riscv: Disallow PR_GET_TAGGED_ADDR_CTRL without Supm

When the prctl() interface for pointer masking was added, it did not
check that the pointer masking ISA extension was supported, only the
individ

riscv: Disallow PR_GET_TAGGED_ADDR_CTRL without Supm

When the prctl() interface for pointer masking was added, it did not
check that the pointer masking ISA extension was supported, only the
individual submodes. Userspace could still attempt to disable pointer
masking and query the pointer masking state. commit 81de1afb2dd1
("riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL") disallowed
the former, as the senvcfg write could crash on older systems.
PR_GET_TAGGED_ADDR_CTRL state does not crash, because it reads only
kernel-internal state and not senvcfg, but it should still be disallowed
for consistency.

Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking")
Signed-off-by: Samuel Holland <[email protected]>
Reviewed-by: Nam Cao <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Ghiti <[email protected]>

show more ...

riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL

When userspace does PR_SET_TAGGED_ADDR_CTRL, but Supm extension is not
available, the kernel crashes:

Oops - illegal instruction [#1]
[sni

riscv: Fix kernel crash due to PR_SET_TAGGED_ADDR_CTRL

When userspace does PR_SET_TAGGED_ADDR_CTRL, but Supm extension is not
available, the kernel crashes:

Oops - illegal instruction [#1]
[snip]
epc : set_tagged_addr_ctrl+0x112/0x15a
ra : set_tagged_addr_ctrl+0x74/0x15a
epc : ffffffff80011ace ra : ffffffff80011a30 sp : ffffffc60039be10
[snip]
status: 0000000200000120 badaddr: 0000000010a79073 cause: 0000000000000002
set_tagged_addr_ctrl+0x112/0x15a
__riscv_sys_prctl+0x352/0x73c
do_trap_ecall_u+0x17c/0x20c
andle_exception+0x150/0x15c

Fix it by checking if Supm is available.

Fixes: 09d6775f503b ("riscv: Add support for userspace pointer masking")
Signed-off-by: Nam Cao <[email protected]>
Cc: [email protected]
Reviewed-by: Samuel Holland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Ghiti <[email protected]>

show more ...

treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysc

treewide: const qualify ctl_tables where applicable

Add the const qualifier to all the ctl_tables in the tree except for
watchdog_hardlockup_sysctl, memory_allocation_profiling_sysctls,
loadpin_sysctl_table and the ones calling register_net_sysctl (./net,
drivers/inifiniband dirs). These are special cases as they use a
registration function with a non-const qualified ctl_table argument or
modify the arrays before passing them on to the registration function.

Constifying ctl_table structs will prevent the modification of
proc_handler function pointers as the arrays would reside in .rodata.
This is made possible after commit 78eb4ea25cd5 ("sysctl: treewide:
constify the ctl_table argument of proc_handlers") constified all the
proc_handlers.

Created this by running an spatch followed by a sed command:
Spatch:
virtual patch

@
depends on !(file in "net")
disable optional_qualifier
@

identifier table_name != {
watchdog_hardlockup_sysctl,
iwcm_ctl_table,
ucma_ctl_table,
memory_allocation_profiling_sysctls,
loadpin_sysctl_table
};
@@

+ const
struct ctl_table table_name [] = { ... };

sed:
sed --in-place \
-e "s/struct ctl_table .table = &uts_kern/const struct ctl_table *table = \&uts_kern/" \
kernel/utsname_sysctl.c

Reviewed-by: Song Liu <[email protected]>
Acked-by: Steven Rostedt (Google) <[email protected]> # for kernel/trace/
Reviewed-by: Martin K. Petersen <[email protected]> # SCSI
Reviewed-by: Darrick J. Wong <[email protected]> # xfs
Acked-by: Jani Nikula <[email protected]>
Acked-by: Corey Minyard <[email protected]>
Acked-by: Wei Liu <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Reviewed-by: Bill O'Donnell <[email protected]>
Acked-by: Baoquan He <[email protected]>
Acked-by: Ashutosh Dixit <[email protected]>
Acked-by: Anna Schumaker <[email protected]>
Signed-off-by: Joel Granados <[email protected]>

show more ...

riscv: vector: Support xtheadvector save/restore

Use alternatives to add support for xtheadvector vector save/restore
routines.

Signed-off-by: Charlie Jenkins <[email protected]>
Reviewed-by: Co

riscv: vector: Support xtheadvector save/restore

Use alternatives to add support for xtheadvector vector save/restore
routines.

Signed-off-by: Charlie Jenkins <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Tested-by: Yangyu Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Add support for the tagged address ABI

When pointer masking is enabled for userspace, the kernel can accept
tagged pointers as arguments to some system calls. Allow this by
untagging the poin

riscv: Add support for the tagged address ABI

When pointer masking is enabled for userspace, the kernel can accept
tagged pointers as arguments to some system calls. Allow this by
untagging the pointers in access_ok() and the uaccess routines. The
uaccess routines must peform untagging in software because U-mode and
S-mode have entirely separate pointer masking configurations. In fact,
hardware may not even implement pointer masking for S-mode.

Since the number of tag bits is variable, untagged_addr_remote() needs
to know what PMLEN to use for the remote mm. Therefore, the pointer
masking mode must be the same for all threads sharing an mm. Enforce
this with a lock flag in the mm context, as x86 does for LAM. The flag
gets reset in init_new_context() during fork(), as the new mm is no
longer multithreaded.

Reviewed-by: Charlie Jenkins <[email protected]>
Tested-by: Charlie Jenkins <[email protected]>
Signed-off-by: Samuel Holland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Add support for userspace pointer masking

RISC-V supports pointer masking with a variable number of tag bits
(which is called "PMLEN" in the specification) and which is configured
at the next

riscv: Add support for userspace pointer masking

RISC-V supports pointer masking with a variable number of tag bits
(which is called "PMLEN" in the specification) and which is configured
at the next higher privilege level.

Wire up the PR_SET_TAGGED_ADDR_CTRL and PR_GET_TAGGED_ADDR_CTRL prctls
so userspace can request a lower bound on the number of tag bits and
determine the actual number of tag bits. As with arm64's
PR_TAGGED_ADDR_ENABLE, the pointer masking configuration is
thread-scoped, inherited on clone() and fork() and cleared on execve().

Reviewed-by: Charlie Jenkins <[email protected]>
Tested-by: Charlie Jenkins <[email protected]>
Signed-off-by: Samuel Holland <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Randomize lower bits of stack address

Implement arch_align_stack() to randomize the lower bits
of the stack address.

Signed-off-by: Yunhui Cui <[email protected]>
Link: https://lore.ke

riscv: Randomize lower bits of stack address

Implement arch_align_stack() to randomize the lower bits
of the stack address.

Signed-off-by: Yunhui Cui <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: process: Fix kernel gp leakage

childregs represents the registers which are active for the new thread
in user context. For a kernel thread, childregs->gp is never used since
the kernel gp is

riscv: process: Fix kernel gp leakage

childregs represents the registers which are active for the new thread
in user context. For a kernel thread, childregs->gp is never used since
the kernel gp is not touched by switch_to. For a user mode helper, the
gp value can be observed in user space after execve or possibly by other
means.

[From the email thread]

The /* Kernel thread */ comment is somewhat inaccurate in that it is also used
for user_mode_helper threads, which exec a user process, e.g. /sbin/init or
when /proc/sys/kernel/core_pattern is a pipe. Such threads do not have
PF_KTHREAD set and are valid targets for ptrace etc. even before they exec.

childregs is the *user* context during syscall execution and it is observable
from userspace in at least five ways:

1. kernel_execve does not currently clear integer registers, so the starting
register state for PID 1 and other user processes started by the kernel has
sp = user stack, gp = kernel __global_pointer$, all other integer registers
zeroed by the memset in the patch comment.

This is a bug in its own right, but I'm unwilling to bet that it is the only
way to exploit the issue addressed by this patch.

2. ptrace(PTRACE_GETREGSET): you can PTRACE_ATTACH to a user_mode_helper thread
before it execs, but ptrace requires SIGSTOP to be delivered which can only
happen at user/kernel boundaries.

3. /proc/*/task/*/syscall: this is perfectly happy to read pt_regs for
user_mode_helpers before the exec completes, but gp is not one of the
registers it returns.

4. PERF_SAMPLE_REGS_USER: LOCKDOWN_PERF normally prevents access to kernel
addresses via PERF_SAMPLE_REGS_INTR, but due to this bug kernel addresses
are also exposed via PERF_SAMPLE_REGS_USER which is permitted under
LOCKDOWN_PERF. I have not attempted to write exploit code.

5. Much of the tracing infrastructure allows access to user registers. I have
not attempted to determine which forms of tracing allow access to user
registers without already allowing access to kernel registers.

Fixes: 7db91e57a0ac ("RISC-V: Task implementation")
Cc: [email protected]
Signed-off-by: Stefan O'Rear <[email protected]>
Reviewed-by: Alexandre Ghiti <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Fix warning by declaring arch_cpu_idle() as noinstr

The following warning appears when using ftrace:

[89855.443413] RCU not on for: arch_cpu_idle+0x0/0x1c
[89855.445640] WARNING: CPU: 5 PID:

riscv: Fix warning by declaring arch_cpu_idle() as noinstr

The following warning appears when using ftrace:

[89855.443413] RCU not on for: arch_cpu_idle+0x0/0x1c
[89855.445640] WARNING: CPU: 5 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x208/0x228
[89855.445824] Modules linked in: xt_conntrack(E) nft_chain_nat(E) xt_MASQUERADE(E) nf_conntrack_netlink(E) xt_addrtype(E) nft_compat(E) nf_tables(E) nfnetlink(E) br_netfilter(E) cfg80211(E) nls_iso8859_1(E) ofpart(E) redboot(E) cmdlinepart(E) cfi_cmdset_0001(E) virtio_net(E) cfi_probe(E) cfi_util(E) 9pnet_virtio(E) gen_probe(E) net_failover(E) virtio_rng(E) failover(E) 9pnet(E) physmap(E) map_funcs(E) chipreg(E) mtd(E) uio_pdrv_genirq(E) uio(E) dm_multipath(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) drm(E) efi_pstore(E) backlight(E) ip_tables(E) x_tables(E) raid10(E) raid456(E) async_raid6_recov(E) async_memcpy(E) async_pq(E) async_xor(E) xor(E) async_tx(E) raid6_pq(E) raid1(E) raid0(E) virtio_blk(E)
[89855.451563] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G E 6.8.0-rc6ubuntu-defconfig #2
[89855.451726] Hardware name: riscv-virtio,qemu (DT)
[89855.451899] epc : arch_ftrace_ops_list_func+0x208/0x228
[89855.452016] ra : arch_ftrace_ops_list_func+0x208/0x228
[89855.452119] epc : ffffffff8016b216 ra : ffffffff8016b216 sp : ffffaf808090fdb0
[89855.452171] gp : ffffffff827c7680 tp : ffffaf808089ad40 t0 : ffffffff800c0dd8
[89855.452216] t1 : 0000000000000001 t2 : 0000000000000000 s0 : ffffaf808090fe30
[89855.452306] s1 : 0000000000000000 a0 : 0000000000000026 a1 : ffffffff82cd6ac8
[89855.452423] a2 : ffffffff800458c8 a3 : ffffaf80b1870640 a4 : 0000000000000000
[89855.452646] a5 : 0000000000000000 a6 : 00000000ffffffff a7 : ffffffffffffffff
[89855.452698] s2 : ffffffff82766872 s3 : ffffffff80004caa s4 : ffffffff80ebea90
[89855.452743] s5 : ffffaf808089bd40 s6 : 8000000a00006e00 s7 : 0000000000000008
[89855.452787] s8 : 0000000000002000 s9 : 0000000080043700 s10: 0000000000000000
[89855.452831] s11: 0000000000000000 t3 : 0000000000100000 t4 : 0000000000000064
[89855.452874] t5 : 000000000000000c t6 : ffffaf80b182dbfc
[89855.452929] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003
[89855.453053] [<ffffffff8016b216>] arch_ftrace_ops_list_func+0x208/0x228
[89855.453191] [<ffffffff8000e082>] ftrace_call+0x8/0x22
[89855.453265] [<ffffffff800a149c>] do_idle+0x24c/0x2ca
[89855.453357] [<ffffffff8000da54>] return_to_handler+0x0/0x26
[89855.453429] [<ffffffff8000b716>] smp_callin+0x92/0xb6
[89855.453785] ---[ end trace 0000000000000000 ]---

To fix this, mark arch_cpu_idle() as noinstr, like it is done in commit
a9cbc1b471d2 ("s390/idle: mark arch_cpu_idle() noinstr").

Reported-by: Evgenii Shatokhin <[email protected]>
Closes: https://lore.kernel.org/linux-riscv/[email protected]/
Fixes: cfbc4f81c9d0 ("riscv: Select ARCH_WANTS_NO_INSTR")
Signed-off-by: Alexandre Ghiti <[email protected]>
Reviewed-by: Andy Chiu <[email protected]>
Tested-by: Andy Chiu <[email protected]>
Acked-by: Puranjay Mohan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: vector: allow kernel-mode Vector with preemption

Add kernel_vstate to keep track of kernel-mode Vector registers when
trap introduced context switch happens. Also, provide riscv_v_flags to
le

riscv: vector: allow kernel-mode Vector with preemption

Add kernel_vstate to keep track of kernel-mode Vector registers when
trap introduced context switch happens. Also, provide riscv_v_flags to
let context save/restore routine track context status. Context tracking
happens whenever the core starts its in-kernel Vector executions. An
active (dirty) kernel task's V contexts will be saved to memory whenever
a trap-introduced context switch happens. Or, when a softirq, which
happens to nest on top of it, uses Vector. Context retoring happens when
the execution transfer back to the original Kernel context where it
first enable preempt_v.

Also, provide a config CONFIG_RISCV_ISA_V_PREEMPTIVE to give users an
option to disable preemptible kernel-mode Vector at build time. Users
with constraint memory may want to disable this config as preemptible
kernel-mode Vector needs extra space for tracking of per thread's
kernel-mode V context. Or, users might as well want to disable it if all
kernel-mode Vector code is time sensitive and cannot tolerate context
switch overhead.

Signed-off-by: Andy Chiu <[email protected]>
Tested-by: Björn Töpel <[email protected]>
Tested-by: Lad Prabhakar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: vector: use kmem_cache to manage vector context

The allocation size of thread.vstate.datap is always riscv_v_vsize. So
it is possbile to use kmem_cache_* to manage the allocation. This gives

riscv: vector: use kmem_cache to manage vector context

The allocation size of thread.vstate.datap is always riscv_v_vsize. So
it is possbile to use kmem_cache_* to manage the allocation. This gives
users more information regarding allocation of vector context via
/proc/slabinfo. And it potentially reduces the latency of the first-use
trap because of the allocation caches.

Signed-off-by: Andy Chiu <[email protected]>
Tested-by: Björn Töpel <[email protected]>
Tested-by: Lad Prabhakar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: sched: defer restoring Vector context for user

User will use its Vector registers only after the kernel really returns
to the userspace. So we can delay restoring Vector registers as long as

riscv: sched: defer restoring Vector context for user

User will use its Vector registers only after the kernel really returns
to the userspace. So we can delay restoring Vector registers as long as
we are still running in kernel mode. So, add a thread flag to indicates
the need of restoring Vector and do the restore at the last
arch-specific exit-to-user hook. This save the context restoring cost
when we switch over multiple processes that run V in kernel mode. For
example, if the kernel performs a context swicth from A->B->C, and
returns to C's userspace, then there is no need to restore B's
V-register.

Besides, this also prevents us from repeatedly restoring V context when
executing kernel-mode Vector multiple times.

The cost of this is that we must disable preemption and mark vector as
busy during vstate_{save,restore}. Because then the V context will not
get restored back immediately when a trap-causing context switch happens
in the middle of vstate_{save,restore}.

Signed-off-by: Andy Chiu <[email protected]>
Acked-by: Conor Dooley <[email protected]>
Tested-by: Björn Töpel <[email protected]>
Tested-by: Lad Prabhakar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Add support for kernel mode vector

Add kernel_vector_begin() and kernel_vector_end() function declarations
and corresponding definitions in kernel_mode_vector.c

These are needed to wrap uses

riscv: Add support for kernel mode vector

Add kernel_vector_begin() and kernel_vector_end() function declarations
and corresponding definitions in kernel_mode_vector.c

These are needed to wrap uses of vector in kernel mode.

Co-developed-by: Vincent Chen <[email protected]>
Signed-off-by: Vincent Chen <[email protected]>
Signed-off-by: Greentime Hu <[email protected]>
Signed-off-by: Andy Chiu <[email protected]>
Reviewed-by: Eric Biggers <[email protected]>
Tested-by: Björn Töpel <[email protected]>
Tested-by: Lad Prabhakar <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: add support for PR_SET_UNALIGN and PR_GET_UNALIGN

Now that trap support is ready to handle misalignment errors in S-mode,
allow the user to control the behavior of misaligned accesses using
p

riscv: add support for PR_SET_UNALIGN and PR_GET_UNALIGN

Now that trap support is ready to handle misalignment errors in S-mode,
allow the user to control the behavior of misaligned accesses using
prctl(PR_SET_UNALIGN). Add an align_ctl flag in thread_struct which
will be used to determine if we should SIGBUS the process or not on
such fault.

Signed-off-by: Clément Léger <[email protected]>
Reviewed-by: Björn Töpel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Add prctl controls for userspace vector management

This patch add two riscv-specific prctls, to allow usespace control the
use of vector unit:

* PR_RISCV_V_SET_CONTROL: control the permissi

riscv: Add prctl controls for userspace vector management

This patch add two riscv-specific prctls, to allow usespace control the
use of vector unit:

* PR_RISCV_V_SET_CONTROL: control the permission to use Vector at next,
or all following execve for a thread. Turning off a thread's Vector
live is not possible since libraries may have registered ifunc that
may execute Vector instructions.
* PR_RISCV_V_GET_CONTROL: get the same permission setting for the
current thread, and the setting for following execve(s).

Signed-off-by: Andy Chiu <[email protected]>
Reviewed-by: Greentime Hu <[email protected]>
Reviewed-by: Vincent Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: Add task switch support for vector

This patch adds task switch support for vector. It also supports all
lengths of vlen.

Suggested-by: Andrew Waterman <[email protected]>
Co-developed-by: Ni

riscv: Add task switch support for vector

This patch adds task switch support for vector. It also supports all
lengths of vlen.

Suggested-by: Andrew Waterman <[email protected]>
Co-developed-by: Nick Knight <[email protected]>
Signed-off-by: Nick Knight <[email protected]>
Co-developed-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Co-developed-by: Vincent Chen <[email protected]>
Signed-off-by: Vincent Chen <[email protected]>
Co-developed-by: Ruinland Tsai <[email protected]>
Signed-off-by: Ruinland Tsai <[email protected]>
Signed-off-by: Greentime Hu <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>
Signed-off-by: Andy Chiu <[email protected]>
Reviewed-by: Conor Dooley <[email protected]>
Reviewed-by: Björn Töpel <[email protected]>
Reviewed-by: Heiko Stuebner <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork

The ret_from_kernel_thread() behaves similarly with ret_from_fork(),
the only difference is whether call the fn(arg) or not, this

riscv: entry: Consolidate ret_from_kernel_thread into ret_from_fork

The ret_from_kernel_thread() behaves similarly with ret_from_fork(),
the only difference is whether call the fn(arg) or not, this can be
achieved by testing fn is NULL or not, I.E s0 is 0 or not. Many
architectures have done the same thing, it makes entry.S more clean.

Signed-off-by: Jisheng Zhang <[email protected]>
Reviewed-by: Björn Töpel <[email protected]>
Reviewed-by: Guo Ren <[email protected]>
Tested-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled

Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the

arch/idle: Change arch_cpu_idle() behavior: always exit with IRQs disabled

Current arch_cpu_idle() is called with IRQs disabled, but will return
with IRQs enabled.

However, the very first thing the generic code does after calling
arch_cpu_idle() is raw_local_irq_disable(). This means that
architectures that can idle with IRQs disabled end up doing a
pointless 'enable-disable' dance.

Therefore, push this IRQ disabling into the idle function, meaning
that those architectures can avoid the pointless IRQ state flipping.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Tony Lindgren <[email protected]>
Tested-by: Ulf Hansson <[email protected]>
Reviewed-by: Gautham R. Shenoy <[email protected]>
Acked-by: Mark Rutland <[email protected]> [arm64]
Acked-by: Rafael J. Wysocki <[email protected]>
Acked-by: Guo Ren <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

show more ...

riscv: process: fix kernel info leakage

thread_struct's s[12] may contain random kernel memory content, which
may be finally leaked to userspace. This is a security hole. Fix it
by clearing the s[12

riscv: process: fix kernel info leakage

thread_struct's s[12] may contain random kernel memory content, which
may be finally leaked to userspace. This is a security hole. Fix it
by clearing the s[12] array in thread_struct when fork.

As for kthread case, it's better to clear the s[12] array as well.

Fixes: 7db91e57a0ac ("RISC-V: Task implementation")
Signed-off-by: Jisheng Zhang <[email protected]>
Tested-by: Guo Ren <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Guo Ren <[email protected]>
Link: https://lore.kernel.org/r/CAJF2gTSdVyAaM12T%[email protected]/
Signed-off-by: Palmer Dabbelt <[email protected]>

show more ...

riscv: compat: s/failed/unsupported if compat mode isn't supported

When compat mode isn't supported(I believe this is the most case now),
kernel will emit somthing as:
[ 0.050407] riscv: ELF comp

riscv: compat: s/failed/unsupported if compat mode isn't supported

When compat mode isn't supported(I believe this is the most case now),
kernel will emit somthing as:
[ 0.050407] riscv: ELF compat mode failed

This msg may make users think there's something wrong with the kernel
itself, replace "failed" with "unsupported" to make it clear. In fact
this is the real compat_mode_supported meaning. After the patch, the
msg would be:
[ 0.050407] riscv: ELF compat mode unsupported

Signed-off-by: Jisheng Zhang <[email protected]>
Acked-by: Guo Ren <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/
Signed-off-by: Palmer Dabbelt <[email protected]>

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fork: Generalize PF_IO_WORKER handling

Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any ta

fork: Generalize PF_IO_WORKER handling

Add fn and fn_arg members into struct kernel_clone_args and test for
them in copy_thread (instead of testing for PF_KTHREAD | PF_IO_WORKER).
This allows any task that wants to be a user space task that only runs
in kernel mode to use this functionality.

The code on x86 is an exception and still retains a PF_KTHREAD test
because x86 unlikely everything else handles kthreads slightly
differently than user space tasks that start with a function.

The functions that created tasks that start with a function
have been updated to set ".fn" and ".fn_arg" instead of
".stack" and ".stack_size". These functions are fork_idle(),
create_io_thread(), kernel_thread(), and user_mode_thread().

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

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fork: Pass struct kernel_clone_args into copy_thread

With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel

fork: Pass struct kernel_clone_args into copy_thread

With io_uring we have started supporting tasks that are for most
purposes user space tasks that exclusively run code in kernel mode.

The kernel task that exec's init and tasks that exec user mode
helpers are also user mode tasks that just run kernel code
until they call kernel execve.

Pass kernel_clone_args into copy_thread so these oddball
tasks can be supported more cleanly and easily.

v2: Fix spelling of kenrel_clone_args on h8300
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: "Eric W. Biederman" <[email protected]>

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riscv: compat: Add hw capability check for elf

Detect hardware COMPAT (32bit U-mode) capability in rv64. If not
support COMPAT mode in hw, compat_elf_check_arch would return
false by compat_binfmt_e

riscv: compat: Add hw capability check for elf

Detect hardware COMPAT (32bit U-mode) capability in rv64. If not
support COMPAT mode in hw, compat_elf_check_arch would return
false by compat_binfmt_elf.c

Add CLASS to enhance (compat_)elf_check_arch to distinguish
32BIT/64BIT elf.

Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

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riscv: compat: process: Add UXL_32 support in start_thread

If the current task is in COMPAT mode, set SR_UXL_32 in status for
returning userspace. We need CONFIG _COMPAT to prevent compiling
errors

riscv: compat: process: Add UXL_32 support in start_thread

If the current task is in COMPAT mode, set SR_UXL_32 in status for
returning userspace. We need CONFIG _COMPAT to prevent compiling
errors with rv32 defconfig.

Signed-off-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Tested-by: Heiko Stuebner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

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RISC-V: Enable CPU_IDLE drivers

We force select CPU_PM and provide asm/cpuidle.h so that we can
use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by: Anup Patel <[email protected]>
Signed-o

RISC-V: Enable CPU_IDLE drivers

We force select CPU_PM and provide asm/cpuidle.h so that we can
use CPU IDLE drivers for Linux RISC-V kernel.

Signed-off-by: Anup Patel <[email protected]>
Signed-off-by: Anup Patel <[email protected]>
Reviewed-by: Guo Ren <[email protected]>
Reviewed-by: Atish Patra <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>

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