/* * Copyright (c) 2007 Apple Inc. All rights reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #include #include #define UC_TRAD 1 #define UC_TRAD64 20 #define UC_TRAD64_VEC 25 #define UC_FLAVOR 30 #define UC_FLAVOR_VEC 35 #define UC_FLAVOR64 40 #define UC_FLAVOR64_VEC 45 #define UC_DUAL 50 #define UC_DUAL_VEC 55 /* Structure fields and sizes for ucontext and mcontext. */ #define UCONTEXT_UC_MCSIZE MODE_CHOICE (24, 40) #define UCONTEXT_UC_MCONTEXT MODE_CHOICE (28, 48) #define MCONTEXT_SIZE 1032 #define MCONTEXT64_SIZE 1176 #define UC_FLAVOR64_SIZE 600 #define UC_FLAVOR64_VEC_SIZE MCONTEXT64_SIZE #define MCONTEXT_ES_EXCEPTION 8 #define MCONTEXT_SS_SRR0 32 #define MCONTEXT_SS_SRR1 36 #define MCONTEXT_SS_R0 40 #define MCONTEXT_SS_CR 168 #define MCONTEXT_SS_XER 172 #define MCONTEXT_SS_LR 176 #define MCONTEXT_SS_CTR 180 #define MCONTEXT_SS_MQ 184 #define MCONTEXT_SS_VRSAVE 188 #define MCONTEXT_FS_FPREGS 192 #define MCONTEXT_FS_FPSCR 448 #define MCONTEXT_VS_SAVE_VR 456 #define MCONTEXT_VS_VSCR 968 #define MCONTEXT64_ES_EXCEPTION 12 #define MCONTEXT64_SS_SRR0 32 #define MCONTEXT64_SS_SRR1 40 #define MCONTEXT64_SS_R0 48 #define MCONTEXT64_SS_CR 304 #define MCONTEXT64_SS_XER 308 #define MCONTEXT64_SS_LR 316 #define MCONTEXT64_SS_CTR 324 #define MCONTEXT64_SS_VRSAVE 332 #define MCONTEXT64_FS_FPREGS 336 #define MCONTEXT64_FS_FPSCR 592 #define MCONTEXT64_VS_SAVE_VR 600 #define MCONTEXT64_VS_VSCR 1112 /* Exception types. I believe the MCONTEXT_ES_EXCEPTION field is set from the address called to handle the exception, for example a Program Exception jumps to address 0x00700 and so the field has value 7. */ #define EXCEPTION_DSI 3 #define EXCEPTION_ISI 4 #define EXCEPTION_INTERRUPT 5 #define EXCEPTION_ALIGN 6 #define EXCEPTION_PROGRAM 7 #define EXCEPTION_FPUNAVAIL 8 #define EXCEPTION_DEC 9 #define EXCEPTION_SC 0xC #define EXCEPTION_TRACE 0xD #define EXCEPTION_FPASSIST 0xE /* register allocation: r0 : scratch, also used by MI_* macros r3 : parameter union __sigaction_u __sigaction_u r4 : parameter int sigstyle r5 : parameter int sig r6 : parameter siginfo_t *sinfo r7 : parameter ucontext_t *uctx r8 : value of __in_sigtramp r9 : &__in_sigtramp r12: scratch used by MI_* macros r29 : sigstyle r28 : uctx r27 : uctx->uc_mcontext */ MI_ENTRY_POINT(__sigtramp) /* Save away sigstyle and uctx. This code doesn't need to restore the callee-saved registers, since sigreturn will do it. */ mr r28,r7 mr r29,r4 #if defined(__DYNAMIC__) /* ++__in_sigtramp; */ MI_GET_ADDRESS (r9, ___in_sigtramp) lwz r8,0(r9) addi r8,r8,1 stw r8,0(r9) #endif /* Having this here shortens the unwind tables significantly. */ lg r27,UCONTEXT_UC_MCONTEXT(r7) /* Call the signal handler. Some variants are not supposed to get the last two parameters, but the test to prevent this is more expensive than just passing them. */ mtctr r3 mr r3,r5 mr r4,r6 mr r5,r7 Lcall_start: bctrl Lcall_end: /* Call __finish_sigtramp in sigtramp.c to complete processing for ppc, or just return to the kernel using sigtramp for ppc64. */ mr r3,r28 mr r4,r29 b MODE_CHOICE (___finish_sigtramp, ___sigreturn) /* Does not return. */ /* DWARF unwind table #defines. */ #define DW_CFA_advance_loc_4 0x44 #define DW_CFA_def_cfa 0x0c #define DW_CFA_def_cfa_expression 0x0F #define DW_CFA_expression 0x10 #define DW_CFA_val_expression 0x16 #define DW_CFA_offset(column) 0x80+(column) /* DWARF expression #defines. */ #define DW_OP_deref 0x06 #define DW_OP_const1u 0x08 #define DW_OP_dup 0x12 #define DW_OP_drop 0x13 #define DW_OP_over 0x14 #define DW_OP_pick 0x15 #define DW_OP_swap 0x16 #define DW_OP_rot 0x17 #define DW_OP_abs 0x19 #define DW_OP_and 0x1a #define DW_OP_div 0x1b #define DW_OP_minus 0x1c #define DW_OP_mod 0x1d #define DW_OP_mul 0x1e #define DW_OP_neg 0x1f #define DW_OP_not 0x20 #define DW_OP_or 0x21 #define DW_OP_plus 0x22 #define DW_OP_plus_uconst 0x23 #define DW_OP_shl 0x24 #define DW_OP_shr 0x25 #define DW_OP_shra 0x26 #define DW_OP_xor 0x27 #define DW_OP_skip 0x2f #define DW_OP_bra 0x28 #define DW_OP_eq 0x29 #define DW_OP_ge 0x2A #define DW_OP_gt 0x2B #define DW_OP_le 0x2C #define DW_OP_lt 0x2D #define DW_OP_ne 0x2E #define DW_OP_lit(n) 0x30+(n) #define DW_OP_breg(n) 0x70+(n) #define DW_OP_deref_size 0x94 /* The location expressions we'll use. */ #ifdef __ppc__ /* The ppc versions test register 29 for UC_TRAD64, UC_TRAD64_VEC, UC_FLAVOR64, UC_FLAVOR64_VEC, and then use the appropriate offset off r27 (either the offset for a mcontext or a mcontext64). The expression computed has been somewhat optimised to reduce the size of the unwind entries, and is of the form (r27 + offs + ((r29/10)==UC_TRAD64/10 || (r29/10)==UC_FLAVOR64/10)*(offs64-offs)) */ /* For when REGNO < 128 and OFFS < 64. */ #define loc_expr_for_reg_sml(regno, offs, offs64) \ .byte DW_CFA_expression, regno, 17 /* block length */, \ DW_OP_breg(27), offs, \ DW_OP_breg(29), 0, DW_OP_lit(10), DW_OP_div, \ DW_OP_dup, DW_OP_lit(UC_TRAD64/10), DW_OP_eq, \ DW_OP_swap, DW_OP_lit(UC_FLAVOR64/10), DW_OP_eq, DW_OP_or, \ DW_OP_const1u, offs64-(offs), DW_OP_mul, DW_OP_plus /* For when REGNO < 128 and OFFS >= 64. */ #define loc_expr_for_reg(regno, offs, offs64) \ .byte DW_CFA_expression, regno, 18 /* block length */, \ DW_OP_breg(27), (offs & 0x7F) | 0x80, (offs >> 7), \ DW_OP_breg(29), 0, DW_OP_lit(10), DW_OP_div, \ DW_OP_dup, DW_OP_lit(UC_TRAD64/10), DW_OP_eq, \ DW_OP_swap, DW_OP_lit(UC_FLAVOR64/10), DW_OP_eq, DW_OP_or, \ DW_OP_const1u, offs64-(offs), DW_OP_mul, DW_OP_plus #else /* The kernel always gives a ppc64 process a mcontext64, so just use that offset. */ #define loc_expr_for_reg(regno, offs, offs64) \ .byte DW_CFA_expression, regno, 3 /* block length */, \ DW_OP_breg(27), (offs64 & 0x7F) | 0x80, (offs64 >> 7) #define loc_expr_for_reg_sml(regno, offs, offs64) \ loc_expr_for_reg(regno, offs, offs64) #endif /* __ppc__ */ #define loc_expr_varying(regno, offs, offs64) \ loc_expr_for_reg (regno, offs, (offs64+MODE_CHOICE(4,0))) /* For REGNO < 22 */ #define loc_expr_gpr_sml(regno) \ loc_expr_for_reg_sml (regno, MCONTEXT_SS_R0+(4*regno), \ MCONTEXT64_SS_R0+(8*regno)+MODE_CHOICE (4,0)) /* For REGNO >= 22 */ #define loc_expr_gpr(regno) \ loc_expr_varying (regno, MCONTEXT_SS_R0+(4*regno), \ MCONTEXT64_SS_R0+(8*regno)) #define loc_expr_fpr(regno) \ loc_expr_for_reg (regno+32, MCONTEXT_FS_FPREGS+(8*regno), \ MCONTEXT64_FS_FPREGS+(8*regno)) #define loc_expr_vr(regno) \ loc_expr_for_reg (regno+77, MCONTEXT_VS_SAVE_VR+(16*regno), \ MCONTEXT64_VS_SAVE_VR+(16*regno)) /* Unwind tables. */ .section __TEXT,__eh_frame,coalesced,no_toc+strip_static_syms+live_support EH_frame1: .set L$set$0,LECIE1-LSCIE1 .long L$set$0 ; Length of Common Information Entry LSCIE1: .long 0 ; CIE Identifier Tag .byte 0x3 ; CIE Version .ascii "zR\0" ; CIE Augmentation ;; Both these alignment values are unused. .byte 0x1 ; uleb128 0x1; CIE Code Alignment Factor .byte 0x7c ; sleb128 -4; CIE Data Alignment Factor /* The choice of column for the return address is somewhat tricky. Fortunately, the actual choice is private to this file, and the space it's reserved from is the GCC register space, not the DWARF2 numbering. So any free element of the right size is an OK choice. Thus: */ .byte 67 ; CIE RA Column .byte 0x1 ; uleb128 0x1; Augmentation size .byte 0x10 ; FDE Encoding (pcrel) .byte 0xc ; DW_CFA_def_cfa .byte 0x1 ; uleb128 0x1 .byte 0x0 ; uleb128 0x0 .align LOG2_GPR_BYTES LECIE1: .globl _sigtramp.eh _sigtramp.eh: LSFDE1: .set L$set$1,LEFDE1-LASFDE1 .long L$set$1 ; FDE Length LASFDE1: .long LASFDE1-EH_frame1 ; FDE CIE offset .g_long Lcall_start-. ; FDE initial location .set L$set$2,Lcall_end-Lcall_start .g_long L$set$2 ; FDE address range .byte 0x0 ; uleb128 0x0; Augmentation size /* Now for the expressions, which all compute uctx->uc_mcontext->register for each register. uctx->uc_mcontext is already in r27, so the tricky part is that this might be a 64-bit context, in which case the offset would be different. In the case of a dual context, only the low half of a GPR is restored. Restore even the registers that are not call-saved because they might be being used in the prologue to save other registers, for instance GPR0 is sometimes used to save LR. */ loc_expr_gpr_sml (0) loc_expr_gpr_sml (1) loc_expr_gpr_sml (2) loc_expr_gpr_sml (3) loc_expr_gpr_sml (4) loc_expr_gpr_sml (5) loc_expr_gpr (6) loc_expr_gpr (7) loc_expr_gpr (8) loc_expr_gpr (9) loc_expr_gpr (10) loc_expr_gpr (11) loc_expr_gpr (12) loc_expr_gpr (13) loc_expr_gpr (14) loc_expr_gpr (15) loc_expr_gpr (16) loc_expr_gpr (17) loc_expr_gpr (18) loc_expr_gpr (19) loc_expr_gpr (20) loc_expr_gpr (21) loc_expr_gpr (22) loc_expr_gpr (23) loc_expr_gpr (24) loc_expr_gpr (25) loc_expr_gpr (26) loc_expr_gpr (27) loc_expr_gpr (28) loc_expr_gpr (29) loc_expr_gpr (30) loc_expr_gpr (31) loc_expr_for_reg (64, MCONTEXT_SS_CR, MCONTEXT64_SS_CR) loc_expr_varying (76, MCONTEXT_SS_XER, MCONTEXT64_SS_XER) loc_expr_varying (65, MCONTEXT_SS_LR, MCONTEXT64_SS_LR) loc_expr_varying (66, MCONTEXT_SS_CTR, MCONTEXT64_SS_CTR) loc_expr_for_reg (109, MCONTEXT_SS_VRSAVE, MCONTEXT64_SS_VRSAVE) loc_expr_fpr (0) loc_expr_fpr (1) loc_expr_fpr (2) loc_expr_fpr (3) loc_expr_fpr (4) loc_expr_fpr (5) loc_expr_fpr (6) loc_expr_fpr (7) loc_expr_fpr (8) loc_expr_fpr (9) loc_expr_fpr (10) loc_expr_fpr (11) loc_expr_fpr (12) loc_expr_fpr (13) loc_expr_fpr (14) loc_expr_fpr (15) loc_expr_fpr (16) loc_expr_fpr (17) loc_expr_fpr (18) loc_expr_fpr (19) loc_expr_fpr (20) loc_expr_fpr (21) loc_expr_fpr (22) loc_expr_fpr (23) loc_expr_fpr (24) loc_expr_fpr (25) loc_expr_fpr (26) loc_expr_fpr (27) loc_expr_fpr (28) loc_expr_fpr (29) loc_expr_fpr (30) loc_expr_fpr (31) loc_expr_for_reg (112, MCONTEXT_FS_FPSCR, MCONTEXT64_FS_FPSCR) loc_expr_vr (0) loc_expr_vr (1) loc_expr_vr (2) loc_expr_vr (3) loc_expr_vr (4) loc_expr_vr (5) loc_expr_vr (6) loc_expr_vr (7) loc_expr_vr (8) loc_expr_vr (9) loc_expr_vr (10) loc_expr_vr (11) loc_expr_vr (12) loc_expr_vr (13) loc_expr_vr (14) loc_expr_vr (15) loc_expr_vr (16) loc_expr_vr (17) loc_expr_vr (18) loc_expr_vr (19) loc_expr_vr (20) loc_expr_vr (21) loc_expr_vr (22) loc_expr_vr (23) loc_expr_vr (24) loc_expr_vr (25) loc_expr_vr (26) loc_expr_vr (27) loc_expr_vr (28) loc_expr_vr (29) loc_expr_vr (30) loc_expr_vr (31) loc_expr_for_reg (110, MCONTEXT_VS_VSCR, MCONTEXT64_VS_VSCR) /* The return address is even more complicated, because it needs to be the actual address to which to return, and so depends on the signal thrown, because some signals have SRR0 as the address of the faulting instruction, and others have it as the next address to execute. Although MCONTEXT_SS_SRR0 is the same as MCONTEXT64_SS_SRR0, that doesn't really simplify things much, since if the context is a 64-bit context for a 32-bit process, we'll need to add 4 to get to the low word. */ /* The exception types that point to the faulting instruction are: EXCEPTION_DSI, EXCEPTION_ALIGN, EXCEPTION_FPUNAVAIL, and EXCEPTION_PROGRAM when SRR1[47] is clear. The others point to the next instruction to execute. EXCEPTION_ISI is a special case. There are these possibilies: - program calls a subroutine which is NULL, in which case SRR0 holds NULL and LR-4 is the faulting instruction. - program executes a computed goto to NULL, in which case there is no way to know the faulting instruction. - program runs off end of its text, in which case SRR0-4 is the faulting instruction - program executes a wild branch. I think this code most needs to handle the first case, as the other cases are rare or can't be handled. */ .byte DW_CFA_val_expression, 67 .set L$set$3,Lpc_end-Lpc_start .byte L$set$3 Lpc_start: #ifdef __ppc__ /* On ppc, compute whether or not a 64-bit exception frame is in use. */ .byte DW_OP_breg(29), 0, DW_OP_lit(10), DW_OP_div .byte DW_OP_dup, DW_OP_lit(UC_TRAD64/10), DW_OP_eq .byte DW_OP_swap, DW_OP_lit(UC_FLAVOR64/10), DW_OP_eq, DW_OP_or /* Find the value of SRR0. */ .byte DW_OP_dup .byte DW_OP_lit(MCONTEXT64_SS_SRR0+4-MCONTEXT_SS_SRR0), DW_OP_mul .byte DW_OP_breg(27), MCONTEXT_SS_SRR0 .byte DW_OP_plus, DW_OP_deref /* Determine the exception type. */ .byte DW_OP_swap, DW_OP_dup .byte DW_OP_lit(MCONTEXT64_ES_EXCEPTION-MCONTEXT_ES_EXCEPTION) .byte DW_OP_mul .byte DW_OP_breg(27), MCONTEXT_ES_EXCEPTION .byte DW_OP_plus, DW_OP_deref /* Find the value of SRR1. */ .byte DW_OP_swap, DW_OP_dup .byte DW_OP_lit(MCONTEXT64_SS_SRR1+4-MCONTEXT_SS_SRR1), DW_OP_mul .byte DW_OP_breg(27), MCONTEXT_SS_SRR1 .byte DW_OP_plus, DW_OP_deref /* Find the value of LR. */ .byte DW_OP_swap .byte DW_OP_const1u, MCONTEXT64_SS_LR+4-MCONTEXT_SS_LR, DW_OP_mul .byte DW_OP_breg(27), MCONTEXT_SS_LR, MCONTEXT_SS_LR >> 7 .byte DW_OP_plus, DW_OP_deref #else /* Find the value of SRR0. */ .byte DW_OP_breg(27), MCONTEXT64_SS_SRR0, DW_OP_deref /* Determine the exception type. */ .byte DW_OP_breg(27), MCONTEXT64_ES_EXCEPTION, DW_OP_deref_size, 4 /* Find the value of SRR1. */ .byte DW_OP_breg(27), MCONTEXT64_SS_SRR1, DW_OP_deref /* Find the value of LR. */ .byte DW_OP_breg(27), MCONTEXT64_SS_LR & 0x7f | 0x80 .byte MCONTEXT64_SS_LR >> 7 .byte DW_OP_deref #endif /* At this point, the stack contains LR, SRR1, the exception type, SRR0, and the base CFA address (which this doesn't use). */ /* If the exception type is EXCEPTION_ISI, the result is LR. */ .byte DW_OP_pick, 2 .byte DW_OP_lit(EXCEPTION_ISI), DW_OP_eq .byte DW_OP_bra ; 'bra' is a conditional branch. .set L$set$5,Lpc_end-0f .short L$set$5 0: .byte DW_OP_drop /* Otherwise, start by determining if SRR1[47] is clear... */ .byte DW_OP_not, DW_OP_lit(16), DW_OP_shr, DW_OP_lit(1), DW_OP_and /* ...and the exception type is EXCEPTION_PROGRAM. */ .byte DW_OP_over, DW_OP_lit(EXCEPTION_PROGRAM), DW_OP_eq, DW_OP_and /* Check if any of the other exception cases are present. */ .byte DW_OP_over, DW_OP_lit(EXCEPTION_DSI), DW_OP_eq, DW_OP_or .byte DW_OP_over, DW_OP_lit(EXCEPTION_ALIGN), DW_OP_eq, DW_OP_or .byte DW_OP_swap, DW_OP_lit(EXCEPTION_FPUNAVAIL) .byte DW_OP_eq, DW_OP_or /* If the exception points to the faulting instruction, add 4 to point past the faulting instruction. */ .byte DW_OP_lit(4), DW_OP_mul, DW_OP_plus Lpc_end: /* The CFA will have been saved as the value of R1. */ .byte DW_CFA_def_cfa_expression .set L$set$4,Lcfa_end-Lcfa_start .byte L$set$4 Lcfa_start: #ifdef __ppc__ .byte DW_OP_breg(27), MCONTEXT_SS_R0+4 .byte DW_OP_breg(29), 0, DW_OP_lit(10), DW_OP_div .byte DW_OP_dup, DW_OP_lit(UC_TRAD64/10), DW_OP_eq .byte DW_OP_swap, DW_OP_lit(UC_FLAVOR64/10), DW_OP_eq, DW_OP_or .byte DW_OP_lit(MCONTEXT64_SS_R0+12-MCONTEXT_SS_R0-4) .byte DW_OP_mul, DW_OP_plus .byte DW_OP_deref #else .byte DW_OP_breg(27), MCONTEXT64_SS_R0+8, DW_OP_deref #endif Lcfa_end: .align LOG2_GPR_BYTES LEFDE1: .subsections_via_symbols