user/sven/linux.git/arch/csky/kernel, branch v5.4.262

csky: Fix function name in csky_alignment() and die()

2023-02-06T06:52:49Z

commit 751971af2e3615dc5bd12674080bc795505fefeb upstream. When building ARCH=csky defconfig: arch/csky/kernel/traps.c: In function 'die': arch/csky/kernel/traps.c:112:17: error: implicit declaration of function 'make_dead_task' [-Werror=implicit-function-declaration] 112 | make_dead_task(SIGSEGV); | ^~~~~~~~~~~~~~ The function's name is make_task_dead(), change it so there is no more build error. Fixes: 0e25498f8cd4 ("exit: Add and use make_task_dead.") Signed-off-by: Nathan Chancellor Reviewed-by: Guo Ren Link: https://lkml.kernel.org/r/20211227184851.2297759-4-nathan@kernel.org Signed-off-by: Eric W. Biederman Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

exit: Add and use make_task_dead.

2023-02-06T06:52:49Z

commit 0e25498f8cd43c1b5aa327f373dd094e9a006da7 upstream. There are two big uses of do_exit. The first is it's design use to be the guts of the exit(2) system call. The second use is to terminate a task after something catastrophic has happened like a NULL pointer in kernel code. Add a function make_task_dead that is initialy exactly the same as do_exit to cover the cases where do_exit is called to handle catastrophic failure. In time this can probably be reduced to just a light wrapper around do_task_dead. For now keep it exactly the same so that there will be no behavioral differences introducing this new concept. Replace all of the uses of do_exit that use it for catastraphic task cleanup with make_task_dead to make it clear what the code is doing. As part of this rename rewind_stack_do_exit rewind_stack_and_make_dead. Signed-off-by: "Eric W. Biederman" Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

perf: Protect perf_guest_cbs with RCU

2022-01-20T08:19:18Z

commit ff083a2d972f56bebfd82409ca62e5dfce950961 upstream. Protect perf_guest_cbs with RCU to fix multiple possible errors. Luckily, all paths that read perf_guest_cbs already require RCU protection, e.g. to protect the callback chains, so only the direct perf_guest_cbs touchpoints need to be modified. Bug #1 is a simple lack of WRITE_ONCE/READ_ONCE behavior to ensure perf_guest_cbs isn't reloaded between a !NULL check and a dereference. Fixed via the READ_ONCE() in rcu_dereference(). Bug #2 is that on weakly-ordered architectures, updates to the callbacks themselves are not guaranteed to be visible before the pointer is made visible to readers. Fixed by the smp_store_release() in rcu_assign_pointer() when the new pointer is non-NULL. Bug #3 is that, because the callbacks are global, it's possible for readers to run in parallel with an unregisters, and thus a module implementing the callbacks can be unloaded while readers are in flight, resulting in a use-after-free. Fixed by a synchronize_rcu() call when unregistering callbacks. Bug #1 escaped notice because it's extremely unlikely a compiler will reload perf_guest_cbs in this sequence. perf_guest_cbs does get reloaded for future derefs, e.g. for ->is_user_mode(), but the ->is_in_guest() guard all but guarantees the consumer will win the race, e.g. to nullify perf_guest_cbs, KVM has to completely exit the guest and teardown down all VMs before KVM start its module unload / unregister sequence. This also makes it all but impossible to encounter bug #3. Bug #2 has not been a problem because all architectures that register callbacks are strongly ordered and/or have a static set of callbacks. But with help, unloading kvm_intel can trigger bug #1 e.g. wrapping perf_guest_cbs with READ_ONCE in perf_misc_flags() while spamming kvm_intel module load/unload leads to: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP CPU: 6 PID: 1825 Comm: stress Not tainted 5.14.0-rc2+ #459 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:perf_misc_flags+0x1c/0x70 Call Trace: perf_prepare_sample+0x53/0x6b0 perf_event_output_forward+0x67/0x160 __perf_event_overflow+0x52/0xf0 handle_pmi_common+0x207/0x300 intel_pmu_handle_irq+0xcf/0x410 perf_event_nmi_handler+0x28/0x50 nmi_handle+0xc7/0x260 default_do_nmi+0x6b/0x170 exc_nmi+0x103/0x130 asm_exc_nmi+0x76/0xbf Fixes: 39447b386c84 ("perf: Enhance perf to allow for guest statistic collection from host") Signed-off-by: Sean Christopherson Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Paolo Bonzini Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211111020738.2512932-2-seanjc@google.com Signed-off-by: Greg Kroah-Hartman

csky: Fixup regs.sr broken in ptrace

2021-10-20T09:40:12Z

commit af89ebaa64de726ca0a39bbb0bf0c81a1f43ad50 upstream. gpr_get() return the entire pt_regs (include sr) to userspace, if we don't restore the C bit in gpr_set, it may break the ALU result in that context. So the C flag bit is part of gpr context, that's why riscv totally remove the C bit in the ISA. That makes sr reg clear from userspace to supervisor privilege. Signed-off-by: Guo Ren Cc: Al Viro Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

csky: don't let sigreturn play with priveleged bits of status register

2021-10-20T09:40:12Z

commit fbd63c08cdcca5fb1315aca3172b3c9c272cfb4f upstream. csky restore_sigcontext() blindly overwrites regs->sr with the value it finds in sigcontext. Attacker can store whatever they want in there, which includes things like S-bit. Userland shouldn't be able to set that, or anything other than C flag (bit 0). Do the same thing other architectures with protected bits in flags register do - preserve everything that shouldn't be settable in user mode, picking the rest from the value saved is sigcontext. Signed-off-by: Al Viro Signed-off-by: Guo Ren Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

csky: Fixup abiv2 syscall_trace break a4 & a5

2020-06-17T14:40:21Z

[ Upstream commit e0bbb53843b5fdfe464b099217e3b9d97e8a75d7 ] Current implementation could destory a4 & a5 when strace, so we need to get them from pt_regs by SAVE_ALL. Signed-off-by: Guo Ren Signed-off-by: Sasha Levin

csky: Fixup remove duplicate irq_disable

2020-06-03T06:21:14Z

[ Upstream commit 6633a5aa8eb6bda70eb3a9837efd28a67ccc6e0a ] Interrupt has been disabled in __schedule() with local_irq_disable() and enabled in finish_task_switch->finish_lock_switch() with local_irq_enabled(), So needn't to disable irq here. Signed-off-by: Liu Yibin Signed-off-by: Guo Ren Signed-off-by: Sasha Levin

csky: Fixup perf callchain unwind

2020-06-03T06:21:14Z

[ Upstream commit 229a0ddee1108a3f82a873e6cbbe35c92c540444 ] [ 5221.974084] Unable to handle kernel paging request at virtual address 0xfffff000, pc: 0x8002c18e [ 5221.985929] Oops: 00000000 [ 5221.989488] [ 5221.989488] CURRENT PROCESS: [ 5221.989488] [ 5221.992877] COMM=callchain_test PID=11962 [ 5221.995213] TEXT=00008000-000087e0 DATA=00009f1c-0000a018 BSS=0000a018-0000b000 [ 5221.999037] USER-STACK=7fc18e20 KERNEL-STACK=be204680 [ 5221.999037] [ 5222.003292] PC: 0x8002c18e (perf_callchain_kernel+0x3e/0xd4) [ 5222.007957] LR: 0x8002c198 (perf_callchain_kernel+0x48/0xd4) [ 5222.074873] Call Trace: [ 5222.074873] [<800a248e>] get_perf_callchain+0x20a/0x29c [ 5222.074873] [<8009d964>] perf_callchain+0x64/0x80 [ 5222.074873] [<8009dc1c>] perf_prepare_sample+0x29c/0x4b8 [ 5222.074873] [<8009de6e>] perf_event_output_forward+0x36/0x98 [ 5222.074873] [<800497e0>] search_exception_tables+0x20/0x44 [ 5222.074873] [<8002cbb6>] do_page_fault+0x92/0x378 [ 5222.074873] [<80098608>] __perf_event_overflow+0x54/0xdc [ 5222.074873] [<80098778>] perf_swevent_hrtimer+0xe8/0x164 [ 5222.074873] [<8002ddd0>] update_mmu_cache+0x0/0xd8 [ 5222.074873] [<8002c014>] user_backtrace+0x58/0xc4 [ 5222.074873] [<8002c0b4>] perf_callchain_user+0x34/0xd0 [ 5222.074873] [<800a2442>] get_perf_callchain+0x1be/0x29c [ 5222.074873] [<8009d964>] perf_callchain+0x64/0x80 [ 5222.074873] [<8009d834>] perf_output_sample+0x78c/0x858 [ 5222.074873] [<8009dc1c>] perf_prepare_sample+0x29c/0x4b8 [ 5222.074873] [<8009de94>] perf_event_output_forward+0x5c/0x98 [ 5222.097846] [ 5222.097846] [<800a0300>] perf_event_exit_task+0x58/0x43c [ 5222.097846] [<8006c874>] hrtimer_interrupt+0x104/0x2ec [ 5222.097846] [<800a0300>] perf_event_exit_task+0x58/0x43c [ 5222.097846] [<80437bb6>] dw_apb_clockevent_irq+0x2a/0x4c [ 5222.097846] [<8006c770>] hrtimer_interrupt+0x0/0x2ec [ 5222.097846] [<8005f2e4>] __handle_irq_event_percpu+0xac/0x19c [ 5222.097846] [<80437bb6>] dw_apb_clockevent_irq+0x2a/0x4c [ 5222.097846] [<8005f408>] handle_irq_event_percpu+0x34/0x88 [ 5222.097846] [<8005f480>] handle_irq_event+0x24/0x64 [ 5222.097846] [<8006218c>] handle_level_irq+0x68/0xdc [ 5222.097846] [<8005ec76>] __handle_domain_irq+0x56/0xa8 [ 5222.097846] [<80450e90>] ck_irq_handler+0xac/0xe4 [ 5222.097846] [<80029012>] csky_do_IRQ+0x12/0x24 [ 5222.097846] [<8002a3a0>] csky_irq+0x70/0x80 [ 5222.097846] [<800ca612>] alloc_set_pte+0xd2/0x238 [ 5222.097846] [<8002ddd0>] update_mmu_cache+0x0/0xd8 [ 5222.097846] [<800a0340>] perf_event_exit_task+0x98/0x43c The original fp check doesn't base on the real kernal stack region. Invalid fp address may cause kernel panic. Signed-off-by: Mao Han Signed-off-by: Guo Ren Signed-off-by: Sasha Levin

csky: Fixup init_fpu compile warning with __init

2020-04-23T08:36:41Z

[ Upstream commit 12879bda3c2a974b7e4fe199a9c21f0c5f6bca04 ] WARNING: vmlinux.o(.text+0x2366): Section mismatch in reference from the function csky_start_secondary() to the function .init.text:init_fpu() The function csky_start_secondary() references the function __init init_fpu(). This is often because csky_start_secondary lacks a __init annotation or the annotation of init_fpu is wrong. Reported-by: Lu Chongzhi Signed-off-by: Guo Ren Signed-off-by: Sasha Levin

csky: Fixup get wrong psr value from phyical reg

2020-04-23T08:36:38Z

[ Upstream commit 9c0e343d7654a329d1f9b53d253cbf7fb6eff85d ] We should get psr value from regs->psr in stack, not directly get it from phyiscal register then save the vector number in tsk->trap_no. Signed-off-by: Guo Ren Signed-off-by: Sasha Levin