ARM: net: bpf: correct stack layout documentation (0005e55a) · Commits · 戴 / test

arch/arm/net/bpf_jit_32.c

+27 −8

Original line number	Diff line number	Diff line
		@@ -28,24 +28,43 @@
		int bpf_jit_enable __read_mostly;

		/*
		* eBPF prog stack layout
		* eBPF prog stack layout:
		*
		* high
		* original ARM_SP => +-----+ eBPF prologue
		* \|FP/LR\|
		* current ARM_FP => +-----+
		* \| ... \| callee saved registers
		* eBPF fp register => +-----+ <= (BPF_FP)
		* original ARM_SP => +-----+
		* \| \| callee saved registers
		* +-----+ <= (BPF_FP + SCRATCH_SIZE)
		* \| ... \| eBPF JIT scratch space
		* \| \| eBPF prog stack
		* eBPF fp register => +-----+
		* (BPF_FP) \| ... \| eBPF prog stack
		* +-----+
		* \|RSVD \| JIT scratchpad
		* current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE)
		* current ARM_SP => +-----+ <= (BPF_FP - STACK_SIZE + SCRATCH_SIZE)
		* \| \|
		* \| ... \| Function call stack
		* \| \|
		* +-----+
		* low
		*
		* The callee saved registers depends on whether frame pointers are enabled.
		* With frame pointers (to be compliant with the ABI):
		*
		* high
		* original ARM_SP => +------------------+ \
		* \| pc \| \|
		* current ARM_FP => +------------------+ } callee saved registers
		* \|r4-r8,r10,fp,ip,lr\| \|
		* +------------------+ /
		* low
		*
		* Without frame pointers:
		*
		* high
		* original ARM_SP => +------------------+
		* \| lr \| (optional)
		* \| r4-r8,r10 \| callee saved registers
		* +------------------+
		* low
		*/

		#define STACK_OFFSET(k) (k)