On MIPS, __current_thread_info is defined as global register variable
locating in $gp, and is simply assigned with new address during kernel
relocation.
This however is broken with LLVM, which always restores $gp if it finds
$gp is clobbered in any form, including when intentionally through a
global register variable. This is against GCC's documentation[1], which
requires a callee-saved register used as global register variable not to
be restored if it's clobbered.
As a result, $gp will continue to point to the unrelocated kernel after
the epilog of relocate_kernel(), leading to an early crash in init_idle,
[ 0.000000] CPU 0 Unable to handle kernel paging request at virtual address 0000000000000000, epc == ffffffff81afada8, ra == ffffffff81afad90
[ 0.000000] Oops[#1]:
[ 0.000000] CPU: 0 UID: 0 PID: 0 Comm: swapper Tainted: G W 6.19.0-rc5-00262-gd3eeb99bbc99-dirty #188 VOLUNTARY
[ 0.000000] Tainted: [W]=WARN
[ 0.000000] Hardware name: loongson,loongson64v-4core-virtio
[ 0.000000] $ 0 : 0000000000000000 0000000000000000 0000000000000001 0000000000000000
[ 0.000000] $ 4 : ffffffff80b80ec0 ffffffff80b53d48 0000000000000000 00000000000f4240
[ 0.000000] $ 8 : 0000000000000100 ffffffff81d82f80 ffffffff81d82f80 0000000000000001
[ 0.000000] $12 : 0000000000000000 ffffffff81776f58 00000000000005da 0000000000000002
[ 0.000000] $16 : ffffffff80b80e40 0000000000000000 ffffffff80b81614 9800000005dfbe80
[ 0.000000] $20 : 00000000540000e0 ffffffff81980000 0000000000000000 ffffffff80f81c80
[ 0.000000] $24 : 0000000000000a26 ffffffff8114fb90
[ 0.000000] $28 : ffffffff80b50000 ffffffff80b53d40 0000000000000000 ffffffff81afad90
[ 0.000000] Hi : 0000000000000000
[ 0.000000] Lo : 0000000000000000
[ 0.000000] epc : ffffffff81afada8 init_idle+0x130/0x270
[ 0.000000] ra : ffffffff81afad90 init_idle+0x118/0x270
[ 0.000000] Status: 540000e2 KX SX UX KERNEL EXL
[ 0.000000] Cause : 00000008 (ExcCode 02)
[ 0.000000] BadVA : 0000000000000000
[ 0.000000] PrId : 00006305 (ICT Loongson-3)
[ 0.000000] Process swapper (pid: 0, threadinfo=(____ptrval____), task=(____ptrval____), tls=0000000000000000)
[ 0.000000] Stack : 9800000005dfbf00 ffffffff8178e950 0000000000000000 0000000000000000
[ 0.000000] 0000000000000000 ffffffff81970000 000000000000003f ffffffff810a6528
[ 0.000000] 0000000000000001 9800000005dfbe80 9800000005dfbf00 ffffffff81980000
[ 0.000000] ffffffff810a6450 ffffffff81afb6c0 0000000000000000 ffffffff810a2258
[ 0.000000] ffffffff81d82ec8 ffffffff8198d010 ffffffff81b67e80 ffffffff8197dd98
[ 0.000000] ffffffff81d81c80 ffffffff81930000 0000000000000040 0000000000000000
[ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 0.000000] 0000000000000000 000000000000009e ffffffff9fc01000 0000000000000000
[ 0.000000] 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 0.000000] 0000000000000000 ffffffff81ae86dc ffffffff81b3c741 0000000000000002
[ 0.000000] ...
[ 0.000000] Call Trace:
[ 0.000000] [<ffffffff81afada8>] init_idle+0x130/0x270
[ 0.000000] [<ffffffff81afb6c0>] sched_init+0x5c8/0x6c0
[ 0.000000] [<ffffffff81ae86dc>] start_kernel+0x27c/0x7a8
This bug has been reported to LLVM[2] and affects version from (at
least) 18 to 21. Let's work around this by using inline assembly to
assign $gp before a fix is widely available.
Cc: stable@vger.kernel.org
Link: https://gcc.gnu.org/onlinedocs/gcc-15.2.0/gcc/Global-Register-Variables.html # [1]
Link: https://github.com/llvm/llvm-project/issues/176546 # [2]
Signed-off-by: Yao Zi <me@ziyao.cc>
Acked-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Loongson2ef reserves io range below 0x4000 (LOONGSON_PCI_IO_START) while
ISA-mode only IDE controller on the south bridge still has a hard
dependency on ISA IO ports.
The reservation was done by lifting loongson_pci_io_resource.start onto
0x4000. Prior to commit ae81aad5c2e1 ("MIPS: PCI: Use
pci_enable_resources()"), the arch specific pcibios_enable_resources()
did not check if the resources were claimed, which diverges from what
PCI core checks, effectively hiding the fact that IDE IO resources were
not properly within the resource tree. After starting to use
pcibios_enable_resources() from PCI core, enabling IDE controller fails:
pata_cs5536 0000:00:0e.2: BAR 0 [io 0x01f0-0x01f7]: not claimed; can't enable device
pata_cs5536 0000:00:0e.2: probe with driver pata_cs5536 failed with error -22
MIPS PCI code already has support for enforcing lower bounds using
PCIBIOS_MIN_IO in pcibios_align_resource() without altering the IO
window start address itself. Make Loongson2ef PCI code use
PCIBIOS_MIN_IO too.
Fixes: ae81aad5c2e1 ("MIPS: PCI: Use pci_enable_resources()")
Cc: stable@vger.kernel.org
Tested-by: Beiyan Yun <root@infi.wang>
Tested-by: Yao Zi <me@ziyao.cc>
Signed-off-by: Rong Zhang <rongrong@oss.cipunited.com>
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
We are about to set loongson_pci_io_resource.start to 0 and adopt
PCIBIOS_MIN_IO. As the first step, PCI controller needs to be registered
in early stage to make it the root of other resources (e.g., i8259) and
prevent resource conflicts.
Register it in plat_mem_setup() instead of arch_initcall().
Fixes: ae81aad5c2e1 ("MIPS: PCI: Use pci_enable_resources()")
Cc: stable@vger.kernel.org
Tested-by: Beiyan Yun <root@infi.wang>
Tested-by: Yao Zi <me@ziyao.cc>
Signed-off-by: Rong Zhang <rongrong@oss.cipunited.com>
Acked-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Commit 69896119dc9d ("MIPS: vdso: Switch to generic storage
implementation") switches to a generic vdso storage, which increases
the number of data pages from 1 to 4. But there is only one page
reserved, which causes segementation faults depending where the VDSO
area is randomized to. To fix this use the same size of reservation
and allocation of the VDSO data pages.
Fixes: 69896119dc9d ("MIPS: vdso: Switch to generic storage implementation")
Reviewed-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
When KCOV is enabled all functions get instrumented, unless
the __no_sanitize_coverage attribute is used. To prepare for
__no_sanitize_coverage being applied to __init functions, we
have to handle differences in how GCC's inline optimizations get
resolved. For mips this requires adding the __init annotation on
init_mips_clocksource().
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20250717232519.2984886-9-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
mc146818_get_cmos_time() is now mostly equivalent to mc146818_get_time()
from drivers/rtc/rtc-mc146818-lib.c, with the latter using a more
advanced algorithm (which checks the UIP bit in the CMOS). The Malta
and Loongson2ef platforms, the only users of mc146818_get_cmos_time()
have RTC devices that should be MC146818 compatible.
So, rewrite mc146818_get_cmos_time() in a way that uses
mc146818_get_time() and add CONFIG_RTC_MC146818_LIB as a dependency of
CONFIG_MIPS_MALTA and CONFIG_CPU_LOONGSON2EF.
The should be safe as:
- malta_defconfig already uses a standard RTC CMOS driver
(CONFIG_RTC_DRV_CMOS=y). The Malta board has an Intel 82371EB (PIIX4E)
south bridge with the CMOS RTC, so should work correctly with the
modification,
- Loongson2e and 2f apparently use the VIA686B south bridge and the AMD
CS5536 south bridge respectively (at least according to Kconfig). I
have checked datasheets of both and these appear to be MC146818
software compatible.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The mc146818_decode_year macro is used only in mc146818_get_cmos_time(),
which in turn is called only in
arch/mips/loongson2ef/common/time.c
and
arch/mips/mti-malta/malta-time.c
so on mach-jazz it is unused and can be removed. On other platforms it
is defined in the same way, so it can be safely folded into
mc146818_get_cmos_time().
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
The mc146818_decode_year macro is used only in mc146818_get_cmos_time,
which in turn is called only in
arch/mips/loongson2ef/common/time.c
and
arch/mips/mti-malta/malta-time.c
So no SNI or mach-rm content. SNI did not use mc146818_get_cmos_time
apparently since
commit 06cf5583fd9a ("[MIPS] SNI RM updates")
in 2007.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
I have checked carefully: this function is unused, so remove it.
The last caller appears to have been removed in 2007 in
commit 4b550488f894 ("[MIPS] Deforest the function pointer jungle in the time code.")
mc146818-time.h is included only in three files:
- arch/mips/mti-malta/malta-time.c
- arch/mips/loongson64/numa.c
- arch/mips/loongson2ef/common/time.c
Also, remove unused macros USEC_AFTER/USEC_BEFORE.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Not all tasks have an ABI associated or vDSO mapped,
for example kthreads never do.
If such a task ever ends up calling stack_top(), it will derefence the
NULL ABI pointer and crash.
This can for example happen when using kunit:
mips_stack_top+0x28/0xc0
arch_pick_mmap_layout+0x190/0x220
kunit_vm_mmap_init+0xf8/0x138
__kunit_add_resource+0x40/0xa8
kunit_vm_mmap+0x88/0xd8
usercopy_test_init+0xb8/0x240
kunit_try_run_case+0x5c/0x1a8
kunit_generic_run_threadfn_adapter+0x28/0x50
kthread+0x118/0x240
ret_from_kernel_thread+0x14/0x1c
Only dereference the ABI point if it is set.
The GIC page is also included as it is specific to the vDSO.
Also move the randomization adjustment into the same conditional.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
After commit a934a57a42f64a4 ("scripts/misc-check: check missing #include
<linux/export.h> when W=1") and 7d95680d64ac8e836c ("scripts/misc-check:
check unnecessary #include <linux/export.h> when W=1"), we get some build
warnings with W=1:
arch/mips/loongson64/setup.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present
So fix these build warnings for MIPS/Loongson.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Fix the dtc warnings:
arch/mips/boot/dts/loongson/ls7a-pch.dtsi:68.16-416.5: Warning (interrupt_provider): /bus@10000000/pci@1a000000: '#interrupt-cells' found, but node is not an interrupt provider
arch/mips/boot/dts/loongson/ls7a-pch.dtsi:68.16-416.5: Warning (interrupt_provider): /bus@10000000/pci@1a000000: '#interrupt-cells' found, but node is not an interrupt provider
arch/mips/boot/dts/loongson/loongson64g_4core_ls7a.dtb: Warning (interrupt_map): Failed prerequisite 'interrupt_provider'
And a runtime warning introduced in commit 045b14ca5c36 ("of: WARN on
deprecated #address-cells/#size-cells handling"):
WARNING: CPU: 0 PID: 1 at drivers/of/base.c:106 of_bus_n_addr_cells+0x9c/0xe0
Missing '#address-cells' in /bus@10000000/pci@1a000000/pci_bridge@9,0
The fix is similar to commit d89a415ff8d5 ("MIPS: Loongson64: DTS: Fix PCIe
port nodes for ls7a"), which has fixed the issue for ls2k (despite its
subject mentions ls7a).
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: michael <michael5hzg@gmail.com>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
Yao Zi