linux-toradex.git/arch/mips/kernel/r4k_fpu.S, branch v3.15.6

Revert "MIPS: Save/restore MSA context around signals"

2014-07-07T01:59:09+00:00

commit 16f77de82f2d2f628306dab9bc4799df0d28a199 upstream.

This reverts commit eec43a224cf1 "MIPS: Save/restore MSA context around
signals" and the MSA parts of ca750649e08c "MIPS: kernel: signal:
Prevent save/restore FPU context in user memory" (the restore path of
which appears incorrect anyway...).

The reverted patch took care not to break compatibility with userland
users of struct sigcontext, but inadvertantly changed the offset of the
uc_sigmask field of struct ucontext. Thus Linux v3.15 breaks the
userland ABI. The MSA context will need to be saved via some other
opt-in mechanism, but for now revert the change to reduce the fallout.

This will have minimal impact upon use of MSA since the only supported
CPU which includes it (the P5600) is 32-bit and therefore requires that
the experimental CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option be selected
before the kernel will set FR=1 for a task, a requirement for MSA use.
Thus the users of MSA are limited to known small groups of people & this
patch won't be breaking any previously working MSA-using userland
outside of experimental settings.

[ralf@linux-mips.org: Fixed rejects.]

Reported-by: Joseph S. Myers 
Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7107/
Signed-off-by: Ralf Baechle 
Signed-off-by: Greg Kroah-Hartman

Merge branch '3.14-fixes' into mips-for-linux-next

2014-03-31T16:17:33+00:00

MIPS: Fix gigaton of warning building with microMIPS.

2014-03-31T16:17:12+00:00

With binutils 2.24 the attempt to switch with microMIPS mode to MIPS III
mode through .set mips3 results in *lots* of warnings like

{standard input}: Assembler messages:
{standard input}:397: Warning: the 64-bit MIPS architecture does not support the `smartmips' extension

during a kernel build.  Fixed by using .set arch=r4000 instead.

This breaks support for building the kernel with binutils 2.13 which
was supported for 32 bit kernels only anyway and 2.14 which was a bad
vintage for MIPS anyway.

Signed-off-by: Ralf Baechle

MIPS: Save/restore MSA context around signals

2014-03-26T22:09:11+00:00

This patch extends sigcontext in order to hold the most significant 64
bits of each vector register in addition to the MSA control & status
register. The least significant 64 bits are already saved as the scalar
FP context. This makes things a little awkward since the least & most
significant 64 bits of each vector register are not contiguous in
memory. Thus the copy_u & insert instructions are used to transfer the
values of the most significant 64 bits via GP registers.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6533/
Signed-off-by: Ralf Baechle

MIPS: FPU: Fix conflict of register usage

2014-03-14T16:49:23+00:00

In _restore_fp_context/_restore_fp_context32, t0 is used for both
CP0_Status and CP1_FCSR. This is a mistake and cause FP exeception on
boot, so fix it.

Signed-off-by: Huacai Chen 
Tested-by: Aaro Koskinen 
Tested-by: Andreas Barth 
Cc: John Crispin 
Cc: Steven J. Hill 
Cc: Aurelien Jarno 
Cc: linux-mips@linux-mips.org
Cc: Fuxin Zhang 
Cc: Zhangjin Wu 
Patchwork: https://patchwork.linux-mips.org/patch/6507/
Signed-off-by: Ralf Baechle

MIPS: Replace CONFIG_MIPS64 and CONFIG_MIPS32_R2

2014-03-14T16:49:16+00:00

Commit 597ce1723e0f ("MIPS: Support for 64-bit FP with O32 binaries")
introduced references to two undefined Kconfig macros. CONFIG_MIPS32_R2
should clearly be replaced with CONFIG_CPU_MIPS32_R2. And CONFIG_MIPS64
should be replaced with CONFIG_64BIT.

Signed-off-by: Paul Bolle 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/6522/
Tested-by: Aaro Koskinen 
Signed-off-by: Ralf Baechle

MIPS: Support for 64-bit FP with O32 binaries

2014-01-13T22:40:56+00:00

CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs
do. In order to preserve backwards compatibility a 64-bit FPU will act
like a 32-bit FPU (by accessing doubles from the least significant 32
bits of an even-odd pair of FP registers) when the Status.FR bit is
zero, again just like a mips64 CPU. The standard O32 ABI is defined
expecting a 32-bit FPU, however recent toolchains support use of a
64-bit FPU from an O32 MIPS32 executable. When an ELF executable is
built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF
header.

With this patch the kernel will check the EF_MIPS_FP64 flag when
executing an O32 binary, and set Status.FR accordingly. The addition
of O32 64-bit FP support lessens the opportunity for optimisation in
the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is
introduced to allow this support to be disabled for those that don't
require it.

Inspired by an earlier patch by Leonid Yegoshin, but implemented more
cleanly & correctly.

Signed-off-by: Paul Burton 
Cc: linux-mips@linux-mips.org
Cc: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/6154/
Signed-off-by: Ralf Baechle

update David Miller's old email address

2011-04-06T13:19:38+00:00

Signed-off-by: Justin P. Mattock 
Acked-by: David S. Miller 
Signed-off-by: Jiri Kosina

[MIPS] Check FCSR for pending interrupts, alternative version

2007-03-17T01:03:25+00:00

Commit 6d6671066a311703bca1b91645bb1e04cc983387 is incomplete and misses
non-r4k CPUs.  This patch reverts the commit and fixes in other way.

 o Do FCSR checking in caller of restore_fp_context.
 o Send SIGFPE if the signal handler set any FPU exception bits.

Signed-off-by: Atsushi Nemoto 
Signed-off-by: Ralf Baechle

[MIPS] Move .set reorder out of conditional code

2007-02-06T16:53:23+00:00

Signed-off-by: Chris Dearman 
Signed-off-by: Ralf Baechle