Re: [PATCH v3 4/8] powerpc/signal64: Remove TM ifdefery in middle of if/else block
flat view
From: Christophe Leroy <hidden>
Date: 2021-01-11 13:34:17
Le 09/01/2021 à 04:25, Christopher M. Riedl a écrit :
quoted hunk ↗ jump to hunk
Rework the messy ifdef breaking up the if-else for TM similar to commit f1cf4f93de2f ("powerpc/signal32: Remove ifdefery in middle of if/else"). Unlike that commit for ppc32, the ifdef can't be removed entirely since uc_transact in sigframe depends on CONFIG_PPC_TRANSACTIONAL_MEM. Signed-off-by: Christopher M. Riedl <redacted> --- arch/powerpc/kernel/signal_64.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-)diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index b211a8ea4f6e..dd3787f67a78 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c@@ -710,9 +710,7 @@ SYSCALL_DEFINE0(rt_sigreturn) struct pt_regs *regs = current_pt_regs(); struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1]; sigset_t set; -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM unsigned long msr; -#endif /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall;@@ -762,10 +760,12 @@ SYSCALL_DEFINE0(rt_sigreturn) * restore_tm_sigcontexts. */ regs->msr &= ~MSR_TS_MASK; +#endif if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) goto badframe;
This means you are doing that __get_user() even when msr is not used. That should be avoided.
quoted hunk ↗ jump to hunk
if (MSR_TM_ACTIVE(msr)) { +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* We recheckpoint on return. */ struct ucontext __user *uc_transact;@@ -778,9 +778,8 @@ SYSCALL_DEFINE0(rt_sigreturn) if (restore_tm_sigcontexts(current, &uc->uc_mcontext, &uc_transact->uc_mcontext)) goto badframe; - } else #endif - { + } else { /* * Fall through, for non-TM restore *@@ -818,10 +817,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, unsigned long newsp = 0; long err = 0; struct pt_regs *regs = tsk->thread.regs; -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* Save the thread's msr before get_tm_stackpointer() changes it */ - unsigned long msr = regs->msr; -#endif + unsigned long msr __maybe_unused = regs->msr;
I don't thing __maybe_unused() is the right solution. I think MSR_TM_ACTIVE() should be fixed instead, either by changing it into a static inline function, or doing something similar to https://github.com/linuxppc/linux/commit/05a4ab823983d9136a460b7b5e0d49ee709a6f86
quoted hunk ↗ jump to hunk
frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); if (!access_ok(frame, sizeof(*frame)))@@ -836,8 +833,9 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __save_altstack(&frame->uc.uc_stack, regs->gpr[1]); -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM + if (MSR_TM_ACTIVE(msr)) { +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* The ucontext_t passed to userland points to the second * ucontext_t (for transactional state) with its uc_link ptr. */@@ -847,9 +845,8 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, tsk, ksig->sig, NULL, (unsigned long)ksig->ka.sa.sa_handler, msr); - } else #endif - { + } else { err |= __put_user(0, &frame->uc.uc_link); prepare_setup_sigcontext(tsk, 1); err |= setup_sigcontext(&frame->uc.uc_mcontext, tsk, ksig->sig,
Christophe