1 | /* |
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2 | * EFI call stub. |
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3 | * |
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4 | * Copyright (C) 1999-2001 Hewlett-Packard Co |
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5 | * David Mosberger <davidm@hpl.hp.com> |
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6 | * |
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7 | * This stub allows us to make EFI calls in physical mode with interrupts |
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8 | * turned off. We need this because we can't call SetVirtualMap() until |
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9 | * the kernel has booted far enough to allow allocation of struct vma_struct |
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10 | * entries (which we would need to map stuff with memory attributes other |
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11 | * than uncached or writeback...). Since the GetTime() service gets called |
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12 | * earlier than that, we need to be able to make physical mode EFI calls from |
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13 | * the kernel. |
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14 | */ |
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15 | |
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16 | /* |
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17 | * PSR settings as per SAL spec (Chapter 8 in the "IA-64 System |
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18 | * Abstraction Layer Specification", revision 2.6e). Note that |
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19 | * psr.dfl and psr.dfh MUST be cleared, despite what this manual says. |
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20 | * Otherwise, SAL dies whenever it's trying to do an IA-32 BIOS call |
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21 | * (the br.ia instruction fails unless psr.dfl and psr.dfh are |
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22 | * cleared). Fortunately, SAL promises not to touch the floating |
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23 | * point regs, so at least we don't have to save f2-f127. |
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24 | */ |
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25 | #define PSR_BITS_TO_CLEAR \ |
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26 | (IA64_PSR_I | IA64_PSR_IT | IA64_PSR_DT | IA64_PSR_RT | \ |
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27 | IA64_PSR_DD | IA64_PSR_SS | IA64_PSR_RI | IA64_PSR_ED | \ |
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28 | IA64_PSR_DFL | IA64_PSR_DFH) |
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29 | |
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30 | #define PSR_BITS_TO_SET \ |
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31 | (IA64_PSR_BN) |
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32 | |
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33 | #include <asm/processor.h> |
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34 | #include <asm/asmmacro.h> |
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35 | |
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36 | /* |
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37 | * Inputs: |
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38 | * in0 = address of function descriptor of EFI routine to call |
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39 | * in1..in7 = arguments to routine |
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40 | * |
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41 | * Outputs: |
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42 | * r8 = EFI_STATUS returned by called function |
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43 | */ |
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44 | |
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45 | GLOBAL_ENTRY(efi_call_phys) |
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46 | .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(8) |
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47 | alloc loc1=ar.pfs,8,7,7,0 |
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48 | ld8 r2=[in0],8 // load EFI function's entry point |
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49 | mov loc0=rp |
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50 | .body |
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51 | ;; |
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52 | mov loc2=gp // save global pointer |
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53 | mov loc4=ar.rsc // save RSE configuration |
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54 | mov ar.rsc=0 // put RSE in enforced lazy, LE mode |
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55 | ;; |
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56 | ld8 gp=[in0] // load EFI function's global pointer |
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57 | movl r16=PSR_BITS_TO_CLEAR |
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58 | mov loc3=psr // save processor status word |
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59 | movl r17=PSR_BITS_TO_SET |
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60 | ;; |
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61 | or loc3=loc3,r17 |
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62 | mov b6=r2 |
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63 | ;; |
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64 | andcm r16=loc3,r16 // get psr with IT, DT, and RT bits cleared |
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65 | br.call.sptk.many rp=ia64_switch_mode_phys |
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66 | .ret0: mov out4=in5 |
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67 | mov out0=in1 |
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68 | mov out1=in2 |
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69 | mov out2=in3 |
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70 | mov out3=in4 |
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71 | mov out5=in6 |
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72 | mov out6=in7 |
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73 | mov loc5=r19 |
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74 | mov loc6=r20 |
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75 | br.call.sptk.many rp=b6 // call the EFI function |
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76 | .ret1: mov ar.rsc=0 // put RSE in enforced lazy, LE mode |
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77 | mov r16=loc3 |
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78 | mov r19=loc5 |
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79 | mov r20=loc6 |
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80 | br.call.sptk.many rp=ia64_switch_mode_virt // return to virtual mode |
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81 | .ret2: mov ar.rsc=loc4 // restore RSE configuration |
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82 | mov ar.pfs=loc1 |
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83 | mov rp=loc0 |
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84 | mov gp=loc2 |
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85 | br.ret.sptk.many rp |
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86 | END(efi_call_phys) |
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