Commit 9bdc1ab5 authored by Chenghao Duan's avatar Chenghao Duan Committed by Huacai Chen
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LoongArch: Enable exception fixup for specific ADE subcode 



This patch allows the LoongArch BPF JIT to handle recoverable memory
access errors generated by BPF_PROBE_MEM* instructions.

When a BPF program performs memory access operations, the instructions
it executes may trigger ADEM exceptions. The kernel’s built-in BPF
exception table mechanism (EX_TYPE_BPF) will generate corresponding
exception fixup entries in the JIT compilation phase; however, the
architecture-specific trap handling function needs to proactively call
the common fixup routine to achieve exception recovery.

do_ade(): fix EX_TYPE_BPF memory access exceptions for BPF programs,
ensure safe execution.

Relevant test cases: illegal address access tests in module_attach and
subprogs_extable of selftests/bpf.

Signed-off-by: default avatarChenghao Duan <duanchenghao@kylinos.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 4cd641a7

arch/loongarch/kernel/traps.c

+5 −0
Original line number Diff line number Diff line
@@ -535,10 +535,15 @@ asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcsr) 
asmlinkage void noinstr do_ade(struct pt_regs *regs)

{

	irqentry_state_t state = irqentry_enter(regs);

	unsigned int esubcode = FIELD_GET(CSR_ESTAT_ESUBCODE, regs->csr_estat);



	if ((esubcode == EXSUBCODE_ADEM) && fixup_exception(regs))

		goto out;



	die_if_kernel("Kernel ade access", regs);

	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);



out:

	irqentry_exit(regs, state);

}