Initial import

1 files changed, 209 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/reloc_32.S b/arch/powerpc/kernel/reloc_32.S
new file mode 100644
index 000000000..f366fedb0
--- /dev/null
+++ b/arch/powerpc/kernel/reloc_32.S
@@ -0,0 +1,209 @@
+/*
+ * Code to process dynamic relocations for PPC32.
+ *
+ * Copyrights (C) IBM Corporation, 2011.
+ *	Author: Suzuki Poulose <suzuki@in.ibm.com>
+ *
+ *  - Based on ppc64 code - reloc_64.S
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <asm/ppc_asm.h>
+
+/* Dynamic section table entry tags */
+DT_RELA = 7			/* Tag for Elf32_Rela section */
+DT_RELASZ = 8			/* Size of the Rela relocs */
+DT_RELAENT = 9			/* Size of one Rela reloc entry */
+
+STN_UNDEF = 0			/* Undefined symbol index */
+STB_LOCAL = 0			/* Local binding for the symbol */
+
+R_PPC_ADDR16_LO = 4		/* Lower half of (S+A) */
+R_PPC_ADDR16_HI = 5		/* Upper half of (S+A) */
+R_PPC_ADDR16_HA = 6		/* High Adjusted (S+A) */
+R_PPC_RELATIVE = 22
+
+/*
+ * r3 = desired final address
+ */
+
+_GLOBAL(relocate)
+
+	mflr	r0		/* Save our LR */
+	bl	0f		/* Find our current runtime address */
+0:	mflr	r12		/* Make it accessible */
+	mtlr	r0
+
+	lwz	r11, (p_dyn - 0b)(r12)
+	add	r11, r11, r12	/* runtime address of .dynamic section */
+	lwz	r9, (p_rela - 0b)(r12)
+	add	r9, r9, r12	/* runtime address of .rela.dyn section */
+	lwz	r10, (p_st - 0b)(r12)
+	add	r10, r10, r12	/* runtime address of _stext section */
+	lwz	r13, (p_sym - 0b)(r12)
+	add	r13, r13, r12	/* runtime address of .dynsym section */
+
+	/*
+	 * Scan the dynamic section for RELA, RELASZ entries
+	 */
+	li	r6, 0
+	li	r7, 0
+	li	r8, 0
+1:	lwz	r5, 0(r11)	/* ELF_Dyn.d_tag */
+	cmpwi	r5, 0		/* End of ELF_Dyn[] */
+	beq	eodyn
+	cmpwi	r5, DT_RELA
+	bne	relasz
+	lwz	r7, 4(r11)	/* r7 = rela.link */
+	b	skip
+relasz:
+	cmpwi	r5, DT_RELASZ
+	bne	relaent
+	lwz	r8, 4(r11)	/* r8 = Total Rela relocs size */
+	b	skip
+relaent:
+	cmpwi	r5, DT_RELAENT
+	bne	skip
+	lwz	r6, 4(r11)	/* r6 = Size of one Rela reloc */
+skip:
+	addi	r11, r11, 8
+	b	1b
+eodyn:				/* End of Dyn Table scan */
+
+	/* Check if we have found all the entries */
+	cmpwi	r7, 0
+	beq	done
+	cmpwi	r8, 0
+	beq	done
+	cmpwi	r6, 0
+	beq	done
+
+
+	/*
+	 * Work out the current offset from the link time address of .rela
+	 * section.
+	 *  cur_offset[r7] = rela.run[r9] - rela.link [r7]
+	 *  _stext.link[r12] = _stext.run[r10] - cur_offset[r7]
+	 *  final_offset[r3] = _stext.final[r3] - _stext.link[r12]
+	 */
+	subf	r7, r7, r9	/* cur_offset */
+	subf	r12, r7, r10
+	subf	r3, r12, r3	/* final_offset */
+
+	subf	r8, r6, r8	/* relaz -= relaent */
+	/*
+	 * Scan through the .rela table and process each entry
+	 * r9	- points to the current .rela table entry
+	 * r13	- points to the symbol table
+	 */
+
+	/*
+	 * Check if we have a relocation based on symbol
+	 * r5 will hold the value of the symbol.
+	 */
+applyrela:
+	lwz	r4, 4(r9)		/* r4 = rela.r_info */
+	srwi	r5, r4, 8		/* ELF32_R_SYM(r_info) */
+	cmpwi	r5, STN_UNDEF	/* sym == STN_UNDEF ? */
+	beq	get_type	/* value = 0 */
+	/* Find the value of the symbol at index(r5) */
+	slwi	r5, r5, 4		/* r5 = r5 * sizeof(Elf32_Sym) */
+	add	r12, r13, r5	/* r12 = &__dyn_sym[Index] */
+
+	/*
+	 * GNU ld has a bug, where dynamic relocs based on
+	 * STB_LOCAL symbols, the value should be assumed
+	 * to be zero. - Alan Modra
+	 */
+	/* XXX: Do we need to check if we are using GNU ld ? */
+	lbz	r5, 12(r12)	/* r5 = dyn_sym[Index].st_info */
+	extrwi	r5, r5, 4, 24	/* r5 = ELF32_ST_BIND(r5) */
+	cmpwi	r5, STB_LOCAL	/* st_value = 0, ld bug */
+	beq	get_type	/* We have r5 = 0 */
+	lwz	r5, 4(r12)	/* r5 = __dyn_sym[Index].st_value */
+
+get_type:
+	/* Load the relocation type to r4 */
+	extrwi	r4, r4, 8, 24	/* r4 = ELF32_R_TYPE(r_info) = ((char*)r4)[3] */
+
+	/* R_PPC_RELATIVE */
+	cmpwi	r4, R_PPC_RELATIVE
+	bne	hi16
+	lwz	r4, 0(r9)	/* r_offset */
+	lwz	r0, 8(r9)	/* r_addend */
+	add	r0, r0, r3	/* final addend */
+	stwx	r0, r4, r7	/* memory[r4+r7]) = (u32)r0 */
+	b	nxtrela		/* continue */
+
+	/* R_PPC_ADDR16_HI */
+hi16:
+	cmpwi	r4, R_PPC_ADDR16_HI
+	bne	ha16
+	lwz	r4, 0(r9)	/* r_offset */
+	lwz	r0, 8(r9)	/* r_addend */
+	add	r0, r0, r3
+	add	r0, r0, r5	/* r0 = (S+A+Offset) */
+	extrwi	r0, r0, 16, 0	/* r0 = (r0 >> 16) */
+	b	store_half
+
+	/* R_PPC_ADDR16_HA */
+ha16:
+	cmpwi	r4, R_PPC_ADDR16_HA
+	bne	lo16
+	lwz	r4, 0(r9)	/* r_offset */
+	lwz	r0, 8(r9)	/* r_addend */
+	add	r0, r0, r3
+	add	r0, r0, r5	/* r0 = (S+A+Offset) */
+	extrwi	r5, r0, 1, 16	/* Extract bit 16 */
+	extrwi	r0, r0, 16, 0	/* r0 = (r0 >> 16) */
+	add	r0, r0, r5	/* Add it to r0 */
+	b	store_half
+
+	/* R_PPC_ADDR16_LO */
+lo16:
+	cmpwi	r4, R_PPC_ADDR16_LO
+	bne	unknown_type
+	lwz	r4, 0(r9)	/* r_offset */
+	lwz	r0, 8(r9)	/* r_addend */
+	add	r0, r0, r3
+	add	r0, r0, r5	/* r0 = (S+A+Offset) */
+	extrwi	r0, r0, 16, 16	/* r0 &= 0xffff */
+	/* Fall through to */
+
+	/* Store half word */
+store_half:
+	sthx	r0, r4, r7	/* memory[r4+r7] = (u16)r0 */
+
+nxtrela:
+	/*
+	 * We have to flush the modified instructions to the
+	 * main storage from the d-cache. And also, invalidate the
+	 * cached instructions in i-cache which has been modified.
+	 *
+	 * We delay the sync / isync operation till the end, since
+	 * we won't be executing the modified instructions until
+	 * we return from here.
+	 */
+	dcbst	r4,r7
+	sync			/* Ensure the data is flushed before icbi */
+	icbi	r4,r7
+unknown_type:
+	cmpwi	r8, 0		/* relasz = 0 ? */
+	ble	done
+	add	r9, r9, r6	/* move to next entry in the .rela table */
+	subf	r8, r6, r8	/* relasz -= relaent */
+	b	applyrela
+
+done:
+	sync			/* Wait for the flush to finish */
+	isync			/* Discard prefetched instructions */
+	blr
+
+p_dyn:		.long	__dynamic_start - 0b
+p_rela:		.long	__rela_dyn_start - 0b
+p_sym:		.long	__dynamic_symtab - 0b
+p_st:		.long	_stext - 0b