From ee50871d980c9f61df31eb7fa6264ff65ebb40f9 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Wed, 29 Nov 2006 19:54:16 +0000 Subject: 2006-11-29 Daniel Jacobowitz Jakub Jelinek Jan Kratochvil * sysdeps/unix/sysv/linux/x86_64/sigaction.c (restore_rt): Add correct unwind information. * sysdeps/unix/sysv/linux/x86_64/Makefile: Provide symbols for 'restore_rt' even in the 'signal' directory. * sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym: Extend the regs list. --- sysdeps/unix/sysv/linux/x86_64/Makefile | 2 +- sysdeps/unix/sysv/linux/x86_64/sigaction.c | 96 ++++++++++++++++++++++++--- sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym | 3 + 3 files changed, 91 insertions(+), 10 deletions(-) (limited to 'sysdeps/unix') diff --git a/sysdeps/unix/sysv/linux/x86_64/Makefile b/sysdeps/unix/sysv/linux/x86_64/Makefile index 0f20367236..bdad5063df 100644 --- a/sysdeps/unix/sysv/linux/x86_64/Makefile +++ b/sysdeps/unix/sysv/linux/x86_64/Makefile @@ -10,6 +10,6 @@ ifeq ($(subdir),stdlib) sysdep_routines += __start_context endif -ifeq ($(subdir),stdlib) +ifeq ($(subdir),csu) gen-as-const-headers += ucontext_i.sym endif diff --git a/sysdeps/unix/sysv/linux/x86_64/sigaction.c b/sysdeps/unix/sysv/linux/x86_64/sigaction.c index b83e98a77e..0d56364ab7 100644 --- a/sysdeps/unix/sysv/linux/x86_64/sigaction.c +++ b/sysdeps/unix/sysv/linux/x86_64/sigaction.c @@ -33,6 +33,8 @@ translate it here. */ #include +#include "ucontext_i.h" + /* We do not globally define the SA_RESTORER flag so do it here. */ #define SA_RESTORER 0x04000000 @@ -90,18 +92,94 @@ weak_alias (__libc_sigaction, sigaction) signal handlers work right. Important are both the names (__restore_rt) and the exact instruction sequence. If you ever feel the need to make any changes, please notify the - appropriate GDB maintainer. */ + appropriate GDB maintainer. + + The unwind information starts a byte before __restore_rt, so that + it is found when unwinding, to get an address the unwinder assumes + will be in the middle of a call instruction. See the Linux kernel + (the i386 vsyscall, in particular) for an explanation of the complex + unwind information used here in order to get the traditional CFA. + We do not restore cs - it's only stored as two bytes here so that's + a bit tricky. We don't use the gas cfi directives, so that we can + reliably add .cfi_signal_frame. */ + +#define do_cfa_expr \ + " .byte 0x0f\n" /* DW_CFA_def_cfa_expression */ \ + " .uleb128 2f-1f\n" /* length */ \ + "1: .byte 0x77\n" /* DW_OP_breg7 */ \ + " .sleb128 " CFI_STRINGIFY (oRSP) "\n" \ + " .byte 0x06\n" /* DW_OP_deref */ \ + "2:" + +#define do_expr(regno, offset) \ + " .byte 0x10\n" /* DW_CFA_expression */ \ + " .uleb128 " CFI_STRINGIFY (regno) "\n" \ + " .uleb128 2f-1f\n" /* length */ \ + "1: .byte 0x77\n" /* DW_OP_breg7 */ \ + " .sleb128 " CFI_STRINGIFY (offset) "\n" \ + "2:" #define RESTORE(name, syscall) RESTORE2 (name, syscall) # define RESTORE2(name, syscall) \ -asm \ - ( \ - ".align 16\n" \ - CFI_STARTPROC "\n" \ - "__" #name ":\n" \ - " movq $" #syscall ", %rax\n" \ - " syscall\n" \ - CFI_ENDPROC "\n" \ +asm \ + ( \ + /* `nop' for debuggers assuming `call' should not disalign the code. */ \ + " nop\n" \ + ".align 16\n" \ + ".LSTART_" #name ":\n" \ + " .type __" #name ",@function\n" \ + "__" #name ":\n" \ + " movq $" #syscall ", %rax\n" \ + " syscall\n" \ + ".LEND_" #name ":\n" \ + ".section .eh_frame,\"a\",@progbits\n" \ + ".LSTARTFRAME_" #name ":\n" \ + " .long .LENDCIE_" #name "-.LSTARTCIE_" #name "\n" \ + ".LSTARTCIE_" #name ":\n" \ + " .long 0\n" /* CIE ID */ \ + " .byte 1\n" /* Version number */ \ + " .string \"zRS\"\n" /* NUL-terminated augmentation string */ \ + " .uleb128 1\n" /* Code alignment factor */ \ + " .sleb128 -8\n" /* Data alignment factor */ \ + " .uleb128 16\n" /* Return address register column (rip) */ \ + /* Augmentation value length */ \ + " .uleb128 .LENDAUGMNT_" #name "-.LSTARTAUGMNT_" #name "\n" \ + ".LSTARTAUGMNT_" #name ":\n" \ + " .byte 0x1b\n" /* DW_EH_PE_pcrel|DW_EH_PE_sdata4. */ \ + ".LENDAUGMNT_" #name ":\n" \ + " .align 8\n" \ + ".LENDCIE_" #name ":\n" \ + " .long .LENDFDE_" #name "-.LSTARTFDE_" #name "\n" /* FDE len */ \ + ".LSTARTFDE_" #name ":\n" \ + " .long .LSTARTFDE_" #name "-.LSTARTFRAME_" #name "\n" /* CIE */ \ + /* `LSTART_' is subtracted 1 as debuggers assume a `call' here. */ \ + " .long (.LSTART_" #name "-1)-.\n" /* PC-relative start addr. */ \ + " .long .LEND_" #name "-(.LSTART_" #name "-1)\n" \ + " .uleb128 0\n" /* FDE augmentation length */ \ + do_cfa_expr \ + do_expr (8 /* r8 */, oR8) \ + do_expr (9 /* r9 */, oR9) \ + do_expr (10 /* r10 */, oR10) \ + do_expr (11 /* r11 */, oR11) \ + do_expr (12 /* r12 */, oR12) \ + do_expr (13 /* r13 */, oR13) \ + do_expr (14 /* r14 */, oR14) \ + do_expr (15 /* r15 */, oR15) \ + do_expr (5 /* rdi */, oRDI) \ + do_expr (4 /* rsi */, oRSI) \ + do_expr (6 /* rbp */, oRBP) \ + do_expr (3 /* rbx */, oRBX) \ + do_expr (1 /* rdx */, oRDX) \ + do_expr (0 /* rax */, oRAX) \ + do_expr (2 /* rcx */, oRCX) \ + do_expr (7 /* rsp */, oRSP) \ + do_expr (16 /* rip */, oRIP) \ + do_expr (49 /* rflags */, oEFL) \ + /* `cs'/`ds'/`fs' are unaligned and a different size. */ \ + /* gas: Error: register save offset not a multiple of 8 */ \ + " .align 8\n" \ + ".LENDFDE_" #name ":\n" \ + " .previous\n" \ ); /* The return code for realtime-signals. */ RESTORE (restore_rt, __NR_rt_sigreturn) diff --git a/sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym b/sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym index b3cfe9aa4c..af3e0e544b 100644 --- a/sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym +++ b/sysdeps/unix/sysv/linux/x86_64/ucontext_i.sym @@ -18,6 +18,8 @@ oRSP mreg (RSP) oRBX mreg (RBX) oR8 mreg (R8) oR9 mreg (R9) +oR10 mreg (R10) +oR11 mreg (R11) oR12 mreg (R12) oR13 mreg (R13) oR14 mreg (R14) @@ -28,6 +30,7 @@ oRDX mreg (RDX) oRAX mreg (RAX) oRCX mreg (RCX) oRIP mreg (RIP) +oEFL mreg (EFL) oFPREGS mcontext (fpregs) oSIGMASK ucontext (uc_sigmask) oFPREGSMEM ucontext (__fpregs_mem) -- cgit 1.4.1