diff options
| author | Rohan McLure <rmclure@linux.ibm.com> | 2023-05-10 06:31:10 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-06-21 08:13:57 +0300 |
| commit | be286b8637d417a7d7eb25dc3a509c10d0afef66 (patch) | |
| tree | 8478d86bc6c86a05ebc435ecfbdd1590fabf6832 | |
| parent | 6f3136326ee47ae2dd5dac9306c9b08ccbc7e81e (diff) | |
| download | linux-be286b8637d417a7d7eb25dc3a509c10d0afef66.tar.xz | |
powerpc: Mark [h]ssr_valid accesses in check_return_regs_valid
Checks to see if the [H]SRR registers have been clobbered by (soft)
NMI interrupts imply the possibility for a data race on the
[h]srr_valid entries in the PACA. Annotate accesses to these fields with
READ_ONCE, removing the need for the barrier.
The diagnostic can use plain-access reads and writes, but annotate with
data_race.
Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230510033117.1395895-5-rmclure@linux.ibm.com
| -rw-r--r-- | arch/powerpc/include/asm/ptrace.h | 4 | ||||
| -rw-r--r-- | arch/powerpc/kernel/interrupt.c | 14 |
2 files changed, 8 insertions, 10 deletions
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h index 0eb90a013346..9db8b16567e2 100644 --- a/arch/powerpc/include/asm/ptrace.h +++ b/arch/powerpc/include/asm/ptrace.h @@ -180,8 +180,8 @@ void do_syscall_trace_leave(struct pt_regs *regs); static inline void set_return_regs_changed(void) { #ifdef CONFIG_PPC_BOOK3S_64 - local_paca->hsrr_valid = 0; - local_paca->srr_valid = 0; + WRITE_ONCE(local_paca->hsrr_valid, 0); + WRITE_ONCE(local_paca->srr_valid, 0); #endif } diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index f3fc5fe919d9..c4f6d3c69ba9 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -125,7 +125,7 @@ static notrace void check_return_regs_valid(struct pt_regs *regs) case 0x1600: case 0x1800: validp = &local_paca->hsrr_valid; - if (!*validp) + if (!READ_ONCE(*validp)) return; srr0 = mfspr(SPRN_HSRR0); @@ -135,7 +135,7 @@ static notrace void check_return_regs_valid(struct pt_regs *regs) break; default: validp = &local_paca->srr_valid; - if (!*validp) + if (!READ_ONCE(*validp)) return; srr0 = mfspr(SPRN_SRR0); @@ -161,19 +161,17 @@ static notrace void check_return_regs_valid(struct pt_regs *regs) * such things will get caught most of the time, statistically * enough to be able to get a warning out. */ - barrier(); - - if (!*validp) + if (!READ_ONCE(*validp)) return; - if (!warned) { - warned = true; + if (!data_race(warned)) { + data_race(warned = true); printk("%sSRR0 was: %lx should be: %lx\n", h, srr0, regs->nip); printk("%sSRR1 was: %lx should be: %lx\n", h, srr1, regs->msr); show_regs(regs); } - *validp = 0; /* fixup */ + WRITE_ONCE(*validp, 0); /* fixup */ #endif } |