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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-07-14 20:52:54 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-08-20 10:12:27 +1000 |
| commit | ee43eb788b3a06425fffb912677e2e1c8b00dd3b (patch) | |
| tree | 7233cb47647837ab00af81270b3a16555d88a1f1 /arch/powerpc/mm | |
| parent | 8aa34ab8b2dc96ca6c4feecfb87ed13f0d40ef98 (diff) | |
| download | blackbird-obmc-linux-ee43eb788b3a06425fffb912677e2e1c8b00dd3b.tar.gz blackbird-obmc-linux-ee43eb788b3a06425fffb912677e2e1c8b00dd3b.zip | |
powerpc: Use names rather than numbers for SPRGs (v2)
The kernel uses SPRG registers for various purposes, typically in
low level assembly code as scratch registers or to hold per-cpu
global infos such as the PACA or the current thread_info pointer.
We want to be able to easily shuffle the usage of those registers
as some implementations have specific constraints realted to some
of them, for example, some have userspace readable aliases, etc..
and the current choice isn't always the best.
This patch should not change any code generation, and replaces the
usage of SPRN_SPRGn everywhere in the kernel with a named replacement
and adds documentation next to the definition of the names as to
what those are used for on each processor family.
The only parts that still use the original numbers are bits of KVM
or suspend/resume code that just blindly needs to save/restore all
the SPRGs.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/hash_low_32.S | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/mm/hash_low_32.S b/arch/powerpc/mm/hash_low_32.S index 14af8cedab70..b13d58932bf6 100644 --- a/arch/powerpc/mm/hash_low_32.S +++ b/arch/powerpc/mm/hash_low_32.S @@ -40,7 +40,7 @@ mmu_hash_lock: * The address is in r4, and r3 contains an access flag: * _PAGE_RW (0x400) if a write. * r9 contains the SRR1 value, from which we use the MSR_PR bit. - * SPRG3 contains the physical address of the current task's thread. + * SPRG_THREAD contains the physical address of the current task's thread. * * Returns to the caller if the access is illegal or there is no * mapping for the address. Otherwise it places an appropriate PTE @@ -68,7 +68,7 @@ _GLOBAL(hash_page) /* Get PTE (linux-style) and check access */ lis r0,KERNELBASE@h /* check if kernel address */ cmplw 0,r4,r0 - mfspr r8,SPRN_SPRG3 /* current task's THREAD (phys) */ + mfspr r8,SPRN_SPRG_THREAD /* current task's THREAD (phys) */ ori r3,r3,_PAGE_USER|_PAGE_PRESENT /* test low addresses as user */ lwz r5,PGDIR(r8) /* virt page-table root */ blt+ 112f /* assume user more likely */ |
