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: Chenghao Duan <[email protected]> --- arch/loongarch/kernel/traps.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c index 004b8ebf0051..201c9a5532f4 100644 --- a/arch/loongarch/kernel/traps.c +++ b/arch/loongarch/kernel/traps.c @@ -534,11 +534,18 @@ 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); + irqentry_state_t state; + unsigned int esubcode = FIELD_GET(CSR_ESTAT_ESUBCODE, regs->csr_estat); + + state = irqentry_enter(regs); + + 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); } -- 2.25.1
