|author||Paul Mackerras <email@example.com>||2008-08-30 11:41:12 +1000|
|committer||Paul Mackerras <firstname.lastname@example.org>||2008-09-15 11:08:35 -0700|
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 <email@example.com>
Diffstat (limited to 'arch/powerpc/include/asm/ppc_asm.h')
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h
index 0966899d974..c4a029ccb4d 100644
@@ -268,7 +268,7 @@ n:
* Loads the value of the constant expression 'expr' into register 'rn'
* using immediate instructions only. Use this when it's important not
* to reference other data (i.e. on ppc64 when the TOC pointer is not
- * valid).
+ * valid) and when 'expr' is a constant or absolute address.
* LOAD_REG_ADDR(rn, name)
* Loads the address of label 'name' into register 'rn'. Use this when