da929f6af4
Analysis of the assembly code shows that when using user_mode(regs), at least the 'andi.' is redone all the time, and also the 'lwz ,132(r31)' most of the time. With the new form, the 'is_user' is mapped to cr4, then all further use of is_user results in just things like 'beq cr4,218 <do_page_fault+0x218>' Without the patch: 50: 81 1e 00 84 lwz r8,132(r30) 54: 71 09 40 00 andi. r9,r8,16384 58: 40 82 00 0c bne 64 <do_page_fault+0x64> 84: 81 3e 00 84 lwz r9,132(r30) 8c: 71 2a 40 00 andi. r10,r9,16384 90: 41 a2 01 64 beq 1f4 <do_page_fault+0x1f4> d4: 81 3e 00 84 lwz r9,132(r30) dc: 71 28 40 00 andi. r8,r9,16384 e0: 41 82 02 08 beq 2e8 <do_page_fault+0x2e8> 108: 81 3e 00 84 lwz r9,132(r30) 110: 71 28 40 00 andi. r8,r9,16384 118: 41 82 02 28 beq 340 <do_page_fault+0x340> 1e4: 81 3e 00 84 lwz r9,132(r30) 1e8: 71 2a 40 00 andi. r10,r9,16384 1ec: 40 82 01 68 bne 354 <do_page_fault+0x354> 228: 81 3e 00 84 lwz r9,132(r30) 22c: 71 28 40 00 andi. r8,r9,16384 230: 41 82 ff c4 beq 1f4 <do_page_fault+0x1f4> 288: 71 2a 40 00 andi. r10,r9,16384 294: 41 a2 fe 60 beq f4 <do_page_fault+0xf4> 50c: 81 3e 00 84 lwz r9,132(r30) 514: 71 2a 40 00 andi. r10,r9,16384 518: 40 a2 fc e0 bne 1f8 <do_page_fault+0x1f8> 534: 81 3e 00 84 lwz r9,132(r30) 53c: 71 2a 40 00 andi. r10,r9,16384 540: 41 82 fc b8 beq 1f8 <do_page_fault+0x1f8> This patch creates a local var called 'is_user' which contains the result of user_mode(regs) With the patch: 20: 81 03 00 84 lwz r8,132(r3) 48: 55 09 97 fe rlwinm r9,r8,18,31,31 58: 2e 09 00 00 cmpwi cr4,r9,0 5c: 40 92 00 0c bne cr4,68 <do_page_fault+0x68> 88: 41 b2 01 90 beq cr4,218 <do_page_fault+0x218> d4: 40 92 01 d0 bne cr4,2a4 <do_page_fault+0x2a4> 120: 41 b2 00 f8 beq cr4,218 <do_page_fault+0x218> 138: 41 b2 ff a0 beq cr4,d8 <do_page_fault+0xd8> 1d4: 40 92 00 e0 bne cr4,2b4 <do_page_fault+0x2b4> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> |
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.. | ||
8xx_mmu.c | ||
40x_mmu.c | ||
44x_mmu.c | ||
copro_fault.c | ||
dma-noncoherent.c | ||
dump_hashpagetable.c | ||
dump_linuxpagetables.c | ||
fault.c | ||
fsl_booke_mmu.c | ||
hash64_4k.c | ||
hash64_64k.c | ||
hash_low_32.S | ||
hash_native_64.c | ||
hash_utils_64.c | ||
highmem.c | ||
hugepage-hash64.c | ||
hugetlbpage-book3e.c | ||
hugetlbpage-hash64.c | ||
hugetlbpage-radix.c | ||
hugetlbpage.c | ||
icswx.c | ||
icswx.h | ||
icswx_pid.c | ||
init-common.c | ||
init_32.c | ||
init_64.c | ||
Makefile | ||
mem.c | ||
mmap.c | ||
mmu_context_book3s64.c | ||
mmu_context_hash32.c | ||
mmu_context_iommu.c | ||
mmu_context_nohash.c | ||
mmu_decl.h | ||
numa.c | ||
pgtable-book3e.c | ||
pgtable-book3s64.c | ||
pgtable-hash64.c | ||
pgtable-radix.c | ||
pgtable.c | ||
pgtable_32.c | ||
pgtable_64.c | ||
ppc_mmu_32.c | ||
slb.c | ||
slb_low.S | ||
slice.c | ||
subpage-prot.c | ||
tlb-radix.c | ||
tlb_hash32.c | ||
tlb_hash64.c | ||
tlb_low_64e.S | ||
tlb_nohash.c | ||
tlb_nohash_low.S | ||
vphn.c | ||
vphn.h |