Commit 6aaa8b55 authored by Jon Medhurst's avatar Jon Medhurst Committed by Tixy
Browse files

ARM: kprobes: Add it_advance() 



This advances the ITSTATE bits in CPSR to their values for the next
instruction.

Signed-off-by: default avatarJon Medhurst <tixy@yxit.co.uk>
Acked-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
parent eaf4f33f

arch/arm/kernel/kprobes.h

+25 −0
Original line number Diff line number Diff line
@@ -68,6 +68,31 @@ void __init find_str_pc_offset(void); 
#endif





/*

 * Update ITSTATE after normal execution of an IT block instruction.

 *

 * The 8 IT state bits are split into two parts in CPSR:

 *	ITSTATE<1:0> are in CPSR<26:25>

 *	ITSTATE<7:2> are in CPSR<15:10>

 */

static inline unsigned long it_advance(unsigned long cpsr)

	{

	if ((cpsr & 0x06000400) == 0) {

		/* ITSTATE<2:0> == 0 means end of IT block, so clear IT state */

		cpsr &= ~PSR_IT_MASK;

	} else {

		/* We need to shift left ITSTATE<4:0> */

		const unsigned long mask = 0x06001c00;  /* Mask ITSTATE<4:0> */

		unsigned long it = cpsr & mask;

		it <<= 1;

		it |= it >> (27 - 10);  /* Carry ITSTATE<2> to correct place */

		it &= mask;

		cpsr &= ~mask;

		cpsr |= it;

	}

	return cpsr;

}



/*

 * Test if load/store instructions writeback the address register.

 * if P (bit 24) == 0 or W (bit 21) == 1