From 4e0e45b07d790253643ee05300784ab2156e2d5e Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Thu, 7 May 2020 22:13:32 +1000 Subject: powerpc: Use trap metadata to prevent double restart rather than zeroing trap It's not very nice to zero trap for this, because then system calls no longer have trap_is_syscall(regs) invariant, and we can't distinguish between sc and scv system calls (in a later patch). Take one last unused bit from the low bits of the pt_regs.trap word for this instead. There is not a really good reason why it should be in trap as opposed to another field, but trap has some concept of flags and it exists. Ideally I think we would move trap to 2-byte field and have 2 more bytes available independently. Add a selftests case for this, which can be seen to fail if trap_norestart() is changed to return false. Signed-off-by: Nicholas Piggin [mpe: Make them static inlines] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200507121332.2233629-4-mpe@ellerman.id.au --- arch/powerpc/kernel/signal_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/signal_32.c') diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c index 4f96d29a22bf..ae3da7440b2f 100644 --- a/arch/powerpc/kernel/signal_32.c +++ b/arch/powerpc/kernel/signal_32.c @@ -500,7 +500,7 @@ static long restore_user_regs(struct pt_regs *regs, if (!sig) save_r2 = (unsigned int)regs->gpr[2]; err = restore_general_regs(regs, sr); - regs->trap = 0; + set_trap_norestart(regs); err |= __get_user(msr, &sr->mc_gregs[PT_MSR]); if (!sig) regs->gpr[2] = (unsigned long) save_r2; -- cgit