From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Michal Suchanek <msuchanek@suse.de>, Nicholas Piggin <npiggin@gmail.com>
Subject: [PATCH] powerpc/64: system call implement the bulk of the logic in C fix
Date: Tue, 28 Jan 2020 00:17:12 +1000 [thread overview]
Message-ID: <20200127141712.96738-1-npiggin@gmail.com> (raw)
This incremental patch fixes several soft-mask debug and unsafe
smp_processor_id messages due to tracing and false positives in
"unreconciled" code.
It also fixes a bug with syscall tracing functions that set registers
(e.g., PTRACE_SETREG) not setting GPRs properly.
There was a bug reported with the TM selftests, I haven't been able
to reproduce that one.
I can squash this into the main patch and resend the series if it
helps but the incremental helps to see the bug fixes.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/cputime.h | 39 +++++++++++++++++-------------
arch/powerpc/kernel/syscall_64.c | 26 ++++++++++++++------
2 files changed, 41 insertions(+), 24 deletions(-)
diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h
index c43614cffaac..6639a6847cc0 100644
--- a/arch/powerpc/include/asm/cputime.h
+++ b/arch/powerpc/include/asm/cputime.h
@@ -44,6 +44,28 @@ static inline unsigned long cputime_to_usecs(const cputime_t ct)
#ifdef CONFIG_PPC64
#define get_accounting(tsk) (&get_paca()->accounting)
static inline void arch_vtime_task_switch(struct task_struct *tsk) { }
+
+/*
+ * account_cpu_user_entry/exit runs "unreconciled", so can't trace,
+ * can't use use get_paca()
+ */
+static notrace inline void account_cpu_user_entry(void)
+{
+ unsigned long tb = mftb();
+ struct cpu_accounting_data *acct = &local_paca->accounting;
+
+ acct->utime += (tb - acct->starttime_user);
+ acct->starttime = tb;
+}
+static notrace inline void account_cpu_user_exit(void)
+{
+ unsigned long tb = mftb();
+ struct cpu_accounting_data *acct = &local_paca->accounting;
+
+ acct->stime += (tb - acct->starttime);
+ acct->starttime_user = tb;
+}
+
#else
#define get_accounting(tsk) (&task_thread_info(tsk)->accounting)
/*
@@ -60,23 +82,6 @@ static inline void arch_vtime_task_switch(struct task_struct *prev)
}
#endif
-static inline void account_cpu_user_entry(void)
-{
- unsigned long tb = mftb();
- struct cpu_accounting_data *acct = get_accounting(current);
-
- acct->utime += (tb - acct->starttime_user);
- acct->starttime = tb;
-}
-static inline void account_cpu_user_exit(void)
-{
- unsigned long tb = mftb();
- struct cpu_accounting_data *acct = get_accounting(current);
-
- acct->stime += (tb - acct->starttime);
- acct->starttime_user = tb;
-}
-
#endif /* __KERNEL__ */
#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
static inline void account_cpu_user_entry(void)
diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
index 529393a1ff1e..cfe458adde07 100644
--- a/arch/powerpc/kernel/syscall_64.c
+++ b/arch/powerpc/kernel/syscall_64.c
@@ -19,7 +19,8 @@ extern void __noreturn tabort_syscall(void);
typedef long (*syscall_fn)(long, long, long, long, long, long);
-long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
+/* Has to run notrace because it is entered "unreconciled" */
+notrace long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
unsigned long r0, struct pt_regs *regs)
{
unsigned long ti_flags;
@@ -36,7 +37,7 @@ long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
#ifdef CONFIG_PPC_SPLPAR
if (IS_ENABLED(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) &&
firmware_has_feature(FW_FEATURE_SPLPAR)) {
- struct lppaca *lp = get_lppaca();
+ struct lppaca *lp = local_paca->lppaca_ptr;
if (unlikely(local_paca->dtl_ridx != be64_to_cpu(lp->dtl_idx)))
accumulate_stolen_time();
@@ -71,13 +72,22 @@ long system_call_exception(long r3, long r4, long r5, long r6, long r7, long r8,
* We use the return value of do_syscall_trace_enter() as the
* syscall number. If the syscall was rejected for any reason
* do_syscall_trace_enter() returns an invalid syscall number
- * and the test below against NR_syscalls will fail.
+ * and the test against NR_syscalls will fail and the return
+ * value to be used is in regs->gpr[3].
*/
r0 = do_syscall_trace_enter(regs);
- }
-
- if (unlikely(r0 >= NR_syscalls))
+ if (unlikely(r0 >= NR_syscalls))
+ return regs->gpr[3];
+ r3 = regs->gpr[3];
+ r4 = regs->gpr[4];
+ r5 = regs->gpr[5];
+ r6 = regs->gpr[6];
+ r7 = regs->gpr[7];
+ r8 = regs->gpr[8];
+
+ } else if (unlikely(r0 >= NR_syscalls)) {
return -ENOSYS;
+ }
/* May be faster to do array_index_nospec? */
barrier_nospec();
@@ -139,8 +149,10 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3,
regs->gpr[3] = r3;
}
- if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE))
+ if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) {
do_syscall_trace_leave(regs);
+ ret |= _TIF_RESTOREALL;
+ }
again:
local_irq_disable();
--
2.23.0
next reply other threads:[~2020-01-27 14:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 14:17 Nicholas Piggin [this message]
2020-01-27 18:08 ` [PATCH] powerpc/64: system call implement the bulk of the logic in C fix Michal Suchánek
2020-01-28 0:41 ` Nicholas Piggin
2020-01-28 9:41 ` Michal Suchánek
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