Commit d1220efd authored by Russell King's avatar Russell King
Browse files

ARM: net: bpf: fix stack alignment 



As per 2dede2d8 ("ARM EABI: stack pointer must be 64-bit aligned
after a CPU exception") the stack should be aligned to a 64-bit boundary
on EABI systems.  Ensure that the eBPF JIT appropraitely aligns the
stack.

Fixes: 39c13c20 ("arm: eBPF JIT compiler")
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent f4483f2c

arch/arm/net/bpf_jit_32.c

+8 −3
Original line number Diff line number Diff line
@@ -179,8 +179,13 @@ static void jit_fill_hole(void *area, unsigned int size) 
		*ptr++ = __opcode_to_mem_arm(ARM_INST_UDF);

}



/* Stack must be multiples of 16 Bytes */

#define STACK_ALIGN(sz) (((sz) + 3) & ~3)

#if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)

/* EABI requires the stack to be aligned to 64-bit boundaries */

#define STACK_ALIGNMENT	8

#else

/* Stack must be aligned to 32-bit boundaries */

#define STACK_ALIGNMENT	4

#endif



/* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4,

 * BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9,
@@ -194,7 +199,7 @@ static void jit_fill_hole(void *area, unsigned int size) 
	 + SCRATCH_SIZE + \

	 + 4 /* extra for skb_copy_bits buffer */)



#define STACK_SIZE STACK_ALIGN(_STACK_SIZE)

#define STACK_SIZE ALIGN(_STACK_SIZE, STACK_ALIGNMENT)



/* Get the offset of eBPF REGISTERs stored on scratch space. */

#define STACK_VAR(off) (STACK_SIZE-off-4)

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