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Hi! On Mon, 28 May 2012 08:23:34 +0900, Kaz Kojima <kkojima@rr.iij4u.or.jp> wrote: > Thomas Schwinge <thomas@codesourcery.com> wrote: > >> 3) The SYSCALL_ERROR_HANDLER macro in > >> sysdeps/unix/sysv/linux/sh/sysdep.h has been changed to use CFI > >> directives to mark r12's save/restore. The RTLD_PRIVATE_ERRNO version > >> is not dealt with, because simply, r12 there is never saved. > > > > Hmm, I don't quite understand how that code can get away with not > > preserving r12 -- Kaz, do you have an explanation? The code in question: > > I don't remember any explanation. Maybe just my oversight. > I agree that r12 should be preserved there. I found some more places, and now pushed the following as commit 58f902b8d8cd47e8f4f2fcd64721a6289400422e: * sysdeps/sh/____longjmp_chk.S (CALL_FAIL): Preserve r12 and pr registers for frame unwinding purposes, add CFI directives. * sysdeps/unix/sysv/linux/sh/____longjmp_chk.S (CALL_FAIL): Likewise. * sysdeps/unix/sysv/linux/sh/makecontext.S (.Lexitcode): Likewise * sysdeps/unix/sysv/linux/sh/sysdep.h (SYSCALL_ERROR_HANDLER): Likewise. diff --git a/sysdeps/sh/____longjmp_chk.S b/sysdeps/sh/____longjmp_chk.S index e8d5f68..b37a948 100644 --- a/sysdeps/sh/____longjmp_chk.S +++ b/sysdeps/sh/____longjmp_chk.S @@ -28,9 +28,16 @@ longjmp_msg: # define CALL_FAIL \ mov.l .Lfail, r1; \ mov.l .Lstr, r4; \ + mov.l r12, @-r15; \ + cfi_remember_state; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (r12, 0); \ mova .Lgot, r0; \ mov.l .Lgot, r12; \ add r0, r12; \ + sts.l pr, @-r15; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (pr, 0); \ bsrf r1; \ add r12, r4; \ /* Unreachable. */ \ @@ -41,11 +48,16 @@ longjmp_msg: .Lstr: \ .long longjmp_msg@GOTOFF; \ .Lfail: \ - .long __GI___fortify_fail@PLT-(.Lfail0-.); + .long __GI___fortify_fail@PLT-(.Lfail0-.); \ + cfi_restore_state; #else # define CALL_FAIL \ mov.l .Lfail, r1; \ mov.l .Lstr, r4; \ + sts.l pr, @-r15; \ + cfi_remember_state; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (pr, 0); \ jsr @r1; \ nop; \ /* Unreachable. */ \ @@ -53,7 +65,8 @@ longjmp_msg: .Lstr: \ .long longjmp_msg; \ .Lfail: \ - .long __fortify_fail; + .long __fortify_fail; \ + cfi_restore_state; #endif #define CHECK_SP(reg) \ diff --git a/sysdeps/unix/sysv/linux/sh/____longjmp_chk.S b/sysdeps/unix/sysv/linux/sh/____longjmp_chk.S index bcf828b..d74caa2 100644 --- a/sysdeps/unix/sysv/linux/sh/____longjmp_chk.S +++ b/sysdeps/unix/sysv/linux/sh/____longjmp_chk.S @@ -32,9 +32,16 @@ longjmp_msg: # define CALL_FAIL \ mov.l .Lfail, r1; \ mov.l .Lstr, r4; \ + mov.l r12, @-r15; \ + cfi_remember_state; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (r12, 0); \ mova .Lgot, r0; \ mov.l .Lgot, r12; \ add r0, r12; \ + sts.l pr, @-r15; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (pr, 0); \ bsrf r1; \ add r12, r4; \ .Lfail0: \ @@ -45,11 +52,16 @@ longjmp_msg: .Lstr: \ .long longjmp_msg@GOTOFF; \ .Lfail: \ - .long __GI___fortify_fail@PLT-(.Lfail0-.); + .long __GI___fortify_fail@PLT-(.Lfail0-.); \ + cfi_restore_state; #else # define CALL_FAIL \ mov.l .Lfail, r1; \ mov.l .Lstr, r4; \ + sts.l pr, @-r15; \ + cfi_remember_state; \ + cfi_adjust_cfa_offset (4); \ + cfi_rel_offset (pr, 0); \ jsr @r1; \ nop; \ /* Unreachable. */ \ @@ -57,7 +69,8 @@ longjmp_msg: .Lstr: \ .long longjmp_msg; \ .Lfail: \ - .long __fortify_fail; + .long __fortify_fail; \ + cfi_restore_state; #endif #define CHECK_SP(reg) \ diff --git a/sysdeps/unix/sysv/linux/sh/makecontext.S b/sysdeps/unix/sysv/linux/sh/makecontext.S index ec9ce91..a04bc9f 100644 --- a/sysdeps/unix/sysv/linux/sh/makecontext.S +++ b/sysdeps/unix/sysv/linux/sh/makecontext.S @@ -97,8 +97,12 @@ ENTRY(__makecontext) cfi_endproc .align 5 + cfi_startproc .Lexitcode: #ifdef PIC + mov.l r12, @-r15 + cfi_adjust_cfa_offset (4) + cfi_rel_offset (r12, 0) mova .Lgot, r0 mov.l .Lgot, r12 add r0, r12 @@ -107,6 +111,9 @@ ENTRY(__makecontext) bt/s 2f mov r8, r4 /* r4 <- ucb->uc_link */ mov.l .Lsetcontext, r1 + sts.l pr, @-r15 + cfi_adjust_cfa_offset (4) + cfi_rel_offset (pr, 0) #ifdef PIC bsrf r1 .LPCS0: @@ -115,6 +122,10 @@ ENTRY(__makecontext) jsr @r1 nop #endif + /* Restore to keep CFI/CFA balanced. */ + lds.l @r15+, pr + cfi_adjust_cfa_offset (-4) + cfi_restore (pr) /* If this returns (which can happen if the syscall fails) we'll exit the program with the return error value (-1). */ @@ -143,7 +154,6 @@ ENTRY(__makecontext) .Lexit: .long HIDDEN_JUMPTARGET(exit) #endif - cfi_startproc PSEUDO_END(__makecontext) weak_alias (__makecontext, makecontext) diff --git a/sysdeps/unix/sysv/linux/sh/sysdep.h b/sysdeps/unix/sysv/linux/sh/sysdep.h index 5215a84..ce72c66 100644 --- a/sysdeps/unix/sysv/linux/sh/sysdep.h +++ b/sysdeps/unix/sysv/linux/sh/sysdep.h @@ -100,11 +99,15 @@ # if RTLD_PRIVATE_ERRNO # define SYSCALL_ERROR_HANDLER \ neg r0,r1; \ + mov r12,r2; \ + cfi_register (r12, r2); \ mov.l 0f,r12; \ mova 0f,r0; \ add r0,r12; \ mov.l 1f,r0; \ mov.l r1,@(r0,r12); \ + mov r2,r12; \ + cfi_restore (r12); \ bra .Lpseudo_end; \ mov _IMM1,r0; \ .align 2; \ @@ -121,6 +124,7 @@ # define SYSCALL_ERROR_HANDLER \ neg r0,r1; \ mov r12,r2; \ + cfi_register (r12, r2); \ mov.l 0f,r12; \ mova 0f,r0; \ add r0,r12; \ @@ -128,6 +132,7 @@ stc gbr, r4; \ mov.l @(r0,r12),r0; \ mov r2,r12; \ + cfi_restore (r12); \ add r4,r0; \ mov.l r1,@r0; \ bra .Lpseudo_end; \ @@ -140,12 +145,14 @@ # define SYSCALL_ERROR_HANDLER \ neg r0,r1; \ mov r12,r2; \ + cfi_register (r12, r2); \ mov.l 0f,r12; \ mova 0f,r0; \ add r0,r12; \ mov.l 1f,r0; \ mov.l @(r0,r12),r0; \ mov r2,r12; \ + cfi_restore (r12); \ mov.l r1,@r0; \ bra .Lpseudo_end; \ mov _IMM1,r0; \ GrÃÃe, Thomas
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