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powerpc/64/kuap: Move kuap checks out of MSR[RI]=0 regions of exit code

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Any kind of WARN causes a program check that will crash with
unrecoverable exception if it occurs when RI is clear.

Fixes: 68b34588e2 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200429065654.1677541-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin 2020-04-29 16:56:49 +10:00 committed by Michael Ellerman
parent 0094368e3b
commit c0d7dcf89e
1 changed files with 8 additions and 6 deletions
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14
arch/powerpc/kernel/syscall_64.c
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@ -35,6 +35,8 @@ notrace long system_call_exception(long r3, long r4, long r5,
BUG_ON(!FULL_REGS(regs));
BUG_ON(regs->softe != IRQS_ENABLED);
kuap_check_amr();
account_cpu_user_entry();
#ifdef CONFIG_PPC_SPLPAR
@ -47,8 +49,6 @@ notrace long system_call_exception(long r3, long r4, long r5,
}
#endif
kuap_check_amr();
/*
* This is not required for the syscall exit path, but makes the
* stack frame look nicer. If this was initialised in the first stack
@ -117,6 +117,8 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
unsigned long ti_flags;
unsigned long ret = 0;
kuap_check_amr();
regs->result = r3;
/* Check whether the syscall is issued inside a restartable sequence */
@ -204,8 +206,6 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
local_paca->tm_scratch = regs->msr;
#endif
kuap_check_amr();
account_cpu_user_exit();
return ret;
@ -228,6 +228,8 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
BUG_ON(!FULL_REGS(regs));
BUG_ON(regs->softe != IRQS_ENABLED);
kuap_check_amr();
local_irq_save(flags);
again:
@ -292,8 +294,6 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs, unsigned
local_paca->tm_scratch = regs->msr;
#endif
kuap_check_amr();
account_cpu_user_exit();
return ret;
@ -313,6 +313,8 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs, unsign
BUG_ON(regs->msr & MSR_PR);
BUG_ON(!FULL_REGS(regs));
kuap_check_amr();
if (unlikely(*ti_flagsp & _TIF_EMULATE_STACK_STORE)) {
clear_bits(_TIF_EMULATE_STACK_STORE, ti_flagsp);
ret = 1;