Re: [PATCH v5 05/10] powerpc/signal64: Remove TM ifdefery in middle of if/else block
flat view
From: Daniel Axtens <hidden>
Date: 2021-02-12 05:23:12
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Hi Chris,
Rework the messy ifdef breaking up the if-else for TM similar to
commit f1cf4f93de2f ("powerpc/signal32: Remove ifdefery in middle of if/else").I'm not sure what 'the messy ifdef' and 'the if-else for TM' is (yet): perhaps you could start the commit message with a tiny bit of background.
quoted hunk ↗ jump to hunk
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 | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-)diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index b211a8ea4f6e..8e1d804ce552 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;@@ -765,7 +763,10 @@ SYSCALL_DEFINE0(rt_sigreturn) if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) goto badframe; +#endif + if (MSR_TM_ACTIVE(msr)) { +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* We recheckpoint on return. */ struct ucontext __user *uc_transact;@@ -778,9 +779,8 @@ 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 *
I think you can get rid of all the ifdefs in _this function_ by providing a couple of stubs:
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index a66f435dabbf..19059a4b798f 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c@@ -1120,6 +1120,7 @@ void restore_tm_state(struct pt_regs *regs) #else #define tm_recheckpoint_new_task(new) #define __switch_to_tm(prev, new) +void tm_reclaim_current(uint8_t cause) {} #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ static inline void save_sprs(struct thread_struct *t)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 8e1d804ce552..ed58ca019ad9 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c@@ -594,6 +594,13 @@ static long restore_tm_sigcontexts(struct task_struct *tsk, return err; } +#else +static long restore_tm_sigcontexts(struct task_struct *tsk, + struct sigcontext __user *sc, + struct sigcontext __user *tm_sc) +{ + return -EINVAL; +} #endif /*
@@ -722,7 +729,6 @@ SYSCALL_DEFINE0(rt_sigreturn) goto badframe; set_current_blocked(&set); -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* * If there is a transactional state then throw it away. * The purpose of a sigreturn is to destroy all traces of the
@@ -763,10 +769,8 @@ SYSCALL_DEFINE0(rt_sigreturn) if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) goto badframe; -#endif if (MSR_TM_ACTIVE(msr)) { -#ifdef CONFIG_PPC_TRANSACTIONAL_MEM /* We recheckpoint on return. */ struct ucontext __user *uc_transact;
@@ -779,7 +783,6 @@ SYSCALL_DEFINE0(rt_sigreturn) if (restore_tm_sigcontexts(current, &uc->uc_mcontext, &uc_transact->uc_mcontext)) goto badframe; -#endif } else { /* * Fall through, for non-TM restore
My only concern here was whether it was valid to access if (__get_user(msr, &uc->uc_mcontext.gp_regs[PT_MSR])) if CONFIG_PPC_TRANSACTIONAL_MEM was not defined, but I didn't think of any obvious reason why it wouldn't be...
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@@ -818,10 +818,8 @@ 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
I wondered if that comment still makes sense in the absence of the
ifdef. It is preserved in commit f1cf4f93de2f ("powerpc/signal32: Remove
ifdefery in middle of if/else"), and I can't figure out how you would
improve it, so I guess it's probably good as it is.
quoted hunk ↗ jump to hunk
frame = get_sigframe(ksig, tsk, sizeof(*frame), 0); if (!access_ok(frame, sizeof(*frame)))@@ -836,8 +834,9 @@ 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 +846,8 @@ 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,
That seems reasonable to me. Kind regards, Daniel