linux-stable/arch/powerpc/kernel/misc.S
Paul Mackerras e31aa453bb powerpc: Use LOAD_REG_IMMEDIATE only for constants on 64-bit
Using LOAD_REG_IMMEDIATE to get the address of kernel symbols
generates 5 instructions where LOAD_REG_ADDR can do it in one,
and will generate R_PPC64_ADDR16_* relocations in the output when
we get to making the kernel as a position-independent executable,
which we'd rather not have to handle.  This changes various bits
of assembly code to use LOAD_REG_ADDR when we need to get the
address of a symbol, or to use suitable position-independent code
for cases where we can't access the TOC for various reasons, or
if we're not running at the address we were linked at.

It also cleans up a few minor things; there's no reason to save and
restore SRR0/1 around RTAS calls, __mmu_off can get the return
address from LR more conveniently than the caller can supply it in
R4 (and we already assume elsewhere that EA == RA if the MMU is on
in early boot), and enable_64b_mode was using 5 instructions where
2 would do.

Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-09-15 11:08:35 -07:00

129 lines
2.5 KiB
ArmAsm

/*
* This file contains miscellaneous low-level functions.
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
*
* Adapted for iSeries by Mike Corrigan (mikejc@us.ibm.com)
* PPC64 updates by Dave Engebretsen (engebret@us.ibm.com)
*
* setjmp/longjmp code by Paul Mackerras.
*
* 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>
#include <asm/unistd.h>
#include <asm/asm-compat.h>
#include <asm/asm-offsets.h>
.text
/*
* Returns (address we are running at) - (address we were linked at)
* for use before the text and data are mapped to KERNELBASE.
*/
_GLOBAL(reloc_offset)
mflr r0
bl 1f
1: mflr r3
PPC_LL r4,(2f-1b)(r3)
subf r3,r4,r3
mtlr r0
blr
.align 3
2: PPC_LONG 1b
/*
* add_reloc_offset(x) returns x + reloc_offset().
*/
_GLOBAL(add_reloc_offset)
mflr r0
bl 1f
1: mflr r5
PPC_LL r4,(2f-1b)(r5)
subf r5,r4,r5
add r3,r3,r5
mtlr r0
blr
.align 3
2: PPC_LONG 1b
_GLOBAL(kernel_execve)
li r0,__NR_execve
sc
bnslr
neg r3,r3
blr
_GLOBAL(setjmp)
mflr r0
PPC_STL r0,0(r3)
PPC_STL r1,SZL(r3)
PPC_STL r2,2*SZL(r3)
mfcr r0
PPC_STL r0,3*SZL(r3)
PPC_STL r13,4*SZL(r3)
PPC_STL r14,5*SZL(r3)
PPC_STL r15,6*SZL(r3)
PPC_STL r16,7*SZL(r3)
PPC_STL r17,8*SZL(r3)
PPC_STL r18,9*SZL(r3)
PPC_STL r19,10*SZL(r3)
PPC_STL r20,11*SZL(r3)
PPC_STL r21,12*SZL(r3)
PPC_STL r22,13*SZL(r3)
PPC_STL r23,14*SZL(r3)
PPC_STL r24,15*SZL(r3)
PPC_STL r25,16*SZL(r3)
PPC_STL r26,17*SZL(r3)
PPC_STL r27,18*SZL(r3)
PPC_STL r28,19*SZL(r3)
PPC_STL r29,20*SZL(r3)
PPC_STL r30,21*SZL(r3)
PPC_STL r31,22*SZL(r3)
li r3,0
blr
_GLOBAL(longjmp)
PPC_LCMPI r4,0
bne 1f
li r4,1
1: PPC_LL r13,4*SZL(r3)
PPC_LL r14,5*SZL(r3)
PPC_LL r15,6*SZL(r3)
PPC_LL r16,7*SZL(r3)
PPC_LL r17,8*SZL(r3)
PPC_LL r18,9*SZL(r3)
PPC_LL r19,10*SZL(r3)
PPC_LL r20,11*SZL(r3)
PPC_LL r21,12*SZL(r3)
PPC_LL r22,13*SZL(r3)
PPC_LL r23,14*SZL(r3)
PPC_LL r24,15*SZL(r3)
PPC_LL r25,16*SZL(r3)
PPC_LL r26,17*SZL(r3)
PPC_LL r27,18*SZL(r3)
PPC_LL r28,19*SZL(r3)
PPC_LL r29,20*SZL(r3)
PPC_LL r30,21*SZL(r3)
PPC_LL r31,22*SZL(r3)
PPC_LL r0,3*SZL(r3)
mtcrf 0x38,r0
PPC_LL r0,0(r3)
PPC_LL r1,SZL(r3)
PPC_LL r2,2*SZL(r3)
mtlr r0
mr r3,r4
blr
_GLOBAL(__setup_cpu_power7)
_GLOBAL(__restore_cpu_power7)
/* place holder */
blr