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authorPaul Mackerras <paulus@samba.org>2008-08-30 11:41:12 +1000
committerPaul Mackerras <paulus@samba.org>2008-09-15 11:08:35 -0700
commite31aa453bbc4886a7bd33e5c2afa526d6f55bd7a (patch)
treefefa13c13d7b1803fdaeb92143f83b1971f0ec8d /arch/powerpc/kernel/misc.S
parent1f6a93e4c35e75d547b51f56ba8139ab1a91628c (diff)
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>
Diffstat (limited to 'arch/powerpc/kernel/misc.S')
-rw-r--r--arch/powerpc/kernel/misc.S10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S
index 85cb6f34084..2d29752cbe1 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -31,11 +31,14 @@ _GLOBAL(reloc_offset)
mflr r0
bl 1f
1: mflr r3
- LOAD_REG_IMMEDIATE(r4,1b)
+ 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().
*/
@@ -43,12 +46,15 @@ _GLOBAL(add_reloc_offset)
mflr r0
bl 1f
1: mflr r5
- LOAD_REG_IMMEDIATE(r4,1b)
+ 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