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author | 2022-12-08 16:07:53 -0800 | |
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committer | 2022-12-08 18:19:59 -0800 | |
commit | 837e8ac871499d337212e2161c046f5adf1bad33 (patch) | |
tree | 2d7bb495b5ce2bce04bf18afd6a57116391efabc /arch/riscv/kernel/traps.c | |
parent | Merge branch 'mlx4-better-big-tcp-support' (diff) | |
parent | Merge tag 'net-6.1-rc9' of git://git.kernel.org/pub/scm/linux/kernel/git/netd... (diff) | |
download | linux-837e8ac871499d337212e2161c046f5adf1bad33.tar.gz linux-837e8ac871499d337212e2161c046f5adf1bad33.tar.bz2 linux-837e8ac871499d337212e2161c046f5adf1bad33.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
No conflicts.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'arch/riscv/kernel/traps.c')
-rw-r--r-- | arch/riscv/kernel/traps.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index f3e96d60a2ff..7abd8e4c4df6 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -221,11 +221,29 @@ asmlinkage unsigned long get_overflow_stack(void) OVERFLOW_STACK_SIZE; } +/* + * A pseudo spinlock to protect the shadow stack from being used by multiple + * harts concurrently. This isn't a real spinlock because the lock side must + * be taken without a valid stack and only a single register, it's only taken + * while in the process of panicing anyway so the performance and error + * checking a proper spinlock gives us doesn't matter. + */ +unsigned long spin_shadow_stack; + asmlinkage void handle_bad_stack(struct pt_regs *regs) { unsigned long tsk_stk = (unsigned long)current->stack; unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); + /* + * We're done with the shadow stack by this point, as we're on the + * overflow stack. Tell any other concurrent overflowing harts that + * they can proceed with panicing by releasing the pseudo-spinlock. + * + * This pairs with an amoswap.aq in handle_kernel_stack_overflow. + */ + smp_store_release(&spin_shadow_stack, 0); + console_verbose(); pr_emerg("Insufficient stack space to handle exception!\n"); |