diff options
Diffstat (limited to 'arch/powerpc/perf/callchain.h')
| -rw-r--r-- | arch/powerpc/perf/callchain.h | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/arch/powerpc/perf/callchain.h b/arch/powerpc/perf/callchain.h index 7a2cb9e1181a..ae24d4a00da6 100644 --- a/arch/powerpc/perf/callchain.h +++ b/arch/powerpc/perf/callchain.h @@ -2,7 +2,7 @@ #ifndef _POWERPC_PERF_CALLCHAIN_H #define _POWERPC_PERF_CALLCHAIN_H -int read_user_stack_slow(void __user *ptr, void *buf, int nb); +int read_user_stack_slow(const void __user *ptr, void *buf, int nb); void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs); void perf_callchain_user_32(struct perf_callchain_entry_ctx *entry, @@ -16,4 +16,27 @@ static inline bool invalid_user_sp(unsigned long sp) return (!sp || (sp & mask) || (sp > top)); } +/* + * On 32-bit we just access the address and let hash_page create a + * HPTE if necessary, so there is no need to fall back to reading + * the page tables. Since this is called at interrupt level, + * do_page_fault() won't treat a DSI as a page fault. + */ +static inline int __read_user_stack(const void __user *ptr, void *ret, + size_t size) +{ + unsigned long addr = (unsigned long)ptr; + int rc; + + if (addr > TASK_SIZE - size || (addr & (size - 1))) + return -EFAULT; + + rc = copy_from_user_nofault(ret, ptr, size); + + if (IS_ENABLED(CONFIG_PPC64) && rc) + return read_user_stack_slow(ptr, ret, size); + + return rc; +} + #endif /* _POWERPC_PERF_CALLCHAIN_H */ |