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Commit bef8968d authored by Russell King's avatar Russell King Committed by Daniel Borkmann
Browse files

ARM: net: bpf: always use odd/even register pair 



Always use an odd/even register pair for our 64-bit registers, so that
we're able to use the double-word load/store instructions in the future.

Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent b5045229

arch/arm/net/bpf_jit_32.c

+14 −14
Original line number Diff line number Diff line
@@ -48,26 +48,26 @@ 
 * With frame pointers (to be compliant with the ABI):

 *

 *                              high

 * original ARM_SP =>     +------------------+ \

 * original ARM_SP =>     +--------------+ \

 *                        |      pc      | |

 * current ARM_FP =>      +------------------+ } callee saved registers

 *                        |r4-r8,r10,fp,ip,lr| |

 *                        +------------------+ /

 * current ARM_FP =>      +--------------+ } callee saved registers

 *                        |r4-r9,fp,ip,lr| |

 *                        +--------------+ /

 *                              low

 *

 * Without frame pointers:

 *

 *                              high

 * original ARM_SP =>     +------------------+

 *                        | r4-r8,r10,fp,lr  | callee saved registers

 * current ARM_FP =>      +------------------+

 * original ARM_SP =>     +--------------+

 *                        |  r4-r9,fp,lr | callee saved registers

 * current ARM_FP =>      +--------------+

 *                              low

 *

 * When popping registers off the stack at the end of a BPF function, we

 * reference them via the current ARM_FP register.

 */

#define CALLEE_MASK	(1 << ARM_R4 | 1 << ARM_R5 | 1 << ARM_R6 | \

			 1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R10 | \

			 1 << ARM_R7 | 1 << ARM_R8 | 1 << ARM_R9 | \

			 1 << ARM_FP)

#define CALLEE_PUSH_MASK (CALLEE_MASK | 1 << ARM_LR)

#define CALLEE_POP_MASK  (CALLEE_MASK | 1 << ARM_PC)
@@ -157,7 +157,7 @@ static const s8 bpf2a32[][2] = { 
	 * for constant blindings and others.

	 */

	[TMP_REG_1] = {ARM_R7, ARM_R6},

	[TMP_REG_2] = {ARM_R10, ARM_R8},

	[TMP_REG_2] = {ARM_R9, ARM_R8},

	/* Tail call count. Stored on stack scratch space. */

	[TCALL_CNT] = {STACK_OFFSET(BPF_TC_HI), STACK_OFFSET(BPF_TC_LO)},

	/* temporary register for blinding constants.