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Commit a2b6f26c authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/module64: Use symbolic instructions names. 



To increase readability/maintainability, replace hard coded
instructions values by symbolic names.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
[mpe: Fix R_PPC64_ENTRY case, the addi reads from r2 not r12]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 4eb4516e

arch/powerpc/kernel/module_64.c

+35 −18
Original line number Diff line number Diff line
@@ -133,20 +133,27 @@ struct ppc64_stub_entry 
 * the stub, but it's significantly shorter to put these values at the

 * end of the stub code, and patch the stub address (32-bits relative

 * to the TOC ptr, r2) into the stub.

 *

 * addis   r11,r2, <high>

 * addi    r11,r11, <low>

 * std     r2,R2_STACK_OFFSET(r1)

 * ld      r12,32(r11)

 * ld      r2,40(r11)

 * mtctr   r12

 * bctr

 */



static u32 ppc64_stub_insns[] = {

	0x3d620000,			/* addis   r11,r2, <high> */

	0x396b0000,			/* addi    r11,r11, <low> */

	PPC_INST_ADDIS | __PPC_RT(R11) | __PPC_RA(R2),

	PPC_INST_ADDI | __PPC_RT(R11) | __PPC_RA(R11),

	/* Save current r2 value in magic place on the stack. */

	0xf8410000|R2_STACK_OFFSET,	/* std     r2,R2_STACK_OFFSET(r1) */

	0xe98b0020,			/* ld      r12,32(r11) */

	PPC_INST_STD | __PPC_RS(R2) | __PPC_RA(R1) | R2_STACK_OFFSET,

	PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R11) | 32,

#ifdef PPC64_ELF_ABI_v1

	/* Set up new r2 from function descriptor */

	0xe84b0028,			/* ld      r2,40(r11) */

	PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R11) | 40,

#endif

	0x7d8903a6,			/* mtctr   r12 */

	0x4e800420			/* bctr */

	PPC_INST_MTCTR | __PPC_RS(R12),

	PPC_INST_BCTR,

};



#ifdef CONFIG_DYNAMIC_FTRACE
@@ -704,18 +711,21 @@ int apply_relocate_add(Elf64_Shdr *sechdrs, 
		         *	ld r2, ...(r12)

			 *	add r2, r2, r12

			 */

			if ((((uint32_t *)location)[0] & ~0xfffc)

			    != 0xe84c0000)

			if ((((uint32_t *)location)[0] & ~0xfffc) !=

			    (PPC_INST_LD | __PPC_RT(R2) | __PPC_RA(R12)))

				break;

			if (((uint32_t *)location)[1] != 0x7c426214)

			if (((uint32_t *)location)[1] !=

			    (PPC_INST_ADD | __PPC_RT(R2) | __PPC_RA(R2) | __PPC_RB(R12)))

				break;

			/*

			 * If found, replace it with:

			 *	addis r2, r12, (.TOC.-func)@ha

			 *	addi  r2,  r2, (.TOC.-func)@l

			 */

			((uint32_t *)location)[0] = 0x3c4c0000 + PPC_HA(value);

			((uint32_t *)location)[1] = 0x38420000 + PPC_LO(value);

			((uint32_t *)location)[0] = PPC_INST_ADDIS | __PPC_RT(R2) |

						    __PPC_RA(R12) | PPC_HA(value);

			((uint32_t *)location)[1] = PPC_INST_ADDI | __PPC_RT(R2) |

						    __PPC_RA(R2) | PPC_LO(value);

			break;



		case R_PPC64_REL16_HA:
@@ -769,12 +779,19 @@ static unsigned long create_ftrace_stub(const Elf64_Shdr *sechdrs, 
{

	struct ppc64_stub_entry *entry;

	unsigned int i, num_stubs;

	/*

	 * ld      r12,PACATOC(r13)

	 * addis   r12,r12,<high>

	 * addi    r12,r12,<low>

	 * mtctr   r12

	 * bctr

	 */

	static u32 stub_insns[] = {

		0xe98d0000 | PACATOC, 	/* ld      r12,PACATOC(r13)	*/

		0x3d8c0000,		/* addis   r12,r12,<high>	*/

		0x398c0000, 		/* addi    r12,r12,<low>	*/

		0x7d8903a6, 		/* mtctr   r12			*/

		0x4e800420, 		/* bctr				*/

		PPC_INST_LD | __PPC_RT(R12) | __PPC_RA(R13) | PACATOC,

		PPC_INST_ADDIS | __PPC_RT(R12) | __PPC_RA(R12),

		PPC_INST_ADDI | __PPC_RT(R12) | __PPC_RA(R12),

		PPC_INST_MTCTR | __PPC_RS(R12),

		PPC_INST_BCTR,

	};

	long reladdr;