[PATCH v3 2/3] powerpc: Refactor verification of MSR_RI

From: Christophe Leroy
Date: Mon Aug 23 2021 - 04:25:07 EST

Next message: Aakash Hemadri: "Re: [PATCH v2 2/5] staging: r8188eu: cast to restricted __be32"
Previous message: Christophe Leroy: "[PATCH v3 3/3] powerpc: Define and use MSR_RI only on non booke/40x"
In reply to: Christophe Leroy: "[PATCH v3 3/3] powerpc: Define and use MSR_RI only on non booke/40x"
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40x and BOOKE don't have MSR_RI therefore all tests involving
MSR_RI may be problematic on those plateforms.

Create helpers to check or set MSR_RI in regs, and use them
in common code.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
v2: Remove superflous {
---
arch/powerpc/include/asm/ptrace.h | 23 +++++++++++++++++++
arch/powerpc/kernel/interrupt.c | 9 +++-----
arch/powerpc/kernel/traps.c | 8 +++----
arch/powerpc/mm/book3s64/slb.c | 2 +-
arch/powerpc/platforms/embedded6xx/holly.c | 2 +-
.../platforms/embedded6xx/mpc7448_hpc2.c | 2 +-
arch/powerpc/platforms/pasemi/idle.c | 2 +-
arch/powerpc/platforms/powernv/opal.c | 2 +-
arch/powerpc/platforms/pseries/ras.c | 2 +-
arch/powerpc/sysdev/fsl_rio.c | 2 +-
arch/powerpc/xmon/xmon.c | 16 +++----------
11 files changed, 40 insertions(+), 30 deletions(-)

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index fd60538737a0..0cdb7b9c2c9c 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -22,6 +22,7 @@
#include <linux/err.h>
#include <uapi/asm/ptrace.h>
#include <asm/asm-const.h>
+#include <asm/reg.h>

#ifndef __ASSEMBLY__
struct pt_regs
@@ -282,6 +283,28 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
regs->gpr[3] = rc;
}

+static inline bool cpu_has_msr_ri(void)
+{
+ return !IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x);
+}
+
+static inline bool regs_is_unrecoverable(struct pt_regs *regs)
+{
+ return unlikely(cpu_has_msr_ri() && !(regs->msr & MSR_RI));
+}
+
+static inline void regs_set_recoverable(struct pt_regs *regs)
+{
+ if (cpu_has_msr_ri())
+ regs_set_return_msr(regs, regs->msr | MSR_RI);
+}
+
+static inline void regs_set_unrecoverable(struct pt_regs *regs)
+{
+ if (cpu_has_msr_ri())
+ regs_set_return_msr(regs, regs->msr & ~MSR_RI);
+}
+
#define arch_has_single_step() (1)
#define arch_has_block_step() (true)
#define ARCH_HAS_USER_SINGLE_STEP_REPORT
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c
index f26caf911ab5..f06c38e8fe36 100644
--- a/arch/powerpc/kernel/interrupt.c
+++ b/arch/powerpc/kernel/interrupt.c
@@ -93,8 +93,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
CT_WARN_ON(ct_state() == CONTEXT_KERNEL);
user_exit_irqoff();

- if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x))
- BUG_ON(!(regs->msr & MSR_RI));
+ BUG_ON(regs_is_unrecoverable(regs));
BUG_ON(!(regs->msr & MSR_PR));
BUG_ON(arch_irq_disabled_regs(regs));

@@ -463,8 +462,7 @@ notrace unsigned long interrupt_exit_user_prepare(struct pt_regs *regs)
{
unsigned long ret;

- if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x))
- BUG_ON(!(regs->msr & MSR_RI));
+ BUG_ON(regs_is_unrecoverable(regs));
BUG_ON(arch_irq_disabled_regs(regs));
CT_WARN_ON(ct_state() == CONTEXT_USER);

@@ -495,8 +493,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs)
bool stack_store = current_thread_info()->flags &
_TIF_EMULATE_STACK_STORE;

- if (!IS_ENABLED(CONFIG_BOOKE) && !IS_ENABLED(CONFIG_40x) &&
- unlikely(!(regs->msr & MSR_RI)))
+ if (regs_is_unrecoverable(regs))
unrecoverable_exception(regs);
/*
* CT_WARN_ON comes here via program_check_exception,
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 3e2adb3487e7..8310147b5e7b 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -428,7 +428,7 @@ void hv_nmi_check_nonrecoverable(struct pt_regs *regs)
return;

nonrecoverable:
- regs_set_return_msr(regs, regs->msr & ~MSR_RI);
+ regs_set_unrecoverable(regs);
#endif
}
DEFINE_INTERRUPT_HANDLER_NMI(system_reset_exception)
@@ -498,7 +498,7 @@ DEFINE_INTERRUPT_HANDLER_NMI(system_reset_exception)
die("Unrecoverable nested System Reset", regs, SIGABRT);
#endif
/* Must die if the interrupt is not recoverable */
- if (!(regs->msr & MSR_RI)) {
+ if (regs_is_unrecoverable(regs)) {
/* For the reason explained in die_mce, nmi_exit before die */
nmi_exit();
die("Unrecoverable System Reset", regs, SIGABRT);
@@ -550,7 +550,7 @@ static inline int check_io_access(struct pt_regs *regs)
printk(KERN_DEBUG "%s bad port %lx at %p\n",
(*nip & 0x100)? "OUT to": "IN from",
regs->gpr[rb] - _IO_BASE, nip);
- regs_set_return_msr(regs, regs->msr | MSR_RI);
+ regs_set_recoverable(regs);
regs_set_return_ip(regs, extable_fixup(entry));
return 1;
}
@@ -840,7 +840,7 @@ DEFINE_INTERRUPT_HANDLER_NMI(machine_check_exception)

bail:
/* Must die if the interrupt is not recoverable */
- if (!(regs->msr & MSR_RI))
+ if (regs_is_unrecoverable(regs))
die_mce("Unrecoverable Machine check", regs, SIGBUS);

#ifdef CONFIG_PPC_BOOK3S_64
diff --git a/arch/powerpc/mm/book3s64/slb.c b/arch/powerpc/mm/book3s64/slb.c
index c91bd85eb90e..f0037bcc47a0 100644
--- a/arch/powerpc/mm/book3s64/slb.c
+++ b/arch/powerpc/mm/book3s64/slb.c
@@ -822,7 +822,7 @@ DEFINE_INTERRUPT_HANDLER_RAW(do_slb_fault)
/* IRQs are not reconciled here, so can't check irqs_disabled */
VM_WARN_ON(mfmsr() & MSR_EE);

- if (unlikely(!(regs->msr & MSR_RI)))
+ if (regs_is_unrecoverable(regs))
return -EINVAL;

/*
diff --git a/arch/powerpc/platforms/embedded6xx/holly.c b/arch/powerpc/platforms/embedded6xx/holly.c
index 85521b3e7098..7a85b117f7a4 100644
--- a/arch/powerpc/platforms/embedded6xx/holly.c
+++ b/arch/powerpc/platforms/embedded6xx/holly.c
@@ -251,7 +251,7 @@ static int ppc750_machine_check_exception(struct pt_regs *regs)
/* Are we prepared to handle this fault */
if ((entry = search_exception_tables(regs->nip)) != NULL) {
tsi108_clear_pci_cfg_error();
- regs_set_return_msr(regs, regs->msr | MSR_RI);
+ regs_set_recoverable(regs);
regs_set_return_ip(regs, extable_fixup(entry));
return 1;
}
diff --git a/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c b/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
index d8da6a483e59..9eb9abb5bce2 100644
--- a/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
+++ b/arch/powerpc/platforms/embedded6xx/mpc7448_hpc2.c
@@ -173,7 +173,7 @@ static int mpc7448_machine_check_exception(struct pt_regs *regs)
/* Are we prepared to handle this fault */
if ((entry = search_exception_tables(regs->nip)) != NULL) {
tsi108_clear_pci_cfg_error();
- regs_set_return_msr(regs, regs->msr | MSR_RI);
+ regs_set_recoverable(regs);
regs_set_return_ip(regs, extable_fixup(entry));
return 1;
}
diff --git a/arch/powerpc/platforms/pasemi/idle.c b/arch/powerpc/platforms/pasemi/idle.c
index 534b0317fc15..6087c70ed2ef 100644
--- a/arch/powerpc/platforms/pasemi/idle.c
+++ b/arch/powerpc/platforms/pasemi/idle.c
@@ -59,7 +59,7 @@ static int pasemi_system_reset_exception(struct pt_regs *regs)
restore_astate(hard_smp_processor_id());

/* everything handled */
- regs_set_return_msr(regs, regs->msr | MSR_RI);
+ regs_set_recoverable(regs);
return 1;
}

diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 2835376e61a4..e9d18519e650 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -588,7 +588,7 @@ static int opal_recover_mce(struct pt_regs *regs,
{
int recovered = 0;

- if (!(regs->msr & MSR_RI)) {
+ if (regs_is_unrecoverable(regs)) {
/* If MSR_RI isn't set, we cannot recover */
pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
recovered = 0;
diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
index 167f2e1b8d39..56092dccfdb8 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -783,7 +783,7 @@ static int recover_mce(struct pt_regs *regs, struct machine_check_event *evt)
{
int recovered = 0;

- if (!(regs->msr & MSR_RI)) {
+ if (regs_is_unrecoverable(regs)) {
/* If MSR_RI isn't set, we cannot recover */
pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
recovered = 0;
diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index 5a95b8ea23d8..ff7906b48ca1 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -108,7 +108,7 @@ int fsl_rio_mcheck_exception(struct pt_regs *regs)
__func__);
out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
0);
- regs_set_return_msr(regs, regs->msr | MSR_RI);
+ regs_set_recoverable(regs);
regs_set_return_ip(regs, extable_fixup(entry));
return 1;
}
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index ead460b80905..dd8241c009e5 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -482,16 +482,6 @@ static inline void get_output_lock(void) {}
static inline void release_output_lock(void) {}
#endif

-static inline int unrecoverable_excp(struct pt_regs *regs)
-{
-#if defined(CONFIG_4xx) || defined(CONFIG_PPC_BOOK3E)
- /* We have no MSR_RI bit on 4xx or Book3e, so we simply return false */
- return 0;
-#else
- return ((regs->msr & MSR_RI) == 0);
-#endif
-}
-
static void xmon_touch_watchdogs(void)
{
touch_softlockup_watchdog_sync();
@@ -565,7 +555,7 @@ static int xmon_core(struct pt_regs *regs, volatile int fromipi)
bp = NULL;
if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT))
bp = at_breakpoint(regs->nip);
- if (bp || unrecoverable_excp(regs))
+ if (bp || regs_is_unrecoverable(regs))
fromipi = 0;

if (!fromipi) {
@@ -577,7 +567,7 @@ static int xmon_core(struct pt_regs *regs, volatile int fromipi)
cpu, BP_NUM(bp));
xmon_print_symbol(regs->nip, " ", ")\n");
}
- if (unrecoverable_excp(regs))
+ if (regs_is_unrecoverable(regs))
printf("WARNING: exception is not recoverable, "
"can't continue\n");
release_output_lock();
@@ -693,7 +683,7 @@ static int xmon_core(struct pt_regs *regs, volatile int fromipi)
printf("Stopped at breakpoint %tx (", BP_NUM(bp));
xmon_print_symbol(regs->nip, " ", ")\n");
}
- if (unrecoverable_excp(regs))
+ if (regs_is_unrecoverable(regs))
printf("WARNING: exception is not recoverable, "
"can't continue\n");
remove_bpts();
--
2.25.0

Next message: Aakash Hemadri: "Re: [PATCH v2 2/5] staging: r8188eu: cast to restricted __be32"
Previous message: Christophe Leroy: "[PATCH v3 3/3] powerpc: Define and use MSR_RI only on non booke/40x"
In reply to: Christophe Leroy: "[PATCH v3 3/3] powerpc: Define and use MSR_RI only on non booke/40x"
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