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flush_tlb_kernel_range() may use IPIs to flush the TLBs of all the
cores, which triggers the following warning when the irqs are disabled:
[ 3.455330] WARNING: CPU: 1 PID: 0 at kernel/smp.c:815 smp_call_function_many_cond+0x452/0x520
[ 3.456647] Modules linked in:
[ 3.457218] CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.12.0-rc7-00010-g91d3de7240b8 #1
[ 3.457416] Hardware name: QEMU QEMU Virtual Machine, BIOS
[ 3.457633] epc : smp_call_function_many_cond+0x452/0x520
[ 3.457736] ra : on_each_cpu_cond_mask+0x1e/0x30
[ 3.457786] epc : ffffffff800b669a ra : ffffffff800b67c2 sp : ff2000000000bb50
[ 3.457824] gp : ffffffff815212b8 tp : ff6000008014f080 t0 : 000000000000003f
[ 3.457859] t1 : ffffffff815221e0 t2 : 000000000000000f s0 : ff2000000000bc10
[ 3.457920] s1 : 0000000000000040 a0 : ffffffff815221e0 a1 : 0000000000000001
[ 3.457953] a2 : 0000000000010000 a3 : 0000000000000003 a4 : 0000000000000000
[ 3.458006] a5 : 0000000000000000 a6 : ffffffffffffffff a7 : 0000000000000000
[ 3.458042] s2 : ffffffff815223be s3 : 00fffffffffff000 s4 : ff600001ffe38fc0
[ 3.458076] s5 : ff600001ff950d00 s6 : 0000000200000120 s7 : 0000000000000001
[ 3.458109] s8 : 0000000000000001 s9 : ff60000080841ef0 s10: 0000000000000001
[ 3.458141] s11: ffffffff81524812 t3 : 0000000000000001 t4 : ff60000080092bc0
[ 3.458172] t5 : 0000000000000000 t6 : ff200000000236d0
[ 3.458203] status: 0000000200000100 badaddr: ffffffff800b669a cause: 0000000000000003
[ 3.458373] [<ffffffff800b669a>] smp_call_function_many_cond+0x452/0x520
[ 3.458593] [<ffffffff800b67c2>] on_each_cpu_cond_mask+0x1e/0x30
[ 3.458625] [<ffffffff8000e4ca>] __flush_tlb_range+0x118/0x1ca
[ 3.458656] [<ffffffff8000e6b2>] flush_tlb_kernel_range+0x1e/0x26
[ 3.458683] [<ffffffff801ea56a>] kfence_protect+0xc0/0xce
[ 3.458717] [<ffffffff801e9456>] kfence_guarded_free+0xc6/0x1c0
[ 3.458742] [<ffffffff801e9d6c>] __kfence_free+0x62/0xc6
[ 3.458764] [<ffffffff801c57d8>] kfree+0x106/0x32c
[ 3.458786] [<ffffffff80588cf2>] detach_buf_split+0x188/0x1a8
[ 3.458816] [<ffffffff8058708c>] virtqueue_get_buf_ctx+0xb6/0x1f6
[ 3.458839] [<ffffffff805871da>] virtqueue_get_buf+0xe/0x16
[ 3.458880] [<ffffffff80613d6a>] virtblk_done+0x5c/0xe2
[ 3.458908] [<ffffffff8058766e>] vring_interrupt+0x6a/0x74
[ 3.458930] [<ffffffff800747d8>] __handle_irq_event_percpu+0x7c/0xe2
[ 3.458956] [<ffffffff800748f0>] handle_irq_event+0x3c/0x86
[ 3.458978] [<ffffffff800786cc>] handle_simple_irq+0x9e/0xbe
[ 3.459004] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a
[ 3.459027] [<ffffffff804bf87c>] imsic_handle_irq+0xba/0x120
[ 3.459056] [<ffffffff80073934>] generic_handle_domain_irq+0x1c/0x2a
[ 3.459080] [<ffffffff804bdb76>] riscv_intc_aia_irq+0x24/0x34
[ 3.459103] [<ffffffff809d0452>] handle_riscv_irq+0x2e/0x4c
[ 3.459133] [<ffffffff809d923e>] call_on_irq_stack+0x32/0x40
So only flush the local TLB and let the lazy kfence page fault handling
deal with the faults which could happen when a core has an old protected
pte version cached in its TLB. That leads to potential inaccuracies which
can be tolerated when using kfence.
Fixes: 47513f243b45 ("riscv: Enable KFENCE for riscv64")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20241209074125.52322-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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As very well explained in commit 20a004e7b017 ("arm64: mm: Use
READ_ONCE/WRITE_ONCE when accessing page tables"), an architecture whose
page table walker can modify the PTE in parallel must use
READ_ONCE()/WRITE_ONCE() macro to avoid any compiler transformation.
So apply that to riscv which is such architecture.
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20231213203001.179237-5-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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RISC-V Kfence implementation used to rely on the fact the linear mapping
was backed by at most PMD hugepages, which is not true anymore since
commit 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear
mapping").
Instead of splitting PUD/P4D/PGD mappings afterwards, directly map the
kfence pool region using PTE mappings by allocating this region before
setup_vm_final().
Reported-by: syzbot+a74d57bddabbedd75135@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=a74d57bddabbedd75135
Fixes: 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear mapping")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230606130444.25090-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
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Add architecture specific implementation details for KFENCE and enable
KFENCE for the riscv64 architecture. In particular, this implements the
required interface in <asm/kfence.h>.
KFENCE requires that attributes for pages from its memory pool can
individually be set. Therefore, force the kfence pool to be mapped at
page granularity.
Testing this patch using the testcases in kfence_test.c and all passed.
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
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