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authorChristophe Leroy <christophe.leroy@c-s.fr>2019-08-20 14:34:12 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2019-08-27 13:03:36 +1000
commitc691b4b83b6a348f7b9d13c36916e73c2e1d85e4 (patch)
tree86e35a779a1f8eea5dfa32654d4afff910c32aa5 /arch/powerpc/kernel/exceptions-64e.S
parent163918fc5741d755cf9d477ebfcb761f09b82982 (diff)
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powerpc: rewrite LOAD_REG_IMMEDIATE() as an intelligent macro
Today LOAD_REG_IMMEDIATE() is a basic #define which loads all parts on a value into a register, including the parts that are NUL. This means always 2 instructions on PPC32 and always 5 instructions on PPC64. And those instructions cannot run in parallele as they are updating the same register. Ex: LOAD_REG_IMMEDIATE(r1,THREAD_SIZE) in head_64.S results in: 3c 20 00 00 lis r1,0 60 21 00 00 ori r1,r1,0 78 21 07 c6 rldicr r1,r1,32,31 64 21 00 00 oris r1,r1,0 60 21 40 00 ori r1,r1,16384 Rewrite LOAD_REG_IMMEDIATE() with GAS macro in order to skip the parts that are NUL. Rename existing LOAD_REG_IMMEDIATE() as LOAD_REG_IMMEDIATE_SYM() and use that one for loading value of symbols which are not known at compile time. Now LOAD_REG_IMMEDIATE(r1,THREAD_SIZE) in head_64.S results in: 38 20 40 00 li r1,16384 Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/d60ce8dd3a383c7adbfc322bf1d53d81724a6000.1566311636.git.christophe.leroy@c-s.fr
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64e.S')
-rw-r--r--arch/powerpc/kernel/exceptions-64e.S10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
index 1cfb3da4a84a..898aae6da167 100644
--- a/arch/powerpc/kernel/exceptions-64e.S
+++ b/arch/powerpc/kernel/exceptions-64e.S
@@ -751,8 +751,8 @@ END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
ld r14,interrupt_base_book3e@got(r15)
ld r15,__end_interrupts@got(r15)
#else
- LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e)
- LOAD_REG_IMMEDIATE(r15,__end_interrupts)
+ LOAD_REG_IMMEDIATE_SYM(r14,interrupt_base_book3e)
+ LOAD_REG_IMMEDIATE_SYM(r15,__end_interrupts)
#endif
cmpld cr0,r10,r14
cmpld cr1,r10,r15
@@ -821,8 +821,8 @@ kernel_dbg_exc:
ld r14,interrupt_base_book3e@got(r15)
ld r15,__end_interrupts@got(r15)
#else
- LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e)
- LOAD_REG_IMMEDIATE(r15,__end_interrupts)
+ LOAD_REG_IMMEDIATE_SYM(r14,interrupt_base_book3e)
+ LOAD_REG_IMMEDIATE_SYM(r15,__end_interrupts)
#endif
cmpld cr0,r10,r14
cmpld cr1,r10,r15
@@ -1449,7 +1449,7 @@ a2_tlbinit_code_start:
a2_tlbinit_after_linear_map:
/* Now we branch the new virtual address mapped by this entry */
- LOAD_REG_IMMEDIATE(r3,1f)
+ LOAD_REG_IMMEDIATE_SYM(r3,1f)
mtctr r3
bctr