linux.git/arch/mips/kernel/head.S, branch v6.8

MIPS: of: Introduce helper function to get DTB

2021-02-04T12:34:51+00:00

Selection of the DTB to be used was burried in more or less readable
code in head.S. Move this code into a inline helper function and
use it.

Signed-off-by: Thomas Bogendoerfer 
Acked-by: Florian Fainelli

MIPS: Loongson-3: Enable COP2 usage in kernel

2020-09-21T20:15:03+00:00

Loongson-3's COP2 is Multi-Media coprocessor, it is disabled in kernel
mode by default. However, gslq/gssq (16-bytes load/store instructions)
overrides the instruction format of lwc2/swc2. If we wan't to use gslq/
gssq for optimization in kernel, we should enable COP2 usage in kernel.

Please pay attention that in this patch we only enable COP2 in kernel,
which means it will lose ST0_CU2 when a process go to user space (try
to use COP2 in user space will trigger an exception and then grab COP2,
which is similar to FPU). And as a result, we need to modify the context
switching code because the new scheduled process doesn't contain ST0_CU2
in its THERAD_STATUS probably.

For zboot, we disable gslq/gssq be generated by toolchain.

Signed-off-by: Huacai Chen 
Signed-off-by: Thomas Bogendoerfer

MIPS: head.S: Init fw_passed_dtb to builtin DTB

2020-07-31T15:48:02+00:00

Init the 'fw_passed_dtb' pointer to the buit-in Device Tree blob when it
has been compiled in with CONFIG_BUILTIN_DTB.

Signed-off-by: Paul Cercueil 
Signed-off-by: Thomas Bogendoerfer

MIPS: Clear XContext at boot time

2020-04-24T16:37:23+00:00

XContext might be dirty at boot time. We need to clear it
to ensure early stackframe is safe.

Signed-off-by: Jiaxun Yang 
Signed-off-by: Thomas Bogendoerfer

MIPS/head: Store ELF appended dtb in a global variable too

2018-09-25T23:27:24+00:00

Since commit 15f37e158892 ("MIPS: store the appended
dtb address in a variable"),
in kernels with MIPS_RAW_APPENDED_DTB=y, the early boot code detects
the dtb and stores it in the 'fw_passed_dtb' variable.

However, the dtb is not stored in 'fw_passed_dtb' in kernels with
MIPS_ELF_APPENDED_DTB=y.

Under MIPS_ELF_APPENDED_DTB=y, the dtb is also located in the
__appended_dtb section, so we just need to update the #ifdef.

This will allow to access the dtb in a more uniform way.

Fixes: 15f37e158892 ("MIPS: store the appended dtb address in a variable")
Signed-off-by: Yasha Cherikovsky 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20803/
Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org

MIPS/head: Add comments after #endif and #else

2018-09-25T23:27:19+00:00

It makes the code more readable, especially in the nested ifdefs.

Signed-off-by: Yasha Cherikovsky 
Signed-off-by: Paul Burton 
Patchwork: https://patchwork.linux-mips.org/patch/20802/
Cc: Ralf Baechle 
Cc: Paul Burton 
Cc: James Hogan 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org

MIPS: head: Reorder instructions missing a delay slot

2017-06-27T21:35:21+00:00

In this sequence the 'move' is assumed in the delay slot of the 'beq',
but head.S is in reorder mode and the former gets pushed one 'nop'
farther by the assembler.

The corrected behavior made booting with an UHI supplied dtb erratic.

Fixes: 15f37e158892 ("MIPS: store the appended dtb address in a variable")
Signed-off-by: Karl Beldan 
Reviewed-by: James Hogan 
Cc: Jonas Gorski 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16614/
Signed-off-by: Ralf Baechle

MIPS: store the appended dtb address in a variable

2016-08-02T12:00:16+00:00

Instead of rewriting the arguments to match the UHI spec, store the
address of a appended or UHI supplied dtb in fw_supplied_dtb.

That way the original bootloader arugments are kept intact while still
making the use of an appended dtb invisible for mach code.

Mach code can still find out if it is an appended dtb by comparing
fw_arg1 with fw_supplied_dtb.

Signed-off-by: Jonas Gorski 
Cc: Kevin Cernekee 
Cc: Florian Fainelli 
Cc: John Crispin 
Cc: Paul Burton 
Cc: James Hogan 
Cc: Alban Bedel 
Cc: Daniel Gimpelevich 
Cc: Antony Pavlov 
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13699/
Signed-off-by: Ralf Baechle

MIPS: Remove redundant asm/pgtable-bits.h inclusions

2016-05-13T13:30:25+00:00

asm/pgtable-bits.h is included in 2 assembly files and thus has to
ifdef around C code, however nothing defined by the header is used
in either of the assembly files that include it.

Remove the redundant inclusions such that asm/pgtable-bits.h doesn't
need to #ifdef around C code, for cleanliness and in preparation for
later patches which will add more C.

Signed-off-by: Paul Burton 
Reviewed-by: James Hogan 
Cc: Maciej W. Rozycki 
Cc: Jonas Gorski 
Cc: Alex Smith 
Cc: Kirill A. Shutemov 
Cc: Andrew Morton 
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13114/
Signed-off-by: Ralf Baechle

MIPS: Call relocate_kernel if CONFIG_RELOCATABLE=y

2016-05-13T12:02:03+00:00

If CONFIG_RELOCATABLE is enabled, call relocate_kernel.

This function will return the entry point of the relocated kernel if
copy/relocate is sucessful or the original entry point if not. The stack
pointer must then be pointed into the new image.

Signed-off-by: Matt Redfearn 
Cc: Jonas Gorski 
Cc: linux-mips@linux-mips.org
Cc: kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12984/
Signed-off-by: Ralf Baechle