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| author | Paul Mackerras <paulus@samba.org> | 2008-08-30 11:41:12 +1000 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-09-15 11:08:35 -0700 |
| commit | e31aa453bbc4886a7bd33e5c2afa526d6f55bd7a (patch) | |
| tree | fefa13c13d7b1803fdaeb92143f83b1971f0ec8d /arch/powerpc/kernel/entry_64.S | |
| parent | 1f6a93e4c35e75d547b51f56ba8139ab1a91628c (diff) | |
| download | linux-stable-e31aa453bbc4886a7bd33e5c2afa526d6f55bd7a.tar.gz linux-stable-e31aa453bbc4886a7bd33e5c2afa526d6f55bd7a.tar.bz2 linux-stable-e31aa453bbc4886a7bd33e5c2afa526d6f55bd7a.zip | |
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/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 55445f1dba8a..fd8b4bae9b04 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -690,10 +690,6 @@ _GLOBAL(enter_rtas) std r7,_DAR(r1) mfdsisr r8 std r8,_DSISR(r1) - mfsrr0 r9 - std r9,_SRR0(r1) - mfsrr1 r10 - std r10,_SRR1(r1) /* Temporary workaround to clear CR until RTAS can be modified to * ignore all bits. @@ -754,6 +750,10 @@ _STATIC(rtas_return_loc) mfspr r4,SPRN_SPRG3 /* Get PACA */ clrldi r4,r4,2 /* convert to realmode address */ + bcl 20,31,$+4 +0: mflr r3 + ld r3,(1f-0b)(r3) /* get &.rtas_restore_regs */ + mfmsr r6 li r0,MSR_RI andc r6,r6,r0 @@ -761,7 +761,6 @@ _STATIC(rtas_return_loc) mtmsrd r6 ld r1,PACAR1(r4) /* Restore our SP */ - LOAD_REG_IMMEDIATE(r3,.rtas_restore_regs) ld r4,PACASAVEDMSR(r4) /* Restore our MSR */ mtspr SPRN_SRR0,r3 @@ -769,6 +768,9 @@ _STATIC(rtas_return_loc) rfid b . /* prevent speculative execution */ + .align 3 +1: .llong .rtas_restore_regs + _STATIC(rtas_restore_regs) /* relocation is on at this point */ REST_GPR(2, r1) /* Restore the TOC */ @@ -788,10 +790,6 @@ _STATIC(rtas_restore_regs) mtdar r7 ld r8,_DSISR(r1) mtdsisr r8 - ld r9,_SRR0(r1) - mtsrr0 r9 - ld r10,_SRR1(r1) - mtsrr1 r10 addi r1,r1,RTAS_FRAME_SIZE /* Unstack our frame */ ld r0,16(r1) /* get return address */ |