c/0x44
[ 4.107666] LR is at __und_usr_fault_32+0x0/0x8
It turns out that the context save/restore fix unmasked a latent bug
in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make
VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is
booted on a pre-VFPv3 core, the code attempts to save and restore the
d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so
this results in an undefined instruction exception. The code didn't
crash before commit 846a136 because the save and restore code was
only touching d0-d15, present on all VFP.
Fix by implementing a request from Russell King to add a new HWCAP
flag that affirmatively indicates the presence of the d16-d31
registers:
http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2
and some feedback from Måns to clarify the name of the HWCAP flag.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Martin <dave.martin@linaro.org>
Cc: Måns Rullgård <mans.rullgard@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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Modern ARMv7-A cores can optionally implement these new hardware
features:
- VFPv4:
The latest version of the ARMv7 vector floating-point extensions,
including hardware support for fused multiple accumulate. D16 or D32
variants may be implemented.
- Integer divide:
The SDIV and UDIV instructions provide signed and unsigned integer
division in hardware. When implemented, these instructions may be
available in either both Thumb and ARM, or Thumb only.
This patch adds new HWCAP defines to describe these new features. The
integer divide capabilities are split into two bits for ARM and Thumb
respectively. Whilst HWCAP_IDIVA should never be set if HWCAP_IDIVT is
clear, separating the bits makes it easier to interpret from userspace.
Signed-off-by: Will Deacon <will.deacon@arm.com>
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The HWCAP numbers are defined as constants, each one being a power of 2.
This has become slightly unwieldy now that we have reached 32k.
This patch changes the HWCAP defines to use (1 << n) instead of coding
the constant directly. The values remain unchanged.
Signed-off-by: Will Deacon <will.deacon@arm.com>
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The TLS register is only available on ARM1136 r1p0 and later.
Set HWCAP_TLS flags if hardware TLS is available and test for
it if CONFIG_CPU_32v6K is not set for V6.
Note that we set the TLS instruction in __kuser_get_tls
dynamically as suggested by Jamie Lokier <jamie@shareable.org>.
Also the __switch_to code is optimized out in most cases as
suggested by Nicolas Pitre <nico@fluxnic.net>.
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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The VFPv3D16 is a VFPv3 CPU configuration where only 16 double registers
are present, as the VFPv2 configuration. This patch adds the
corresponding hwcap bits so that applications or debuggers have more
information about the supported features.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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