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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-02-15 11:55:16 -0200 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2019-04-17 15:14:41 -0300 |
commit | ffe8a9a8318e1db225b22da8bc067408494bac5c (patch) | |
tree | 601c619deb524e26d7eeae63c6a8969435c527d6 /sysdeps/unix/sysv/linux/powerpc/powerpc64 | |
parent | 0e169691290a6d2187a4ff41495fc5678cbfdcdc (diff) | |
download | glibc-ffe8a9a8318e1db225b22da8bc067408494bac5c.tar.gz glibc-ffe8a9a8318e1db225b22da8bc067408494bac5c.tar.xz glibc-ffe8a9a8318e1db225b22da8bc067408494bac5c.zip |
powerpc: Remove rt_sigreturn usage on context function
As described in a recent glibc thread [1], the rt_sigreturn syscall on setcontext and swapcontext is not used on default use and its intention is no really supported since neither setcontext nor swapcontext are async-signal-safe. Checked on powerpc64-linux-gnu and powerpc-linux-gnu. * sysdeps/unix/sysv/linux/powerpc/powerpc32/setcontext-common.S: Remove rt_sigreturn call. * sysdeps/unix/sysv/linux/powerpc/powerpc32/swapcontext-common.S: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S: Likewie. * sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S: Likewise. [1] https://sourceware.org/ml/libc-alpha/2019-02/msg00367.html
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/powerpc64')
-rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S | 59 | ||||
-rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S | 58 |
2 files changed, 0 insertions, 117 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S index 4e3ab6647a..d311a22c58 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/setcontext.S @@ -46,20 +46,6 @@ ENTRY(__novec_setcontext) cfi_adjust_cfa_offset (128) mr r31,r3 -/* - * If this ucontext refers to the point where we were interrupted - * by a signal, we have to use the rt_sigreturn system call to - * return to the context so we get both LR and CTR restored. - * - * Otherwise, the context we are restoring is either just after - * a procedure call (getcontext/swapcontext) or at the beginning - * of a procedure call (makecontext), so we don't need to restore - * msr and ctr. We don't restore r13 since it will be used as - * the TLS pointer. */ - ld r0,(SIGCONTEXT_GP_REGS+(PT_MSR*8))(r31) - cmpdi r0,0 - bne L(nv_do_sigret) - li r5,0 addi r4,r3,UCONTEXT_SIGMASK li r3,SIG_SETMASK @@ -200,22 +186,6 @@ L(nv_error_exit): mtlr r0 ld r31,-8(r1) blr - - /* At this point we assume that the ucontext was created by a - rt_signal and we should use rt_sigreturn to restore the original - state. As of the 2.4.21 kernel the ucontext is the first thing - (offset 0) in the rt_signal frame and rt_sigreturn expects the - ucontext address in R1. Normally the rt-signal trampoline handles - this by popping dummy frame before the rt_signal syscall. In our - case the stack may not be in its original (signal handler return with - R1 pointing at the dummy frame) state. We do have the ucontext - address in R3, so simply copy R3 to R1 before the syscall. */ -L(nv_do_sigret): - mr r1,r3, - li r0,SYS_ify(rt_sigreturn) - sc - /* No return. */ - PSEUDO_END(__novec_setcontext) compat_symbol (libc, __novec_setcontext, setcontext, GLIBC_2_3) @@ -235,20 +205,6 @@ ENTRY(__setcontext) cfi_adjust_cfa_offset (128) mr r31,r3 -/* - * If this ucontext refers to the point where we were interrupted - * by a signal, we have to use the rt_sigreturn system call to - * return to the context so we get both LR and CTR restored. - * - * Otherwise, the context we are restoring is either just after - * a procedure call (getcontext/swapcontext) or at the beginning - * of a procedure call (makecontext), so we don't need to restore - * msr and ctr. We don't restore r13 since it will be used as - * the TLS pointer. */ - ld r0,(SIGCONTEXT_GP_REGS+(PT_MSR*8))(r31) - cmpdi r0,0 - bne L(do_sigret) - li r5,0 addi r4,r3,UCONTEXT_SIGMASK li r3,SIG_SETMASK @@ -493,21 +449,6 @@ L(error_exit): ld r31,-8(r1) blr - /* At this point we assume that the ucontext was created by a - rt_signal and we should use rt_sigreturn to restore the original - state. As of the 2.4.21 kernel the ucontext is the first thing - (offset 0) in the rt_signal frame and rt_sigreturn expects the - ucontext address in R1. Normally the rt-signal trampoline handles - this by popping dummy frame before the rt_signal syscall. In our - case the stack may not be in its original (signal handler return with - R1 pointing at the dummy frame) state. We do have the ucontext - address in R3, so simply copy R3 to R1 before the syscall. */ -L(do_sigret): - mr r1,r3, - li r0,SYS_ify(rt_sigreturn) - sc - /* No return. */ - PSEUDO_END(__setcontext) versioned_symbol (libc, __setcontext, setcontext, GLIBC_2_3_4) diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S index af5b108e8c..6d07b1c36b 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/swapcontext.S @@ -149,20 +149,6 @@ ENTRY(__novec_swapcontext) cmpdi r3,0 bne L(nv_error_exit) -/* - * If this new ucontext refers to the point where we were interrupted - * by a signal, we have to use the rt_sigreturn system call to - * return to the context so we get both LR and CTR restored. - * - * Otherwise, the context we are restoring is either just after - * a procedure call (getcontext/swapcontext) or at the beginning - * of a procedure call (makecontext), so we don't need to restore - * msr and ctr. We don't restore r13 since it will be used as - * the TLS pointer. */ - ld r0,(SIGCONTEXT_GP_REGS+(PT_MSR*8))(r31) - cmpdi r0,0 - bne L(nv_do_sigret) - ld r8,.LC__dl_hwcap@toc(r2) # ifdef SHARED /* Load _rtld-global._dl_hwcap. */ @@ -288,21 +274,6 @@ L(nv_error_exit): ld r31,-8(r1) blr - /* At this point we assume that the ucontext was created by a - rt_signal and we should use rt_sigreturn to restore the original - state. As of the 2.4.21 kernel the ucontext is the first thing - (offset 0) in the rt_signal frame and rt_sigreturn expects the - ucontext address in R1. Normally the rt-signal trampoline handles - this by popping dummy frame before the rt_signal syscall. In our - case the stack may not be in its original (signal handler return with - R1 pointing at the dummy frame) state. We do have the ucontext - address in R3, so simply copy R3 to R1 before the syscall. */ -L(nv_do_sigret): - mr r1,r3, - li r0,SYS_ify(rt_sigreturn) - sc - /* No return. */ - PSEUDO_END(__novec_swapcontext) compat_symbol (libc, __novec_swapcontext, swapcontext, GLIBC_2_3) @@ -535,20 +506,6 @@ L(has_no_vec): cmpdi r3,0 bne L(error_exit) -/* - * If this new ucontext refers to the point where we were interrupted - * by a signal, we have to use the rt_sigreturn system call to - * return to the context so we get both LR and CTR restored. - * - * Otherwise, the context we are restoring is either just after - * a procedure call (getcontext/swapcontext) or at the beginning - * of a procedure call (makecontext), so we don't need to restore - * msr and ctr. We don't restore r13 since it will be used as - * the TLS pointer. */ - ld r0,(SIGCONTEXT_GP_REGS+(PT_MSR*8))(r31) - cmpdi r0,0 - bne L(do_sigret) - ld r8,.LC__dl_hwcap@toc(r2) ld r10,(SIGCONTEXT_V_REGS_PTR)(r31) # ifdef SHARED @@ -777,21 +734,6 @@ L(error_exit): ld r31,-8(r1) blr - /* At this point we assume that the ucontext was created by a - rt_signal and we should use rt_sigreturn to restore the original - state. As of the 2.4.21 kernel the ucontext is the first thing - (offset 0) in the rt_signal frame and rt_sigreturn expects the - ucontext address in R1. Normally the rt-signal trampoline handles - this by popping dummy frame before the rt_signal syscall. In our - case the stack may not be in its original (signal handler return with - R1 pointing at the dummy frame) state. We do have the ucontext - address in R3, so simply copy R3 to R1 before the syscall. */ -L(do_sigret): - mr r1,r3, - li r0,SYS_ify(rt_sigreturn) - sc - /* No return. */ - PSEUDO_END(__swapcontext) versioned_symbol (libc, __swapcontext, swapcontext, GLIBC_2_3_4) |