Commit 1acbf27e authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/code-patching: Inline is_offset_in_{cond}_branch_range() 



Test in is_offset_in_branch_range() and is_offset_in_cond_branch_range()
are simple tests that are worth inlining.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a05be0ccb7373e6a9789a1988fcd0c810f5f9269.1652074503.git.christophe.leroy@csgroup.eu
parent ae3a2a21

arch/powerpc/include/asm/code-patching.h

+27 −2
Original line number Diff line number Diff line
@@ -24,8 +24,33 @@ 


DECLARE_STATIC_KEY_FALSE(init_mem_is_free);



bool is_offset_in_branch_range(long offset);

bool is_offset_in_cond_branch_range(long offset);

/*

 * Powerpc branch instruction is :

 *

 *  0         6                 30   31

 *  +---------+----------------+---+---+

 *  | opcode  |     LI         |AA |LK |

 *  +---------+----------------+---+---+

 *  Where AA = 0 and LK = 0

 *

 * LI is a signed 24 bits integer. The real branch offset is computed

 * by: imm32 = SignExtend(LI:'0b00', 32);

 *

 * So the maximum forward branch should be:

 *   (0x007fffff << 2) = 0x01fffffc =  0x1fffffc

 * The maximum backward branch should be:

 *   (0xff800000 << 2) = 0xfe000000 = -0x2000000

 */

static inline bool is_offset_in_branch_range(long offset)

{

	return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));

}



static inline bool is_offset_in_cond_branch_range(long offset)

{

	return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);

}



int create_branch(ppc_inst_t *instr, const u32 *addr,

		  unsigned long target, int flags);

int create_cond_branch(ppc_inst_t *instr, const u32 *addr,

arch/powerpc/lib/code-patching.c

+0 −27
Original line number Diff line number Diff line
@@ -214,33 +214,6 @@ int patch_branch(u32 *addr, unsigned long target, int flags) 
	return patch_instruction(addr, instr);

}



bool is_offset_in_branch_range(long offset)

{

	/*

	 * Powerpc branch instruction is :

	 *

	 *  0         6                 30   31

	 *  +---------+----------------+---+---+

	 *  | opcode  |     LI         |AA |LK |

	 *  +---------+----------------+---+---+

	 *  Where AA = 0 and LK = 0

	 *

	 * LI is a signed 24 bits integer. The real branch offset is computed

	 * by: imm32 = SignExtend(LI:'0b00', 32);

	 *

	 * So the maximum forward branch should be:

	 *   (0x007fffff << 2) = 0x01fffffc =  0x1fffffc

	 * The maximum backward branch should be:

	 *   (0xff800000 << 2) = 0xfe000000 = -0x2000000

	 */

	return (offset >= -0x2000000 && offset <= 0x1fffffc && !(offset & 0x3));

}



bool is_offset_in_cond_branch_range(long offset)

{

	return offset >= -0x8000 && offset <= 0x7fff && !(offset & 0x3);

}



/*

 * Helper to check if a given instruction is a conditional branch

 * Derived from the conditional checks in analyse_instr()