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authorAnshuman Khandual <khandual@linux.vnet.ibm.com>2018-03-29 11:53:37 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2018-04-10 11:23:23 +1000
commit709b973c844c0b4d115ac3a227a2e5a68722c912 (patch)
tree003f922542c606be3d9ede19c0e14e9172f6e8e3 /arch
parent501a78cbc17c329fabf8e9750a1e9ab810c88a0e (diff)
downloadlinux-709b973c844c0b4d115ac3a227a2e5a68722c912.tar.bz2
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 <khandual@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/traps.c32
1 files 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