From c0d7dcf89e5151b2259d1c2c1b922da3b881d02e Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Wed, 29 Apr 2020 16:56:49 +1000
Subject: [PATCH] powerpc/64/kuap: Move kuap checks out of MSR[RI]=0 regions of
exit code
References: jsc#SLE-9246
Patch-mainline: v5.7-rc6
Git-commit: c0d7dcf89e5151b2259d1c2c1b922da3b881d02e
Any kind of WARN causes a program check that will crash with
unrecoverable exception if it occurs when RI is clear.
Fixes: 68b34588e202 ("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
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kernel/syscall_64.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index 1fe94dd9de32..7b7c89cad901 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -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;
--
2.28.0