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由 Russell King 提交于
The compiler does not conditionalize the assembly instructions for the tlb operations, which leads to sub-optimal code being generated when building a kernel for multiple CPUs. We can tweak things fairly simply as the code fragment below shows: 17f8: e3120001 tst r2, #1 ; 0x1 ... 1800: 0a000000 beq 1808 <handle_pte_fault+0x194> 1804: ee061f10 mcr 15, 0, r1, cr6, cr0, {0} 1808: e3120004 tst r2, #4 ; 0x4 180c: 0a000000 beq 1814 <handle_pte_fault+0x1a0> 1810: ee081f36 mcr 15, 0, r1, cr8, cr6, {1} becomes: 17f0: e3120001 tst r2, #1 ; 0x1 17f4: 1e063f10 mcrne 15, 0, r3, cr6, cr0, {0} 17f8: e3120004 tst r2, #4 ; 0x4 17fc: 1e083f36 mcrne 15, 0, r3, cr8, cr6, {1} Overall, for Realview with V6 and V7 CPUs configured: text data bss dec hex filename 4153998 207340 5371036 9732374 948116 ../build/realview/vmlinux.before 4153366 207332 5371036 9731734 947e96 ../build/realview/vmlinux.after Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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