From 709b973c844c0b4d115ac3a227a2e5a68722c912 Mon Sep 17 00:00:00 2001 From: Anshuman Khandual Date: Thu, 29 Mar 2018 11:53:37 +0530 Subject: [PATCH] powerpc/fscr: Enable interrupts earlier before calling get_user() The function get_user() can sleep while trying to fetch instruction from user address space and causes the following warning from the scheduler. BUG: sleeping function called from invalid context Though interrupts get enabled back but it happens bit later after get_user() is called. This change moves enabling these interrupts earlier covering the function get_user(). While at this, lets check for kernel mode and crash as this interrupt should not have been triggered from the kernel context. Signed-off-by: Anshuman Khandual Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/traps.c | 32 +++++++++++++++++--------------- 1 file changed, 17 insertions(+), 15 deletions(-) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index a2ef0c0e6c31..0904492e7032 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1613,6 +1613,22 @@ void facility_unavailable_exception(struct pt_regs *regs) value = mfspr(SPRN_FSCR); status = value >> 56; + if ((hv || status >= 2) && + (status < ARRAY_SIZE(facility_strings)) && + facility_strings[status]) + facility = facility_strings[status]; + + /* We should not have taken this interrupt in kernel */ + if (!user_mode(regs)) { + pr_emerg("Facility '%s' unavailable (%d) exception in kernel mode at %lx\n", + facility, status, regs->nip); + die("Unexpected facility unavailable exception", regs, SIGABRT); + } + + /* We restore the interrupt state now */ + if (!arch_irq_disabled_regs(regs)) + local_irq_enable(); + if (status == FSCR_DSCR_LG) { /* * User is accessing the DSCR register using the problem @@ -1679,25 +1695,11 @@ void facility_unavailable_exception(struct pt_regs *regs) return; } - if ((hv || status >= 2) && - (status < ARRAY_SIZE(facility_strings)) && - facility_strings[status]) - facility = facility_strings[status]; - - /* We restore the interrupt state now */ - if (!arch_irq_disabled_regs(regs)) - local_irq_enable(); - pr_err_ratelimited("%sFacility '%s' unavailable (%d), exception at 0x%lx, MSR=%lx\n", hv ? "Hypervisor " : "", facility, status, regs->nip, regs->msr); out: - if (user_mode(regs)) { - _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); - return; - } - - die("Unexpected facility unavailable exception", regs, SIGABRT); + _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); } #endif -- 2.30.2