Re: [PATCH v2 5/5] powerpc/signal: Use unsafe_copy_siginfo_to_user()
From: Eric W. Biederman <hidden>
Date: 2021-09-02 18:38:55
Also in:
lkml
Christophe Leroy [off-list ref] writes:
Use unsafe_copy_siginfo_to_user() in order to do the copy within the user access block. On an mpc 8321 (book3s/32) the improvment is about 5% on a process sending a signal to itself.
Nacked-by: "Eric W. Biederman" [off-list ref] copy_siginfo_to_user is not the same as copy_siginfo_to_user32. As in this patch breaks 32bit userspace on powerpc.
quoted hunk
Signed-off-by: Christophe Leroy <redacted> --- arch/powerpc/kernel/signal_32.c | 13 ++++++------- arch/powerpc/kernel/signal_64.c | 5 +---- 2 files changed, 7 insertions(+), 11 deletions(-)diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index ff101e2b3bab..f9e16d108bc8 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c@@ -710,12 +710,6 @@ static long restore_tm_user_regs(struct pt_regs *regs, struct mcontext __user *s } #endif -#ifdef CONFIG_PPC64 - -#define copy_siginfo_to_user copy_siginfo_to_user32 - -#endif /* CONFIG_PPC64 */ - /* * Set up a signal frame for a "real-time" signal handler * (one which gets siginfo).@@ -779,14 +773,19 @@ int handle_rt_signal32(struct ksignal *ksig, sigset_t *oldset, asm("dcbst %y0; sync; icbi %y0; sync" :: "Z" (mctx->mc_pad[0])); } unsafe_put_sigset_t(&frame->uc.uc_sigmask, oldset, failed); +#ifndef CONFIG_COMPAT + unsafe_copy_siginfo_to_user(&frame->info, &ksig->info, failed); +#endif /* create a stack frame for the caller of the handler */ unsafe_put_user(regs->gpr[1], newsp, failed); user_access_end(); - if (copy_siginfo_to_user(&frame->info, &ksig->info)) +#ifdef CONFIG_COMPAT + if (copy_siginfo_to_user32(&frame->info, &ksig->info)) goto badframe; +#endif regs->link = tramp;diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c index 2cca6c8febe1..82b73fbd937d 100644 --- a/arch/powerpc/kernel/signal_64.c +++ b/arch/powerpc/kernel/signal_64.c@@ -901,15 +901,12 @@ int handle_rt_signal64(struct ksignal *ksig, sigset_t *set, } unsafe_copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set), badframe_block); + unsafe_copy_siginfo_to_user(&frame->info, &ksig->info, badframe_block); /* Allocate a dummy caller frame for the signal handler. */ unsafe_put_user(regs->gpr[1], newsp, badframe_block); user_write_access_end(); - /* Save the siginfo outside of the unsafe block. */ - if (copy_siginfo_to_user(&frame->info, &ksig->info)) - goto badframe; - /* Make sure signal handler doesn't get spurious FP exceptions */ tsk->thread.fp_state.fpscr = 0;