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bc6e8dc112
linux/arch/mips/kernel
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WANG Xuerui bc6e8dc112 MIPS: handle Loongson-specific GSExc exception 
Newer Loongson cores (Loongson-3A R2 and newer) use the
implementation-dependent ExcCode 16 to signal Loongson-specific
exceptions. The extended cause is put in the non-standard CP0.Diag1
register which is CP0 Register 22 Select 1, called GSCause in Loongson
manuals. Inside is an exception code bitfield called GSExcCode, only
codes 0 to 6 inclusive are documented (so far, in the Loongson 3A3000
User Manual, Volume 2).

During experiments, it was found that some undocumented unprivileged
instructions can trigger the also-undocumented GSExcCode 8 on Loongson
3A4000. Processor state is not corrupted, but we cannot continue without
further knowledge, and Loongson is not providing that information as of
this writing. So we send SIGILL on seeing this exception code to thwart
easy local DoS attacks.

Other exception codes are made fatal, partly because of insufficient
knowledge, also partly because they are not as easily reproduced. None
of them are encountered in the wild with upstream kernels and userspace
so far.

Some older cores (Loongson-3A1000 and Loongson-3B1500) have ExcCode 16
too, but the semantic is equivalent to GSExcCode 0. Because the
respective manuals did not mention the CP0.Diag1 register or its read
behavior, these cores are not covered in this patch, as MFC0 from
non-existent CP0 registers is UNDEFINED according to the MIPS
architecture spec.

Reviewed-by: Huacai Chen <chenhc@lemote.com>
Signed-off-by: WANG Xuerui <git@xen0n.name>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2020-07-31 17:52:47 +02:00
..
syscalls vfs: add faccessat2 syscall 2020-05-14 16:44:25 +02:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
asm-offsets.c MIPS: Remove struct task_struct fpu state when CONFIG_MIPS_FP_SUPPORT=n 2018-11-09 10:23:19 -08:00
binfmt_elfn32.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
binfmt_elfo32.c y2038: elfcore: Use __kernel_old_timeval for process times 2019-11-15 14:38:29 +01:00
bmips_5xxx_init.S MIPS: BCM5xxx: Remove dead init_fpu code 2018-11-08 11:20:57 -08:00
bmips_vec.S
branch.c MIPS: Use fallthrough for arch/mips 2020-05-07 11:55:47 +02:00
cacheinfo.c mips: cacheinfo: report shared CPU map 2019-11-26 10:33:08 -08:00
cevt-bcm1480.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
cevt-ds1287.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
cevt-gt641xx.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
cevt-r4k.c mips: cevt-r4k: Update the r4k-clockevent frequency in sync with CPU 2020-05-22 09:14:32 +02:00
cevt-sb1250.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
cevt-txx9.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
cmpxchg.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cps-vec-ns16550.S mips: Add CPS_NS16550_WIDTH config 2020-05-22 09:12:52 +02:00
cps-vec.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cpu-probe.c MIPS: handle Loongson-specific GSExc exception 2020-07-31 17:52:47 +02:00
crash_dump.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
crash.c mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
csrc-bcm1480.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
csrc-ioasic.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
csrc-r4k.c mips: csrc-r4k: Mark R4K timer as unstable if CPU freq changes 2020-05-22 09:14:06 +02:00
csrc-sb1250.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
early_printk_8250.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
early_printk.c mips: unify prom_putchar() declarations 2018-07-17 09:40:17 -07:00
elf.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
entry.S mips: Add MIPS Release 5 support 2020-05-22 09:09:01 +02:00
ftrace.c MIPS: ftrace: Reword prepare_ftrace_return() comment block 2019-06-11 15:46:21 -07:00
genex.S MIPS: handle Loongson-specific GSExc exception 2020-07-31 17:52:47 +02:00
gpio_txx9.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
head.S MIPS: head.S: Init fw_passed_dtb to builtin DTB 2020-07-31 17:48:02 +02:00
i8253.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
idle.c MIPS: Use fallthrough for arch/mips 2020-05-07 11:55:47 +02:00
irq_txx9.c
irq-gt641xx.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
irq-msc01.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
irq-rm7000.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
irq.c MIPS: irq: Allocate accurate order pages for irq stack 2019-02-19 12:45:01 -08:00
jump_label.c MIPS: jump_label: Use compact branches for >= r6 2019-04-09 16:21:30 -07:00
kgdb.c MIPS: KGDB: fix kgdb support for SMP platforms. 2019-03-28 11:35:58 -07:00
kprobes.c mm, kprobes: generalize and rename notify_page_fault() as kprobe_page_fault() 2019-07-16 19:23:22 -07:00
linux32.c MIPS: Delete unused code in linux32.c 2018-08-01 13:20:27 -07:00
machine_kexec.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
Makefile MIPS: Remove legacy MIPS_MACHINE option 2020-07-28 10:21:17 +02:00
mcount.S mips: ftrace: fix static function graph tracing 2018-06-19 15:00:12 -07:00
mips-cm.c mips: cm: Add L2 ECC/parity errors reporting 2020-05-07 13:11:38 +02:00
mips-cpc.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
mips-mt-fpaff.c sched/core: Provide a pointer to the valid CPU mask 2019-06-03 11:49:37 +02:00
mips-mt.c MIPS: MT: Remove norps command line parameter 2018-11-26 22:49:14 -08:00
mips-r2-to-r6-emul.c MIPS: Use fallthrough for arch/mips 2020-05-07 11:55:47 +02:00
module.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
octeon_switch.S Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
perf_event_mipsxx.c MIPS: perf: Remove unnecessary "fallthrough" pseudo keywords 2020-05-02 13:21:09 +02:00
perf_event.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
pm-cps.c MIPS: barrier: Add __SYNC() infrastructure 2019-10-07 09:42:17 -07:00
pm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
probes-common.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
proc.c mips: Add MIPS Release 5 support 2020-05-22 09:09:01 +02:00
process.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
prom.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
ptrace32.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
ptrace.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
r4k_fpu.S mips: Add MIPS Release 5 support 2020-05-22 09:09:01 +02:00
r4k_switch.S Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
r4k-bugs64.c MIPS: r4k-bugs64: Drop CONFIG_CPU_MIPSR6 checks 2019-10-07 09:38:54 -07:00
r2300_fpu.S MIPS: Simplify FP context initialization 2018-11-09 10:23:13 -08:00
r2300_switch.S Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables 2018-06-14 12:21:18 +09:00
relocate_kernel.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
relocate.c MIPS: Remove no-op/identity casts 2018-08-31 11:49:20 -07:00
reset.c MIPS: Hang more efficiently on halt/powerdown/restart 2018-03-09 11:22:43 +00:00
rtlx-cmp.c
rtlx-mt.c MIPS: Replace setup_irq() by request_irq() 2020-03-05 16:47:35 +01:00
rtlx.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
scall32-o32.S mips: remove nargs from __SYSCALL 2019-07-30 10:50:30 -07:00
scall64-n32.S mips: remove nargs from __SYSCALL 2019-07-30 10:50:30 -07:00
scall64-n64.S mips: remove nargs from __SYSCALL 2019-07-30 10:50:30 -07:00
scall64-o32.S MIPS: asm: Rename some macros to avoid build errors 2020-05-07 13:20:05 +02:00
segment.c mips: kernel: no need to check return value of debugfs_create functions 2019-01-22 11:17:20 -08:00
setup.c MIPS: Fix unable to reserve memory for Crash kernel 2020-07-26 13:55:51 +02:00
signal32.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
signal_n32.c Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2019-07-08 21:48:15 -07:00
signal_o32.c signal: Remove task parameter from force_sig 2019-05-27 09:36:28 -05:00
signal-common.h
signal.c MIPS: Replace zero-length array with flexible-array 2020-05-08 12:01:02 +02:00
smp-bmips.c mm: don't include asm/pgtable.h if linux/mm.h is already included 2020-06-09 09:39:13 -07:00
smp-cmp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
smp-cps.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
smp-mt.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 182 2019-05-30 11:29:20 -07:00
smp-up.c MIPS: SMP: Allow boot_secondary SMP op to return errors 2017-08-30 00:57:27 +02:00
smp.c MIPS updates for v5.7: 2020-03-31 08:51:45 -07:00
spinlock_test.c mips: kernel: no need to check return value of debugfs_create functions 2019-01-22 11:17:20 -08:00
spram.c mips: Add CONFIG/CONFIG6/Cause reg fields macro 2020-05-22 09:12:22 +02:00
stacktrace.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
sync-r4k.c MIPS: sync-r4k: do slave counter synchronization with disabled HW interrupts 2020-01-22 10:16:18 -08:00
syscall.c MIPS: syscall: Emit Loongson3 sync workarounds within asm 2019-10-07 09:43:05 -07:00
sysrq.c MIPS: constify sysrq_key_op 2020-05-15 14:53:19 +02:00
time.c mips: Add udelay lpj numbers adjustment 2020-05-22 09:13:32 +02:00
topology.c MIPS: CPU#0 is not hotpluggable 2020-07-26 10:18:35 +02:00
traps.c MIPS: handle Loongson-specific GSExc exception 2020-07-31 17:52:47 +02:00
unaligned.c MIPS: Fix build warning about "PTR_STR" redefinition 2020-05-30 10:58:30 +02:00
uprobes.c MIPS: uprobes: remove set but not used variable 'epc' 2019-05-29 13:20:30 -07:00
vdso.c mmap locking API: use coccinelle to convert mmap_sem rwsem call sites 2020-06-09 09:39:14 -07:00
vmlinux.lds.S MIPS: Truncate link address into 32bit for 32bit kernel 2020-05-07 10:31:01 +02:00
vpe-cmp.c
vpe-mt.c
vpe.c MIPS: VPE: Fix a double free and a memory leak in 'release_vpe()' 2020-02-15 12:44:03 -08:00
watch.c MIPS: Use fallthrough for arch/mips 2020-05-07 11:55:47 +02:00