| Linus Torvalds | bafaecd | 2010-01-12 18:16:42 -0800 | [diff] [blame] | 1 | /* |
| 2 | * x86-64 rwsem wrappers |
| 3 | * |
| 4 | * This interfaces the inline asm code to the slow-path |
| 5 | * C routines. We need to save the call-clobbered regs |
| 6 | * that the asm does not mark as clobbered, and move the |
| 7 | * argument from %rax to %rdi. |
| 8 | * |
| 9 | * NOTE! We don't need to save %rax, because the functions |
| 10 | * will always return the semaphore pointer in %rax (which |
| 11 | * is also the input argument to these helpers) |
| 12 | * |
| 13 | * The following can clobber %rdx because the asm clobbers it: |
| 14 | * call_rwsem_down_write_failed |
| 15 | * call_rwsem_wake |
| 16 | * but %rdi, %rsi, %rcx, %r8-r11 always need saving. |
| 17 | */ |
| 18 | |
| 19 | #include <linux/linkage.h> |
| 20 | #include <asm/rwlock.h> |
| 21 | #include <asm/alternative-asm.h> |
| 22 | #include <asm/frame.h> |
| 23 | #include <asm/dwarf2.h> |
| 24 | |
| 25 | #define save_common_regs \ |
| 26 | pushq %rdi; \ |
| 27 | pushq %rsi; \ |
| 28 | pushq %rcx; \ |
| 29 | pushq %r8; \ |
| 30 | pushq %r9; \ |
| 31 | pushq %r10; \ |
| 32 | pushq %r11 |
| 33 | |
| 34 | #define restore_common_regs \ |
| 35 | popq %r11; \ |
| 36 | popq %r10; \ |
| 37 | popq %r9; \ |
| 38 | popq %r8; \ |
| 39 | popq %rcx; \ |
| 40 | popq %rsi; \ |
| 41 | popq %rdi |
| 42 | |
| 43 | /* Fix up special calling conventions */ |
| 44 | ENTRY(call_rwsem_down_read_failed) |
| 45 | save_common_regs |
| 46 | pushq %rdx |
| 47 | movq %rax,%rdi |
| 48 | call rwsem_down_read_failed |
| 49 | popq %rdx |
| 50 | restore_common_regs |
| 51 | ret |
| 52 | ENDPROC(call_rwsem_down_read_failed) |
| 53 | |
| 54 | ENTRY(call_rwsem_down_write_failed) |
| 55 | save_common_regs |
| 56 | movq %rax,%rdi |
| 57 | call rwsem_down_write_failed |
| 58 | restore_common_regs |
| 59 | ret |
| 60 | ENDPROC(call_rwsem_down_write_failed) |
| 61 | |
| 62 | ENTRY(call_rwsem_wake) |
| David Howells | a66f637 | 2010-05-04 13:42:53 +0100 | [diff] [blame] | 63 | decl %edx /* do nothing if still outstanding active readers */ |
| Linus Torvalds | bafaecd | 2010-01-12 18:16:42 -0800 | [diff] [blame] | 64 | jnz 1f |
| 65 | save_common_regs |
| 66 | movq %rax,%rdi |
| 67 | call rwsem_wake |
| 68 | restore_common_regs |
| 69 | 1: ret |
| 70 | ENDPROC(call_rwsem_wake) |
| 71 | |
| 72 | /* Fix up special calling conventions */ |
| 73 | ENTRY(call_rwsem_downgrade_wake) |
| 74 | save_common_regs |
| 75 | pushq %rdx |
| 76 | movq %rax,%rdi |
| 77 | call rwsem_downgrade_wake |
| 78 | popq %rdx |
| 79 | restore_common_regs |
| 80 | ret |
| 81 | ENDPROC(call_rwsem_downgrade_wake) |